Document:

EXHIBIT 10.23

                               JOINDER AGREEMENT

       This Joinder  Agreement (the  "JOINDER") is entered into as of August 16,
2000 by and between GENE FUND, LP (the "NEW NON-PREFERRED HOLDER") and INFORMAX,
INC., a Delaware corporation (the "COMPANY").

       WHEREAS,  the non-preferred  holders of the Company who are listed on the
signature pages of the Non-Preferred Holder Rights Agreement (collectively,  the
"NON-PREFERRED   HOLDERS")  and  the  Company,   are  parties  to  that  certain
Non-Preferred  Holder Rights Agreement dated March 29, 2000 (the  "NON-PREFERRED
AGREEMENT");

       WHEREAS,  pursuant to a Stock Purchase Agreement dated August 16, 2000 by
and  between  the New  Non-Preferred  Holder  and  James E.  Bernstein,  the New
Non-Preferred  Holder acquired shares of non-voting  common stock of the Company
(the "STOCK PURCHASE AGREEMENT"); and

       WHEREAS,  a condition to the  obligations  of the parties under the Stock
Purchase  Agreement is that the New Non-Preferred  Holder becomes a party to the
Non-Preferred  Agreement  concurrently  with the  execution  and delivery of the
Stock Purchase Agreement.

       NOW,  THEREFORE,  in  consideration  of the premises,  and other good and
valuable  consideration,   the  receipt  and  sufficiency  of  which  is  hereby
acknowledged,  the New  Non-Preferred  Holder and the  Company  hereby  agree as
follows:

       1.  The  New  Non-Preferred   Holder  is  hereby  made  a  party  to  the
Non-Preferred  Agreement as a "Non-Preferred  Holder" in accordance with Section
4.11 thereunder,  and the New Non-Preferred  Holder hereby agrees to be bound by
all the terms and conditions of the Non-Preferred  Agreement as a "Non-Preferred
Holder"  thereunder.  The terms and  conditions of the  Non-Preferred  Agreement
shall  apply to the  shares  of  common  stock  acquired  pursuant  to the Stock
Purchase Agreement.

       2. The New  Non-Preferred  Holder  represents and warrants to the Company
and the other Non-Preferred  Holders that the New Non-Preferred  Holder: (a) has
reviewed the Joinder and the  Non-Preferred  Agreement  (as attached  hereto) in
their  entireties,  and fully  understands all provisions of the Joinder and the
Non-Preferred   Agreement,   and  (b)  in  accordance  with  the  terms  of  the
Non-Preferred  Agreement the New Non-Preferred Holder has become a Non-Preferred
Holder  under  the  Non-Preferred  Agreement  and is bound by all the  terms and
conditions of the Non-Preferred Agreement with the same effect as though the New
Non-Preferred Holder was a subscribing party to the Non-Preferred Agreement.

       3.  All  references  in the  Non-Preferred  Agreement  to  "Non-Preferred
Holder"  or  "Non-Preferred   Holders"  shall  be  deemed  to  include  the  New
Non-Preferred Holder.

<PAGE>

       4. All of the terms and  conditions  of the  Non-Preferred  Agreement are
unmodified and shall continue in full force and effect and shall be binding upon
the parties  hereto and their  respective  assigns in accordance  with the terms
thereof.

       5. This Joinder may be executed  (including  by facsimile) in one or more
counterparts,  each of  which  shall  be  deemed  an  original  but all of which
together will constitute one and the same instrument.

             [THE REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK]

                                      -2-

<PAGE>

       IN WITNESS  WHEREOF,  the parties hereto have executed this Joinder as of
the date first above written.

                                             COMPANY

                                             INFORMAX, INC.

                                             By:  /s/ Alexander Titomirov
                                                --------------------------------
                                                Name: Alexander Titomirov
                                                Title: President

                                             NEW NONPREFERRED HOLDER

                                             GENE FUND, LP

                                             By:  /s/ William F. Snider
                                                --------------------------------
                                                Name: William F. Snider
                                                Title: General PartnerExhibit 10.1

                              AGREEMENT TO SUBLEASE

                                  by and among

                   SBC WIRELESS, INC., a Delaware corporation,
            for itself and on behalf of the other Sublessor Entities

                                       and

                         SPECTRASITE HOLDINGS, INC. and

                              SOUTHERN TOWERS, INC.

                                 August 25, 2000

<PAGE>
TABLE OF CONTENTS

                                                                            Page

                                    ARTICLE I
                                   DEFINITIONS

         SECTION 1.1. Definitions...........................................2
         SECTION 1.2. Other Capitalized Terms..............................10

                                   ARTICLE II
                               AGREEMENT DOCUMENTS

                                   ARTICLE III
                          CONVEYANCE AND CONSIDERATION

         SECTION 3.1. Conveyance...........................................11
         SECTION 3.2. Consideration........................................11
         SECTION 3.3. Consents Under Ground Leases.........................13

                                   ARTICLE IV
                                    CLOSINGS

         SECTION 4.1. Closings. 14
         SECTION 4.2. Transactions and Documents at the Closings...........15
         SECTION 4.3. Costs of Closing.....................................16
         SECTION 4.4. Further Assurances; Corrections......................16
         SECTION 4.5. Site Designation Supplements.........................17
         SECTION 4.6. Deferral of Closings; Updating of Representations....17
         SECTION 4.7. Re-Recordation.......................................18
         SECTION 4.8. Substitution of Sites................................18
         SECTION 4.9. Value Adjustments....................................18

                                    ARTICLE V
                              additional agreements

         SECTION 5.1. Expenses............................................ 19
         SECTION 5.2. Brokers............................................  19
         SECTION 5.3. Risk of Loss and Insurance...........................20
         SECTION 5.4. Condemnation.........................................20
         SECTION 5.5. Publicity.20
         SECTION 5.6. TowerCo's Access and Inspection......................20
         SECTION 5.7. Cooperation..........................................21
         SECTION 5.8. Governmental Filings.................................21
         SECTION 5.9. Confidentiality......................................21
         SECTION 5.10. Real Estate Matters.................................22
         SECTION 5.11. No Solicitation of Employees........................23

                                       i
<PAGE>

         SECTION 5.12. Update of Information...............................23
         SECTION 5.13. TowerCo Parent's Guaranty...........................24
         SECTION 5.14. Registration Statement..............................25
         SECTION 5.15. Parent Stock........................................26
         SECTION 5.16. Co-Location Agreement...............................26

                                   ARTICLE VI
         REPRESENTATIONS, WARRANTIES AND COVENANTS OF SUBLESSOR ENTITIES

         SECTION 6.1. Organization, Authority and Qualification............27
         SECTION 6.2. Capacity; Inconsistent Obligations...................27
         SECTION 6.3. Consents. 27
         SECTION 6.4. No Violation; Compliance with Laws...................28
         SECTION 6.5. Litigation; Contingencies............................28
         SECTION 6.6. Leased and Owned Sites...............................28
         SECTION 6.7. Real Property........................................28
         SECTION 6.8. Eminent Domain.......................................29
         SECTION 6.9. Taxes.    29
         SECTION 6.10. Governmental Permits................................29
         SECTION 6.11. Environmental Matters...............................30
         SECTION 6.12. Existing Leases; Colocation Agreements; Master Licen30
         SECTION 6.13. No Undisclosed Liabilities..........................30
         SECTION 6.14. Authorization.......................................30
         SECTION 6.15. No Other Warranties.................................30

                                   ARTICLE VII
                REPRESENTATIONS, WARRANTIES AND COVENANTS OF SBCW

         SECTION 7.1. Organization, Authority and Qualification............31
         SECTION 7.2. Capacity, Inconsistent Obligations...................31
         SECTION 7.3. Authorization........................................32
         SECTION 7.4. No Other Warranties..................................32

                                  ARTICLE VIII
              REPRESENTATIONS, WARRANTIES AND COVENANTS OF TOWERCO

         SECTION 8.1. Organization, Authority and Qualification............32
         SECTION 8.2. Ownership of Shares; Subsidiaries....................32
         SECTION 8.3. Capacity; Inconsistent Obligations...................33
         SECTION 8.4. Consents. 33
         SECTION 8.5. No Violation; Compliance with Laws...................34
         SECTION 8.6. TowerCo Matters......................................34
         SECTION 8.7. Litigation; Contingencies............................34
         SECTION 8.8. Sufficient Funding...................................34
         SECTION 8.9. No Broker.34
         SECTION 8.10. No Other Warranties.................................34

                                       ii
<PAGE>

                                   ARTICLE IX
           REPRESENTATIONS, WARRANTIES AND COVENANTS OF TowerCo Parent

         SECTION 9.1. Organization, Authority and Qualification............35
         SECTION 9.2. Capacity; Inconsistent Obligations...................35
         SECTION 9.3. Consents. 35
         SECTION 9.4. No Violation, Compliance with Laws...................36
         SECTION 9.5. Litigation; Contingencies............................36
         SECTION 9.6. No Other Warranties..................................36
         SECTION 9.7. SEC Reports..........................................36
         SECTION 9.8. Absence of Certain Changes or Events.................37

                                    ARTICLE X
                     CONDUCT OF BUSINESS PENDING OF CLOSINGS

         SECTION 10.1. Conduct of Business by SBCW and the Sublessor Entiti37
         SECTION 10.2. Conduct of Business by TowerCo Parent and TowerCo...38

                                   ARTICLE XI
          CONDITIONS TO OBLIGATIONS OF SBCW and THE SUBLESSOR ENTITIES

         SECTION 11.1. Representations and Warranties......................39
         SECTION 11.2. Compliance with Agreements and Conditions...........39
         SECTION 11.3. Closing Certificates................................39
         SECTION 11.4. Consents and Approvals..............................39
         SECTION 11.5. No Litigation.......................................40
         SECTION 11.6. Fundamental Transactions............................40
         SECTION 11.7. Build-to-Suit Agreement.............................40
         SECTION 11.8. Sublease.40
         SECTION 11.9. Opinion. 40
         SECTION 11.10. Registration Rights Agreement......................41
         SECTION 11.11. Stockholders'Agreement.............................41
         SECTION 11.12. Registration Statement.............................41

                                   ARTICLE XII
             CONDITIONS TO OBLIGATIONS OF TowerCo Parent AND TOWERCO

         SECTION 12.1. Representations and Warranties......................41
         SECTION 12.2. Compliance with Agreements and Conditions...........42
         SECTION 12.3. Closing Certificates................................42
         SECTION 12.4. Consents and Approvals..............................42
         SECTION 12.5. No Litigation.......................................42
         SECTION 12.6. Build-to-Suit Agreement.............................42
         SECTION 12.7. SBCW Sublease.......................................43
         SECTION 12.8. Stockholders'Agreement..............................43
         SECTION 12.9. Incomplete Sites....................................43
         SECTION 12.10. Site Marketing Agreement...........................43

                                      iii
<PAGE>

                                  ARTICLE XIII
                                 INDEMNIFICATION

         SECTION 13.1. Indemnification by Sublessor Entity.................43
         SECTION 13.2. Indemnification by TowerCo Parent...................44
         SECTION 13.3. Indemnification by TowerCo..........................45
         SECTION 13.4. Procedure for Claims................................45
         SECTION 13.5. Defense of Claims...................................45
         SECTION 13.6. Certain Limitations.................................46
         SECTION 13.7. Limitation on Liability.............................47
         SECTION 13.8. Survival.47

                                   ARTICLE XIV
                                   TERMINATION

         SECTION 14.1. Termination for Certain Causes by SBCW..............48
         SECTION 14.2. Termination for Passage of Time.....................48
         SECTION 14.3. TowerCo's Remedies..................................49

                                   ARTICLE XV
                              RIGHT OF FIRST OFFER

                                   ARTICLE XVI
                               GENERAL PROVISIONS

         SECTION 16.1. Notices. 50
         SECTION 16.2. Facsimile as Writing................................52
         SECTION 16.3. No Assignment; Binding Effect.......................52
         SECTION 16.4. Headings.52
         SECTION 16.5. Exhibits and Schedules..............................52
         SECTION 16.6. Defined Terms.......................................53
         SECTION 16.7. Waiver of Jury Trial................................53
         SECTION 16.8. Partial Invalidity and Severability.................53
         SECTION 16.9. Waiver.  53
         SECTION 16.10. Rights Cumulative..................................53
         SECTION 16.11. Time of Essence; Dates.............................54
         SECTION 16.12. Governing Law......................................54
         SECTION 16.13. Counterparts.......................................54
         SECTION 16.14. Attorneys'Fees.....................................54
         SECTION 16.15. Authority..........................................54
         SECTION 16.16. Counsel.54
         SECTION 16.17. Number and Gender..................................55
         SECTION 16.18. No Construction Against Preparer...................55
         SECTION 16.19. Entire Agreement; Modification.....................55
         SECTION 16.20. Power of Attorney:  Appointing SBCW................55
         SECTION 16.21. Power of Attorney:  Appointing SBCW................56

                                       iv

<PAGE>

                              AGREEMENT TO SUBLEASE

         THIS  AGREEMENT  TO  SUBLEASE,  made and  entered  into this 25h day of
August,  2000 (the  "Agreement"),  by and among SBC  WIRELESS,  INC., a Delaware
corporation  ("SBCW"),  for  itself  and on  behalf of the  Sublessor  Entities,
SPECTRASITE  HOLDINGS,  INC.,  a Delaware  corporation  ("TowerCo  Parent")  and
SOUTHERN TOWERS, INC., a Delaware corporation ("TowerCo").

                              W I T N E S S E T H:

         WHEREAS,  SBCW and the  Sublessor  Entities (as defined  herein) own or
lease wireless  communications  cell site locations used in connection  with the
operation  by certain  SBCW  Affiliates  (the "SBC  Operating  Companies")  of a
cellular communications network; and

         WHEREAS,  TowerCo is engaged in the business  of,  among other  things,
developing,   constructing,  managing,  maintaining,  marketing,  operating  and
leasing networks of communications tower facilities, including the management of
wireless communications sites; and

         WHEREAS,  SpectraSite  Communications,  Inc.,  SBC  Wireless,  Inc. and
certain  Sublessor  Entities  intend  to enter  into a  certain  Site  Marketing
Agreement  substantially  on the terms set forth in  Exhibit F  attached  hereto
("Site  Marketing  Agreement")  relating to the marketing of Existing  Sites (as
defined herein); and

         WHEREAS,  in order to optimize the  utilization and value of SBCW's and
the Sublessor Entities' cell site locations and network, SBCW, for itself and on
behalf of the Sublessor Entities, desire to enter into an agreement relating to:
(i) the design,  construction  and  installation by TowerCo on certain cell site
locations  wireless  transmission  tower  structures and other  Improvements (as
defined  herein)  pursuant to the terms and conditions of the Agreement to Build
to  Suit,  in  substantially   the  form  attached  hereto  as  Exhibit  D  (the
"Build-to-Suit Agreement"), among SBCW, for itself and as agent for certain SBCW
Parties (as defined  therein),  TowerCo Parent and  SpectraSite  Communications,
Inc., space on which shall be leased and subleased by SBCW and the SBC Operating
Companies,  on the one hand,  from TowerCo,  on the other hand,  pursuant to the
Sublease (BTS) (the "BTS Sublease");  (ii) the lease or sublease of certain cell
site locations,  by SBCW and the other Sublessor Entities,  on the one hand, and
TowerCo,  on the other hand,  pursuant to the terms and  conditions of the Lease
and Sublease,  in substantially the form attached hereto as Exhibit E (the "SBCW
Sublease");  and (iii) various other  agreements  with respect to the respective
rights,  duties and  obligations  of the parties  relating to the subject matter
hereof,  all as more  particularly  described  in and  subject  to the terms and
conditions of this Agreement; and

         WHEREAS, a portion of the aggregate Rent that TowerCo is willing to pay
with respect to the transactions  contemplated herein consists of TowerCo Parent
common stock, par value $0.001 per share (the "Parent Stock") and subject to the
further  requirement  that any Parent  Stock  issued by TowerCo  Parent  only be
distributed  to SBCW or a direct or  indirect  wholly  owned  subsidiary  of SBC
Communications Inc.; <PAGE>

         NOW, THEREFORE, for and in consideration of the premises, and for other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

                                   ARTICLE I
                                   DEFINITIONS

SECTION 1.1.      Definitions.

         For purposes of this Agreement,  the following  capitalized  terms have
the following respective meanings:

                  "Action"  means  any  action,  suit,  litigation,   complaint,
         counterclaim,  claim,  petition,  mediation contest,  or administrative
         proceeding, whether at law, in equity, in arbitration or otherwise, and
         whether conducted by or before any Government or other Person.

                  "Affiliate"   of  a  party  means  any   individual  or  firm,
         corporation, partnership, limited liability company, association, trust
         or other entity which,  whether  directly or indirectly,  Controls,  is
         Controlled by, or is under common Control with the subject party.

                  "Agreement"   means  this   Agreement  and  the  Exhibits  and
         Schedules  hereto,  as any of the foregoing  may, from time to time, be
         amended, modified or restated in accordance with the provisions hereof.

                  "Ameritech"  has the meaning given to such term in Section
         5.16.

                  "Applicable Sublessor Entities" has the meaning given to such
         term in Section 12.1.

                  "Build-to-Suit Agreement" has the meaning given to such term
         in the Preamble.

                  "BTS Sublease" has the meaning given to such term in the
         Preamble.

                  "Cash Consideration" has the meaning given such term in
         Section 3.2(a).

                  "Cash Portion" means 75.1474458%.

                  "Change of Control" shall mean the merger or  consolidation of
         TowerCo  Parent  with or into  another  entity or the merger of another
         entity with or into TowerCo Parent where the  outstanding  common stock
         of TowerCo Parent is changed into or exchanged for cash,  securities or
         other  property,  unless pursuant to such  transaction  such shares are
         changed into or exchanged for, in addition to any other  consideration,
         securities of the surviving  entity that  represent  immediately  after
         such  transaction  a  majority  of the  aggregate  voting  power of the
         surviving entity.

                                       2
<PAGE>

                  "Change of Control  Payment" shall mean an amount equal to the
         product of (a) the aggregate number of shares of Parent Stock issued to
         SBCW  and any SBCW  Affiliates  pursuant  to  Section  3.2(b)  and held
         beneficially  and of record by such  Persons  immediately  prior to the
         consummation of the Change of Control (the "SBC Change of Control Stock
         Amount") and (b) the excess, if any, of the Share Price over the Change
         of Control Price.  Notwithstanding  anything to the contrary herein, in
         no event shall the Change of Control  Payment exceed the product of (i)
         $139,750,000  and (ii) a fraction,  the  numerator of which is equal to
         the SBC Change of Control Stock Amount, and the denominator of which is
         equal to the aggregate  number of shares of Parent Stock issued to SBCW
         and any SBCW Affiliates under Section 3.2(b).

                  "Change of Control  Price"  shall mean,  with  respect to each
         share of Parent Stock, the gross proceeds, whether in the form of cash,
         securities or other  property,  received by a holder of Parent Stock in
         connection with the Change of Control.

                  "Closing(s)" has the meaning given to such term in Section
         4.1(a).

                  "Closing Date(s)" has the meaning given to such term in
         Section 4.1(a).

                  "Closing  Price" of the Parent Stock as of any day,  means (i)
         the last  reported sale price of such stock (as  customarily  reported)
         or, in case no such sale takes  place on such day,  the  average of the
         closing  bid and  asked  prices,  in  either  case as  reported  on the
         principal  national  securities  exchange on which the Parent  Stock is
         listed or admitted to trading or (ii) if the Parent Stock is not listed
         or admitted to trading on any national  securities  exchange,  the last
         reported  sale price or, in case no such sale takes  place on such day,
         the  average of the  highest  reported  bid and lowest  reported  asked
         quotation  for the Parent  Stock,  in either  case as  reported  on the
         National  Association of Securities  Dealers,  Inc. Automated Quotation
         System  ("Nasdaq"),  or a  similar  service  if  Nasdaq  is  no  longer
         reporting such information.

                  "Closing Schedule" has the meaning given to such term in
         Section 4.1(a).

                  "Colocation Agreements" has the meaning given to such term
         in the SBCW Sublease.

                  "Confidential Information" has the meaning given to such term
         in Section 5.9(b).

                  "Control"  means the  ownership,  directly or  indirectly,  of
         sufficient  voting shares of an entity,  or otherwise  the  possession,
         directly or  indirectly,  of the power to direct or cause the direction
         of the  management  and  policies  of an entity,  whether  through  the
         ownership of voting securities, by contract or otherwise.

                  "Current  Market Price" shall mean, with respect to each share
         of Parent Stock as of any date, the average of the daily Closing Prices
         per share of Parent  Stock for the  trading  days in the 60 day  period
         prior to such date.

                  "Deductible Amount" has the meaning given to such term in
         Section 13.6(b).

                                        3
<PAGE>

                  "Disclosee" has the meaning given to such term in Section
         5.9(a).

                  "Disclosing Party" has the meaning given to such term in
         Section 5.9(a).

                  "Disclosure Schedule" has the meaning given to such term in
         Section 4.6(b).

                  "Effective Date" means the date of this Agreement.

                  "End Date" shall mean the third anniversary of the Initial
         Closing Date.

                  "End Date  Adjustment  Payment"  shall mean an amount equal to
         the  product  of (a) the  aggregate  number of  shares of Parent  Stock
         issued to SBCW and SBCW Affiliates  pursuant to Section 3.2(b) and held
         beneficially  and of record by such  Persons  at the End Date (the "SBC
         End Date Stock Amount") and (b) the excess,  if any, of the Share Price
         over  the  Current  Market  Price  (determined  as of  the  End  Date).
         Notwithstanding  anything to the contrary herein, in no event shall the
         End Date Adjustment  Payment exceed the product of (i) $139,750,000 and
         (ii) a fraction,  the  numerator of which is equal to the SBCW End Date
         Stock Amount,  and the  denominator  of which is equal to the aggregate
         number of shares of  Parent  Stock  issued to SBCW and SBCW  Affiliates
         pursuant to Section 3.2(b).

                  "Environmental  Laws"  means all Laws and  Orders in effect at
         the time of the applicable Closing, relating to the Hazardous Materials
         and/or protection of the environment from pollution or contamination.

                  "Environmental   Conditions"  means,  as  to  each  Site,  any
         conditions or circumstances, including without limitation, the presence
         of Hazardous Materials,  that (i) require abatement or correction under
         the  Environmental  Laws,  (ii)  give  rise to any  civil  or  criminal
         Liability under any  Environmental Law relating to the use or occupancy
         of any Site or (iii) constitute a public or private nuisance.

                  "Excluded  Sites"  means  any  Site  excluded  from  the  SBCW
         Sublease pursuant to the terms of this Agreement.

                  "Existing Leases" means, collectively, Existing Subleases
         under the SBCW Sublease.

                  "Existing  Sites" means the Sites, the Towers and Improvements
         listed in Annex A attached hereto, as may be amended from time to time;
         provided  that the Sites  listed on Annex A which are  denoted  as "not
         completed"  shall not be  considered  Existing  Sites until the date of
         their completion.

                  "FAA" means the Federal Aviation Administration.

                  "FCC" means the Federal Communications Commission.

                  "Final Closing" has the meaning given to such term in
         Section 4.1(b).

                  "Final Closing Date" has the meaning given to such term in
         Section 4.1(b).

                                       4
<PAGE>

                  "Forum" means any federal,  national,  state, local, municipal
         or foreign court,  governmental agency,  administrative body or agency,
         tribunal, private alternative dispute resolution system, or arbitration
         panel.

                  "GAAP" means generally accepted accounting principles,
         consistently applied.

                  "Government" means any federal,  state,  territorial,  county,
         municipal,  local or other government or governmental agency or body or
         any  other  type of  regulatory  body,  whether  domestic  or  foreign,
         including without limitation the FCC and the FAA.

                  "Governmental   Permits"   means  any  and  all   governmental
         approvals, permits, licenses, registrations, certificates of occupancy,
         approvals and other governmental authorizations.

                  "Ground Lease" has the meaning given to such term in the SBCW
         Sublease.

                  "Ground Lessor" has the meaning given to such term in the SBCW
         Sublease.

                  "Ground Lessor Consent" has the meaning given to such term in
         Section 3.3.

                  "Ground Rent" has the meaning given to such term in the
         applicable Sublease.

                  "Hazardous  Materials" means and includes petroleum  products,
         flammable explosives,  radioactive materials,  asbestos or any material
         containing asbestos, polychlorinated biphenyls, or any hazardous, toxic
         or dangerous waste, substance or material defined as such or defined as
         a hazardous  substance or any similar term,  by, in or for the purposes
         of  the  Environmental  Laws,  including,  without  limitation  Section
         101(14) of the Comprehensive  Environmental Response,  Compensation and
         Liability Act of 1980. The term Hazardous Materials excludes quantities
         of materials  or  substances  maintained  by the  applicable  Sublessor
         Entity on or about any of its Sites  (including  Tower and Improvements
         thereon) in the ordinary course of business,  so long as such materials
         are maintained in accordance with the applicable Environmental Laws.

                  "Improvements" has the meaning given to such term in the
         applicable Sublease.

                  "Included  Sites" means any Existing Sites that become subject
         to the SBCW Sublease.

                  "Indemnified  Losses"  means  collectively,  SBCW  Indemnified
         Losses and TowerCo Indemnified Losses.

                  "Indemnified Party" has the meaning given to such term in
         Section 13.4.

                  "Indemnifying Party" has the meaning given to such term in
         Section 13.4.

                  "Initial Closing" has the meaning given to such term in
         Section 4.1(b).

                                       5
<PAGE>

                  "Initial Closing Date" has the meaning given to such term in
         Section 4.1(b).

                  "known,"  "to the best  knowledge  of," or  words  of  similar
         import  means,  as to each party  hereto,  the actual  knowledge of any
         person who is a senior manager of such party (and any person succeeding
         to any such position  prior to the Final Closing but only to the extent
         they acquire actual knowledge).

                 "Land" has the meaning given to such term in the SBCW Sublease.

                  "Laws" means all federal,  state, county,  municipal and other
         governmental constitutions,  statutes,  ordinances, codes, regulations,
         resolutions,  rules,  requirements  and  directives  and all decisions,
         judgments,  writs,  injunctions,  orders, decrees or demands of courts,
         administrative  bodies  and  other  authorities  construing  any of the
         foregoing.

                  "Leased  Site"  means any Site that is  leased,  subleased  or
         licensed to TowerCo pursuant to the SBCW Sublease.

                  "Liability" means any liability or obligation whether asserted
         or unasserted, absolute or contingent, accrued or unaccrued, liquidated
         or unliquidated and whether due or to become due.

                  "Liens"  means an interest  or a claim by a Person  other than
         SBCW,  any  other  Sublessor  Entity  or their  respective  Affiliates,
         whether such interest or claim is based on the common law, statute,  or
         contract,   including,  without  limitation,  liens,  charges,  claims,
         security interests,  pledges, Mortgages, leases, licenses,  conditional
         agreements, title retention agreements,  preference,  priority or other
         security   agreements  or   preferential   arrangements  of  any  kind,
         reservations,  exceptions,  encroachments,   easements,  rights-of-way,
         covenants,  conditions,  restrictions  and other title  exceptions  and
         encumbrances  affecting  all  or  any  part  of  Land,  the  Tower  and
         Improvements thereon.

                  "Liquidity Event" shall mean any sale or sales of Parent Stock
         in an underwritten registered public offering pursuant to Sections 4, 5
         or 6 of the Registration  Rights Agreement where the aggregate offering
         price of the Parent Stock to be  registered  is, in the judgment of the
         underwriter  of such  offering,  equal to or greater  than $75 million;
         provided,  however,  that  a  Liquidity  Event  will  not  include  any
         registration initiated by SBCW or any SBCW Affiliates.

                  "Liquidity  Event  Payment"  shall mean an amount equal to the
         product of (a) with  respect to the  shares of Parent  Stock  issued to
         SBCW and SBCW  Affiliates  pursuant to Section  3.2(b),  the  aggregate
         number of shares of Parent  Stock sold by such  Persons in a  Liquidity
         Event; provided that for purposes of this definition, such amount shall
         in no event exceed the  greatest  number of shares of Parent Stock sold
         by any single Person and SBCW  Affiliates in such Liquidity  Event (the
         "SBCW Liquidity Event Stock  Amount"),  and (b) the excess,  if any, of
         the  Share  Price  over  the  Liquidity  Event  Price.  Notwithstanding
         anything to the contrary herein,  in no event shall the Liquidity Event
         Payment exceed the product of (i) $139,750,000 and (ii) a fraction, the
         numerator of which is equal to the SBCW  Liquidity  Event Stock Amount,
         and the denominator of which is equal to the aggregate number of shares
         of Parent Stock issued to SBCW and SBCW Affiliates  pursuant to Section
         3.2(b).
                                       6
<PAGE>

                  "Liquidity Event Price" shall mean, with respect to each share
         of Parent Stock,  the gross price received by SBCW and SBCW  Affiliates
         in connection with a Liquidity Event.

                  "Master Lease" has the meaning given to such term in Section
         5.16.

                  "Material  Adverse  Effect"  means as to any Site,  a material
         adverse  effect on any  Subleased  Interest  granted  by the  Sublessor
         Entity in respect of such Site.

                  "Maximum Indemnification" has the meaning given to such term
         in Section 13.6(c).

                  "Mortgages" means any recorded mortgage,  deed to secure debt,
         deed of  trust,  trust  deed or other  conveyance  of,  or  encumbrance
         against the Sites or the Subleased Interests as security for any debt.

                  "Obligations" has the meaning given to such term in Section
         5.13(a).

                  "Option  Purchase  Price Amount" has the meaning given to such
         term in the SBCW Sublease.

                  "Orders"  means  all  applicable  orders,  writs,   judgments,
         decrees, rulings, consent agreements,  and awards of or by any Forum or
         entered by consent of the party to be bound.

                  "Owned Site" means any Site that is owned by SBCW or any other
         Sublessor Entity.

                  "Parent Stock" has the meaning given to such term in the
         Preamble.

                  "Person"  means an  individual,  partnership,  joint  venture,
         limited liability company, association, corporation, trust or any other
         legal entity.

                  "Permitted  Liens" means: (i) statutory liens for current real
         or personal  property  taxes not yet due and  payable;  (ii)  worker's,
         carrier's and  materialman's  liens incurred in the ordinary  course of
         business   related  to  obligations  not  yet  due  and  payable  (iii)
         easements,  rights of way or similar  grants of rights to a third party
         for access to or across any Site, including, without limitation, rights
         of way or similar  rights  granted to any utility or similar  entity in
         connection  with  the  provision  of  electric,  telephone  or  similar
         services;  (iv) Colocation Agreements;  (v) Existing Leases; (vi) liens
         that are  immaterial  in  character,  amount or extent,  or that do not
         materially detract from the value and interfere in any material respect
         with the Permitted Use of any Site;  (vii)  restrictions and conditions
         due  to  zoning  laws  and   regulations;   and  (viii)   reservations,
         restrictions, limitations, conditions and other liens of public record.

                                       7
<PAGE>

                  "Permitted Use" has the meaning given to such term in the
         applicable Sublease.

                  "Paging Tenant" has the meaning given to such term in Section
         5.16.

                  "Prepaid  Expenses" means any and all prepaid items,  unbilled
         costs and fees,  and rents,  revenues,  payments,  accounts,  notes and
         other receivables  under any service  contracts,  Existing Leases,  and
         Colocation Agreements as of the applicable Closing Date.

                  "Qualifying  Interest"  means any possessory  interest in real
         property  held  by  a  Sublessor   Entity  that  is  capable  of  being
         transferred  to TowerCo as a  Subleased  Interest  consistent  with the
         terms of the Sublease in all material respects.

                  "Real  Estate   Representation"  means  (i)  any  real  estate
         representation  or warranty made by SBCW or any other Sublessor  Entity
         in Sections 6.1 through 6.5, or (ii) a representation  or warranty made
         by SBCW or any other Sublessor Entity in any of Sections 6.6, 6.7, 6.8,
         6.9, 6.10, 6.11, 6.12 or 6.13.

                  "Registration  Rights Agreement" shall mean the Second Amended
         and Restated Registration Rights Agreement of TowerCo Parent,  together
         with the Joinder Agreement thereto dated January 5, 2000, each attached
         hereto  as  Exhibit  G  (as  the  same  may  be  amended,  modified  or
         supplemented from time to time).

                  "Rent" means,  as to any Site,  the rental  amount  prepaid by
         TowerCo for the leasing of such Site,  which rental amount is set forth
         on Annex A.

                  "Reserved Space" has the meaning given to such term in the
         SBCW Sublease.

                  "Returns" has the meaning given to such term in Section 6.9.

                  "SBC Operating Companies" has the meaning given to such term
         in the Preamble.

                  "SBCW Affiliate" has the meaning given to such term in the
         SBCW Sublease.

                  "SBCW Indemnified Losses" has the meaning given to such term
         in Section 13.2(a).

                  "SBCW  Indemnitee"  means SBCW,  SBCW  Affiliates  (including,
         without  limitation  the SBC Operating  Companies),  and the respective
         directors,  officers,  employees,  and  agents  of  SBCW  or  any  SBCW
         Affiliate (including, without limitation the SBC Operating Companies).

                  "SBCW Sublease" has the meaning given to such term in the
         Preamble.

                  "SBCW" has the meaning given to such term in the Preamble.

                  "SEC" means the Securities and Exchange and Commission.

                                       8
<PAGE>

                  "Share Price" means $22.74 per share,  subject to  appropriate
         adjustments in the event of any stock  dividend,  splits,  combinations
         and subdivisions.

                  "Sites" means all cell tower sites that are owned or leased by
         SBCW and the other Sublessor Entities that are now or hereafter subject
         to the Transaction  Documents.  Sites shall include  Existing Sites and
         Excluded Sites.

                  "Site Marketing Agreement" has the meaning given to such term
         in the Preamble.

                  "Stock Consideration" has the meaning given such term in
         Section 3.2(a).

                  "Stock Portion" means 24.8525542%.

                  "Stockholders"  shall  mean the  stockholders  of the  TowerCo
         Parent who are signatories to the Registration Rights Agreement.

                  "Stockholders'  Agreement"  shall mean the Third  Amended  and
         Restated Stockholders'  Agreement attached hereto as Exhibit H (as same
         may be amended, modified or supplemented from time to time).

                  "Subleased Interests" has the meaning given to such term in
         Section 3.1(a).

                  "Subleased Property" has the meaning given to such term in the
         SBCW Sublease.

                  "Subleases" means collectively the SBCW Sublease and the BTS
         Sublease.

                  "Sublessor Entities" means, collectively, SBCW and those legal
         entities  including SBCW Affiliates which own or lease the Sites listed
         on Annex A.

                  "Substitute  Site" shall have the  meaning  given such term in
         Section 4.8.

                  "Survival Period" has the meaning given to such term in
         Section 13.8.

                  "Taxes"  means all taxes,  duties,  charges,  fees,  levies or
         other assessments imposed by any taxing authority,  whether domestic or
         foreign,  including,  without  limitation,  income (net, gross or other
         including  recapture of any tax items such as investment  tax credits),
         alternative  or add-on  minimum tax,  capital  gains,  gross  receipts,
         value-added, excise, withholding, personal property, real estate, sale,
         use, ad valorem, license, lease, service,  severance,  stamp, transfer,
         payroll,  employment,  customs,  duties,  alternative,   estimated  and
         franchisee taxes (including any interest, levies, charges, penalties or
         additions  attributable  to or imposed  on or with  respect to any such
         assessment).

                  "Termination Fee" has the meaning given to such term in
         Section 14.1(b).

                  "Tower" has the meaning given to such term in the SBCW
         Sublease.

                  "TowerCo Indemnified Losses" has the meaning set forth in
         Section 13.1(a).

                                       9
<PAGE>

                  "TowerCo  Indemnitees" means TowerCo, its Affiliates,  and the
         respective directors,  officers,  employees,  and agents, of TowerCo or
         its Affiliates.

                  "TowerCo Parent" means SpectraSite Holdings,  Inc., a Delaware
         corporation,  which  indirectly owns all of the  outstanding  shares of
         stock of TowerCo through a wholly-owned subsidiary.

                  "Transaction Documents" means collectively this Agreement, the
         Subleases,  the Build-to-Suit  Agreement,  the Site Marketing Agreement
         and each of the other  documents and agreements  listed in Articles IV,
         XI and XII.

SECTION 1.2.      Other Capitalized Terms.

(a) Any other capitalized terms used in this Agreement shall have the respective
meanings given to them elsewhere in this Agreement.

                                   ARTICLE II
                               AGREEMENT DOCUMENTS

         This  Agreement  shall consist of the following  documents,  as amended
from time to time as provided herein:

(a)      this Agreement document;

(b)      the following Exhibits:

                  Annex A  List of Sites
                  Annex B  Consideration Summary
                  Exhibit A         Form of Assignment and Assumption Agreement
                  Exhibit B         Form of Joinder Agreement
                  Exhibit C         Form of Amendment to the Stockholders'
                                    Agreement
                  Exhibit D         Form of Build-to-Suit Agreement
                  Exhibit E         Form of Lease and Sublease
                  Exhibit F         Site Marketing Term Sheet
                  Exhibit G         Registration Rights Agreement
                  Exhibit H         Stockholders' Agreement

(c) such  additional  documents  as are  incorporated  by  reference,  including
without  limitation the Schedules  attached hereto and each Disclosure  Schedule
provided by the Sublessor Entities.

If any of the  foregoing are  inconsistent,  this  Agreement  shall prevail over
Exhibits and additional incorporated documents.

                                       10
<PAGE>

                                  ARTICLE III
                          CONVEYANCE AND CONSIDERATION

SECTION 3.1.      Conveyance.

(a) Subject to the terms and conditions of this Agreement, each Sublessor Entity
agrees to grant,  convey and deliver to TowerCo,  and TowerCo agrees to take and
accept from such Sublessor  Entity, at the Closings,  a leasehold,  subleasehold
interest,  or other interest consistent with the terms of the SBCW Sublease,  as
applicable,  in and to the Subleased Property of all of the Existing Sites which
the  applicable  Sublessor  Entity is not  legally  precluded  from  leasing  or
subleasing to TowerCo,  as more particularly  described in the SBCW Sublease and
applicable   Site   Designation   Supplements   (collectively,   the  "Subleased
Interests").

(b)  Notwithstanding  anything to the contrary  contained in Section 3.1(a), the
Subleased Interests shall not include, without limitation, any of the following:
(i) under the SBCW Sublease,  SBCW's and/or SBCW Affiliates' Improvements on the
Included Sites; (ii) any equipment or transmissions  systems used for the remote
monitoring of the Included  Sites;  (iii) any and all rights that accrue or will
accrue to SBCW or any SBCW Affiliate under the Transaction Documents, including,
without  limitation,  the Rent payments due to the Sublessor  Entities under the
SBCW Sublease; (iv) any and all rights retained by and/or granted to SBCW or any
SBCW  Affiliate  pursuant to the  Transaction  Documents;  and (v) the  Excluded
Sites.

SECTION 3.2.      Consideration.

(a)  Attached  as Annex B is a summary  of the  aggregate  agreed  upon Rent and
Option Purchase Price Amount (assuming 3,900 Included Sites). The aggregate Rent
(assuming 3,900 Included Sites) payable in advance by TowerCo and TowerCo Parent
shall be equal to  $1,307,712,668  (the  "Consideration")  and  shall be paid as
follows:   (i)  $982,712,668  in  cash  (the  "Cash   Consideration")  and  (ii)
$325,000,000 in shares (the "Stock Consideration") of Parent Stock valued at the
Share Price (for a total of 14,291,997  shares),  subject to the adjustment made
in accordance with Section 3.2(c) through (i).

(b) The Consideration shall be due and payable, at each Closing, as follows:

(i)      with respect to each Included Site being conveyed at a Closing, TowerCo
         shall pay to the applicable  Sublessor  Entity,  an amount equal to the
         prepaid  Rent for such Site  (provided  for in  Section  10 of the SBCW
         Sublease),  which  amount  shall be payable in a Cash  Portion and in a
         Stock Portion;

(ii)     the  amount  of  cash  to be paid  at  each  Closing  shall  be paid in
         immediately  available  funds and shall be equal to the  product of (a)
         the Cash  Portion  and (b) the amount of  prepaid  Rent  calculated  in
         accordance with (i) above; and

(iii)    the number of shares of Parent Stock to be issued at each Closing shall
         be equal to the product of (a) the Stock  Portion and (b) the amount of
         prepaid  Rent  calculated  in  accordance  with  subsection  (i) above,
         divided by the Share Price.

                                       11
<PAGE>

(c) The  Parent  Stock is to be  issued  to  direct  or  indirect  wholly  owned
subsidiaries  of SBC  Communications  Inc. that own interests in the  Applicable
Sublessor  Entities.  The Parent Stock shall be subject to an  adjustment  to be
calculated  and paid in accordance  with the  provisions of this Section  3.2(c)
through Section 3.2(i) below.

(d) If the End Date  occurs  prior to the  consummation  of a Change of Control,
then within two Business Days  following the End Date,  TowerCo Parent shall pay
the End Date Adjustment  Payment to SBCW. The End Date Adjustment Payment may be
paid,  at  TowerCo  Parent's  option,  in  cash  or in  Parent  Stock  or in any
combination of the foregoing. If TowerCo Parent elects to pay some or all of the
End Date Adjustment  Payment in Parent Stock,  TowerCo Parent shall (x) issue to
SBCW the number of shares of Parent  Stock  equal to (i) the  amount  payable in
Parent Stock divided by (ii) the Current Market Price (as of the End Date),  and
(y) pay the balance, if any, of the End Date Adjustment Payment to SBCW in cash.
Notwithstanding  the  foregoing,  if TowerCo Parent elects to pay some or all of
the End Date Adjustment Payment in Parent Stock, the maximum number of shares of
Parent  Stock  TowerCo  Parent will be required to issue in order to satisfy its
obligation  with  respect to such  payment  shall not exceed the  product of (x)
10,783,179  shares of Parent Stock and (y) a fraction the  numerator of which is
equal to the SBCW End Date Stock Amount,  and the  denominator of which is equal
to the  aggregate  number  of shares  of  Parent  Stock  issued to SBCW and SBCW
Affiliates under Section 3.2(b).

(e) If a  Change  of  Control  is  consummated  prior  to  the  End  Date,  then
immediately prior to the consummation of such Change of Control,  TowerCo Parent
shall pay the Change of Control  Payment to SBCW. The Change of Control  Payment
may be paid, at TowerCo  Parent's  option,  in cash or in Parent Stock or in any
combination of the foregoing. If TowerCo Parent elects to pay some or all of the
Change of Control  Payment in Parent  Stock,  TowerCo  Parent shall (x) issue to
SBCW the number of shares of Parent  Stock  equal to (i) the  amount  payable in
Parent  Stock  divided  by (ii) the  Change of  Control  Price,  and (y) pay the
balance,   if  any,  of  the  Change  of  Control  Payment,  to  SBCW  in  cash.
Notwithstanding  the  foregoing,  if TowerCo Parent elects to pay some or all of
the Change of Control  Payment in Parent Stock,  the maximum number of shares of
Parent  Stock  TowerCo  Parent will be required to issue in order to satisfy its
obligation  with  respect to such  payment  shall not exceed the  product of (x)
10,783,179  shares of Parent Stock and (y) a fraction the  numerator of which is
equal to the SBCW Change of Control Stock Amount,  and the  denominator of which
is equal to the  aggregate  number of shares of Parent  Stock issued to SBCW and
SBCW Affiliates under Section 3.2(b).

(f) If any  Liquidity  Event  occurs  prior to the  earlier  to occur of (x) the
consummation  of a Change of  Control  and (y) the End  Date,  then  within  two
Business Days  following any such  Liquidity  Event,  TowerCo Parent shall pay a
Liquidity  Event Payment to SBCW.  The  Liquidity  Event Payment may be paid, at
TowerCo Parent's option, in cash or in Parent Stock or in any combination of the
foregoing.  If TowerCo  Parent elects to pay some or all of the Liquidity  Event
Payment in Parent  Stock,  TowerCo  Parent shall (x) issue to SBCW the number of
shares of Parent Stock equal to (i) the amount  payable in Parent Stock  divided
by the (ii)  Liquidity  Event  Price,  and (y) pay the  balance,  if any, of the
Liquidity  Event  Payment to SBCW in cash.  Notwithstanding  the  foregoing,  if
TowerCo  Parent  elects to pay some or all of the  Liquidity  Event  Payment  in
Parent Stock,  the maximum  number of shares of Parent Stock TowerCo Parent will
be  required to issue in order to satisfy its  obligation  with  respect to such
payment  shall not exceed the product of (x)  10,783,179  shares of Parent Stock
and (y) a fraction the numerator of which is equal to the SBCW  Liquidity  Event
Stock Amount,  and the denominator of which is equal to the aggregate  number of
shares of Parent Stock issued to SBCW and SBCW Affiliates under Section 3.2(b).

                                       12
<PAGE>

(g) The Cash  Portion of each  payment  under this  Section 3.2 shall be made by
wire transfer of immediately  available funds through the Federal Reserve System
to an account  designated  in writing by SBCW for the benefit of the  applicable
Sublessor  Entities.  To the extent any  payment  under  this  Section  3.2 to a
Sublessor Entity is payable in Parent Stock,  each payment shall be evidenced by
a certificate  issued directly to SBCW (or, as applicable,  a direct or indirect
wholly owned subsidiary of SBC Communications Inc.).

(h) No  fractional  shares of Parent  Stock  shall be  issued  pursuant  to this
Section  3.2  and an  amount  in  cash  (if  any)  shall  be paid in lieu of any
fractional  part of a share  otherwise  resulting from the terms of this Section
3.2 equal to such  fractional  part of a share  multiplied by the relevant Share
Price,  Current Market Price,  Change of Control Price or Liquidity Event Price,
as applicable.

(i) There will be no obligation for TowerCo Parent to pay any adjustment payment
to SBCW under this Section 3.2 for events arising after the End Date  Adjustment
Payment or the Change of Control Payment.

SECTION 3.3.      Consents Under Ground Leases.

         SBCW and TowerCo shall use  commercially  reasonable  efforts to obtain
from each Ground  Lessor from whom consent is required a written  consent to (i)
SBCW's  subleasing  of such Site to TowerCo  and (ii) the  further  sublease  of
portions of the Site by TowerCo to third party tenants whose primary business is
the provision of "radio transmission and/or communication  services" or terms of
similar  meaning  reasonably  acceptable  to  TowerCo  (each,  a "Ground  Lessor
Consent") without making any concessions to the Ground Lessor in terms of Ground
Rent or revenue sharing  arrangements.  TowerCo shall be actively  involved with
SBCW in all material aspects of the efforts to obtain any required Ground Lessor
Consent.  If SBCW is unable,  with the participation and cooperation of TowerCo,
to obtain any required  Ground Lessor  Consent by the  applicable  Closing,  the
parties shall  continue  using  commercially  reasonable  efforts to obtain such
Ground Lessor Consent in accordance with this Section 3.3; provided, that if the
parties  subsequently  obtain such  Ground  Lessor  Consent as to any Site,  the
Closing for such Site shall take place at the Closing next  succeeding  the date
on which such Ground  Lessor  Consent is obtained,  or, if the Final Closing has
occurred,  within six (6) months after the Final Closing at a time agreed by the
parties;  provided  further,  no  Closings  for such Sites shall occur after the
expiration of such six (6) month period, unless the parties otherwise agree.

         SBCW and  TowerCo  shall  mutually  agree on the form of  letter  to be
submitted to the Ground Lessors requesting the aforedescribed consents and shall
each have the right to approve any  modifications  to such form  proposed by any
Ground Lessor and the final form of such consent.

                                       13
<PAGE>

                                   ARTICLE IV
                                    CLOSINGS

SECTION 4.1.      Closings.

(a) Subject to prior  termination  of this Agreement by SBCW pursuant to Article
XIV, the consummation of the transfer and conveyance of the Subleased  Interests
and other  transactions  contemplated  by this Agreement shall occur in multiple
closings (individually, a "Closing", and collectively, the "Closings"), and each
such Closing shall take place at the offices of King & Spalding,  1185 Avenue of
the  Americas,  New York New York 10036,  at such times and on such dates (each,
the  "Closing  Date") as  contemplated  under  Sections (b) and (c) below and as
modified pursuant to the terms hereof (the "Closing Schedule").

(b)  Notwithstanding  anything to the  contrary  contained  herein,  the parties
acknowledge  and agree that each Closing  shall be subject to the  provisions of
Articles  XI and XII of this  Agreement  and  shall  take  place  after  all the
conditions  set forth in such Articles XI and XII have been satisfied or waived.
The parties further acknowledge that the initial Closing (the "Initial Closing")
shall take place on  October  10,  2000 (or,  so long as the  parties  have been
diligently  pursuing the Initial  Closing,  such later date as the parties shall
mutually  agree),  subject to the  satisfaction  of the  conditions set forth in
Articles XI and XII or on such other date as the parties may agree (the "Initial
Closing Date"),  and thereafter each Closing shall take place on the last day of
the  calendar  month during  which the  determination  is made that such Site is
ready to close as provided in the Closing Schedule;  provided,  however, that in
no event shall the Final Closing (the "Final Closing") occur later than the date
which is  eighteen  (18) months  after the  Effective  Date (the "Final  Closing
Date").

(c) The parties  shall use  commercially  reasonable  efforts to include in each
Closing at least two hundred  fifty (250) Sites,  whether as an Included Site or
Excluded Site,  including,  without  limitation,  any Sites deferred pursuant to
Section 4.6 from the previous Closings.

(d) SBCW  shall  provide  to  TowerCo a list of Sites  ("Closing  Sites")  to be
included in a particular  Closing,  and any changes to Annex A or the Disclosure
Schedule with respect to those Sites,  sufficiently in advance of the applicable
Closing Date such that, taking into account the number of Closing Sites, TowerCo
will be  able,  with  the  exercise  of  reasonable  diligence,  to  review  the
information  included  on such  list  (including  any  matters  shown in, or any
changes  to,  Annex A or the  Disclosure  Schedule),  to  determine  whether the
conditions  set forth in  Article  XII of this  Agreement  have  been  satisfied
(including  any required  Ground  Lessor  Consents)  with respect to the Closing
Sites and to  prepare  with  respect to such Sites  those  portions  of the Site
Designation  Supplements  which  TowerCo is obligated  to prepare,  in each case
prior to such Closing Date. In addition,  the parties shall,  promptly after the
date hereof,  use good faith efforts to agree on procedures to effect an orderly
transition  in the  operation  and  maintenance  of the  Sites  from SBCW or the
applicable  Sublessor  Entity to TowerCo.  Notwithstanding  the  foregoing,  the
parties  agree to use their good faith efforts to  consummate  the  transactions
contemplated by this Agreement as expeditiously as reasonably possible,  subject
to the provisions of Section 4.1(b) of this Agreement.

                                       14
<PAGE>

SECTION 4.2.      Transactions and Documents at the Closings.

(a)      At each Closing:

(i)      TowerCo  shall  pay the  applicable  Rent to the  applicable  Sublessor
         Entity by paying the applicable pro rata Cash  Consideration  and Stock
         Consideration  in  respect  of  all of the  Subleased  Interests  being
         subleased at such Closing;

(ii)     TowerCo shall execute and deliver to the  applicable  Sublessor  Entity
         any and all documents and instruments relating to the acceptance of the
         Subleased  Interest of each of its Included Sites,  including,  without
         limitation,  (A) Site Designation Supplements with respect to Subleased
         Interests of the Included Sites being subleased at such Closing, (B) an
         assignment and assumption  agreement in substantially the form attached
         hereto as Exhibit A (each, an "Assignment and Assumption Agreement")

         relating  to  the  assignment  of the  Existing  Leases  affecting  the
         Included Sites subject to such Closing;  and (C) such other  documents,
         certificates, agreements and other papers as set forth in Article XI or
         may be necessary or convenient to effectuate  the  consummation  of the
         transactions  contemplated  by this  Agreement  and  other  Transaction
         Documents, and its purposes and intent.

 (iii)    Each Sublessor  Entity shall execute and deliver to TowerCo
          any and all documents and instruments  relating to the sublease of the
          Subleased   Interest  of  each  Included  Site,   including,   without
          limitation, (A) all consents,  authorizations and approvals in respect
          of the Included Sites that are necessary for the  consummation of each
          Closing, including any and all required consents of Ground Lessors and
          Governmental  Permits;  (B) the Assignment  and  Assumption  Agreement
          relating to assignment of the Existing  Leases  affecting the Included
          Sites subject to such Closing;  (C) Site Designation  Supplements with
          respect to the Subleased Interests of Included Sites being conveyed at
          such  Closing;  (D) a  receipt  for the Rent  delivered  to it at such
          Closing;  and (E) such other documents,  certificates,  agreements and
          other  papers  as set  forth in  Article  XII or may be  necessary  or
          convenient  to  effectuate  the   consummation  of  the   transactions
          contemplated by this Agreement and other  Transaction  Documents,  and
          its purposes and intent.
(iv)     If  necessary,  Annex A to the  Joinder  Agreement  shall be amended to
         include any additional SBCW Affiliates that have received Parent Stock.

(v)      If necessary,  Annex A to the Stockholders'  Agreement shall be amended
         to include any additional  SBCW  Affiliates  that have received  Parent
         Stock.

(b) In addition to and not in limitation of Section 4.2(a):

(i)      At the Initial  Closing,  TowerCo and SBCW (for itself and on behalf of
         the Sublessor  Entities  listed  therein) shall execute and deliver the
         SBCW Sublease;

(ii)     At the Initial  Closing,  TowerCo and SBCW (for itself and as agent for
         certain SBCW  Affiliates)  shall execute and deliver the  Build-to-Suit
         Agreement;

                                       15
<PAGE>

(iii)    At the Initial  Closing,  TowerCo  Parent and SBCW, on behalf of itself
         and the SBCW Affiliates that are issued Parent Stock, shall execute and
         deliver the Joinder Agreement; and

(iv)     At the Initial Closing, TowerCo Parent, certain stockholders of TowerCo
         Parent and SBCW, on behalf of itself and the SBCW  Affiliates  that are
         issued  Parent  Stock  shall  execute  and  deliver  the  Stockholders'
         Agreement; and

(v)      At the Initial Closing, SpectraSite Communications, Inc., SBC Wireless,
         Inc. and certain Sublessor  Entities shall execute and deliver the Site
         Marketing Agreement.

SECTION 4.3.      Costs of Closing.

         Except  as  otherwise  provided  in  the  Transaction  Documents,   the
applicable  Sublessor  Entity  shall  be  responsible  for  and  pay any and all
transfer  Taxes and  routine  closing  costs and  expenses,  including,  without
limitation,  (i) any transfer Tax payable on the SBCW Sublease, if any, and (ii)
all  recording  costs  relating  to  any  title  clearance   matters,   if  any.
Notwithstanding  anything to the contrary  contained herein, (i) any fees, costs
and  expenses  incurred by or on behalf of TowerCo for the  services  ordered or
requested  by TowerCo for which such  Sublessor  Entity is not liable  under the
Transaction  Documents shall be the  responsibility  of and shall be paid for by
TowerCo and (ii) any fees,  costs and  expenses  incurred by or on behalf of any
Sublessor  Entity for services ordered or requested by such Sublessor Entity for
which such Sublessor Entity is expressly liable under the Transaction  Documents
shall be the responsibility of and shall be paid for by such Sublessor Entity.

SECTION 4.4.      Further Assurances; Corrections.

(a) At each Closing,  and from time to time  thereafter,  each Sublessor  Entity
shall do all such additional and further acts, and shall execute and deliver all
such additional and further instruments,  certificates and documents, as TowerCo
may reasonably  require fully to vest in and assure to TowerCo full right, title
and interest in and to the Subleased  Interests to the full extent  contemplated
by  this  Agreement  and  otherwise  to  effectuate  the   consummation  of  the
transactions  contemplated  by this  Agreement.  Each of the parties hereto will
cooperate  with the others and  execute and  deliver to the other  parties  such
other instruments and documents and take such other actions as may be reasonably
requested  from  time to time by any  other  party as  necessary  to carry  out,
evidence and confirm the intended purposes of this Agreement.

(b) If in the review of any Site Designation  Supplement either party identifies
any corrections that in either party's judgment necessitate further revisions to
Exhibit B, C or D to such Site Designation Supplement, the parties may at either
party's  request  effect the correction of such Exhibit B, C or D, and defer the
recordation of such Site  Designation  Supplement until such revisions are made,
for up to thirty (30) days.

(c) In addition,  with respect to the Included Sites, the parties shall have the
right to review and make corrections,  if necessary,  to any and all exhibits to
the Site  Designation  Supplements  applicable to such Included  Sites after the
applicable Closing.  After making any such corrections,  TowerCo shall re-record
any such Site Designation Supplements to reflect such corrections,  if requested
by the applicable Sublessor Entity.

                                       16
<PAGE>

(d) If after any  Closing  any party  discovers  that the name of the  Sublessor
Entity  as set  forth in any  Site  Designation  Supplement  is  incorrect,  the
applicable Sublessor Entity shall re-execute such Site Designation Supplement in
such a manner as to correct such name,  and TowerCo  shall  re-record  such Site
Designation Supplement, unless the parties agree that such re-recordation is not
necessary.  The  foregoing  obligation  shall  survive the Closing in respect of
which such Site  Designation  Supplement  was  executed  for a period of six (6)
months.

(e) The Sublessor Entity shall have the right, at its sole expense, to cause any
amendment to the Site Designation  Supplement to be recorded.  In addition,  the
parties  shall  cooperate  with each  other to cause  changes  to be made in the
documentation  for any Site,  and in the Site  Designation  Supplement  for such
Site,  if such  changes are  requested by the  Sublessor  Entity to evidence any
permitted  changes in the Reserved Space or Subleased  Interest  respecting such
Site, including,  without limitation changes in such Sublessor Entity's antennas
or other  parts of its  communications  facility at such Site.  Such  obligation
shall survive any Closing without limitation.

SECTION 4.5.      Site Designation Supplements.

         Prior to the applicable Closing Date,  TowerCo shall,  collect the data
relating to the applicable  Existing  Sites,  adequately  describe such Existing
Sites  and  prepare  Exhibits  B, C and D for all Site  Designation  Supplements
relating to such Existing Sites,  all in accordance with the terms thereof.  The
parties agree that, as between the parties,  the  description  of Existing Sites
shall be sufficient to adequately describe the Subleased Interests. In addition,
where any discrepancy in Exhibits B, C or D requires  verification in the field,
including without limitation  verification as to the number of antennas,  height
of antennas,  location of antennas or location of antenna mounting hardware, the
parties  shall  provide  adequate   resources  and  personnel  to  resolve  such
discrepancy within thirty (30) days after the applicable Closing.

SECTION 4.6.      Deferral of Closings; Updating of Representations.

(a) Each  Sublessor  Entity  will have the right to defer the  Closing as to any
Site to a later Closing by virtue of (i) the failure of such Site to satisfy any
condition to the obligations of TowerCo respecting such Site (including, without
limitation, the failure to obtain any Ground Lessor Consent or other third party
consent),  or (ii) the  breach by the  applicable  Sublessor  Entity of any Real
Estate  Representation as to such Site. If by the Final Closing,  the applicable
Sublessor Entity fails, after the exercise of reasonable  efforts,  to cause any
such  unsatisfied  (and unwaived)  condition to be satisfied or to cure any such
(unwaived) breach of a Real Estate Representation, such Site shall constitute an
Excluded Site.  TowerCo shall notify SBCW prior to the applicable Closing of any
Site in the event that TowerCo  believes that SBCW or any  applicable  Sublessor
Entity has not satisfied any condition in this  Agreement to its  obligations to
acquire the Subleased Interest in such Site, including,  without limitation,  by
virtue  of a  breach  of a Real  Estate  Representation  as to  such  Site.  The
applicable  Sublessor  Entity  will have the right to cure any such  breach of a
representation, warranty or covenant and/or remedy such condition, and defer the
Closing of such Site to facilitate such cure, as provided above.

                                       17
<PAGE>

(b) As soon as  reasonably  practicable  prior  to the  date  scheduled  for any
Closing pursuant to the Closing Schedule,  the applicable Sublessor Entity shall
disclose in writing any material  information,  known to such  Sublessor  Entity
without additional inquiry,  that is required to (x) be provided pursuant to any
representation  or warranty made by a Sublessor Entity pursuant to Article VI or
(y) cause any Real Estate Representation with respect to any Existing Site to be
true and correct in all  material  respects and to modify,  amend or  supplement
such Real Estate Representation,  including without limitation: (i) to set forth
exceptions to any such  representations  and  warranties,  where such exceptions
were not theretofore set forth in this Agreement or any Schedule hereto, or (ii)
to reflect any lease, sublease or license that becomes an Existing Lease entered
into  after  the date of this  Agreement  in the  ordinary  course  of  business
consistent  with past  practices and matters  related  thereto.  The  applicable
Sublessor  Entity  shall  provide  any  such  disclosure  that  relates  to such
Sublessor Entity and does not constitute a Real Estate  Representation  prior to
the first Closing in which any Sites of such Sublessor  Entity is included.  Any
such  disclosure  shall be deemed to create and constitute a portion of, and all
such disclosures together shall be, the "Disclosure Schedule". Any Existing Site
in  respect  of which the  applicable  Sublessor  Entity  makes  any  disclosure
pursuant to this Section 4.6(b) may, at TowerCo's option, be deferred to a later
Closing Date pursuant to Section  4.6(a),  where the matters so described  would
have a Material Adverse Effect on such Existing Site. The sole remedy of TowerCo
in respect of any such disclosure as to any Site shall be to cause such Site, at
the applicable  Sublessor Entity's option pursuant to this Section 4.6, to be an
Excluded Site hereunder or to defer the Closing for such Site to a later Closing
Date.

SECTION 4.7.      Re-Recordation.

         Whenever in this Agreement either party is required or has the right to
record  or  re-record  any  document,  including  without  limitation  any  Site
Designation Supplement,  Ground Lease or a memorandum thereof, such party shall,
or shall cause the agent  effecting such  recordation  to, deliver a copy of the
document to the other party  promptly  after receipt  thereof,  and in any event
contemporaneously with its first delivery thereof to the recording party.

SECTION 4.8.      Substitution of Sites.

         Notwithstanding  anything to the contrary herein,  SBCW may at any time
amend  Annex A to  substitute  a Site  which has  become an  Excluded  Site with
another Site in a similar market with a similar  structural design capacity,  in
which case such Site shall  constitute  an  Existing  Site  hereunder  (each,  a
"Substitute  Site").  The  Rent  and  Option  Purchase  Price  Amount  for  such
Substitute Site shall be calculated in accordance  with the methodology  used to
calculate  the Rent and Option  Purchase  Price Amount with respect to the Sites
listed on Annex A.

SECTION 4.9.      Value Adjustments.

(a)  Notwithstanding  anything to the contrary herein,  at any Closing occurring
after the second Closing and prior to the Final Closing, if the average Rent per
Site paid by TowerCo for all Sites to be included in the applicable  Closing and
all Included Sites included in all prior Closings exceeds $368,842, then TowerCo
shall  have the right to  require  SBCW to defer the  Closing  as to any Site or
number of Sites in  accordance  with clause (c) below such that the average Rent
per Site paid by TowerCo for all Sites  included in the  applicable  Closing and
all Included Sites included in all prior Closings does not exceed $368,842.

                                       18
<PAGE>

(b)  Notwithstanding  anything to the contrary  herein,  if the average Rent per
Site paid by  TowerCo  for Sites to be  included  in the Final  Closing  and all
Included  Sites included in all prior Closings  exceeds  $352,077,  then TowerCo
shall have the right to require SBCW to designate any Site or number of Sites to
be Excluded  Sites in  accordance  with clause (c) below,  such that the average
Rent per Site paid by TowerCo for all Sites  included  in the Final  Closing and
all Included Sites included in all prior Closings does not exceed $352,077.

(c) TowerCo  and SBCW shall  mutually  agree on the Sites with  respect to which
Closing shall be deferred in accordance  with clause (a) above or which shall be
designated as Excluded Sites in accordance  with clause (b) above, or if TowerCo
and SBCW cannot  mutually  agree on such Sites,  the Sites with respect to which
Closing shall be deferred in accordance  with clause (a) above or which shall be
designated as Excluded  Sites in accordance  with clause (b) above shall consist
first of Sites  otherwise to be included in the  applicable  Closing  having the
highest  amount of aggregate Rent and  continuing  with Sites having  decreasing
amounts of aggregate Rent thereafter.

(d) TowerCo and SBCW agree to  cooperate to  structure  each  Closing  occurring
during  the three  months  prior to the Final  Closing  such that upon the Final
Closing  the  average  Rent per Site paid by TowerCo  for the  aggregate  of all
Included Sites will not exceed $352,077.

ARTICLE V
                              additional agreements

SECTION 5.1.      Expenses.

(a) Except as otherwise  provided  herein,  all expenses  incurred by TowerCo in
connection  with the  negotiations  among the  parties,  and the  authorization,
preparation,  execution and  performance  of the  Transaction  Documents and the
transactions contemplated hereby shall be paid by TowerCo.

(b) Except as otherwise  provided herein,  all expenses incurred by SBCW and the
other Sublessor  Entities in connection with the negotiations among the parties,
and the authorization, preparation, execution and performance of the Transaction
Documents and the transactions contemplated hereby shall be paid by SBCW or such
other Sublessor Entity.

SECTION 5.2.      Brokers.

         Each Sublessor  Entity hereby  represents and warrants to TowerCo that,
except  Goldman,  Sachs & Co.  which is an  advisor  to SBCW  and the  Sublessor
Entities,  no broker or finder has acted on its behalf in  connection  with this
Agreement  or the  transactions  contemplated  herein  and  agrees to  indemnify
TowerCo  Indemnitees  from  and  against  any  and all  claims  or  demands  for
commissions  or other  compensation  by any  broker,  finder  or  similar  agent
claiming  to have been  employed  by or on behalf  of SBCW,  including,  without
limitation,  Goldman, Sachs & Co. TowerCo hereby represents and warrants to SBCW
and each Sublessor  Entity that no broker or finder has acted on their behalf or
on behalf of any of them in connection  with this Agreement or the  transactions
contemplated herein and each of them agrees, jointly and severally, to indemnify
SBCW  Indemnitees from and against any and all claims or demands for commissions
or other  compensation  by any broker,  finder or similar agent claiming to have
been employed by or on behalf of TowerCo or any of its Affiliates.

                                       19
<PAGE>

SECTION 5.3.      Risk of Loss and Insurance.

         Between  the date of this  Agreement  and each  Closing,  the risks and
obligations of ownership and loss of the Subleased Interests with respect to the
Sites  subject to such  Closing and the  correlative  rights  against  insurance
carriers and third parties shall belong to the applicable  Sublessor  Entity. In
the event of the damage or  destruction  of all or a substantial  portion of the
Subleased  Interests  prior to any  Closing,  the  affected  Sites shall  become
Excluded Sites unless the parties agree to the contrary.

SECTION 5.4.      Condemnation.

         In the event of the taking of any part of the Subleased Interest of any
Site,  or  any  interest  therein,  by  eminent  domain   proceedings,   or  the
commencement or bona fide threat of the  commencement  of any such  proceedings,
prior to any Closing,  the affected Sites shall become Excluded Sites unless the
parties agree to the contrary.

SECTION 5.5.      Publicity.

         Except as required by applicable Laws or any applicable  stock exchange
rules,  all press  releases and other public  announcements  with respect to the
subject matter hereof,  including the time,  form and content of such release or
announcement,  shall be made only with the mutual  written  agreement of TowerCo
and SBCW;  provided,  however,  that any  disclosure  required  to be made under
applicable Law may be made only if a party required to make such  disclosure has
determined  in  good  faith  that it is  necessary  to do so and  has  used  its
reasonable best efforts, prior to the issuance of the disclosure, to provide the
other parties with a copy of the proposed disclosure and to discuss the proposed
disclosure with the other parties.

SECTION 5.6.      TowerCo's Access and Inspection.

         SBCW and the other  Sublessor  Entities  shall provide  TowerCo and its
authorized  representatives  (i) reports as to the Sites in electronic  form, to
the  extent  reasonably  available  and (ii)  reasonable  access  during  normal
business  hours from and after the date hereof until the Final  Closing (as such
date may be extended in accordance with Section 3.3) to the books and records of
SBCW  or  such  Sublessor  Entity,  as  applicable,  relating  to the  Subleased
Interests and for physical inspection of the Subleased Interest, for the purpose
of making such  investigation  as TowerCo may reasonably  desire,  and each such
party shall reasonably promptly furnish TowerCo such information  concerning the
Subleased Interests as TowerCo may reasonably request.

                                       20
<PAGE>

SECTION 5.7.      Cooperation.

         The  parties  shall  cooperate  fully  with each  other and with  their
respective  counsel and  accountants in connection with any steps required to be
taken as part of their respective obligations hereunder,  including establishing
mechanics  for the  subleasing  and  Closing of each Site  which are  reasonably
acceptable to both parties,  and all parties shall use  commercially  reasonable
efforts to consummate the transactions  contemplated herein and to fulfill their
obligations hereunder, including, without limitation, causing to be fulfilled at
the earliest  practical date the conditions  precedent to the obligations of the
parties to consummate the transactions contemplated hereby set forth in Articles
XI and XII.  Without the prior written  consent of the other  parties,  no party
hereto may take any intentional action that would cause the conditions precedent
to the obligations of the parties hereto to effect the transactions contemplated
hereby not to be fulfilled, including, without limitation, takings or causing to
be taken any action that would cause the  representations and warranties made by
such party herein not to be true, correct and complete as of each Closing.

SECTION 5.8.      Governmental Filings.

(a) The parties  shall make,  or cause to be made,  all filings and  submissions
required  to be made to any  Government  in  connection  with  the  transactions
contemplated by this Agreement.

(b) Each party hereto agrees to use  commercially  reasonable  efforts to comply
with all legal  requirements  which may be imposed on such party with respect to
the  transactions  contemplated by the  Transaction  Documents and to obtain all
consents,  orders  and  approvals  that  may  be or  become  necessary  for  the
consummation of the transactions  contemplated by the Transaction  Documents and
each party shall furnish to the other  parties such  necessary  information  and
reasonable assistance as other parties may reasonably request in connection with
the preparation of necessary filings or submissions to any governmental or other
regulatory  agency in promptly  seeking to obtain all such consents,  orders and
approvals. SECTION 5.9. Confidentiality.

(a) The parties  acknowledge  and agree that in the course of their  discussions
and negotiations of the Transaction Documents and the transactions  contemplated
herein,  a party hereto (the  "Disclosing  Party") may already have disclosed or
may hereafter  disclose  Confidential  Information  (as defined below) to one or
more of the other parties hereto (each, a  "Disclosee").  Each party agrees that
if the transactions  contemplated herein are not consummated,  it will return to
the Disclosing  Party all documents and other written  information  furnished to
it. Each party  further  agrees to maintain the  confidentiality  of any and all
Confidential  Information  of a  Disclosing  Party and not  disclose or give any
Confidential  Information  to any Person or use such  Confidential  Information,
provided,  however,  that the foregoing  obligations  will not apply to: (i) any
information  which was lawfully known by the Disclosee free of any obligation of
confidentiality  to any Person prior to its disclosure by the Disclosing  Party;
(ii) any  information  which was in the public  domain  prior to the  disclosure
thereof,  (iii) any  information  which comes into the public domain  through no
fault of the Disclosee; (iv) any information which is disclosed to the Disclosee
by a third party,  other than an Affiliate,  having the legal right to make such
disclosure;  (v) any  information  which is required to be disclosed by Order of
any Forum or as required by Law, or (vi) TowerCo's  disclosure on a confidential
basis of  Confidential  Information  to third parties if  reasonably  related to
TowerCo's  Permitted  Use of  the  Sites  as  contemplated  in  the  Transaction
Documents, provided that TowerCo shall be liable for any breach by a third party
of the  confidentiality  provisions  in this  Section  5.9 in the event  TowerCo
provided  Confidential  Information  to such third party.  Without  limiting the
generality of the foregoing, each party agrees that, when acting as a Disclosee,
it will (a) restrict  the  disclosure  of the  Confidential  Information  of the
Disclosing Party to those employees,  advisors,  agents and financing sources of
Disclosee who require such information for the purposes contemplated  hereunder,
(b) notify all of its employees,  advisors, agents and financing sources to whom
Confidential  Information  of the  Disclosing  Party is disclosed  not to use or
disclose  such  Confidential  Information  in violation of this  Agreement,  (c)
prevent use or  disclosure  by its  employees,  advisors,  agents and  financing
sources of the  Confidential  Information  of the  Disclosing  Party,  except as
provided  herein,  and (d) promptly  inform the  Disclosing  Party of any use or
disclosure of the  Confidential  Information  of the Disclosing  Party,  whether
intentional  or not,  which violates the provisions of this Section and of which
Disclosee has any knowledge.

                                       21
<PAGE>

(b) For purposes of this Section 5.9,  "Confidential  Information" means any and
all  technical,  business,  and  other  information  which is (i)  possessed  or
hereafter acquired by a Disclosing Party and (ii) derives economic value, actual
or  potential,  from  not  being  generally  known  to  Persons  other  than the
Disclosing  Party,  including,  without  limitation,  technical or non-technical
data,  compositions,   devices,  methods,  techniques,   drawings,   inventions,
processes,  financial  data,  financial  plans,  lists of  actual  or  potential
customers or suppliers,  information regarding the business plans and operations
of the  Disclosing  Party,  and the existence of  discussions  and  negotiations
between the parties hereto relating to the terms hereof.  The provisions of this
Section 5.9 shall survive any  termination  of this Agreement for any reason and
shall remain in full force and effect from and after the Initial Closing Date.

(c) TowerCo  acknowledges  and agrees that the  databases  respecting  the Sites
maintained  on behalf of SBCW or a  Sublessor  Entity  are owned by SBCW or such
Sublessor Entity and constitute trade secrets of SBCW or such Sublessor  Entity.
Any data from such  databases  provided  to  TowerCo  may be used by  TowerCo in
accordance  with  the  terms of this  Agreement,  including  without  limitation
Section 5.9.

SECTION 5.10.     Real Estate Matters.

(a) Prior to the  applicable  Closing,  TowerCo  shall notify SBCW if the Ground
Lease or a memorandum  thereof has not been recorded for any Site. TowerCo shall
use its commercially reasonable efforts to effect such recordation,  at its sole
cost and expense,  except where prohibited by Law or the terms of the applicable
Ground Lease. The applicable Sublessor Entity shall execute documents reasonably
requested  by TowerCo  to effect  such  recordation,  and shall  cooperate  with
TowerCo in pursuing such recordation.

(b) The applicable  Sublessor Entity and, after the applicable Closing,  TowerCo
shall each have the right to place, each at its sole cost and expense,  accurate
signage  on each Site to put third  parties  on notice of its  interest  in such
Site,  subject to compliance  with  applicable Laws and any Ground Lease for the
Site in question.

                                       22
<PAGE>

(c)  Notwithstanding  anything to the contrary  contained  herein, if TowerCo is
unable to record any unrecorded Ground Lease or memorandum thereof in respect of
any Site, or otherwise to protect the applicable  Sublessor Entity's interest in
such Site and at any time thereafter the applicable  Sublessor  Entity loses its
interest  under the Ground Lease by virtue of a foreclosure  of a prior Mortgage
on the fee interest of such Site, TowerCo will have no claim against SBCW or the
Sublessor Entity in respect thereof.

(d) Following the applicable  Closing,  TowerCo and each Sublessor  Entity whose
Sites were the subject of a Site  Designation  Supplement and whose Ground Lease
or memorandum was not recorded,  shall continue  reasonable efforts to cause the
Ground  Lease or a  memorandum  thereof to be recorded.  Such  obligation  shall
expire on the first  anniversary of the Final Closing.  If any such Ground Lease
or a memorandum is thereafter recorded in respect of any Site, the parties shall
re-record the Site Designation Supplement for such Site.

(e) Each Site Designation  Supplement shall be in recordable form. TowerCo shall
be  responsible   for  effecting  the   recordation  of  all  Site   Designation
Supplements,  unless  prohibited by Law or by the applicable  Ground Lease,  and
TowerCo  shall bear all costs and  expenses  incurred in  connection  therewith.
Promptly  after  effecting such  recordation,  TowerCo shall give the applicable
Sublessor  Entity written  confirmation  of such  recordation  and copies of the
recorded documents.

SECTION 5.11.     No Solicitation of Employees.

         In the event that for any reason this Agreement is terminated,  TowerCo
agrees  that,  for a  period  of  twelve  (12)  months  following  the  date  of
termination,  it will not  employ  or seek to employ  on its own  behalf,  or on
behalf of any of its  Affiliates,  any employee of SBCW or its Affiliates or any
person who was employed by SBCW or its Affiliates  (whether or not such employee
would commit a breach of contract) and who has not ceased to be employed by such
Person for a period of at least one (1) year.

SECTION 5.12.     Update of Information.

(a) At all times prior to the Final Closing,  each party shall promptly  provide
to the other party,  subject to Section 4.6(b), with written notification of any
material fact,  event,  occurrence or other  information of any kind  whatsoever
which affects,  or may affect, the truthfulness,  correctness or completeness of
any representation,  warranty, covenant or agreement made in this Agreement, any
other Transaction Document or any document, agreement,  instrument,  certificate
or writing furnished to any party or its respective Affiliates pursuant to or in
connection  with this  Agreement,  or which  affects or may affect the continued
truthfulness, correctness or completeness of any thereof through the date of the
Final Closing.  Each such written  notification shall specifically  identify all
representations,  warranties,  covenants  and  agreements  affected by the fact,
event,  occurrence or information  that  necessitated  the giving of the notice;
provided,  that,  except as set forth in Section 4.6(b), no such notification of
any material fact,  event,  occurrence or other  information  shall be deemed to
modify,  amend or supplement  any such  representation,  warranty,  covenant and
agreement.

                                       23
<PAGE>

(b) Annex A sets forth,  with respect to each Site listed  thereon,  among other
things,  the name of the Site, its useful life, the Ground Lease expiration date
(if  applicable) the Rent and Option Purchase Price Amount and denotes whether a
Site has been completed or is under  construction.  The parties acknowledge that
the information set forth in Annex A with respect to certain Sites is incomplete
and may be updated  from time to time to:  (i)  reflect  additional  information
which becomes  available,  (ii) reflect  completion of construction of a Site or
(iii) reflect the  substitution  of Sites in  accordance  with Section 4.8 (each
such Site, an "Incomplete  Site").  SBCW represents that the Outside  Expiration
Date with respect to each Site equals (or, as to Incomplete  Sites,  will equal)
not less than 75% or more  than 80% of the  remaining  useful  life of the Tower
included in such Site, as such useful life has been determined by an independent
appraiser  retained by SBCW (the  Parties  acknowledging  that SBCW is making no
representation  as to the  accuracy  of  any  such  appraisal).  Notwithstanding
anything  to the  contrary  contained  in this  Agreement,  the Rent and  Option
Purchase Price Amount for any Incomplete  Site shall be determined in accordance
with the methodology used to determine the Rent and Option Purchase Price Amount
in Annex A hereto.

SECTION 5.13.     TowerCo Parent's Guaranty.

(a) TowerCo Parent  unconditionally  guarantees to SBCW, the Sublessor Entities,
the   SBCW   Affiliates,   and   each   SBCW   Indemnitee   (collectively,   the
"beneficiaries",  individually a "beneficiary")  the full and timely performance
and  observance of all of the terms,  provisions,  covenants and  obligations of
TowerCo under this Agreement and other  Transaction  Documents and any Affiliate
of TowerCo under any Transaction  Documents (the "Obligations").  TowerCo Parent
agrees  that if  TowerCo  or  TowerCo's  Affiliate  defaults  at any time in the
performance of any of the Obligations,  TowerCo Parent shall faithfully  perform
and fulfill all  Obligations  and shall pay to the  applicable  beneficiary  all
reasonable  attorneys'  fees,  court  costs,  and  other  expenses,   costs  and
disbursements  incurred by the applicable  beneficiary on account of any default
by TowerCo or  TowerCo's  Affiliate  and on account of the  enforcement  of this
guaranty.

(b) This  guaranty  obligation  of TowerCo  Parent shall be  enforceable  by the
applicable beneficiary in an Action against TowerCo Parent without the necessity
of any Action by such  applicable  beneficiary of any kind or nature  whatsoever
against TowerCo or its Affiliate, without the necessity of any notice to TowerCo
Parent of TowerCo's or its Affiliate's default or breach under this Agreement or
any  Transaction  Documents,  and without the  necessity  of any other notice or
demand to TowerCo  Parent to which TowerCo  Parent might  otherwise be entitled,
all of which notices  TowerCo  Parent hereby  expressly  waive.  TowerCo  Parent
hereby agrees that the validity of this guaranty and the  obligations of TowerCo
Parent hereunder shall not be terminated,  affected,  diminished, or impaired by
reason of the assertion or the failure to assert by the  applicable  beneficiary
against  TowerCo or its Affiliate any of the rights or remedies  reserved to the
applicable  beneficiary  pursuant to the  provisions  of this  Agreement  or any
Transaction  Documents  or any  other  remedy  or  right  which  the  applicable
beneficiary may have at law or in equity or otherwise.

(c)  TowerCo  Parent  covenants  and agrees that this  guaranty is an  absolute,
unconditional,  irrevocable  and continuing  guaranty.  The liability of TowerCo
Parent hereunder shall not be affected, modified, or diminished by reason of any
modification  or  termination  of  this  Agreement  and  any  other  Transaction
Documents or any modification or waiver of or change in any of the covenants and
terms  of this  Agreement  or any  Transaction  Documents  by  agreement  of the
applicable beneficiary and TowerCo or its Affiliate, or by any unilateral action
of either the  applicable  beneficiary  or TowerCo  or its  Affiliate,  or by an
extension of time that may be granted by the  applicable  beneficiary to TowerCo
or its  Affiliate  or any  indulgence  of any kind  granted  to  TowerCo  or its
Affiliate,  or any dealings or  transactions  occurring  between the  applicable
beneficiary and TowerCo or its Affiliate,  including,  without  limitation,  any
adjustment,  compromise, settlement, accord and satisfaction, or release, or any
bankruptcy, insolvency, reorganization,  arrangement, assignment for the benefit
of creditors,  receivership,  or trusteeship affecting TowerCo or its Affiliate.
TowerCo Parent does hereby expressly waive any suretyship defense it may have by
virtue of any Law of any state or Government.

                                       24
<PAGE>

(d) All of the applicable  beneficiary's rights and remedies under this guaranty
are  intended to be distinct,  separate,  and  cumulative  and no such right and
remedy herein is intended to be the exclusion of or a waiver of any other.

(e) TowerCo Parent hereby waives presentment,  demand for performance, notice of
nonperformance,  protest,  notice of protest,  notice of dishonor, and notice of
acceptance. TowerCo Parent further waives any right to require that an action be
brought  against TowerCo or its Affiliate or any other person or to require that
resort  be  had by the  applicable  beneficiary  to  any  security  held  by the
applicable  beneficiary.  The  provisions of this Section 5.13 shall survive any
termination of this Agreement.

SECTION 5.14.     Registration Statement.

         Within 20 days after signing this  Agreement,  TowerCo Parent agrees to
file a registration  statement on Form S-3 (or other  appropriate form available
for  registering  Parent Stock for sale to the public) and to use all reasonable
efforts  to have such  registration  statement  declared  effective  before  the
expiration  of  thirty  (30)  days  after  the  Initial  Closing  Date.  If such
registration  statement  has not been  declared  effective  prior to the Initial
Closing Date, then promptly after the Initial Closing, but in no event more than
five (5) days after the Initial  Closing Date,  TowerCo Parent will add SBCW and
each  Affiliate  receiving  Stock  Consideration  under  Section  3.2(b) to such
registration  statement to register the resale by them of up to  $25,000,000  of
Parent Stock issued to them at the Initial  Closing  pursuant to Section 3.2(b).
If prior to the Initial Closing,  such registration  statement has been declared
effective,  then promptly after the Initial Closing,  but in no event later than
ten (10)  days  after the  Initial  Closing  Date,  TowerCo  Parent  will file a
registration  statement on Form S-3 (or other  appropriate  form  available  for
registering  Parent  Stock  for  sale  to  the  public)  or  amend  an  existing
registration  statement to register  the resale by SBCW and each SBCW  Affiliate
receiving  Stock  Consideration  under Section  3.2(b) of  $25,000,000 of Parent
Stock issued to them at the Initial Closing  pursuant to Section 3.2(b) and will
use  all  reasonable  efforts  to  have  such  registration  statement  declared
effective  before the  expiration of thirty (30) days after the Initial  Closing
Date.  Notwithstanding  the  foregoing,  TowerCo Parent may at any time elect to
satisfy the  obligation  under this  Section 5.14 by paying to SBCW and the SBCW
Affiliates  that would have  received  Parent  Stock  under  Section  3.2(b) $25
million in cash in lieu of issuing to SBCW and such SBCW  Affiliates $25 million
of Parent Stock at the Initial Closing.  The parties agree that any registration
statement  registering  SBCW and any SBCW  Affiliates  resale  of  Parent  Stock
pursuant to this Section 5.14 will be treated as a registration statement under,
and accordingly  will be subject to the provisions of, the  Registration  Rights
Agreement  which will govern  SBCW's and TowerCo  Parent's  obligations  to each
other in connection therewith.

                                       25
<PAGE>

SECTION 5.15.     Parent Stock.

(a)  There  shall be placed on all  certificates  representing  shares of Parent
Stock issued to SBCW and the SBCW Affiliates under Section 3.2 of this Agreement
appropriate   restrictive  legends  referencing  the  restrictions   imposed  by
applicable  Securities Law. TowerCo Parent shall cause such legend to be removed
upon request of SBCW or such SBCW Affiliates, as applicable,  pursuant to and as
provided in Rule 144 of the  Securities  Act of 1933, as amended.  SBCW and each
SBCW Affiliate  receiving Parent Stock under Section 3.2 represents and warrants
that it is an "accredited  investor" as defined in Rule 501(a) of the Securities
Act and is acquiring  the Parent Stock for its own account,  not as a nominee or
agent for any other person,  and not with a view to, or in connection  with, the
sale or  distribution  thereof in violation of the securities laws of the United
States of any state thereof..

(b)  SBCW  and the  SBCW  Affiliates  receiving  Stock  Consideration  agree  to
cooperate  with TowerCo  Parent in connection  with any  registration  of Parent
Stock  issued  to SBCW or such SBCW  Affiliate  including,  without  limitation,
furnishing to TowerCo Parent such  information  with respect to themselves,  the
Included Sites and the proposed distribution of Parent Stock by them as shall be
reasonably  necessary in order to prepare,  file and have  declared  effective a
registration   statement  in  compliance  with  federal  and  applicable   state
securities laws.

SECTION 5.16.     The Ameritech Paging Colocation Agreement.

         With  respect  to those  Included  Sites on  which  Ameritech  Wireless
Holdings,  Inc.  ("Ameritech")  operates a paging system,  TowerCo will use best
efforts  to cause  Ameritech  (together  with such  other  entity  that owns and
operates such paging  equipment,  "Paging  Tenant") to enter into a master lease
agreement  ("Master Lease") which will be effective as of the applicable Closing
Date for each Site on which such Paging  Tenant's  paging  equipment is located.
The Master  Lease will be on terms  customary  in the  industry,  including  the
following  terms:  (i) a five (5) year term;  (ii)  covering  the  antennas  and
related ground  equipment  (such ground  equipment  shall be located in the SBCW
shelter,  or on available  ground space located  outside the SBCW shelter not to
exceed 12 square  feet);  (ii)  terminable  by Paging Tenant on ninety (90) days
notice;  (iii) rental rate of $600 per month per antenna  with an annual  rental
increase of four percent (4%) per year;  (iv) TowerCo may, in its discretion and
at its cost,  relocate such paging equipment on the Tower so long as it does not
adversely  effect in any material respect such Paging Tenant's use of such Site;
(v) permitted use shall be to locate,  maintain and operate the Paging  Transmit
System  currently on the Tower  together with the related  equipment on the Site
consistent with the then-current use by the Paging Tenant.

                                   ARTICLE VI
                           REPRESENTATIONS, WARRANTIES
                       AND COVENANTS OF SUBLESSOR ENTITIES

         As an  inducement  to  TowerCo  Parent  and  TowerCo  to enter into and
perform each and all  Transaction  Documents,  SBCW (for itself and on behalf of
the  Sublessor  Entities),  severally  and not jointly,  hereby  represents  and
warrants to TowerCo Parent and TowerCo,  as to itself and its Sites,  as follows
(such representations and warranties being deemed made, in the case of Sublessor
Entities  whose  Sites are  included  in a Closing,  only as of the date of such
Closing):

                                       26
<PAGE>

SECTION 6.1.      Organization, Authority and Qualification.

         Each Sublessor  Entity is an entity duly organized,  validity  existing
and in  good  standing  under  the  laws of the  State  of its  formation.  Each
Sublessor Entity is duly authorized, licensed or qualified to do business in any
jurisdiction where the ownership, use or occupancy of the Sites would require it
to be  authorized,  licensed  or  qualified,  except  where  the  failure  to be
authorized, licensed or qualified would not have a Material Adverse Effect. Each
Sublessor Entity has the requisite  corporate power and authority to own, lease,
sublease,  use and  occupy  the  Sites  as they  are now  being  owned,  leased,
subleased, used and occupied by such Sublessor Entity. Each Sublessor Entity has
the right, power and authority to transfer the Subleased  Interests of its Sites
in accordance  with the terms,  provisions  and conditions of this Agreement and
other Transaction Documents.

SECTION 6.2.      Capacity; Inconsistent Obligations.

(a) Each Sublessor Entity has, or will have, prior to the first Closing in which
any of its Sites is included,  the corporate  power and authority to execute and
deliver  the  Transaction  Documents  to which it is a party and to perform  and
comply with the Transaction  Documents to which such Sublessor Entity is a party
in accordance with their respective  terms.  The Transaction  Documents to which
each  Sublessor  Entity is a party  have  been,  or will be,  prior to the first
Closing in which any of its Sites is  included,  duly and validly  executed  and
delivered by such Sublessor Entity and constitute, or will constitute,  prior to
the first  Closing in which any of its Sites is included,  the valid and legally
binding   obligations  of  such  Sublessor  Entity  subject  to  general  equity
principles, enforceable in accordance with their respective terms, except as the
same may be limited by bankruptcy,  insolvency,  reorganization  or similar laws
affecting the rights of creditors generally.

(b) Except as set forth in the  Disclosure  Schedule,  neither the execution and
delivery of the Transaction Documents to which such Sublessor Entity is a party,
nor the consummation of the transactions contemplated therein will (i) result in
a violation of such Sublessor  Entity's  articles of incorporation or bylaws, or
(ii) to such  Sublessor  Entity's  knowledge,  result in a breach of or  default
under any term or provision of any contract or agreement to which such Sublessor
Entity is a party, except where such breach or default would not have a Material
Adverse Effect.

SECTION 6.3.      Consents.

         Except for the  consents  specified  in the  Disclosure  Schedule  with
respect to each Closing and except for any consents of minority  equity  holders
of Sublessor Entities and consents of Ground Lessors, the execution and delivery
by each Sublessor  Entity of this Agreement and other  Transaction  Documents to
which such Sublessor  Entity is a party,  the  consummation of the  transactions
contemplated  herein and therein,  and the performance by such Sublessor  Entity
hereunder and thereunder does not require the consent, approval or action of, or
any filing (except any filing as may be required under the Hart-Scott-Rodino Act
(the "HSR Act")) with or notice to, any Government or other Person.

                                       27
<PAGE>

SECTION 6.4.      No Violation; Compliance with Laws.

         Except as set forth in the Disclosure Schedule,  no Sublessor Entity is
in default under or in violation of (a) its articles of incorporation or bylaws,
(b) to such  Sublessor  Entity's  knowledge,  any Order to which such  Sublessor
Entity is subject,  or (c) any Existing  Leases,  except where such  defaults or
violations would not have a Material  Adverse Effect.  Each Sublessor Entity has
complied with all applicable Laws,  except where the failure to have so complied
would not have a Material Adverse Effect.

SECTION 6.5.      Litigation; Contingencies.

         Except as set forth in the  Disclosure  Schedule,  there are no Actions
pending or to the best of each Sublessor Entity's knowledge, threatened against,
by or affecting such Sublessor Entity which would have a Material Adverse Effect
or which question the validity or enforceability of this Agreement. There are no
unsatisfied  judgments  or  Orders  against  any  Sublessor  Entity to which the
Subleased Interests are subject that would have a Material Adverse Effect.

SECTION 6.6.      Leased and Owned Sites.

         Except as set forth in the Disclosure Schedule:

(a) (i) Such Sublessor  Entity holds a valid leasehold  interest or a Qualifying
Interest in each of its Leased Sites (as defined in the SBCW Sublease)  pursuant
to a Ground Lease,  and (ii) to the best knowledge of the  applicable  Sublessor
Entity,  (x) each of the Ground Leases is in full force and effect,  (y) neither
the  Sublessor  Entity nor the Ground  Lessor is in breach of the Ground  Lease,
except for breaches that would not have a Material Adverse Effect,  and (z) such
Sublessor  Entity has made  available  to TowerCo  Parent  copies of each of the
Ground  Leases,  which  copies are true,  correct and  complete in all  material
respects.

(b) To the knowledge of the applicable  Sublessor Entity,  such Sublessor Entity
holds valid fee simple  title to each of the Owned Sites (as defined in the SBCW
Sublease), free and clear of all Liens other than Permitted Liens.

SECTION 6.7.      Real Property.

         To the  knowledge  of  the  Applicable  Sublessor  Entity,  as to  each
Existing Site, except as set forth in the Disclosure Schedule:

(a) Such Sublessor Entity's ownership,  lease or use of the Land included in the
Subleased  Interests  respecting  such Existing  Site is in compliance  with all
applicable zoning and other land use requirements where the failure to so comply
would materially limit such Sublessor  Entity's ability to use such Land for the
Permitted Use of such Land.

(b) The utility services currently  available to such Existing Site are adequate
for the present use of such Existing Site by such  Sublessor  Entity,  are being
supplied to such Sublessor Entity by utility  companies or pursuant to valid and
enforceable  contracts or tariffs,  and there is no condition which, to the best
of such  Sublessor  Entity's  knowledge,  will result in the  termination of the
present access from such Existing Site to such utility services.

                                       28
<PAGE>

(c) Such Sublessor Entity has obtained all easements and rights-of-way  that are
reasonably  necessary to provide vehicular and pedestrian  ingress and egress to
and from each of the  Existing  Sites for the  purposes  used by such  Sublessor
Entity in the ordinary  course.  No Action is pending or threatened  which would
have the effect of terminating or limiting such access.

(d) No breach or event of default by such  Sublessor  Entity has occurred and is
continuing  under any Existing  Lease,  as  applicable,  respecting  one or more
Sites,  except  where such breach or event of default  would not have a Material
Adverse Effect.

SECTION 6.8.      Eminent Domain.

         Except as set forth in the Disclosure Schedule, no Sublessor Entity has
received  any  written  notice that any  Government  having the power of eminent
domain over any of the Land included in the Subleased Interests has commenced or
intends to exercise the power of eminent  domain or a similar power with respect
to all or any part of such Land.

SECTION 6.9.      Taxes.

         To the  knowledge of the  Applicable  Sublessor  Entity,  except as set
forth in the Disclosure Schedule,  (i) such Sublessor Entity has duly and timely
filed  all  federal,   state,  municipal  and  local  Tax  returns  and  reports
(collectively,  "Returns")  with  respect  to all Taxes  owing in respect of its
Existing Sites,  (ii) all Taxes imposed on a Sublessor  Entity in respect of its
Existing  Sites by any  Government  which have  become  due and  payable by such
Sublessor  Entity for all periods  through the date of this  Agreement have been
paid in full,  (iii) there are no proposed  assessments  against such  Sublessor
Entity of additional  Taxes in respect of its Existing Sites,  and (iv) there is
no dispute or Action  concerning  any Tax  Liability  of such  Sublessor  Entity
raised by a Government in writing.

SECTION 6.10.     Governmental Permits.

         To the best knowledge of the Applicable Sublessor Entity, except as set
forth in the Disclosure  Schedule:  (i) such  Sublessor  Entity has obtained all
Governmental  Permits that are required for the  ownership,  use or occupancy of
its Existing  Sites or the Subleased  Interests,  all of which are in full force
and effect,  except where the failure to obtain any such Governmental  Permit or
of any such Governmental  Permit to be in full force and effect would not have a
material  adverse  effect on such  Sublessor  Entity or its  business  or on the
Permitted  Use;  and (ii)  each  Sublessor  Entity  has  complied  with all such
Governmental  Permits,  except  where the  failure  to  comply  would not have a
material adverse effect on such Sublessor Entity or on the Permitted Use.

                                       29
<PAGE>

SECTION 6.11.     Environmental Matters.

         Except  as set  forth in the  Disclosure  Schedule,  to each  Sublessor
Entity's  knowledge,  no  Environmental  Condition  exists  and  no  pending  or
threatened Action in respect of any Environmental Condition exists at any of its
Existing  Sites which  would have a material  adverse  effect on such  Sublessor
Entity's  use of  such  Existing  Site  consistent  with  past  practices  or on
TowerCo's Permitted Use of such Existing Site consistent with the SBCW Sublease.

SECTION 6.12.     Existing Leases; Colocation Agreements; Master License
Agreements; Other Agreements.

         To the  knowledge  of each  Sublessor  Entity,  except for the Existing
Leases and Colocation Agreements set forth in the Disclosure Schedule, there are
no leases or other  agreements  for use,  occupancy or  possession  presently in
force with respect to all or any portion of the Sites. Each Sublessor Entity has
made available to TowerCo copies of the Existing Leases,  Colocation  Agreements
and other agreements  identified in the Disclosure Schedule. To the knowledge of
each  Sublessor  Entity,  such  copies  are true and  complete  in all  material
respects  and include all material  amendments,  supplements  and  modifications
thereto or material waivers currently in effect thereunder.

SECTION 6.13.     No Undisclosed Liabilities.

         To the  knowledge of the  Applicable  Sublessor  Entity,  except as set
forth  in the  Disclosure  Schedule,  no  liabilities  or  obligations  (whether
pursuant to contracts or otherwise)  of any kind  whatsoever  (whether  accrued,
contingent, absolute, determined,  determinable or otherwise) have been incurred
by any Sublessor  Entity with respect to the Subleased  Interests and which have
had or could  reasonably be expected to have a Material Adverse Effect after the
consummation of the transactions  contemplated hereby, other than liabilities or
obligations disclosed or provided for in the Transaction Documents.

SECTION 6.14.     Authorization.

         SBCW has the requisite power and authority, on its own behalf and prior
to the first Closing in which a Sublessor Entity's Sites are included, will have
the requisite power and authority, on behalf of each and every Sublessor Entity,
to execute this Agreement and the Transaction  Documents to which any of them is
a party and to consummate the  transactions  performed or to be performed by any
or all of them hereunder and thereunder  subject to the receipt of all necessary
third party consents. Such execution, delivery and performance by SBCW have been
or will be duly authorized by all necessary action.  This Agreement  constitutes
and the  Transaction  Documents  (when entered into) will  constitute  valid and
binding  obligations of the Sublessor  Entities,  enforceable in accordance with
their respective terms.

SECTION 6.15.     No Other Warranties.

         Except for the representations,  warranties and covenants expressly set
forth in this Article VI and the SBCW  Sublease,  and subject to Section 3(a) of
the  Sublease,  the  Subleased  Interests  are being  transferred  by  Sublessor
Entities AS IS, WHERE IS, and with all faults, and there are no other warranties
being made by any of the Sublessor Entities INCLUDING,  WITHOUT LIMITATION,  ANY
WARRANTY OF HABITABILITY,  MERCHANTABILITY OR FITNESS FOR A PARTICULAR  PURPOSE,
EXPRESS OR IMPLIED,  IN CONNECTION WITH THE TRANSFER OF THE SUBLEASED  INTERESTS
OR THE OTHER  TRANSACTIONS  CONTEMPLATED BY THE TRANSACTION  DOCUMENTS.  Each of
TowerCo Parent and TowerCo  acknowledges  and agrees that: (i) no examination or
investigation of the Subleased Interests by or on behalf of TowerCo prior to any
Closing  shall in any way  modify,  affect  or  increase  a  Sublessor  Entity's
obligations under the representations,  warranties, covenants and agreements set
forth in this  Article  VI; and (ii) any  representation  or  warranty as to the
adequacy  of any Site or the Tower or  Improvements  thereon  is  limited to the
adequacy to the applicable  Sublessor Entity and not to TowerCo,  TowerCo Parent
or any other Person.

                                       30
<PAGE>

                                  ARTICLE VII
                           REPRESENTATIONS, WARRANTIES
                              AND COVENANTS OF SBCW

         As an  inducement  to  TowerCo  Parent  and  TowerCo  to enter into and
perform each and all  Transaction  Documents,  SBCW (for itself and on behalf of
the Sublessor  Entities),  hereby  represents and warrants to TowerCo Parent and
TowerCo, as follows (such representations and warranties being deemed made as of
the date hereof):

SECTION 7.1.      Organization, Authority and Qualification.

         SBCW is a corporation,  duly  organized,  validly  existing and in good
standing  under  the laws of the  State of  Delaware.  SBCW is duly  authorized,
licensed or qualified to do business in any jurisdiction  where the occupancy of
the Sites would require it to be authorized, licensed or qualified, except where
the failure to be  authorized,  licensed or qualified  would not have a Material
Adverse  Effect.  SBCW  has the  requisite  corporate  power  and  authority  to
sublease, use and occupy the Sites as contemplated hereby.

SECTION 7.2.      Capacity, Inconsistent Obligations.

(a) SBCW has, or will have,  the  corporate  power and  authority to execute and
deliver  the  Transaction  Documents  to which it is a party and to perform  and
comply with the Transaction  Documents to which it is a party in accordance with
their  respective  terms,  subject to the receipt of all  necessary  third party
consents.  The Transaction Documents to which SBCW is a party have been, or will
be, duly and validly  executed  and  delivered by SBCW and  constitute,  or will
constitute, the valid and legally binding obligations of SBCW subject to general
equity principles, enforceable in accordance with their respective terms, except
as the same may be limited by bankruptcy, insolvency,  reorganization or similar
laws affecting the rights of creditors generally.

(b) Neither the  execution  and delivery of the  Transaction  Documents to which
SBCW is a party, nor the consummation of the transactions  contemplated  therein
will (i) result in a violation of SBCW's articles of incorporation or bylaws, or
(ii) to SBCW's  knowledge,  result in a breach of or  default  under any term or
provision of any  contract or  agreement to which SBCW is a party,  except where
such breach or default would not have a Material Adverse Effect.

                                       31
<PAGE>

SECTION 7.3.      Authorization.

         SBCW has the requisite power and authority, on behalf of each and every
Sublessor  Entity  Operating,  to execute  this  Agreement  and the  Transaction
Documents  to which any of them is a party and to  consummate  the  transactions
performed  or to be  performed by any or all of them  hereunder  and  thereunder
subject to the receipt of all necessary  third party  consents.  Such execution,
delivery and  performance  by SBCW have been or will be duly  authorized  by all
necessary  action.  This Agreement and the  Transaction  Documents (when entered
into) will constitute valid and binding  obligations of the Sublessor  Entities,
enforceable in accordance with their respective terms.

SECTION 7.4.      No Other Warranties.

         Except for the representations,  warranties and covenants expressly set
forth in this  Article  VII and in the SBCW  Sublease,  SBCW has not made nor is
making any representations or warranties to Tower Parent or TowerCo,  express or
implied, in connection with transactions contemplated by this Agreement.

                                  ARTICLE VIII
                           REPRESENTATIONS, WARRANTIES
                            AND COVENANTS OF TOWERCO

         As an inducement to SBCW and the other Sublessor Entities to enter into
and perform each and all Transaction  Documents,  TowerCo hereby  represents and
warrants to SBCW and each of the Sublessor Entities as follows:

SECTION 8.1.      Organization, Authority and Qualification.

         TowerCo is a corporation  duly organized and validly existing under the
laws of the State of  Delaware.  TowerCo has its  principal  office and place of
business at 100 Regency  Forest Drive,  Suite 400, Cary,  North Carolina  27511.
TowerCo has or will have at the time of the  applicable  Closing full  corporate
power and authority to carry on its business as it has been, now being conducted
and to own or lease its  properties and to carry on its businesses as and in all
places where such  business is currently  conducted and such  properties  are or
will be owned or  leased.  TowerCo  is or will be at the time of the  applicable
Closing  duly  authorized,  licensed  or  qualified  to do  business  in all the
jurisdictions  where such business and the ownership,  use and occupancy of such
properties  would require it to be  authorized,  licensed or  qualified,  except
where the failure to be so authorized, licensed or qualified would not result in
a material adverse effect on TowerCo or on the transactions contemplated by this
Agreement.

SECTION 8.2.      Ownership of Shares; Subsidiaries.

         A wholly-owned subsidiary of TowerCo Parent is the sole owner of all of
the  issued and  outstanding  shares of  TowerCo,  free and clear of any and all
pledges, security interests,  options or rights of others except for pledges and
security  arrangements  made for the benefit of its  creditors  under the Credit
Agreement (as defined in the SBCW Sublease).

                                       32
<PAGE>

SECTION 8.3.      Capacity; Inconsistent Obligations.

(a) TowerCo has the  corporate  power and  authority  to execute and deliver the
Transaction  Documents to which it is a party and to perform and comply with the
Transaction Documents to which it is a party in accordance with their respective
terms. The Transaction  Documents to which TowerCo is a party have been duly and
validly  executed and delivered by TowerCo and  constitute the valid and legally
binding obligations of TowerCo subject to general equity principles, enforceable
in accordance with their respective terms,  except as the same may be limited by
bankruptcy,  insolvency,  reorganization or similar laws affecting the rights of
creditors generally.

(b) Neither the  execution  and delivery of the  Transaction  Documents to which
TowerCo  is a  party,  nor the  consummation  of the  transactions  contemplated
therein will (i) result in a violation of TowerCo's certificate of incorporation
or bylaws, (ii) to TowerCo's knowledge,  result in a breach of or default (or an
event of  default  which  with  notice or lapse of time or both  would  become a
default)  under any term or  provision  of any  contract or  agreement  to which
TowerCo  is a party  or give to  others  any  right of  termination,  amendment,
acceleration  or  cancellation  of, or result in triggering any payment or other
obligations under any contract or agreement to which TowerCo is a party,  except
where  such  breach or  default  or other  occurrence  would not have a material
adverse effect on TowerCo,  or (iii) result in the creation or imposition of any
Liens upon its properties and assets, other than Permitted Liens.

SECTION 8.4.      Consents.

         Except for  compliance  with (a) the  consents  which will be  obtained
prior to the Initial  Closing,  and (b) the  consents  specified  in the Closing
Schedule with respect to each Closing,  the execution and delivery by TowerCo of
this  Agreement  and other  Transaction  Documents  to which it is a party,  the
consummation  of the  transactions  contemplated  herein  and  therein,  and the
performance by TowerCo  hereunder and  thereunder  does not require the consent,
approval or action of, or any filing (except any filing as may be required under
the HSR Act) with or notice to, any Government or other Person.

                                       33
<PAGE>

SECTION 8.5.      No Violation; Compliance with Laws.

         TowerCo is not in default under or in violation of (a) its  certificate
of  incorporation  or bylaws,  (b) to  TowerCo's  knowledge,  any Order to which
TowerCo is subject,  (c) any  material  contract to which it is a party,  except
where such defaults or violations  would not have a material  adverse  effect on
TowerCo or its business.  TowerCo has complied with all applicable Laws,  except
where the failure to have so complied  would not have a material  adverse effect
on TowerCo or its business.

SECTION 8.6.      TowerCo Matters.

         TowerCo is a  wholly-owned,  indirect  subsidiary  of  TowerCo  Parent.
TowerCo was formed for the purpose of engaging in the transactions  contemplated
hereby  and has not prior to the  Effective  Date (i)  engaged  in any  business
activities,  (ii)  conducted any  operations  other than in connection  with the
transactions  contemplated  hereby or (iii) incurred any liabilities  other than
liabilities  incidental to its formation,  corporate existence and qualification
to do business and liabilities in connection with the transactions  contemplated
hereby.

SECTION 8.7.      Litigation; Contingencies.

         There are no Actions  pending or, to the best of  TowerCo's  knowledge,
threatened  against,  by or  affecting  TowerCo  properties  and assets  that if
adversely  determined  could  reasonably  be  expected  to result in a  material
adverse  effect on TowerCo or its business or  operations  or that  question the
validity or enforceability of this Agreement.

SECTION 8.8.      Sufficient Funding.

         TowerCo has furnished to SBCW copies of  commitments  to provide equity
capital or debt financing to TowerCo.  The amounts that TowerCo may obtain under
such commitments will be sufficient to provide all funds necessary to consummate
the  transactions  contemplated  by this  Agreement  and the  other  Transaction
Documents  to which it is a party and to pay the  related  fees and  expenses of
TowerCo. TowerCo will continue to have sufficient funds available throughout the
term of this Agreement.

SECTION 8.9.      No Broker.

         No broker,  finder or  similar  agent has acted on behalf of TowerCo in
connection with this Agreement or the transactions contemplated herein.

SECTION 8.10.     No Other Warranties.

         Except for the representations,  warranties and covenants expressly set
forth  in  this  Article   VIII,   TowerCo  has  not  made  nor  is  making  any
representations  or  warranties to SBCW or the  Sublessor  Entities,  express or
implied, in connection with the transactions contemplated by this Agreement.

                                       34
<PAGE>

                                   ARTICLE IX
           REPRESENTATIONS, WARRANTIES AND COVENANTS OF TowerCo Parent

         As an inducement  to SBCW and the Sublessor  Entities to enter into and
perform each and all Transaction Documents, TowerCo Parent hereby represents and
warrants to SBCW and each of the Sublessor Entities as follows:

SECTION 9.1.      Organization, Authority and Qualification.

         TowerCo  Parent is a corporation  duly  organized and validly  existing
under  the laws of the State of  Delaware.  TowerCo  Parent is duly  authorized,
licensed  or  qualified  to do  business  in all the  jurisdictions  where  such
authorization, license or qualification is necessary, except where failure to be
so authorized, licensed or qualified would not have a material adverse effect on
TowerCo Parent and its subsidiaries taken as a whole. The Parent Stock delivered
and payable by TowerCo Parent as part of the Consideration, when issued, will be
duly  authorized,  validly issued,  fully paid and  non-assessable  and free and
clear of encumbrances.

SECTION 9.2.      Capacity; Inconsistent Obligations.

(a) TowerCo Parent has the corporate  power and authority to execute and deliver
the Transaction  Documents to which it is a party and to perform and comply with
the  Transaction  Documents  to  which it is a party in  accordance  with  their
respective  terms. The Transaction  Documents to which TowerCo Parent is a party
have  been duly and  validly  executed  and  delivered  by  TowerCo  Parent  and
constitute the valid and legally  binding  obligations of TowerCo Parent subject
to general equity  principles,  enforceable in accordance with their  respective
terms,   except  as  the  same  may  be  limited  by   bankruptcy,   insolvency,
reorganization or similar laws affecting the rights of creditors generally.

(b) Neither the  execution  and delivery of the  Transaction  Documents to which
TowerCo Parent is a party, nor the consummation of the transactions contemplated
therein  including,  but not limited to the issuance of the Parent Stock and its
delivery and payment as the Stock Consideration,  will (i) result in a violation
of TowerCo  Parent's  certificate of  incorporation or bylaws or (ii) to TowerCo
Parent's  knowledge and except as set forth on Schedule 9.3,  result in a breach
of or default (or an event of default which with notice or lapse of time or both
would become a default) under any term or provision of any contract or agreement
to which TowerCo Parent is a party or by which it or any of its  subsidiaries is
bound or  affected,  or give to  others  any  right of  termination,  amendment,
acceleration  or  cancellation  of, or result in triggering any payment or other
obligations  under any contract or agreement to which TowerCo is a party,  or by
which it or any its subsidiaries is bound of affected,  except where such breach
or default or other occurrence with respect to a contract or agreement would not
have a material adverse effect on TowerCo Parent and its subsidiaries taken as a
whole.

SECTION 9.3.      Consents.

         Except for compliance with the consents which will be obtained prior to
the  Initial  Closing,  the  execution  and  delivery  by TowerCo  Parent of the
Transaction   Document  to  which  it  is  a  party,  the  consummation  of  the
transactions  contemplated  therein,  and  the  performance  by  TowerCo  Parent
thereunder  does not require the  consent,  approval or action of, or any filing
with (except any filing as may be required  under the HSR Act) or notice to, any
Government or other Person.  Without  limiting the  generality of the foregoing,
TowerCo  Parent  represents  and warrants that no such consent is required under
any TowerCo  Parent  Indenture,  and agrees that it will not amend or modify any
TowerCo Parent Indenture in any manner that would cause this  representation and
warranty to no longer by true and correct.

                                       35
<PAGE>

SECTION 9.4.      No Violation, Compliance with Laws.

         TowerCo  Parent  is not in  default  under or in  violation  of (a) its
certificate of incorporation or bylaws,  (b) to TowerCo Parent's best knowledge,
any Order to which TowerCo  Parent is subject,  or (c) any material  contract to
which  it is a party  or by  which  it or any of its  subsidiaries  is  bound or
affected,  except  where such  contract  default or  violation  would not have a
material adverse effect on TowerCo Parent and its subsidiaries  taken as a whole
or their  business  taken as a  whole.  TowerCo  Parent  has  complied  with all
applicable  Laws,  except where the failure to have so complied would not have a
material adverse effect on TowerCo Parent and its subsidiaries, taken as a whole
or their business taken as a whole.

SECTION 9.5.      Litigation; Contingencies.

         There  are no  Actions  pending  or to the best  knowledge  of  TowerCo
Parent,  threatened  against,  by or affecting  TowerCo Parent that question the
validity or enforceability of this Agreement or any other Transaction  Document.
As of the date hereof,  there are no Actions pending or to the best knowledge of
TowerCo Parent,  threatened  against,  by or affecting TowerCo Parent that could
reasonably be expected to have a material  adverse  effect on TowerCo Parent and
its  subsidiaries  taken as a whole or on their  business  taken as a whole  and
there are no judgments,  orders,  injunctions,  decrees  stipulations  or awards
(whether rendered by a court, administrative agency, or by arbitration, pursuant
to a grievance or other procedure)  against or relating to TowerCo Parent or its
subsidiaries that could reasonably be expected to have a material adverse effect
on TowerCo  Parent and its  subsidiaries  taken as a whole or on their  business
taken as a whole.

SECTION 9.6.      No Other Warranties.

         Except for the representations,  warranties and covenants expressly set
forth  in this  Article  IX,  TowerCo  Parent  has not made  nor is  making  any
representations  or  warranties  to SBCW or the  Sublessor  Entities  express or
implied, in connection with the transactions contemplated by this Agreement.

SECTION 9.7.      SEC Reports.

(a) TowerCo Parent has filed all material forms, reports and documents, together
with any required  amendments  thereto,  required to be filed by it with the SEC
since December 31, 1999 (collectively,  the "SEC Documents"). TowerCo Parent has
delivered or made available to SBCW true, correct and complete copies of each of
the SEC Documents (other than preliminary  registration and proxy statements and
registration  statements on Forms S8). The SEC Documents (i) were  prepared,  in
all material respects, in accordance with the requirements of the Securities Act
of 1933 or the  Securities  Exchange  Act of 1934,  as the case may be,  and the
rules and regulations promulgated thereunder,  and (ii) did not at the time they
were filed  contain any untrue  statement of a material  fact or omit to state a
material  fact  required to be stated  therein or necessary in order to make the
statements made therein, in the light of the circumstances under which they were
made, not misleading.  No Affiliate  controlled by TowerCo Parent is required to
file any form, report or other document with the SEC.

                                       36
<PAGE>

         Each of the consolidated financial statements (including, in each case,
any notes  thereto)  contained in the SEC  Documents  (i) was prepared  from the
books  of  account  and  other  financial  records  of  TowerCo  Parent  and its
consolidated  subsidiaries,  (ii)  complies as to form in all material  respects
with applicable accounting  requirements and the published rules of the SEC with
respect  thereto,  and  was  prepared  in  accordance  with  generally  accepted
accounting  principals  applied on a  consistent  basis  throughout  the periods
indicated  (except as may be indicated  in the notes  thereto or, in the case of
unaudited  statements,  as permitted by Form 10Q of the SEC) and (iii) presented
fairly, in all material respects, the consolidated financial position of TowerCo
Parent and its consolidated  subsidiaries as at the respective dates thereof and
the results of their operations and their cash flows for the respective  periods
indicated  therein except as otherwise  noted therein  (subject,  in the case of
unaudited  statements,  to normal and recurring year-end  adjustments which were
not and are not expected,  individually or in the aggregate,  to have a material
adverse  effect on the  assets,  liabilities,  financial  condition,  results of
operation or business of TowerCo Parent).

SECTION 9.8.      Absence of Certain Changes or Events.

         Except as contemplated  by this Agreement,  since June 30, 2000 TowerCo
and its  Subsidiaries  have conducted  their  respective  businesses in a manner
substantially  consistent with prior practice and there has not occurred (i) any
event or  condition  that  has had or would  reasonably  be  expected  to have a
material adverse effect on TowerCo Parent and its subsidiaries  taken as a whole
or their  business  taken as a whole,  (ii) any  declaration,  setting  aside or
payment of any  dividend or any other  distribution  with  respect to any of the
capital stock of TowerCo and its  Subsidiaries  or (iii) any material  change in
accounting  methods,  principles  or  practices  employed  by  TowerCo  and  its
Subsidiaries.  The  representations  made  in this  Section  9.8  shall  only be
effective as of the date hereof.

                                   ARTICLE X
                               CONDUCT OF BUSINESS
                               PENDING OF CLOSINGS

SECTION 10.1.     Conduct of Business by SBCW and the Sublessor Entities.

         Each Sublessor  Entity  severally and not jointly  covenants and agrees
that pending each Closing,  except as otherwise agreed to in writing by TowerCo,
and except in connection with the performance of the  transactions  contemplated
hereby, as to its Existing Sites only:

(a) From and after the date hereof such Sublessor Entity shall operate, maintain
and service the Sites in the ordinary  course of business  consistent  with past
practices and in compliance in all material  respects with all applicable  Laws,
including without limitation entering into any leases,  licenses or subleases of
its Sites in the ordinary  course of business for cash  consideration  at market
rates,  provided  that such  leases,  licenses  or  subleases  shall  constitute
Existing Leases. The parties specifically agree that, under the foregoing,  SBCW
may add and subtract  antennas from the Site in the ordinary course of business,
and any net  additions  of  antennas  made  prior to the date  hereof  shall not
constitute a breach of the  foregoing so long as made in the ordinary  course of
business consistent with past practices.

                                       37
<PAGE>

(b) Each  Sublessor  Entity  shall use its  commercially  reasonable  efforts to
conduct  its   business  in  such  a  manner  that  on  each  Closing  Date  the
representations  and  warranties  of such  Sublessor  Entity  contained  in this
Agreement  and  applicable  to  such  Closing  shall  be  true  as  though  such
representations  and warranties were made on and as of such date. Each Sublessor
Entity  shall   cooperate   with  TowerCo  Parent  and  TowerCo  and  use  their
commercially   reasonable  efforts  to  cause  all  of  the  conditions  to  the
obligations  of the parties under this  Agreement to be satisfied on or prior to
each Closing Date.

(c) With  respect to any net  additions  of  antennas  on each  Tower  after the
Effective Date and included in a Closing, Sections 5(b) and 5(c) of the Sublease
shall be applicable.

SECTION 10.2.     Conduct of Business by TowerCo Parent and TowerCo.

         TowerCo  covenants  and agrees that  pending  each  Closing,  except as
otherwise  agreed to in  writing  by SBCW,  and  except in  connection  with the
performance of the transactions contemplated hereby:

(a) Each of TowerCo  Parent and  TowerCo  shall  promptly  disclose  to SBCW any
material information contained in their representations and warranties or any of
the Schedules hereto which, because of an event occurring after the date hereof,
is  incomplete  or is no longer  correct as of all times  after the date  hereof
until the Closing Date with respect to which such representations and warranties
are made;  provided,  however,  that none of such disclosures shall be deemed to
modify, amend or supplement the representations and warranties of TowerCo Parent
and TowerCo or the  Schedules  hereto for the purposes of Articles VII and VIII,
unless SBCW shall have consented thereto in writing.

(b) Each of TowerCo  Parent and TowerCo  shall use its  commercially  reasonable
efforts to conduct its  business in such a manner that on each  Closing Date the
representations  and warranties of TowerCo Parent and TowerCo  contained in this
Agreement  and  applicable  to  such  Closing  shall  be  true  as  though  such
representations and warranties were made on and as of such date. Each of TowerCo
Parent and TowerCo shall  cooperate with SBCW and SBCW and use its  commercially
reasonable  efforts to cause all of the  conditions  to the  obligations  of the
parties under this Agreement to be satisfied on or prior to each Closing Date.

(c) Each of  TowerCo  Parent  and  TowerCo  shall  provide  to SBCW's and SBCW's
officers,  employees,  counsel,  accountants and other  representatives free and
full access to and the right to inspect,  during normal business  hours,  all of
the records,  contracts and other documents  relating to its business,  provided
that  such  inspection  shall  not  unreasonably  interfere  with  the  business
operations of TowerCo Parent and TowerCo.

                                       38
<PAGE>

                                   ARTICLE XI
          CONDITIONS TO OBLIGATIONS OF SBCW AND THE SUBLESSOR ENTITIES

         All obligations of SBCW and the Sublessor Entities hereunder in respect
of any Existing Site included in any Closing are subject to the  fulfillment and
satisfaction,  prior  to or at  such  Closing,  of  each  and  every  one of the
following  conditions,  to the extent such  condition  relates to such  Existing
Site,  any or all of which may be  waived in whole or in part by SBCW,  provided
that no such  waiver  will be  effective  unless  it is set  forth in a  writing
executed by SBCW as of such Closing Date:

SECTION 11.1.     Representations and Warranties.

         The  representations  and  warranties  of TowerCo  Parent  and  TowerCo
contained in this  Agreement  (other than those provided in Sections 8.7 and 9.5
hereof) or in any schedule,  certificate or document delivered by TowerCo Parent
and TowerCo to SBCW  pursuant to the  provision  hereof shall have been true and
correct in all  material  respects  on and as of the date when made and shall be
deemed to be made again at and as of the date of each  Closing and shall be true
and  correct  in all  material  respects  at and as of such date (in the case of
representations  and warranties  which are made only as of a specific date, such
representations  and  warranties  need only be true and correct in all  material
respects at and as of such date).

SECTION 11.2.     Compliance with Agreements and Conditions.

         Each of TowerCo Parent and TowerCo shall have performed and complied in
all material respects with all covenants,  agreements and conditions required by
this  Agreement to be performed or complied  with by each of them prior to or on
the date of each Closing,  and no unwaived  event of default shall have occurred
and be  continuing  under Section 30(d) of the Sublease that would give SBCW the
right to terminate the Sublease as to all Sites.

SECTION 11.3.     Closing Certificates.

         Each of the  Sublessor  Entities and SBCW shall have received from each
of TowerCo Parent and TowerCo  certificates  dated the date of each Closing,  in
each case  certifying  in such detail as SBCW may  reasonably  request as to the
fulfillment and  satisfaction  of the conditions  specified in Sections 11.1 and
11.2 and, in the case of the  certificate  for the  Initial  Closing  only,  the
absence of any material  adverse  change in the  businesses or assets of TowerCo
Parent or TowerCo since June 30, 2000.

SECTION 11.4.     Consents and Approvals.

(a) Each of the Sublessor Entities and SBCW shall have obtained  authorizations,
consents and approvals from any Person whose authorization,  consent or approval
is required or necessary to consummate  the  transactions  contemplated  herein,
including,  without limitation,  (i) if applicable, the consents and approval of
any environmental agency having jurisdiction over the transactions  contemplated
hereby  and  applicable  to such  Closing  shall  have been  obtained,  (ii) the
consents  specified  in the  Disclosure  Schedule  pursuant  to Section  6.3 and
applicable to such Closing shall have been obtained or waived and (iii) consents
of minority equity holders of Sublessor Entities and consents of Ground Lessors,
in each case applicable to such Closing;

                                       39
<PAGE>

(b) all Governmental Permits applicable to such Closing shall have been obtained
or waived, and

(c) the  waiting  period  required  under  the  HSR  Act  for  the  transactions
contemplated hereby shall have expired or been terminated.

SECTION 11.5.     No Litigation.

         No Action shall have been  instituted,  be  threatened in writing or be
pending,  in each case by any  Government or judicial  body (a) against  TowerCo
Parent or TowerCo to restrain or prohibit the  consummation of the  transactions
contemplated in this Agreement,  and (b) by any Government or Person which could
reasonably  be  expected  to have a  material  adverse  effect on the  business,
assets,  properties,  Liabilities,  affairs,  results of operations,  conditions
(financial  or  otherwise),  or cash flow of TowerCo  or TowerCo  Parent and its
subsidiaries taken as a whole.

SECTION 11.6.     Fundamental Transactions.

         Neither  TowerCo nor TowerCo  Parent shall have (a) been a party to any
merger, consolidation or business combination in which TowerCo or TowerCo Parent
was not the surviving corporation,  (b) been liquidated,  wound-up or dissolved,
or  (c)  sold,  transferred  or  disposed  of all  or  substantially  all of its
properties and assets.

SECTION 11.7.     Build-to-Suit Agreement.

         On or prior to the Initial  Closing  Date,  TowerCo  Parent and TowerCo
shall have executed and delivered to SBCW, the Build-to-Suit  Agreement, and the
same shall have become effective as of the Initial Closing Date.

SECTION 11.8.     Sublease.

         On or prior to the Initial  Closing  Date,  TowerCo  Parent and TowerCo
shall have  executed and delivered to SBCW the Subleases and the same shall have
become effective as of the Initial Closing Date.

SECTION 11.9.     Opinion.

         On or prior to the Initial  Closing  Date,  SBCW shall have received an
opinion addressed solely to SBCW in form and substance  reasonably  satisfactory
to SBCW from King & Spalding  acting as special tax  counsel.  Absent a material
change in law or fact,  SBCW has no reason to believe  that it will not  receive
the tax opinion from King & Spalding referenced in this Section 11.9.

                                       40
<PAGE>

SECTION 11.10.    Registration Rights Agreement.

         On or prior to the Initial  Closing  Date,  TowerCo  Parent  shall have
executed,  obtained the necessary  consents for, and delivered to SBCW a Joinder
Agreement  substantially  in the form  provided in Exhibit B, and the same shall
have become effective as of the Initial Closing Date.

SECTION 11.11.    Stockholders' Agreement.

         On or prior to the Initial  Closing  Date,  TowerCo  Parent  shall have
executed and delivered and caused the necessary  stockholders  of TowerCo Parent
to execute  and  deliver to SBCW an  amendment  to the  Stockholders'  Agreement
substantially  in the form provided in Exhibit C, and the same shall have become
effective as of the Initial Closing Date.

SECTION 11.12.    Registration Statement.

         At  the  Initial   Closing,   TowerCo  Parent  meets  the   eligibility
requirements  for a  registration  statement  on Form  S-3;  provided  that this
condition shall be deemed  satisfied if TowerCo Parent elects to pay to SBCW and
the  applicable  SBCW  Affiliates  that would  otherwise  receive  Parent  Stock
pursuant to Section 3.2(b) the first  $25,000,000 of the Stock  Consideration in
cash in lieu of issuing to SBCW and such Affiliates  $25,000,000 of Parent Stock
at the Initial Closing.

SECTION 11.13.    Master Lease.

         On or prior to the Initial  Closing  Date,  TowerCo shall have executed
and delivered to the Paging  Tenant,  the Master Lease,  and the same shall have
become effective as of the Initial Closing Date.

                                  ARTICLE XII
             CONDITIONS TO OBLIGATIONS OF TowerCo Parent AND TOWERCO

         All  obligations of TowerCo Parent and TowerCo  hereunder in respect of
any Existing  Site  included in any Closing are subject to the  fulfillment  and
satisfaction,  prior  to or at  such  Closing,  of  each  and  every  one of the
following  conditions,  to the extent such  condition  relates to such  Existing
Site, any or all of which may be waived in whole or in part by TowerCo, provided
that no such  waiver  will be  effective  unless  it is set  forth in a  writing
executed by TowerCo:

SECTION 12.1.     Representations and Warranties.

         The  representations and warranties (other than the representation made
in  Section  6.5  hereof)  of each of the  Sublessor  Entities  whose  Sites are
included in such Closing  ("Applicable  Sublessor  Entities")  contained in this
Agreement  or in  any  schedule,  certificate  or  document  delivered  by  such
Sublessor  Entities to TowerCo  pursuant to the provision hereof shall have been
true and  correct in all  material  respects on and as of the date when made and
shall be deemed to be made again at and as of the date of each Closing and shall
be true  and  correct  in all  material  respects  at and as of such  time.  For
purposes of determining  under Section 12.1 whether a condition to a Closing has
been  satisfied,  and  not for  any  other  purposes,  the  representations  and
warranties made shall be deemed made,  unless otherwise  specifically  provided,
without  the  qualification  set forth  therein  that such  representations  and
warranties are made subject to the Applicable Sublessor Entity's knowledge.

                                       41
<PAGE>

SECTION 12.2.     Compliance with Agreements and Conditions.

         Each of the Applicable Sublessor Entities and SBCW shall have performed
and  complied  in all  material  respects  with all  covenants,  agreements  and
conditions  required by this  Agreement to be performed or complied with by each
of them prior to or on the date of each Closing.

SECTION 12.3.     Closing Certificates.

         TowerCo  shall have received from each  Applicable  Sublessor  Entity a
certificate  dated the date of each  Closing,  (a)  certifying in such detail as
TowerCo may reasonably request as to (i) the fulfillment and satisfaction of the
conditions specified in Sections 12.1 and 12.2 and (ii) no event or circumstance
having  had a  Material  Adverse  Effect on the Sites of such  Sublessor  Entity
included in such Closing has occurred since July 31, 2000, and (b) setting forth
any net  additions of antennas on each Tower  included in such Closing since the
date hereof.

SECTION 12.4.     Consents and Approvals.

         All necessary  consents and approvals shall have been obtained from any
Government or other  Person,  whose consent or approval is required or necessary
to consummate the transactions contemplated herein, including the following: (a)
the waiting period required under the HSR Act for the transactions  contemplated
hereby shall have expired or been  terminated;  (b) if applicable,  the consents
and  approval  of  any  environmental   agency  having   jurisdiction  over  the
transactions contemplated hereby and applicable to such Closing, shall have been
obtained,  (c) the consents specified in the Disclosure  Schedule and applicable
to such Closing  shall have been  obtained or waived,  and (d) all  Governmental
Permits applicable to such Closing, shall have been obtained or waived.

SECTION 12.5.     No Litigation.

         No Action shall have been  instituted,  be  threatened in writing or be
pending,  in each  case by any  Government  or  judicial  body (a)  against  the
Applicable  Sublessor  Entity to restrain or prohibit  its  consummation  of the
transactions in this Agreement,  and (b) by any Government or Person which could
reasonably  be  expected  to have a  Material  Adverse  Effect on the  Subleased
Interests.

SECTION 12.6.     Build-to-Suit Agreement.

         On or prior to the Initial  Closing Date,  SBCW shall have executed and
delivered  to  TowerCo,  the  Build-to-Suit  Agreement,  and the same shall have
become effective as of the Initial Closing Date.

                                       42
<PAGE>

SECTION 12.7.     SBCW Sublease.

         On or  prior  to the  Initial  Closing  Date,  SBCW  and the  Sublessor
Entities  shall have  executed and  delivered to TowerCo  Parent and TowerCo the
SBCW  Sublease,  and the same  shall have  become  effective  as of the  Initial
Closing Date.

SECTION 12.8.     Stockholders' Agreement.

         On or prior to the  Initial  Closing  Date,  SBCW  and any  other  SBCW
Affiliate  that will be issued Parent Stock shall have executed and delivered to
TowerCo  Parent the  Stockholders'  Agreement,  and the same  shall have  become
effective as of the Initial Closing Date.

SECTION 12.9.     Incomplete Sites.

         TowerCo shall not be obligated to sublease from SBCW or the  applicable
Sublessor  Entity  any Site  listed on Annex A that has not yet been  completed.
Once such Site has been  completed,  it will be  considered an Existing Site and
may be subleased just like any other Existing Site.

SECTION 12.10.    Site Marketing Agreement.

         On or  prior  to the  Initial  Closing  Date,  SBCW  and the  necessary
Sublessor  Entities  shall  have  executed  and  delivered  the  Site  Marketing
Agreement,  and same  shall  have  become  effective  on or before  the  Initial
Closing.

SECTION 12.11.    Master Lease.

         On or prior to the Initial  Closing Date,  the Paging Tenant shall have
executed and  delivered to TowerCo,  the Master  Lease,  and the same shall have
become effective as of the Initial Closing Date.

                                  ARTICLE XIII
                                 INDEMNIFICATION

SECTION 13.1.     Indemnification by Sublessor Entity.

(a) As to each Included Site, from and after the Closing Date of such Site, each
Sublessor Entity,  severally and not jointly,  shall indemnify and hold harmless
each of the  TowerCo  Indemnitees  from  and  against  any and all  Liabilities,
claims, causes of action, demands, judgments, losses, costs, damages or expenses
(including  reasonable  attorneys' fees and  disbursements of every kind, nature
and  description),  subject to the  limitations in Sections 13.6 and 13.7 hereof
incurred by such  TowerCo  Indemnitee  in  connection  therewith  (collectively,
"TowerCo Indemnified  Losses") that such TowerCo Indemnitee may sustain,  suffer
or incur and that result  from,  arise out of or relate to (i) any breach of any
of the  representations,  warranties,  covenants or agreements of such Sublessor
Entity  contained in this Agreement  with respect to the  applicable  Closing or
(ii) such  Sublessor  Entity's  failure to  perform  any  obligations  under any
Existing  Leases  which were  required  to be  performed  under the terms of the
applicable Existing Lease prior to the applicable Site Commencement Date.

                                       43
<PAGE>

(b) TowerCo  acknowledges  and agrees that no  Sublessor  Entity  shall have any
Liability  under any  provision of this  Agreement  for any TowerCo  Indemnified
Losses  to the  extent  that  such  TowerCo  Indemnified  Losses  relate  to the
negligence,  willful  misconduct  or  breach  of any  representation,  warranty,
covenant or agreement of TowerCo  contained in this Agreement or any Transaction
Document  by  TowerCo,  TowerCo  Parent  or any  other  Person  (other  than the
Sublessor  Entities or their Affiliates) or their respective  officers,  agents,
employees, representatives, contractors, licensees, tenants or subtenants.

(c) TowerCo  shall take and shall cause its  Affiliates  to take all  reasonable
steps to mitigate  any TowerCo  Indemnified  Losses upon  becoming  aware of any
event  which  would  reasonably  be  expected  to, or does  give  rise  thereto,
including  incurring  costs only to the minimum  extent  necessary to remedy the
breach which gives rise to the TowerCo Indemnified Losses.

(d) Nothing herein shall be deemed to limit or restrict in any manner any rights
or  remedies  which  TowerCo has or may have,  at law,  in equity or  otherwise,
against any  Sublessor  Entity based on a willful  misrepresentation  or willful
breach of any covenant or agreement of such Sublessor Entity hereunder.

SECTION 13.2.     Indemnification by TowerCo Parent.

(a) From and after the Initial Closing,  TowerCo Parent shall indemnify and hold
harmless each of the SBCW  Indemnitees from and against any and all Liabilities,
claims, causes of action, demands, judgments, losses, costs, damages or expenses
whatsoever  (including  reasonable  attorneys' fees and  disbursements  of every
kind,  nature and  description)  incurred by such SBCW  Indemnitee in connection
therewith  (collectively,  "SBCW Indemnified  Losses") that such SBCW Indemnitee
may sustain, suffer or incur and that result from, arise out of or relate to any
breach of any of the  representations,  warranties,  covenants or  agreements of
TowerCo  Parent  contained  in this  Agreement  with  respect to the  applicable
Closing.

(b) Each  Sublessor  Entity  acknowledges  and agrees that  neither  TowerCo nor
TowerCo  Parent shall have any Liability  under any provision of this  Agreement
for SBCW  Indemnified  Losses to the extent  that such SBCW  Indemnified  Losses
relate to the negligence,  willful  misconduct or breach of any  representation,
warranty,  covenant or  agreement  of such  Sublessor  Entity  contained in this
Agreement or any  Transaction  Document by such Sublessor  Entity,  or any other
Person  (other  than  TowerCo  Parent,  TowerCo  or their  Affiliates)  or their
respective officers, agents, employees, representatives, contractors, licensees,
tenants or subtenants.

(c) Each Sublessor  Entity shall take all reasonable  steps to mitigate any SBCW
Indemnified  Losses upon becoming  aware of any event which would  reasonably be
expected to, or does give rise thereto,  including  incurring  costs only to the
minimum  extent  necessary  to remedy  the breach  which  gives rise to the SBCW
Indemnified Losses.

                                       44
<PAGE>

(d) Nothing herein shall be deemed to limit or restrict in any manner any rights
or remedies  which any  Sublessor  Entity has or may have,  at law, in equity or
otherwise,  against  TowerCo  Parent  based on a  willful  misrepresentation  or
willful breach of any covenants or agreements of TowerCo Parent hereunder.

SECTION 13.3.     Indemnification by TowerCo.

(a) From and  after  the  Initial  Closing,  TowerCo  shall  indemnify  and hold
harmless each SBCW Indemnitee from and against any SBCW Indemnified  Losses that
such SBCW  Indemnitee may sustain,  suffer or incur and that result from,  arise
out of or relate to (i) any  breach of any of the  representations,  warranties,
covenants or agreements of TowerCo  contained in this  Agreement with respect to
the  applicable  Closing or (ii)  TowerCo's  failure to perform any  obligations
under any Existing  Leases which are required to be performed under the terms of
the applicable Existing Lease after the applicable Site Commencement Date.

(b) Each  Sublessor  Entity  shall  take and  cause its  Affiliates  to take all
reasonable steps to mitigate any SBCW Indemnified  Losses upon becoming aware of
any event which would  reasonably  be  expected  to, or does give rise  thereto,
including  incurring  costs only to the minimum  extent  necessary to remedy the
breach which gives rise to the SBCW Indemnified Losses.

(c) Nothing herein shall be deemed to limit or restrict in any manner any rights
or  remedies  which a SBCW  Indemnitee  has or may  have,  at law,  in equity or
otherwise,  against  TowerCo  based on a willful  misrepresentation  or  willful
breach of any covenant or agreement by TowerCo hereunder.

SECTION 13.4.     Procedure for Claims.

         Any  Person  obligated  to  pay or  reimburse  any  Indemnified  Losses
hereunder (whether one or more, an "Indemnifying  Party") shall,  subject to the
provisions  of  Section  13.5,  reimburse  the party  entitled  to  recover  the
Indemnified  Losses,  as the case may be (whether one or more,  an  "Indemnified
Party"),  within  ten (10)  days of  written  demand on the  Indemnifying  Party
therefor.  If the Indemnifying Party objects to any claim made by an Indemnified
Party  hereunder and the  Indemnified  Party initiates legal action with respect
thereto,  the Indemnifying Party agrees, to the extent it can do so, to join all
affected  parties  in such  action so that the  rights  and  liabilities  of the
parties under this  Agreement  with respect to such claim may be resolved in one
action.

SECTION 13.5.     Defense of Claims.

(a) If any Action arises after the date hereof for which an  Indemnifying  Party
may be liable  under the terms of this  Agreement,  then the  Indemnified  Party
shall notify the  Indemnifying  Party within a reasonable time after such Action
arises and is known to the Indemnified  Party,  and shall give the  Indemnifying
Party a reasonable  opportunity:  (i) to conduct any proceedings or negotiations
in connection  therewith and necessary or appropriate to defend the  Indemnified
Party;  (ii) to take all other required steps or proceedings to settle or defend
any such Action;  and (iii) to employ  counsel to contest any such Action in the
name of the Indemnified Party or otherwise.

                                       45
<PAGE>

(b) The expenses of all  proceedings,  contests or lawsuits with respect to such
Actions shall be borne by the  Indemnifying  Party.  If the  Indemnifying  Party
wishes to assume the defense of such Action,  then the Indemnifying  Party shall
give  written  notice to the  Indemnified  Party  within  thirty (30) days after
notice from the Indemnified  Party of such Action (unless the Action  reasonably
requires a response  in less than  thirty (30) days after the notice is given to
the Indemnifying  Party, in which event the Indemnifying  Party shall notify the
Indemnified  Party at least ten days prior to such reasonably  required response
date),  and the Indemnifying  Party shall  thereafter  assume the defense of any
such Action,  through counsel reasonably  satisfactory to the Indemnified Party;
provided,  that the Indemnified Party may participate in such defense at its own
expense.  The  Indemnified  Party shall have the right to control the defense of
the Action unless and until the  Indemnifying  Party shall assume the defense of
such Action.

(c) If the  Indemnifying  Party does not assume the  defense  of, or if after so
assuming  the  Indemnifying  Party fails to defend,  any such  Action,  then the
Indemnified  Party  may  defend  against  such  Action  in such  manner  as such
Indemnified Party may deem appropriate  (provided,  that the Indemnifying  Party
may participate in such defense at its own expense); provided, however, that the
Indemnified  Party may not settle such Action without the  Indemnifying  Party's
prior written consent,  and the Indemnifying  Party shall promptly reimburse the
Indemnified  Party  for  the  amount  of  all  expenses,  legal  and  otherwise,
reasonably and necessarily  incurred by the Indemnified Party in connection with
the defense  against and  settlement  of such Action.  If no  settlement of such
Action is made, the  Indemnifying  Party shall satisfy any judgment  rendered in
such  Action,  before the  Indemnified  Party is  required to do so, and pay all
expenses,  legal  or  otherwise,  reasonably  and  necessarily  incurred  by the
Indemnified Party in the defense of such Action.

(d) If an Order is rendered against the Indemnified  Party in any Action covered
by the indemnification  hereunder, or any Lien in respect of such Order attaches
to any of the assets of the  Indemnified  Party,  the  Indemnifying  Party shall
immediately  upon such entry or attachment pay any amount required by such Order
in full or  discharge  such Lien  unless,  at the  expense  and  request  of the
Indemnifying Party, an appeal is taken under which the execution of the Order or
satisfaction of the Lien is stayed. If and when a final Order is rendered in any
such Action,  the Indemnifying  Party shall forthwith pay any amount required by
such Order or discharge such Lien before the  Indemnified  Party is compelled to
do so.

SECTION 13.6.     Certain Limitations.

(a) Nothing in this Agreement shall be deemed to require any Sublessor Entity to
indemnify  any  TowerCo  Indemnitee  for or in respect of any of the Real Estate
Representations.  Without  limiting the  generality of the  foregoing,  the sole
remedies of TowerCo or TowerCo  Parent in respect of a breach of any Real Estate
Representation  by any  Sublessor  Entity  shall be to cause (i) such  Sublessor
Entity  to  continue  to  use  reasonable   efforts  to  cure  such  breach,  as
contemplated  by Section 4.5,  until the Final Closing Date, or (ii) the Site as
to which such Real Estate  Representation  is breached to be, at the  applicable
Sublessor  Entity's  election,  an Excluded Site or to defer the Closing of such
Site to a later  Closing  Date,  provided  that the failure of any such deferred
Site to  become an  Included  Site on or prior to the  Final  Closing  shall not
constitute a default under this  Agreement or give TowerCo Parent or TowerCo any
remedy.

                                       46
<PAGE>

(b)  Notwithstanding  anything to the contrary  contained  herein,  no Sublessor
Entity shall have any  obligation  under this Section 13 to TowerCo  Indemnitees
with  respect  to  the  breach  of  representations,  warranties,  covenants  or
agreements by SBCW,  unless,  until and only to the extent that the aggregate of
all TowerCo  Indemnified  Losses from all such breaches  exceeds on a cumulative
basis one percent (1%) of the  aggregate  amount of all Rent having been paid to
SBCW or any other  Sublessor  Entity  under the Sublease as of the date on which
the claim for indemnification arose (the "Deductible Amount"),  and then only to
the extent of such excess amount.

(c)  Anything in this  Agreement to the  contrary  notwithstanding,  in no event
shall  any   Sublessor   Entity  be  liable   under  this   Agreement   for  any
indemnification  obligation  pursuant to this Section 13 in excess of 25% of the
aggregate  amount of the Rent having been paid to SBCW or such Sublessor  Entity
under the SBCW Sublease on account of the Site(s) owned by such Sublessor Entity
as of the date on which  the  claim  for  indemnification  arose  (the  "Maximum
Indemnification").

SECTION 13.7.     Limitation on Liability.

         In no event  shall any party  hereto or its  respective  Affiliates  be
liable to the other parties for any special, incidental or consequential damages
suffered  or  incurred  by such  other  parties to this  Agreement  or any third
parties  and  caused by or  arising  out of any  breach  of any  representation,
warranty, covenant or agreement contained in this Agreement.

SECTION 13.8.     Survival.

         The  representations  and  warranties of the parties  contained in this
Agreement  shall  survive  any  investigation  before  or after the date of this
Agreement  made by the other parties and the  consummation  of the  transactions
contemplated  by this  Agreement and shall continue in full force and effect for
the periods specified below ("Survival Period"):

(a) no  representations  and warranties of a Sublessor  Entity  relating to real
estate matters,  including  without  limitation  Sections 6.6 through 6.13 shall
survive the applicable Closing; and

(b) all other  representations  and warranties in this Agreement  shall be of no
further force and effect after the first anniversary of the applicable Closing.

Anything to the contrary notwithstanding,  the Survival Period shall be extended
automatically  to  include  any time  period  necessary  to  resolve a claim for
indemnification which was made before expiration of the Survival Period, but not
resolved prior to its expiration,  and any such extension shall apply only as to
the claims  asserted and not so resolved within the Survival  Period.  Liability
for any such item  shall  continue  until such  claim  shall  have been  finally
settled, decided or adjudicated.

                                       47
<PAGE>

                                   ARTICLE XIV
                                   TERMINATION

SECTION 14.1.     Termination for Certain Causes by SBCW.

(a) This  Agreement  may be terminated at any time prior to the Final Closing by
SBCW upon written  notice to TowerCo,  upon the occurrence of one or more of the
following  events,  effective as of the date designated by SBCW in its notice of
termination:

(i) If any of the conditions set forth in Article XI (other than 11.4,  11.5, or
11.9) have not been  satisfied,  performed  or waived in writing on or as of any
applicable Closing Date;

(ii)     If an unwaived  event of default  shall have occurred and be continuing
         under Section 30(d) of the SBCW Sublease that would give SBCW the right
         to terminate the Sublease as to all Sites:

provided, however that for the events listed in clause (i) above occurring after
the Initial Closing,  SBCW shall have the right to terminate this Agreement only
if such event or events  shall have or would have a  substantial  likelihood  of
preventing or delaying a Closing (it being  understood  that such  prevention or
delay may be caused by SBCW's  exercise of its other rights under this Agreement
in its reasonable discretion),  such termination to be effective after notice to
TowerCo and an  opportunity  for TowerCo to cure all such events  within  twenty
(20) days of such notice.

(b) If this  Agreement is terminated by SBCW pursuant to Section  14.1(a),  then
SBCW shall be  entitled to and TowerCo  Parent  shall pay SBCW,  within five (5)
business days  following the date of such  termination,  a termination  fee (the
"Termination Fee") in the amount of four percent (4%) of the aggregate amount of
Rent that would have been payable to SBCW and all Sublessor  Entities  under the
SBCW Sublease as of the date of such termination. Upon any such termination, all
Transaction  Documents  between the  parties  shall be  terminated,  and, at the
option of SBCW,  all prior  Closings  shall be rescinded.  If SBCW exercises its
option to rescind the prior  Closings,  payment of the  Termination Fee shall be
made by netting it against the amounts  previously paid to Sublessor Entities at
the previous Closings,  and SBCW shall pay to TowerCo Parent any amounts paid to
Sublessor  Entities at the prior Closings which are in excess of the Termination
Fee.

(c) Notwithstanding the foregoing,  SBCW shall not be entitled to terminate this
Agreement  pursuant to this Section 14.1 or receive a  Termination  Fee due to a
breach, after the date hereof, of the representations and warranties provided in
Sections  8.7 or 9.5 or for failure to satisfy the closing  condition in Section
11.5 (it being  understood  that  neither  TowerCo or its  Affiliates  filed the
litigation that causes the delay in Closing).

SECTION 14.2.     Termination for Passage of Time.

         This  Agreement  may be  terminated  by either party (i) if the Initial
Closing  shall not have  occurred on or before the date which is four (4) months
after the Effective Date through no fault of the  terminating  party, or (ii) if
the conditions to Final Closing  contained in Articles XI and XII shall not have
been satisfied or waived through no fault of the terminating party in writing on
or before the date which is eighteen (18) months after the Effective  Date. With
respect  to Sites  not  included  in a prior  Closing  hereunder,  upon any such
termination,  no party shall have any further rights, Liabilities or obligations
hereunder.

                                       48
<PAGE>

SECTION 14.3.     TowerCo's Remedies.

(a)  Notwithstanding  anything to the contrary  contained herein, if the parties
fail to consummate any Closing  contemplated by the Closing Schedule as a result
of SBCW's or SBCW's failure to keep, observe,  perform,  satisfy or comply with,
fully and  completely,  any of the  terms,  covenants,  conditions,  agreements,
requirements,  restrictions or provisions required by this Agreement to be kept,
observed,  performed,  satisfied or complied with by SBCW or SBCW,  then TowerCo
may  exercise  all such rights and remedies as may be provided for or allowed by
law or in equity.  Except as expressly set forth in the  Transaction  Documents,
TowerCo  Parent and TowerCo may, in addition to any other  remedies  that may be
available  at law or in  equity,  bring  an  action  for  specific  performance,
including attorneys' fees and costs of suit.

(b) Each Sublessor  Entity hereby  acknowledges  and agrees that in the event of
such Sublessor Entity's default hereunder, TowerCo shall be entitled to, without
limitation, (i) an Action for specific performance against such Sublessor Entity
and (b) the right to seek,  prove and recover direct damages from such Sublessor
Entity  incurred by TowerCo in connection  with such Action,  including  without
limitation, court costs and attorneys' fees in connection with such Action.

                                   ARTICLE XV
                              RIGHT OF FIRST OFFER

         Following   the  date  of  the  Final   Closing  and  so  long  as  the
Build-to-Suit  Agreement remains in effect, neither SBCW or any Sublessor Entity
may assign,  transfer, sell, lease or dispose of all or substantially all of its
right,  title or  interest in or to an  Excluded  Site  except for  assignments,
transfers  or sales  (A) to an SBCW  Affiliate,  (B) to a  successor  entity  in
connection with the merger,  consolidation  or other  reorganization  of SBCW or
such Sublessor Entity,  (C) in connection with the sale or other transfer or all
or a portion of SBCW's  wireless  business  on a Site by Site  basis,  or (D) in
accordance with the following pre-emption procedures:

(a) SBCW must first offer such Excluded  Sites to TowerCo by providing a written
notice to TowerCo (i) stating  that SBCW  intends to  transfer,  lease,  sell or
otherwise  dispose of such Excluded  Sites,  (ii) the number and location of all
Excluded  Sites  subject to the proposed  transfer,  lease or sale and (iii) the
specified purchase price or other consideration to be paid to SBCW in connection
with such  transfer,  lease or sale (the "SBCW Economic  Offer").  TowerCo shall
have ten (10)  days  after  receipt  of the SBCW  Economic  Offer  (the  "Notice
Period") to elect to purchase  or lease the  Excluded  Sites on the terms of the
Economic  Offer. A failure by TowerCo to respond in writing to SBCW prior to the
end of the Notice  Period  shall be deemed to be a  rejection  by TowerCo of the
offer  for the  Excluded  Sites.  TowerCo  may  elect to  purchase  or lease the
Excluded  Towers on the terms of the SBCW Economic  Offer by delivering  written
notice ("Acceptance Notice") to SBCW prior to the end of the Notice Period.

                                       49
<PAGE>

(b) If TowerCo  delivers an  Acceptance  Notice,  the closing of the transfer or
lease of such  Excluded  Sites to TowerCo shall be held within 60 days after the
date on which the Acceptance Notice is delivered. If an Acceptance Notice is not
delivered by TowerCo prior to the end of the Notice Period,  or TowerCo fails to
close the purchase or lease of the Excluded  Sites on the closing date specified
in the prior  sentence,  SBCW shall be free to transfer  or lease such  Excluded
Sites to a third party on the terms no more  favorable  to such third party than
those  provided in the SBCW Economic  Offer within 180 days after the end of the
Notice Period; provided,  however, that if the offer made to such third party is
more  favorable  to such third  party than that  provided  in the SBCW  Economic
Offer,  SBCW or the applicable  Sublessor Entity shall offer such Excluded Sites
to TowerCo on the new  economic  terms  prior to the  transfer  or lease of such
Excluded Site to a third party in accordance with the provisions of this Article
XV.

(c) If such Excluded  Sites have not been so transferred to a third party within
such 180 day period,  then the  restrictions  provided in this  Article XV shall
again apply with respect to such Excluded Sites, and SBCW shall have no right to
transfer or sell any such Excluded  Sites  without again  offering such Excluded
Sites to TowerCo in accordance with the provisions of this Article XV.

                                  ARTICLE XVI
                               GENERAL PROVISIONS

SECTION 16.1.     Notices.

(a) All notices or other  communications  required or  permitted  to be given or
made  hereunder  shall  be in  writing  and  delivered  personally  or  sent  by
nationally  recognized  overnight  courier  (such  as  Federal  Express)  on  an
overnight basis or pre-paid,  first class certified or registered  mail,  return
receipt  requested,  or by facsimile  transmission,  to the  intended  recipient
thereof at its  address or  facsimile  number set out below.  Any such notice or
communication  shall be deemed to have been duly given  immediately (if given or
made in person,  or by  facsimile  confirmed  by  mailing a copy  thereof to the
recipient in accordance  with this Section 16.1 on the date of such  facsimile),
one day after pickup in the case of delivery by overnight  courier,  or two days
after  mailing  (if  given or made by  mail),  and in  proving  same it shall be
sufficient  to show that the envelope  containing  the same was delivered to the
delivery  service  and  duly  addressed,  or that  receipt  of a  facsimile  was
confirmed by the  recipient  as provided  above.  The  addresses  and  facsimile
numbers of the parties for purposes of this Agreement are:

         If to TowerCo:

                  Southern Towers, Inc.
                  c/o SpectraSite Communications, Inc.
                  100 Regency Forest Drive, Suite 400
                  Cary, North Carolina 27511
                  Attention:  General Counsel
                  Telecopy:  (919) 468-8522

                  with a copy to:

                  Paul, Weiss, Rifkind, Wharton & Garrison
                  1285 Avenue of the Americas
                  New York, New York  10019-6064
                  Attention:  Mitchell L. Berg
                           Bruce A. Gutenplan
                  Telecopy:  (212) 757-3990

                                       50
<PAGE>

         If to SBCW, SBCW, or a Sublessor Entity:

                  SBC Communications Inc.
                  175 E. Houston
                  12th Floor
                  San Antonio, TX  78205
                  Attention: Senior Executive Vice President/Corporate

                  with a copy to:

                  SBC Communications Inc.
                  4th Floor
                  175 E. Houston
                  San Antonio, TX  78205
                  Attention:  Vice President and General Counsel - Mergers and
                              Acquisitions
                  Telecopy:  (210) 351-3488

         If to TowerCo Parent:

                  SpectraSite Holdings, Inc.
                  100 Regency Forest Drive, Suite 400
                  Cary, North Carolina 29511
                  Attention:  General Counsel
                  Telecopy:  (919) 468-8522

                  with a copy to:

                  Paul, Weiss, Rifkind, Wharton & Garrison
                  1285 Avenue of the Americas
                  New York, New York  10019-6064
                  Attention:  Mitchell L. Berg
                           Bruce A. Gutenplan
                  Telecopy:  (212) 757-3990

(b) Either party may change the address to which notices or other communications
to such party shall be delivered or mailed by giving notice thereof to the other
party hereto in the manner provided herein.

                                       51
<PAGE>

SECTION 16.2.     Facsimile as Writing.

         The parties expressly  acknowledge and agree that,  notwithstanding any
statutory or decisional law to the contrary,  the printed product of a facsimile
transmittal  shall be deemed to be "written" and a "writing" for all purposes of
this Agreement.

SECTION 16.3.     No Assignment; Binding Effect.

         SBCW and each  Sublessor  Entity  may  assign,  delegate  or  otherwise
transfer any of their rights or obligations under this Agreement, in whole or in
part, without the consent of TowerCo,  to any SBCW Affiliate it being understood
that upon such  assignment,  such Sublessor Entity will not be released from its
obligations hereunder. Neither TowerCo Parent or TowerCo may assign, delegate or
otherwise  transfer any of their rights or obligations under this Agreement,  in
whole  or  in  part,   without  the  written   consent  of  the  other  parties.
Notwithstanding  anything to the contrary  herein and subject to the  provisions
set forth in the Subleases with respect to a Permitted  Subleasehold  Collateral
Assignee,  TowerCo Parent and TowerCo may collaterally assign, pledge, mortgage,
hypothecate or otherwise  collaterally transfer their interest in this Agreement
to any  Permitted  Subleasehold  Collateral  Assignee  (as  defined  in the SBCW
Sublease)  provided,  however,  that neither TowerCo Parent or TowerCo may enter
into any Permitted  Subleasehold Mortgage (as defined in the SBCW Sublease) with
respect to all or any  portion of the Sites prior to the  applicable  Closing of
such Sites.  This Agreement  shall be binding upon and will inure to the benefit
of the parties hereto and their respective  permitted  successors and assigns. A
Person may become a  Sublessor  Entity  hereunder  and a party  hereto or to any
Transaction  Document by executing and delivering to TowerCo a Site  Designation
Supplement or other written instrument reasonably acceptable to TowerCo, setting
forth its agreement to be bound by the terms hereof or thereof,  whereupon  such
Person shall be a party hereto or thereto.  For the avoidance of doubt,  nothing
contained in this  Agreement or any other  Transaction  Document  shall prohibit
SBCW from assigning its rights or obligations  under any of the Existing  Leases
or any of the Subleased  Interest to an Affiliate of SBCW,  provided,  that such
Affiliate becomes a party to this Agreement.

SECTION 16.4.     Headings.

         The headings of particular  provisions  of this  Agreement are inserted
for convenience  only and are not to be construed as a part of this Agreement or
serve as a limitation or expansion on the scope of any term or provision of this
Agreement.

SECTION 16.5.     Exhibits and Schedules.

         Each and every exhibit and schedule referred to or otherwise  mentioned
in this Agreement is attached to this Agreement and is and shall be construed to
be made a part of this  Agreement  by such  reference  or other  mention at each
point at which such  reference or other mention  occurs,  in the same manner and
with the same effect as if each exhibit and schedule  were set forth in full and
at length every time it is referred to or otherwise mentioned.

                                       52
<PAGE>

SECTION 16.6.     Defined Terms.

         Capitalized  terms  used in this  Agreement  shall  have  the  meanings
ascribed to them at the point where first defined,  irrespective  of where their
use occurs,  with the same effect as if the  definitions  of such terms were set
forth in full and at length every time such terms are used.

SECTION 16.7.     Waiver of Jury Trial

         To the maximum extent  permitted by law, the parties hereby  knowingly,
voluntarily and  intentionally  waive the right to a trial by jury in respect of
any litigation  based hereon,  arising out of, under or in connection  with this
Agreement,  or any course of  conduct,  course of  dealing,  statement  (whether
verbal or  written)  or action of either  party or any  exercise by any party of
their respective rights under this Agreement (including, without limitation, any
action to terminate this Agreement, and any claim or defense asserting that this
Agreement  was  fraudulently  induced or is otherwise  void or  voidable).  This
waiver is a material inducement for the parties to enter into this Agreement.

SECTION 16.8.     Partial Invalidity and Severability.

         All rights and  restrictions  contained herein may be exercised and are
applicable  and  binding  only  to the  extent  that  they  do not  violate  any
applicable Laws and are intended to be limited to the extent necessary to render
this Agreement legal, valid and enforceable.  If any term of this Agreement,  or
part thereof,  not essential to the commercial purpose of this Agreement is held
to be illegal, invalid or unenforceable by a Forum of competent jurisdiction, it
is the  intention  of the  parties  that the  remaining  terms  hereof,  or part
thereof,  constitute  their  agreement with respect to the subject matter hereof
and all such remaining terms, or parts thereof, remain in full force and effect.
To the  extent  legally  permissible,  any  illegal,  invalid  or  unenforceable
provision of this  Agreement  will be replaced by a valid  provision  which will
implement  the  commercial  purpose of the  illegal,  invalid  or  unenforceable
provision.

SECTION 16.9.     Waiver.

         Any term or  condition of this  Agreement  may be waived at any time by
the party which is entitled to the benefit  thereof,  but only if such waiver is
evidenced by a writing signed by such party. No failure on the part of any party
hereto  to  exercise,  and no delay in  exercising  any  right,  power or remedy
created  hereunder,  will  operate as a waiver  thereof,  nor will any single or
partial  exercise of any right,  power or remedy by either  party  preclude  any
other or further exercise  thereof or the exercise of any other right,  power or
remedy. No waiver by either party hereto of any breach of or default in any term
or  condition  of this  Agreement  will  constitute a waiver of or assent to any
succeeding  breach  of or  default  in the same or any other  term or  condition
hereof.

SECTION 16.10.    Rights Cumulative.

         All  rights,  remedies,  powers  and  privileges  conferred  under this
Agreement  on the parties  shall be  cumulative  of and in addition  to, but not
restrictive of or in lieu of, those conferred by law.

                                       53
<PAGE>

SECTION 16.11.    Time of Essence; Dates.

         Time is of the  essence of this  Agreement.  Anywhere a day  certain is
stated for  payment or for  performance  of any  obligation,  the day certain so
stated enters into and becomes a part of the  consideration  for this Agreement.
If any date set forth in this  Agreement  shall fall on, or any time  period set
forth in this  Agreement  shall  expire on, a day which is a  Saturday,  Sunday,
federal  or  state  holiday,   or  other   non-business  day,  such  date  shall
automatically  be extended  to, and the  expiration  of such time  period  shall
automatically  to be extended to, the next day which is not a Saturday,  Sunday,
federal or state  holiday or other  nonbusiness  day.  The final day of any time
period under this Agreement or any deadline  under this  Agreement  shall be the
specified  day or date,  and  shall  include  the  period  of time  through  and
including such  specified day or date.  All  references to the "Effective  Date"
shall be  deemed  to refer to the  later  of the  date of  TowerCo's  or  SBCW's
execution of this Agreement, as indicated below their executions hereon.

SECTION 16.12.    Governing Law.

         The  validity  and  effect  of this  Agreement  shall be  governed  by,
construed  under and interpreted and enforced in accordance with the laws of the
State of New York, without regard to its conflicts of laws or rules.

SECTION 16.13.    Counterparts.

         This Agreement may be executed in several  counterparts,  each of which
shall  be  deemed  an  original,  and all of such  counterparts  together  shall
constitute one and the same instrument.

SECTION 16.14.    Attorneys' Fees.

         In the event of any litigation  between the parties arising under or in
connection  with this  Agreement,  the  prevailing  party  shall be  entitled to
recover from the other party the expenses of  litigation  (including  reasonable
attorneys' fees, expenses and disbursements) incurred by the prevailing party.

SECTION 16.15.    Authority.

         Each party hereto  warrants and represents that such party has full and
complete  authority to enter into this Agreement and that each person  executing
this Agreement on behalf of such party has been fully authorized to execute this
Agreement on behalf of such party and that such party is bound by the  signature
of such representative.

SECTION 16.16.    Counsel.

         Each party  hereto  warrants  and  represents  that each party has been
afforded  the  opportunity  to be  represented  by  counsel  of  its  choice  in
connection with the execution of this Agreement and has had ample opportunity to
read, review, and understand the provisions of this Agreement.

                                       54
<PAGE>

SECTION 16.17.    Number and Gender.

         Where  the  context  requires,  the  use of the  singular  form  herein
includes the plural, the use of the plural includes the singular, and the use of
any gender includes any and all genders.

SECTION 16.18.    No Construction Against Preparer.

         No  provision  of  this  Agreement   shall  be  construed   against  or
interpreted to the disadvantage of any party by any court or other  governmental
or judicial  authority by reason of such party's  having or being deemed to have
prepared or imposed such provision.

SECTION 16.19.    Entire Agreement; Modification.

         This Agreement  supersedes all prior discussions and agreements between
the parties  with  respect to the subject  matter  hereof,  and this  Agreement,
together with all other agreements executed contemporaneously  herewith, contain
the sole and entire  agreement  between the parties  with respect to the matters
covered  hereby.  This  Agreement  will not be altered  or amended  except by an
instrument  in  writing  signed by or on behalf  of the  party  entitled  to the
benefit of the provision against whom enforcement is sought.

SECTION 16.20.    Power of Attorney:  Appointing SBCW.

(a) The Sublessor Entities,  and each of them, hereby irrevocably constitute and
appoint SBCW as their agent to modify,  amend or otherwise  change the Agreement
to Sublease, any other Transaction Documents or any of their respective terms or
provisions  (including  modifications,  amendments or changes  subsequent to any
Closing),  to take  all  actions  and to  execute  all  documents  necessary  or
desirable  to  consummate  the  transactions  contemplated  by the  Agreement to
Sublease,  and to take all  actions and to execute  all  documents  which may be
necessary or desirable in connection therewith, to give and receive consents and
all  notices  hereunder,  to  negotiate  and settle  claims for  indemnification
thereunder  and to perform  any other act  arising  under or  pertaining  to the
Transaction Documents and the transactions  contemplated thereby. Each Sublessor
Entity  agrees  that  service of process  upon SBCW in any action or  proceeding
arising under or pertaining to the  Transaction  Documents shall be deemed to be
valid service of process upon the  undersigned,  and any claim by TowerCo Parent
or TowerCo against any Sublessor Entity in respect to the Transaction  Documents
may be settled by SBCW.  SBCW shall be deemed to have  accepted the  appointment
herein upon its execution of this Agreement.

(b) It is expressly  understood and agreed that the foregoing  power of attorney
and the agency  created  thereby is coupled  with an interest of the  respective
parties  hereto and shall be binding on and  enforceable  against the respective
successors and assigns of the  undersigned,  and each of them, and said power of
attorney  shall not be revoked or  terminated in any event,  including,  without
limitation,  the dissolution,  bankruptcy or insolvency of any Sublessor Entity,
shall continue to be binding and  enforceable in the manner  provided herein and
shall survive any and all Closings.

(c)  Nothing  contained  herein  shall be  deemed  to make  SBCW  liable  to the
Sublessor Entities because of service in its capacity as agent or otherwise.  In
performing any of its duties under this letter  agreement,  SBCW shall not incur
or be  responsible  for any  liabilities,  claims,  causes of  action,  demands,
judgments,  losses,  costs,  damages or expenses  whatsoever  ("Losses")  to the
Sublessor  Entities,   except  for  SBCW's  fraud,   willful  default  or  gross
negligence, and each Sublessor Entity shall indemnify SBCW against all Losses.

                                       55
<PAGE>

SECTION 16.21.    Power of Attorney:  Appointing SBCW.

(a) As provided in Section 7.3 hereof, SBCW represents that it has the requisite
power and authority,  on behalf of each and every Sublessor  Entity,  to modify,
amend or  otherwise  change the  Agreement to  Sublease,  any other  Transaction
Documents  or  any  of  their   respective   terms  or   provisions   (including
modifications,  amendments or changes  subsequent  to any Closing),  to take all
actions and to execute all documents  necessary or desirable to  consummate  the
transactions  contemplated by the Agreement to Sublease, and to take all actions
and to execute all  documents  which may be necessary or desirable in connection
therewith,  to give and receive consents and all notices hereunder, to negotiate
and settle claims for  indemnification  thereunder  and to perform any other act
arising under or pertaining to the  Transaction  Documents and the  transactions
contemplated  thereby.  Each Sublessor Entity has agreed that service of process
upon  SBCW in any  action  or  proceeding  arising  under or  pertaining  to the
Transaction  Documents  shall be deemed to be valid  service of process upon the
Sublessor  Entities,  and any claim by  TowerCo  Parent or TowerCo  against  any
Sublessor Entity in respect to the Transaction Documents may be settled by SBCW.

(b)  It is  expressly  understood  and  has  been  previously  agreed  that  the
aforementioned  power of attorney and the agency created thereby is coupled with
an  interest  of the  respective  parties  thereto  and shall be  binding on and
enforceable  against the  respective  successors  and  assigns of the  Sublessor
Entities,  and each of them,  and said power of attorney shall not be revoked or
terminated  in  any  event,  including,  without  limitation,  the  dissolution,
bankruptcy or insolvency of any Sublessor  Entity,  shall continue to be binding
and  enforceable  in the manner  provided  herein and shall  survive any and all
Closings.

(c)  Nothing  contained  herein  shall be  deemed  to make  SBCW  liable  to the
Sublessor Entities because of service in its capacity as agent or otherwise.  In
performing  any of its duties under the power of attorney,  SBCW shall not incur
or be  responsible  for any  liabilities,  claims,  causes of  action,  demands,
judgments,  losses,  costs,  damages or expenses  whatsoever  ("Losses")  to the
Sublessor  Entities,   except  for  SBCW's  fraud,   willful  default  or  gross
negligence, and each Sublessor Entity shall indemnify SBCW against all Losses.

                  (Remainder of Page Intentionally Left Blank)

                                       56

<PAGE>

         IN WITNESS  WHEREOF,  the  Parties  have caused  this  Agreement  to be
executed and seated by their duly authorized  representatives,  all effective as
of the day and year first written above.

                                        TOWERCO:

                        Southern Towers, Inc.,a Delaware
                                        corporation

                             By /s/ Richard J. Byrne
                                    -------------------------------------------
                             Name: Richard J. Byrne
                              Title: Vice President

                                        SBCW:

                         SBC WIRELESS, INC., a Delaware
                      corporation (for itself and on behalf
                           of the Sublessor Entities)

                                        By /s/ Rick Linder
                                          -------------------------------------
                                Name: Rick Linder
                                Title: Sr. VP-COO

                                        TOWERCO PARENT:

                     SpectraSite Holdings, Inc., a Delaware
                                        corporation

                             By /s/ Adam Stulberger
                                          -------------------------------------
                              Name: Adam Stulberger
                        Title: Chief Development Officer

<PAGE>

                                     ANNEX A

                                  LIST OF SITES

<PAGE>

                                     ANNEX B

                              CONSIDERATION SUMMARY
<TABLE>
<S>                                                                             <C>

Consideration
     Aggregate Rent                                                                   $1,307,712,668
     Present Value of Aggregate Option Purchase Price                                    251,482,606 *
                                                                                 -----------------------
     Present Value of Consideration                                                   $1,559,195,274

Rent Components
     Cash Portion of Aggregate Rent                                                     $982,712,668
     Stock Portion of Aggregate Rent                                                     325,000,000
                                                                                 -----------------------
     Total Aggregate Rent                                                             $1,307,712,668

Share Calculation of Rent
     Share Price                                                                               22.74
     Total Shares of Stock Portion of Aggregate Rent                                      14,291,997

-----------------------------------------------
*    Net  present  value  of  aggregate  Option  Purchase  Price  Amounts  to be
     calculated  using  a 10%  discount  rate  back  from  the  applicable  Site
     Expiration Outside Date to August 25, 2000.

</TABLE>

<PAGE>

                                    EXHIBIT A

                   FORM OF ASSIGNMENT AND ASSUMPTION AGREEMENT

<PAGE>

                                    EXHIBIT A

                                      FORM

                                       of

                       ASSIGNMENT AND ASSUMPTION AGREEMENT

         This ASSIGNMENT AND ASSUMPTION OF AGREEMENT ("Assignment"),  made as of
the ___ day of ________,  2000,  by and among  [Applicable  Sublessor  Entities]
(each  an  "Assignor")  and  Southern  Towers,   Inc.,  a  Delaware  corporation
("Assignee");

                              W I T N E S S E T H:

     WHEREAS, SBC Wireless, Inc., the Sublessor Entities,  Southern Towers, Inc.
and SpectraSite  Holdings,  Inc. entered into that certain Agreement to Sublease
dated as of __________ __, 2000 ("Agreement to Sublease"). All capitalized terms
used  herein,  which  are not  otherwise  defined  herein,  shall  have the same
meanings as set forth in the Agreement to Sublease; and

         WHEREAS,  the Agreement to Sublease provides,  inter alia, that at each
Closing, the Applicable Sublessor Entities shall assign to Assignee the Existing
Leases on Sites included in such Closing,  and that Assignee shall assume all of
the  obligations of Assignors under such Existing Leases from and after the date
of such  assignment,  and that  Assignors  and  Assignee  shall  enter into this
Assignment;

         NOW,  THEREFORE,  in consideration of the premises and mutual covenants
herein contained, the parties hereto hereby agree as follows:

1. Assignment and Assumption of Existing  Leases.  Each Assignor hereby assigns,
sets over and transfers to Assignee all of its right,  title and interest in, to
and under  that  portion  of the  Existing  Leases  listed in Exhibit A attached
hereto  relating  to those  Sites  listed on  Exhibit  B  attached  hereto  (the
"Assigned Leases"),  and delegates to Assignee all of its duties and obligations
thereunder  arising from and after the date hereof.  Assignee hereby accepts all
of each  Assignor's  right,  title and  interest  in, to and under the  Assigned
Leases and assumes all  liabilities  arising  from and after the date hereof and
accepts the delegation of all obligations arising from and after the date hereof
of the respective Assignors under the Assigned Leases.

2. Inconsistent  Provisions.  Notwithstanding anything in this Assignment to the
contrary,  the parties agree that in the event of any conflict or  inconsistency
between the terms of this Assignment and the terms of the Agreement to Sublease,
the terms of the Agreement to Sublease shall control.

<PAGE>

3.  Miscellaneous.  This Assignment and the obligations of the parties hereunder
shall  survive the closing of the  transaction  referred to in the  Agreement to
Sublease and shall not be merged  therein and shall be binding upon and inure to
the benefit of the parties hereto and their  respective  legal  representatives,
successors and assigns.

4. Counterparts.  This Assignment may be executed in counterparts, each of which
shall  be an  original  and  all of  which  counterparts  taken  together  shall
constitute one and the same agreement.

5. No Third Party Benefits.  This Assignment and the agreements contained herein
are for the sole and exclusive  benefit of the parties hereto,  and no provision
hereof is intended to benefit,  nor shall any such provision be enforceable  by,
any person or entity not a party hereto.

6.  Notice.  All notices  hereunder  shall be deemed  validly  given if given in
accordance with the Assignment to Sublease.

7.  Governing  Law.  This  Agreement  shall  be  governed  by and  construed  in
accordance with the laws of the State of New York.

8. Modifications. This Assignment shall not be amended, supplemented or modified
in any  respect,  except  pursuant  to written  agreement  duly  executed by the
parties.

                                             ASSIGNORS:

                                             ------------------------------

                                             By:
                                                ---------------------------
                                      Name:
                                                     ----------------------
                                                Its:
                                                     ----------------------

                                             ASSIGNEE:

                                             ------------------------------

                                             By:
                                                 --------------------------
                                      Name:
                                                     ----------------------
                                                Its:
                                                     ----------------------

<PAGE>

                                    EXHIBIT A

                                 ASSIGNED LEASES

<PAGE>

                                    EXHIBIT B

                                APPLICABLE SITES

<PAGE>

                                    EXHIBIT B

                            FORM OF JOINDER AGREEMENT

<PAGE>

                                    EXHIBIT B

                                JOINDER AGREEMENT
                            TO THE SECOND AMENDED AND
                     RESTATED REGISTRATION RIGHTS AGREEMENT
                          OF SPECTRASITE HOLDINGS, INC.

                                __________, 2000

SBC Communications Inc.
175 E. Houston
San Antonio, TX  78205
Attention:  Senior Vice President/Corporate

Ladies and Gentlemen:

                  Reference is made to that certain  Second Amended and Restated
Registration  Rights Agreement dated April 20, 1999 among SpectraSite  Holdings,
Inc. (the "Company"),  the WCAS  Purchasers,  the Whitney  Purchasers,  the CIBC
Purchasers, the Additional Purchasers,  including TPC (each as defined therein),
as amended by the Joinder  Agreement to the  SpectraSite  Restated  Registration
Rights  Agreement,  dated  January  5,  2000,  among  the  Company  and the Apex
Stockholders (as defined therein) (such agreements, collectively, being referred
to herein as the "Existing  Registration  Rights  Agreement"  and the Purchasers
thereunder being referred to as the "Existing Holders").  Reference is also made
to that certain  Agreement to Sublease,  dated as of August ___,  2000 (the "SBC
Agreement") among the Company,  Southern Towers,  Inc., SBC Wireless,  Inc., for
itself and on behalf of the Sublessor Entities,  ("SBCW", and together with each
SBCW  Affiliate  who  receives  Parent  Stock (as defined in the SBC  Agreement)
pursuant to the SBC Agreement, and are listed on Annex A hereto, as the same may
be amended from time to time to reflect the SBCW  Affiliates that receive Parent
Stock in accordance  with the SBC  Agreement,  the "SBCW  Parties")  pursuant to
which the SBCW Parties will be entitled to become stockholders of the Company.
The Company and the SBCW Parties agree as follows:

1. By SBCW's  execution  of this  Joinder  Agreement on behalf of itself and the
SBCW Parties, subject to the terms and conditions set forth herein, (a) the SBCW
Parties will become a party to the Existing  Registration  Rights Agreement as a
holder of "SBCW Restricted  Stock" (as defined below),  (b) the Parent Stock (as
defined in the  Agreement)  (the "SBCW  Restricted  Stock")  shall be treated as
"Restricted  Stock" as that  term is used in the  Existing  Registration  Rights
Agreement for all purposes thereof, and (c) the SBCW Parties will be entitled to
all of the  benefits  of and  subject to all of the  obligations  of a holder of
"Restricted Stock" under the Existing Registration Rights Agreement as if it had
been an original party thereto.

<PAGE>

2. For purposes of Section 4 of the Existing  Registration Rights Agreement,  it
is  understood  that in measuring  the 25%  threshold,  all shares of Restricted
Stock  currently  outstanding  and subject to the Existing  Registration  Rights
Agreement  and all shares of the SBCW  Parties  Restricted  Stock shall be taken
into account.

3. Section 5 is hereby  amended by deleting  the first  sentence of Section 5(a)
and replacing it in its entirety with the following:

                  "If,  at  any  time  when  Form  S-3  is  available  for  such
registration  and  subject  to the  terms  of  Section  2 of  the  Stockholders'
Agreement,  the Company shall receive from any Institutional  Investor, the SBCW
Parties or TPC a written  request that the Company effect a registration on Form
S-3 of any such  holder's  Restricted  Stock,  the Company  will  promptly  give
written notice of the proposed  registration  to all other holders of Restricted
Stock,  and , as soon as  practicable,  effect  such  registration  and all such
related  qualifications  and  compliances as may be reasonably  requested and as
would permit or facilitate the sale and  distribution of all Restricted Stock as
are  specified in such request and any written  requests of other  holders given
within 20 days after receipt of such notice."

4. For  purposes  of  Sections 4, 5 and 6 of the  Existing  Registration  Rights
Agreement,  it is understood that with respect to any sales of Restricted  Stock
in an underwritten  registered public offering under such sections (other than a
registration initiated by the SBCW Parties or its Affiliates),  the SBCW Parties
obligation to include in such  registration  its Restricted  Stock pursuant to a
request to include such stock in such offering in accordance with the provisions
of  Section  4, 5 or 6,  may be  conditioned,  at the  SBC  Parties  option  (by
expressly  stating  so in its  request),  upon  such  offering  qualifying  as a
Liquidity Event (as defined in the SBC Agreement).

5. The Company  intends to file a  registration  statement on Form S-3 (or other
appropriate  form  available  for  registering  stock for sale to the public) to
register the resale by the SBCW Parties of  $25,000,000  of Restricted  Stock as
contemplated by Section 5.14 of the SBC Agreement.

6. The Company represents and warrants to the undersigned as follows:

(a) The Company has full  corporate  power and  authority to execute and deliver
this Joinder  Agreement and to perform its obligations  hereunder.  This Joinder
Agreement  constitutes the valid and legally binding  obligation of the Company,
enforceable in accordance with its terms and conditions,  subject to bankruptcy,
insolvency,  reorganization,  moratorium  or similar  laws now or  hereafter  in
effect affecting creditors' rights generally.  The Company does not need to give
any notice to, make any filing with, or obtain any  authorization,  consent,  or
approval of any other party in order to consummate the transactions contemplated
by this Joinder  Agreement  other than such  notices,  filings,  authorizations,
consents and approvals as have been obtained prior to the date hereof.

(b) Neither the  execution and the delivery of this Joinder  Agreement,  nor the
consummation  of  the  transactions   contemplated   hereby,   (i)  violate  any
injunction, judgment, order, decree, ruling, charge, or other restriction of any
governmental  authority to which the Company is subject or any  provision of its
charter  or bylaws or (ii)  other than such  notices,  filings,  authorizations,
consents and  approvals as have been  obtained and after giving  effect to them,
violate,  result  in a breach  of,  constitute  a default  under,  result in the
acceleration of, create in any party the right to accelerate, terminate, modify,
or cancel, or require any notice under any agreement,  contract, lease, license,
instrument,  or other arrangement to which the Company is a party or by which it
is bound or to which any of its assets is subject.

                                       2
<PAGE>

7.  Notices,  requests,  consents and other  communications  mailed  pursuant to
Section 13(c) of the Existing  Registration  Rights Agreement,  if mailed to the
SBCW Parties, shall be mailed to:

                           SBC Communications, Inc.
                           175 E. Houston, 12th Floor
                           San Antonio, TX  78205
                           Attention:  Senior Executive Vice President -
                              Corporate Development

                           with a copy to:

                           SBC Communications Inc.
                           175 E. Houston, 4th Floor
                           San Antonio, TX  78205
                 Attention: Vice President and Assistant General
                        Counsel-Mergers and Acquisitions

8. This Joinder  Agreement shall be governed by and construed in accordance with
the laws of the State of New York without  regard to  principles of conflicts of
law of such state.

9. This  Joinder  Agreement,  together  with the  Existing  Registration  Rights
Agreement as modified  hereby,  constitutes the entire  agreement of the parties
with respect to the subject  matter  hereof.  Hereafter,  the Joinder  Agreement
shall be deemed part of and incorporated into the Existing  Registration  Rights
Agreement,  and the  Existing  Registration  Rights  Agreement  (including  this
Joinder  Agreement)  may be modified or amended only in accordance  with Section
13(e) of the Existing  Registration  Rights  Agreement,  taking into account the
SBCW Restricted Stock then  outstanding in measuring the 60% threshold  provided
therein,  except that any  modification or amendment that adversely  affects the
rights or  privileges  of the SBCW Parties and does not affect the other holders
of Restricted Stock and Management Stock in a substantially similar manner shall
require the consent of the SBCW Parties.

10. This Joinder Agreement may be executed in two or more counterparts,  each of
which shall be deemed an original,  but all of which together  shall  constitute
one and the same instrument.

         [The remainder of this page has been intentionally left blank]

                                       3

<PAGE>

                                     Annex A

This Annex A shall  include and be amended from time to time, to include any SBC
Affiliate who receives common stock under the SBC Agreement.

<PAGE>

                                    EXHIBIT C

                FORM OF AMENDMENT TO THE STOCKHOLDERS' AGREEMENT

<PAGE>

                                    EXHIBIT C

                      AMENDMENT NO. 1 TO THE THIRD AMENDED
                      AND RESTATED STOCKHOLDERS' AGREEMENT

                  Amendment  No.  1,  dated as of  ______,  2000,  to the  Third
Amended and Restated  Stockholders'  Agreement,  dated as of April 20, 1999 (the
"Stockholders'  Agreement"),  by and among the Company, the WCAS Purchasers, SBC
Wireless,  Inc.  ("SBCW") and the SBCW Affiliates who receive Common Stock under
the SBC  Agreement (as defined  below) and are listed on Annex A hereto,  as the
same may be  amended  from  time to time to  reflect  the SBCW  Affiliates  that
receive  Parent  Stock in  accordance  with  the SBC  Agreement  (such  parties,
together with SBCW, the "SBC Parties"),  TPC, CIBC II, CIBC III, Caravelle,  JHW
II, JHW III, JHW Strategic III, JHW Mezzanine,  Clark,  Tomick,  Bryne,  Waller,
Kitty Hawk III, Kitty Hawk IV, Eagle Creek, Finley LP, NCEF, Lutkewich, Jackman,
Eckert,  Gupton, Price LP and Benake.  Unless otherwise defined herein,  defined
terms shall have such meanings ascribed to them in the Stockholders' Agreement.

                  WHEREAS,  pursuant to the terms of that  certain  Agreement to
Sublease,  dated as of August __,  2000,  by and among  SBCW (for  itself and on
behalf of the Sublessor  Entities),  the Company and Southern Towers,  Inc. (the
"SBC Agreement"),  the SBC Parties have,  subject to the terms and conditions of
the SBC  Agreement,  the right to receive  shares of Common  Stock as more fully
described in Section 3.2 of the SBC Agreement; and

                  WHEREAS,   pursuant   to  Section  18  of  the   Stockholders'
Agreement, the Company, the Stockholders and the SBC Parties desire to amend the
Stockholders'  Agreement to admit the SBC Parties as a stockholder and make such
amendment, in connection therewith, as more particularly set forth herein.

                  NOW,  THEREFORE,  in  consideration  of the  premises  and the
mutual covenants and agreements  contained  herein,  the parties hereby agree as
follows:

1.       Amendment of the "Stockholders" Definition.

                  The defined term "Stockholders" contained in the Stockholders'
Agreement is hereby  amended to include SBC Wireless,  Inc.  ("SBCW") a Delaware
corporation and the SBCW Affiliates who receive Common Stock pursuant to the SBC
Agreement and are listed on Annex A hereto, as the same may be amended from time
to time with the consent of the Company and SBCW (such  parties,  together  with
SBCW, the "SBC Parties").

2. Amendment of Section 1(a)(i).

                  Section  1(a)(i)  of the  Stockholders'  Agreement  is  hereby
amended in its entirety and replaced by the following:

<PAGE>

                           "(i) An  amendment  to the  by-laws of the Company to
                  provide that the  authorized  number of directors of the board
                  of directors of the Company (the "Board") shall be established
                  at twelve (12)  persons or, at the request of the holders of a
                  majority of the Common Stock then held by the WCAS Purchasers,
                  to increase the size of the Board,  up to a maximum of fifteen
                  (15) persons;".

3. Amendment of Section 1(a)(ii).

                  Section  1(a)(ii)  of the  Stockholders'  Agreement  is hereby
amended  by  deleting  the word  "and" at the end of  paragraph  (d);  by moving
paragraph  (e) in its  entirety  to become  paragraph  (f);  and by adding a new
paragraph (e) after paragraph (d) which shall read in its entirety:

                  "(e)   one  (1)   director   designated   by   SBCW   and  one
                  representative  of the SBC  Parties  who shall be  entitled to
                  attend, as a non-voting observer, all meetings of the Board or
                  any committee thereof and to receive all notices, information,
                  and other materials distributed to the members of the Board or
                  any such  committee at the same time and in the same manner as
                  so distributed; and".

4. Amendment of Section 1(a)(iii).

                  Section  1(a)(iii)  of the  Stockholders'  Agreement is hereby
amended in its entirety and replaced with the following:

                           "(iii) the  removal  from the Board  (with or without
                  cause) of any director or representative elected in accordance
                  with  subpart  a), b), c), d) or e) of clause  (ii) above upon
                  the written request of the  Stockholders  that designated such
                  director or representative; and"

5. Amendment of Section 1(a)(iv).

                  Section  1(a)(iv)  of the  Stockholders'  Agreement  is hereby
amended by deleting  the phrase  "subpart  e)" and  replacing it with the phrase
"subpart f)".

6. Amendment to Section 2(iv).

                  Section 2(iv) of the Stockholders' Agreement is hereby amended
by deleting the word "or" at the end thereof.

7. Amendment to Section 2(v).

                  Section 2(v) of the Stockholders'  Agreement is hereby amended
by adding the word "or" at the end thereof.

                                       2
<PAGE>

8. Amendment to Section 2.

                  Section 2 of the Stockholders'  Agreement is hereby amended by
adding the following new subclause (vi) after subclause (v);

                           "(vi) in the  event  that the  covenant  set forth in
                  Section 5.14 of the SBC  Agreement is satisfied  other than by
                  the payment of  $25,000,000  in cash,  any transfer by any SBC
                  Party of up to an  aggregate  of  $25,000,000  of Common Stock
                  issued  to the SBC  Parties  under  Section  3.2(b) of the SBC
                  Agreement;"

9. Amendment of Section 10(b).

                  Section 10(b) of the Stockholders' Agreement is hereby amended
in its entirety and replaced with the following:

                           "(b)  The  respective  rights  granted  to  the  WCAS
                  Purchasers,  the Whitney Purchasers,  the CIBC Purchasers, the
                  SBC Parties and TPC  pursuant to Section 1 shall  terminate as
                  to any group of Purchasers  or the SBC Parties,  respectively,
                  on the  earlier  to occur of (i) the sale,  transfer  or other
                  disposition  (including a disposition  by a partnership to its
                  partners  or a limited  liability  company to its  members) by
                  such  Purchasers or the SBC Parties,  respectively of at least
                  50% of the shares of Capital Stock held by such  Purchasers or
                  the SBC Parties, respectively on the date of this Amendment or
                  (ii) the ownership of Capital Stock held by such Purchasers or
                  the SBC  Parties,  respectively,  shall  fall  below 8% of the
                  outstanding Capital Stock of the Company."

10. Amendment of Section 18.

                  Section 18 of the Stockholders' Agreement is hereby amended by
deleting  the word "or"  appearing  before the word "TPC" in the  proviso of the
first  sentence and inserting a "comma" in place  thereof;  and by inserting the
phrase "or the SBC Parties" before the phrase "to the extent any".

11.  Continuing  Effect of  Stockholders'  Agreement.  This Amendment  shall not
constitute  an  amendment  or   modification  of  any  other  provision  of  the
Stockholders'  Agreement not expressly  referred to herein.  Except as expressly
amended or modified herein,  the provisions of the  Stockholders'  Agreement are
and shall remain in full force and effect.

12.  Counterparts.  This Amendment may be executed by one or more of the parties
hereto on any number of separate counterparts and all such counterparts shall be
deemed to be one and the same  instrument.  Each party hereto  confirms that any
facsimile  copy of such party's  executed  counterpart of this Amendment (or its
signature page thereof) shall be deemed to be an executed original thereof.

                                       3
<PAGE>

13.  Governing Law. This  Amendment  shall be governed by, and  interpreted  and
construed  in  accordance  with,  the  internal  laws of the State of  Delaware,
without regard to principles of conflicts of law.

                                       4

<PAGE>

                                                                         Annex A

                  This Annex A shall include and be amended,  from time to time,
to include any SBC Affiliate who receive Common Stock under the SBC Agreement.

                                       5
<PAGE>

                                    EXHIBIT D

                         FORM OF BUILD-TO-SUIT AGREEMENT

<PAGE>

                                    EXHIBIT D

                                      FORM

                                       of

                             BUILD-TO-SUIT AGREEMENT

================================================================================

================================================================================

================================================================================
                           AGREEMENT TO BUILD TO SUIT
================================================================================
================================================================================

================================================================================

                                  By and Among

                               SBC WIRELESS, INC.,
           for itself and as Agent for certain SBCW Parties Designated
                         on the signatures Page Hereof,

                                       and

================================================================================
                           SPECTRASITE HOLDINGS, INC.
================================================================================
================================================================================
                                [TowerCo Parent]
================================================================================

                                       and

================================================================================
                        SPECTRASITE COMMUNICATIONS, INC.
================================================================================
================================================================================
              [Vendor, a wholly-owned subsidiary of TowerCo Parent]
================================================================================

                                October ___, 2000

<PAGE>

                                TABLE OF CONTENTS

                                                                           Page

                                    Article I
                                   Definitions

Section 1.01.Definitions...................................................1
Section 1.02.Use of Words and Phrases......................................8

                                   Article II
                               Agreement Documents

                                   Article III
                     Scope Of Work; Nature Of The Engagement

Section 3.01.Engagement of Vendor..........................................9
Section 3.02.Identification of Collocation Sites..........................10
Section 3.03.Term.   11
Section 3.04.Time for Commencement and Completion.........................11
Section 3.05.Relationship.................................................11
Section 3.06.Project Personnel............................................12
Section 3.07.Familiarity with Project and BTS Sites.......................13
Section 3.08.Quality Standard.............................................13
Section 3.09.Books and Records of Vendor, Right of Inspection by SBCW.....13
Section 3.10.Scope of the Project.........................................14
Section 3.11.Available BTS Sites in Event of Condemnation.................15

                               Article IV Vendor's
                                  Undertakings.

Section 4.01.Vendor's Undertakings........................................16
Section 4.02.Governmental Requirements and Permits........................16

                                    Article V
                             Pre-Construction Phase

Section 5.01.Proposal of BTS Sites; Development Plan......................18
Section 5.02.Due Diligence................................................20
Section 5.03.Utilities....................................................20

                                   Article VI
                               Construction Phase

Section 6.01.General......................................................21
Section 6.02.Performance of the Work......................................22
Section 6.03.Implementation Plan..........................................22
Section 6.04.Site Schedule................................................22

                                       i
<PAGE>

Section 6.05.Quality Review...............................................23
Section 6.06.Compliance with Requirements, Permits, Bonds and Insurance during
             Construction.................................................23
Section 6.07.Work Permits.................................................23
Section 6.08.Construction by Vendor.......................................24
Section 6.09.Site Data....................................................24
Section 6.10.Warranty.....................................................24
Section 6.11.Access and Inspection........................................25
Section 6.12.Completion...................................................25

                                   Article VII
                             Guaranty Of Obligations

Section 7.01.TowerCo Parent's Guaranty....................................26

                                  Article VIII
                 Vendor's Additional Obligations As To Bts Sites

Section 8.01.Hazardous Waste and Contamination Investigation..............28
Section 8.02.Geotechnical Subsurface and Soil Investigation...............28
Section 8.03.Additional Environmental Requirements........................28
Section 8.04.FAA/FCC Compliance...........................................29

                                   Article IX
                              Agreement To Sublease

Section 9.01.Execution of the Site Designation Supplement.................29
Section 9.02.Effect of Sublease and Site Designation Supplement...........30

                                    Article X
                                    Insurance

Section 10.01.Vendor's Insurance Requirements.............................30
Section 10.02.Evidence of Insurance.......................................31
Section 10.03.Waiver of Subrogation.......................................31

                                   Article XI
                              Liability; Indemnity

Section 11.01.Liquidated Damages..........................................31
Section 11.02.Indemnity of SBCW...........................................32
Section 11.03.Relationship to Insurance...................................33
Section 11.04.No Third-Party Beneficiaries................................33

                                   Article XII
                    Additional Representations And Warranties

Section 12.01.SBCW's Representations and Warranties.......................33
Section 12.02.Vendor's Representations and Warranties.....................33
Section 12.03.TowerCo Parent's Representations and Warranties.............34

                                       ii
<PAGE>

                                  Article XIII
                             Default And Termination

Section 13.01.Default by Vendor...........................................34
Section 13.02.Obligations upon Termination................................36
Section 13.03.Termination of Agreement by Vendor in Respect of SBCW's
Bankruptcy................................................................36

                                   Article XIV
                                  Force Majeure

Section 14.01.Force Majeure...............................................37
Section 14.02.Effect of Force Majeure.....................................37

                                   Article XV
                      Fire or Other Casualty; Condemnation

Section 15.01.Obligation to Reconstruct; Use of Insurance Proceeds........37
Section 15.02.Condemnation of the Tower or Site; Application of
Compensation..............................................................38

                                   Article XVI
                                  Miscellaneous

Section 16.01.Notices.....................................................38
Section 16.02.Assignment, Binding Effect..................................39
Section 16.03.Authorized Representatives..................................40
Section 16.04.Headings....................................................40
Section 16.05.Annexes, Exhibits and Schedules.............................40
Section 16.06.Publicity...................................................40
Section 16.07.Severability................................................40
Section 16.08.Waiver......................................................41
Section 16.09.Rights Cumulative...........................................41
Section 16.10.Time of Essence, Prompt Responses...........................41
Section 16.11.Applicable Law..............................................41
Section 16.12.Waiver of Jury Trial........................................41
Section 16.13.Entire Agreement............................................41
Section 16.14.Modifications...............................................42
Section 16.15.Counterparts................................................42
Section 16.16.No Brokers..................................................42
Section 16.17.Power of Attorney by SBCW Parties; Authorization............42

Annexes and Schedules

Annex A                    Specifications
Annex B                    Vendor Responsibility Matrix
Annex C                    Project Data Requirements; Form of SARF
Annex D                    Form of Candidate Sheet; Notice to Proceed
Annex E                    Form of Punch List

                                      iii
<PAGE>

Annex F                    Certificate of Completion
Annex G                    Form of Site Data Package; Form of Due Diligence
                           Package
Annex H                    Form of Site Schedule
Annex I                    Collocation Services on TowerCo Existing Sites
                           Summary
Annex J                    Terms of BTS Sublease
Annex K                    SBCW Standard Configuration
Annex L                    Minimum Standards for BTS Sites
Annex M                    Minimum Standards for Potential Collocation Sites
Annex N                    Existing Contracts

Schedule 8.04              Rules, Policies, Regulations and Interpretations of
                           SBCW Relating to or in Connection
                           with Applicable FAA and FCC Regulations
Schedule 3.10(c)           Terms under which SBCW may acquire Sites and develop
                           and construct its own Towers and
                           transfer such Towers to Southern Towers, Inc., an
                           Affiliate of Vendor

                                       iv

<PAGE>

                           AGREEMENT TO BUILD TO SUIT

         THIS  AGREEMENT,  made and  entered  into as of the ___ day of October,
2000 by and between SBC WIRELESS  INC.,  a Delaware  corporation  ("SBCW"),  for
itself and as Agent for  certain  SBCW  Parties  (as  defined  in Section  1.01)
designated on the signature pages hereto, SPECTRASITE HOLDINGS, INC., a Delaware
corporation  ("TowerCo  Parent"),  and  SPECTRASITE   COMMUNICATIONS,   INC.,  a
wholly-owned subsidiary of TowerCo Parent and a Delaware corporation ("Vendor").

                              W I T N E S S E T H:

         WHEREAS,  SBCW  desires  for  Vendor to  identify  potential  cell site
locations  within  specified  search  areas  located  within the  Territory  for
build-to-suit  sites and to cause  each such  cell site  selected  by SBCW to be
acquired or leased by Vendor and to be developed,  among other things, causing a
tower and other improvements to be designed,  constructed and installed thereon,
for the  non-exclusive use and occupancy by SBCW or SBCW Parties pursuant to the
BTS Sublease; and

         WHEREAS,  SBCW and Vendor  desire to enter into this  Agreement  to set
forth their respective  duties and  responsibilities  pertaining to such design,
construction and installation and other matters relating thereto;

         NOW,  THEREFORE,  for and in consideration  of the premises,  and other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereby agree as follows:

                                   Article I
                                   Definitions

Section 1.01.     Definitions.

(a) The following capitalized terms shall have the following respective meanings
for purposes of this Agreement:

                  "Acquisition"  means the acquisition by Vendor of a fee simple
         title to or ground lease interest in each BTS Site, all investigations,
         examinations, tests and inspections, and other due diligence activities
         incidental thereto, and all legal activities incident thereto.

                  "Affiliate" means with respect to either party, any individual
         or  firm,   corporation,   partnership,   limited  liability   company,
         association,   trust  or  other  entity  which,   whether  directly  or
         indirectly, Controls, is Controlled by, or is under common Control with
         the subject party.

                  "Agreement"  means  this  Agreement,  including  any  Annexes,
         Schedules and any amendments hereto or thereto.

<PAGE>

                  "Agreement to Sublease" means the Agreement to Sublease dated
          __________,  among TowerCo Parent, Vendor, SBC TowerCo Inc. and the
          other Sublessor Entities named therein.

                  "BTS Rent" has the meaning given to such term in the BTS
          Sublease.

                  "BTS Sites" means the cell tower site locations located within
         the Territory  that are or will be owned or leased by Vendor or TowerCo
         Affiliates:  (i) on which Vendor  constructs or is to construct  Towers
         and Improvements pursuant to this Agreement;  and (ii) on which SBCW or
         a SBCW Party leases the Leased Space.  BTS Sites include  Completed BTS
         Sites but excludes TowerCo Existing Sites.

                  "BTS Sublease"  means the Sublease (BTS) of even date herewith
         among TowerCo  Parent,  Vendor (or Southern  Towers,  Inc.,  an
         Affiliate  of Vendor) and SBCW.  [NOTE:  The terms of the BTS  Sublease
         are summarized on Annex J attached  hereto.  Prior to the execution of
         this Agreement, the parties will agree on the form of the BTS
         Sublease.]

                  "Business Day" means any day other than a Saturday,  Sunday or
         other  day on which  commercial  banks are  authorized  to close in New
         York.

                  "Claim" has the meaning given to such term in Section 11.02.

                  "Collocation Services" has the meaning given such term in
        Section 3.02.

                  "Communications Equipment" has the meaning given to such term
        in the BTS Sublease.

                  "Completion,"  "Complete"  or  "Completed"  means (i) Vendor's
         receipt of zoning  approvals and other  Permits in accordance  with all
         Governmental  Requirements,  and all  applicable  FAA approvals  and/or
         antennas  structure  registration  ("ASR")  approvals (FCC Form 854 and
         854R) have been  appropriately  filed; (ii) Vendor's  completion of all
         items of  construction in accordance  with the  Specifications  and the
         requirements  of all  Governmental  Authorities so that SBCW or an SBCW
         Party can use the Leased Space of the BTS Site without  interference in
         the  conduct  of  its  ordinary  business  activities;  (iii)  Vendor's
         securing  a  certificate  of  occupancy  or any other  final  municipal
         approval from the applicable Governmental Authority;  (iv) the issuance
         by SBCW of the Completion  Certificate;  (v) ready access by SBCW or an
         SBCW  Party,  its  employees,  agents and  invitees,  to (A) during the
         construction   period,   the  entire  BTS  Site  (including  Tower  and
         Improvements) and (B) after the Completion of construction,  the Leased
         Space;  (vi) all the fixtures  and  equipment to be installed by Vendor
         are installed and in good operating order; (vii) the BTS Site is clean;
         and  (viii)  the  Tower  and  the   Improvements   are  ready  for  the
         installation of SBCW's Improvements.

                  "Completion  Certificate"  means,  as to each  BTS  Site,  the
         certificate of completion  issued by SBCW with respect to such BTS Site
         to the  effect  that the Work is  Completed  in  compliance  with  this
         Agreement, which certificate shall be issued in accordance with Annex F
         attached hereto.

                                       2
<PAGE>

                  "Completion Data" means height verification certifications via
         1-A  survey,  tape  drop or  some  other  agreed  method,  center  line
         measurements,  exact  location of all  equipment on a Tower,  and where
         required,  marking and  lighting  verification  and correct  posting of
         Tower registration numbers.

                  "Completion  Date"  means  the date on  which  the  Tower  and
         Improvements  are Completed with respect to each BTS Site,  pursuant to
         the Implementation Plan and the applicable Site Schedule.

                  "Completed BTS Sites" has the meaning given to such term in
         Section 6.12(c).

                  "Compliance  Data" means a 1-A survey of exact Tower location,
         certified by a registered surveyor, together with a topography map plot
         confirming  the  location  and  providing  the address of the BTS Site,
         FAA/FCC  height  verifications  as certified by either a surveyor or an
         independent  contractor  authorized to perform height  measurements  in
         accordance with SBCW specifications, FAA approvals, where required (FAA
         forms 7460-1,  7460-2),  FCC Tower  registration  forms, where required
         (FCC forms 854 and 854-R),  certification  that the Tower  registration
         number is posted at the BTS Site as  required  by the FCC  regulations,
         certification that correct  marking/lighting  is in place in accordance
         with FAA requirements, and a completed NEPA/EPA checklist demonstrating
         environmental compliance.

                  "Constructed  Improvements" means (i) grounding rings for SBCW
         and SBCW Party  equipment  shelters,  (ii)  connections  for  utilities
         service from the meter to SBCW's Communications Equipment, (iii) one or
         more  foundations,  concrete  equipment  pads or raised  platforms  for
         SBCW's  Communications  Equipment,  equipment  shelters,  buildings and
         constructions,  and (iv) any other  Improvements built for SBCW's or an
         SBCW Party's exclusive use in accordance with the Annexes.

                  "Contract Manager" has the meaning given to such term in
         Section 3.06(e).

                  "Control"  means the  ownership,  directly or  indirectly,  of
         sufficient  voting shares of an entity,  or otherwise  the  possession,
         directly or  indirectly,  of the power to direct or cause the direction
         of the management and policies of an entity, or the power to veto major
         policy  decisions of any such entity,  whether through the ownership of
         voting securities, by contract or otherwise.

                  "Due Diligence  Package" means  collectively  the documents in
         the form of Annex G-2 and  information  collected  by  Vendor  pursuant
         thereto.

                  "Effective Date" means the date first above written, being the
         date on which the parties have executed and delivered this Agreement.

                  "Environmental  Assessment" means the "Phase I" (as defined by
         the National Environmental  Protection Agency) environmental assessment
         of each BTS Site,  and such further  investigations  as are  reasonably
         indicated by the results thereof, to be obtained by Vendor pursuant to
         Article 8 hereof.

                                       3
<PAGE>

                  "Environmental Conditions" has the meaning given to such term
         in the Agreement to Sublease.

                  "Environment, Health and Safety Requirements" means all of the
         terms and conditions of all permits,  licenses and other authorizations
         which are  required  under,  and all other  limitations,  restrictions,
         conditions,   standards,   prohibitions,   requirements,   obligations,
         schedules and timetables which are contained in all federal,  state and
         local laws (including rules,  regulations,  codes,  judgments,  orders,
         decrees, stipulations,  injunctions and demand letters issued, entered,
         promulgated  or  approved  thereunder)  relating  to public  health and
         safety,  worker  health and safety or  pollution or  protection  of the
         environment, including laws relating to emissions, discharges, releases
         or threatened releases of Hazardous Materials into ambient air, surface
         water,  ground water or lands or otherwise relating to the manufacture,
         processing,  distribution, use, treatment, storage, disposal, transport
         or handling of Hazardous Materials and all provisions of FCC regulation
         1.1307 et seq.

                  "Excusable  Delay" means as to any BTS Site,  a Force  Majeure
         event as to such BTS Site,  or an extension or  adjustment  of the Site
         Schedule  only as it applies to the affected BTS Site,  as provided for
         and expressly permitted under the terms of this Agreement.

                  "FAA" means the Federal Aviation Administration.

                  "FCC" means the Federal Communications Commission.

                  "Force  Majeure" means those events  constituting  excuse from
         timely  performance  by Vendor of any duty or  obligation  hereunder to
         which it is subject, as such events are described in Article 13 hereof.

                  "Governmental  Authority" means any federal,  state, county or
         municipal governmental authority, including all executive, legislative,
         judicial and administrative bodies thereof.

                  "Governmental  Requirements" means (i) all federal,  state and
         local laws,  ordinances,  and regulations and all orders and decrees of
         bodies or all Governmental Authorities,  which in any manner affect the
         Services  provided under this  Agreement,  Vendor's  performance of its
         obligations  hereunder  or the  ownership,  use or operation of the BTS
         Sites, and (ii) all Environment, Health and Safety Requirements.

                  "Ground  Lease"  means,  as to a given  BTS Site,  the  ground
         lease,  easement  or other right of use  pursuant to which  Vendor or a
         TowerCo Affiliate holds a leasehold interest, leasehold estate or other
         possessory interest therein.

                  "Ground Lease  Effective  Date" means, as to any Ground Lease,
         the date of execution and delivery by Vendor or a TowerCo  Affiliate of
         a Ground Lease or, as to any option to enter into any Ground Lease, the
         date on which such option is exercised.

                  "Hazardous Materials" has the meaning given to such term in
         the BTS Sublease.

                                       4
<PAGE>

                  "Implementation  Plan"  means,  as to each Site,  a plan to be
         prepared by Vendor that sets forth (i) a narrative description for each
         phase of the  Development  of such BTS  Site  (pre-construction  phase,
         construction phase and post-construction phase and Services),  and (ii)
         an appropriate  Site Schedule  developed and agreed upon by the parties
         pursuant to this Agreement and Annexes attached  hereto,  substantially
         in the form of Annex H.

                  "Improvements" has the meaning given to such term in the BTS
         Sublease.

                  "Leased  Space" has the meaning  given to such term in the BTS
         Sublease;  except that (i)  regardless of the actual number of antennas
         and related equipment placed on the Leased Space of any BTS Site at the
         time of the execution of the applicable  Site  Designation  Supplement,
         the Leased  Space of such BTS Site  shall  include  space  for,  and be
         capable  of  supporting  the  following  equipment  or the  tower  load
         equivalent of: (x) up to twelve (12) panel antennas consistent with the
         (12) panel antenna arrays and related  equipment  specified in Annex A,
         and (y) a microwave dish placed  seventeen  feet (17') below  (measured
         center-line  to  center-line)  the location of such  panels;  provided,
         however,  that the size of such antennas and  microwave  dish shall not
         exceed  that of SBCW's  configuration(s)  for  antennas  and  microwave
         dishes  as more  particularly  described  in Annex  K,  and (ii)  shall
         include a sector frame for such antennas.

                  "Liquidated Damages" has the meaning given to such term in
         Section 11.01.

                  "Notice  to  Proceed"  means  a  written  notice  to  proceed,
         substantially in the form of the Notice to Proceed included in Annex D,
         given by SBCW to Vendor pursuant to this Agreement.

                  "Obligations" has the meaning given to such term in Section
         7.01.

                  "Permit Appeal Action" has the meaning given to such term in
         Section 4.02(h).

                  "Permits" means any and all certificates,  licenses,  permits,
         authorizations,  registrations, consents, special use permits and other
         approvals   by   the   applicable   Governmental   Authorities   having
         jurisdiction in such matters required to be obtained,  issued,  granted
         or  received  for the  performance  of the Work and  Completion  or the
         Permitted Use (other than as to installation  of SBCW's  Communications
         Equipment),  including  without  limitation  any and all  Permits to be
         issued  by all  Governmental  Authorities  that  are  required  for the
         construction of the Tower and Improvements related thereto.

                  "Permitted Use" has the meaning given to such term in the BTS
         Sublease.

                  "Person" means any individual, firm, corporation, partnership,
         limited liability company,  trust,  unincorporated business association
         or Governmental Authority.

                  "Potential Collocation Sites" has the meaning given to such
         term in Section 3.02.

                                       5
<PAGE>

                  "Project"   means   Vendor's   performance  of  the  Work  and
         construction  of the Towers on the BTS Sites and the  provision  of the
         Collocation Services if requested by SBCW.

                  "Punch List" has the meaning given to such term in Section
         6.12(c).

                  "SARF" has the meaning given to such term in Section 5.01(a).

                  "SBCW" has the meaning given to such term in the Preamble to
         this Agreement.

                  "SBCW's Communications Equipment" has the meaning given to
         such term in the BTS Sublease.

                  "SBCW Indemnitee" means each of SBCW, SBCW's  Affiliates,  and
         the respective directors,  officers,  employees,  agents,  contractors,
         subcontractors, advisors and consultants of SBCW and SBCW Parties.

                  "SBCW's Improvements" has the meaning given to such term in
         the BTS Sublease.

                  "SBCW  Party"  means   corporations,   partnerships,   limited
         liability  companies or other  entities  which are  Affiliates of SBCW,
         whose names are set forth on the signature pages hereof.

                  "SBCW Sublease" has the meaning given to such term in Section
         16.02.

                  "Scheduled  Commencement Date" means, with respect to each BTS
         Site,  the date on which  the  Work on such  BTS Site is  scheduled  to
         commence pursuant to the applicable Notice to Proceed given by SBCW.

                  "Services"  means all  services  required to be  performed  or
         procured by Vendor  subject and pursuant to the terms and conditions of
         this Agreement  including,  without  limitation:  (i) identification of
         potential  new locations  for BTS Sites within each  designated  search
         area and  presentation  of such  potential  BTS Sites to SBCW for final
         selection;  (ii)  Acquisition  of BTS  Sites;  (iii)  construction  and
         installation of a Tower and  Improvements on each of the BTS Sites; and
         (iv) the  identification  of  Potential  Collocation  Sites on  TowerCo
         Existing  Sites and the  provision  of other  Collocation  Services  if
         requested  by  SBCW,  all  as  more  particularly   described  in  this
         Agreement, including the Annexes.

                  "Site Data Package"  means  collectively  the documents in the
         form of Annex G-1  attached  hereto and the  information  collected  by
         TowerCo Parent pursuant thereto.

                  "Site  Completion  Date" means, as to each BTS Site, a date of
         execution of the Completion Certificate for such BTS Site.

                  "Site Designation Supplement" has the meaning given to such
         term in the BTS Sublease.

                                       6
<PAGE>

                  "Site  Schedule"  means a  timetable  prepared  by Vendor  and
         reasonably  approved  in writing by SBCW with  respect to each BTS Site
         that  graphically  describes the time periods and completion  dates for
         each of the  activities  necessary to complete the Work with respect to
         such BTS Site in the form and consistent with Annex H and conforming to
         the dates provided in this Agreement.

                  "Space Subtenants" has the meaning given to such term in the
         BTS Sublease.

                  "Specifications"    means   the   drawings    and    technical
         specifications for the Tower and Improvements, as set forth in Annex A.

                  "Substantially  Complete" means, as to any BTS Site, that such
         BTS Site is  Complete,  except for minor items listed on the Punch List
         for such BTS Site that  would not  impair  or  adversely  affect in any
         material respect, or is not likely to impair or adversely affect in any
         material  respect,  SBCW's or SBCW  Party's  use and  operation  of the
         Leased Space on such BTS Site, including Communications Equipment.

                  "Substantially  Completed  BTS  Site"  means any BTS Site that
         would be a Completed  BTS Site,  except for minor  items  listed on the
         Punch List for such BTS Site that would not impair or adversely  affect
         in any material  respect  SBCW's or a SBCW Party's use and operation of
         the Leased Space on such BTS Site, including Communications Equipment.

                  "Term" has the meaning given to such term in Section 3.03.

                  "Territory" means the United States of America, Puerto Rico
         and the U.S. Virgin Islands.

                  "Tower" means a wireless transmission tower structure.  Towers
         shall  not  include  TowerCo  Existing  Sites  and  shall  not  include
         rooftops,   steeples,   chimneys,   water  towers  or  other   existing
         structures,  or other structures that would  constitute  "owned neutral
         host infrastructure" or "in-building applications."

                  "TowerCo  Existing  Sites"  means  all  wireless  transmission
         towers,  now or  hereafter  owned or leased or operated  under  capital
         leases by Vendor, TowerCo Parent or by any entity Controlled by TowerCo
         Parent and located within the Territory,  provided,  however,  that BTS
         Sites shall not constitute TowerCo Existing Sites.

                  "TowerCo Parent" has the meaning given to such term in the
         Preamble to this Agreement.

                  "Vendor Indemnitee" has the meaning given to such term in
         Section 11.02.

                  "Warranty Period" has the meaning given to such term in
         Section 6.10.

                  "Work" means Vendor's  construction  and  installation  of the
         Tower and  Improvements  in  accordance  with the  Specifications,  and
         includes   labor   necessary   to  Complete   such   construction   and
         installation,  and materials and  equipment for such  construction  and
         installation,  as required by this  Agreement to be furnished by Vendor
         or any  subcontractor,  for the  construction  and  installation of the
         Tower and Improvements.

                                       7
<PAGE>

(b) Any other capitalized terms used in this Agreement shall have the respective
meanings given to them elsewhere in this Agreement.

Section 1.02.     Use of Words and Phrases.

(a) Words of the  masculine  gender  shall be deemed  and  construed  to include
correlative  words of the feminine and neuter genders.  Unless the context shall
otherwise  indicate,  the  singular  shall  include  the  plural  as well as the
singular number.  "Herein,"  "hereby,"  "hereunder,"  "hereof," "herein before,"
"hereinafter," and other equivalent words refer to this Agreement and not solely
to the particular portion thereof in which any such word is used.

(b)  Whenever in this  Agreement  either of the words "day" or "days" is used it
means a calendar day unless specifically stated to be a Business Day.

(c) SBCW and Vendor  agree that any  defined  term used  herein  constituting  a
document, instrument, drawing, survey, map, plan, technical description or other
writing, and any other reference herein to a writing, shall include originals or
copies of such writing and any and all amendments,  supplements,  modifications,
renewals,  extensions,  restatements or replacements of or to the same from time
to time.

                                   Article II
                               Agreement Documents

         This  Agreement  shall consist of the following  documents,  as amended
from time to time as provided herein:

(a)      this Agreement document;

(b) the following Annexes and Schedules,  which are incorporated  herein by this
reference:

     Annex A         Specifications
     Annex B         Vendor Responsibility Matrix
     Annex C         Project Data Requirements; Form of SARF
     Annex D         Form of Candidate Sheet; Notice to Proceed
     Annex E         Form of Punch List
     Annex F         Certificate of Completion
     Annex G         Form of Site Data Package; Form of Due Diligence Package
     Annex H         Form of Site Schedule
     Annex I         Collocation Services on TowerCo Existing Sites Summary
     Annex J         Terms of BTS Sublease
     Annex K         SBCW Standard Configuration
     Annex L         Minimum Standards for BTS Sites
     Annex M         Minimum Standards for Potential Collocation Sites
     Annex N         Existing Contracts

                                       8
<PAGE>

     Schedule 8.04             Rules, Policies, Regulations and Interpretations
                               of SBCW Relating to or in Connection with
                               Applicable FAA and FCC Regulations
     Schedule 3.10(c)          Terms under which SBCW may acquire Sites and
                               develop and construct its own Towers and transfer
                               such Towers to Southern Towers, Inc.,an Affiliate
                               of Vendor

(c) such additional documents as are incorporated by reference.

If any of the  foregoing are  inconsistent,  this  Agreement  shall prevail over
Annexes, Schedules and additional incorporated documents.

                                  Article III
                     Scope Of Work; Nature Of The Engagement

Section 3.01.     Engagement of Vendor.

(a) SBCW hereby  engages  Vendor,  for the Term of this Agreement as provided in
Section 3.03, to develop and construct  Towers and Improvements on the BTS Sites
(subject to any right of SBCW to terminate this  Agreement  under any applicable
provision of this  Agreement),  and perform the Services all as required by this
Agreement.  SBCW  reserves  the  right  to  construct  and  install  all  of the
Constructed  Improvements  and its  Communications  Equipment  on the BTS Sites;
provided,  however,  that SBCW  shall  have the  right to  request  that  Vendor
construct and install one or more concrete  equipment  pads or raised  platforms
capable of  accommodating  SBCW's or SBCW Party's  buildings,  huts or equipment
shelters  at each  BTS  Site.  The  parties  acknowledge  that  all  Constructed
Improvements  developed  and  constructed  by SBCW or Vendor on any BTS Site are
intended to constitute a part of SBCW's Improvements, and are not intended to be
shared by Space Subtenants or constitute a part of the Improvements. The parties
further acknowledge that Improvements,  other than Constructed Improvements,  do
not constitute a part of SBCW's Improvements.  Any Affiliate of SBCW operating a
mobile cellular  telephone business that is integrated with SBCW's and its other
Affiliates' current cellular  telecommunications business in the Territory shall
be deemed a SBCW Party for  purposes  of this  Section  3.01 and  Section  3.10;
provided,  however,  that the engagement of Vendor pursuant to this Section 3.01
and the exclusive  rights  provided to Vendor  pursuant to Section 3.10(a) shall
only apply to SBCW and the SBCW Parties set forth on the signature pages to this
Agreement,  and their respective  successors and assigns (but only if and for so
long as such successors or assigns are Affiliates of SBC  Communications  Inc.).
Vendor  hereby  accepts  such  engagement  in  accordance  with  the  terms  and
conditions of this Agreement.  Vendor shall construct the Tower and Improvements
at each BTS Site in accordance with the Implementation  Plan and applicable Site
Schedule.  Vendor  shall  perform and be  responsible  for all  responsibilities
assigned to Vendor in the Vendor  Responsibility Matrix attached hereto as Annex
B. In addition to the  engagement  provided  for in this  Section  3.01,  Vendor
acknowledges  and agrees that SBCW may engage  Vendor on behalf of any Affiliate
of SBCW or of the SBCW Parties (e.g., Bell South wireless  companies) to develop
and  construct up to a maximum of one hundred (100) Towers and  Improvements  on
BTS Sites  located  within the Territory and to perform the Services as required
under this Agreement for such Towers,  and such engagement  shall not be limited
by the  limitation  set forth in the fourth  (4th)  sentence of in this  Section
3.01(a).  Upon completion of such Towers,  the applicable  Affiliate of the SBCW
Parties shall occupy the Leased Space subject to the terms of the BTS Sublease.

                                       9
<PAGE>

(b) Subject to Section 3.02(b), Vendor's compensation for Completion of the Work
on BTS Sites pursuant to this Agreement and performance of the Services,  or any
part  thereof,  will be derived  solely from the payment of the BTS Rent by SBCW
pursuant to the BTS Sublease  (notwithstanding that such BTS Rent may be paid to
an Affiliate of Vendor).  The parties agree that the BTS Rent payable by SBCW to
Vendor with  respect to the Leased  Space of any  Completed  BTS Site or TowerCo
Existing Site shall be $1400 per month subject to an annual increase as provided
in Section __ of the BTS  Sublease  [As  described  on Exhibit J]. This  Section
3.01(b) shall survive any expiration or termination of this Agreement.

Section 3.02.     Identification of Collocation Sites.

(a) Vendor may,  without  delaying any of its obligations  under this Agreement,
including,  without  limitation,  its obligations  pursuant to Article 5, at any
time during the Term,  provide SBCW with a written notice  proposing any TowerCo
Existing Site within a search area specified in the  applicable  SARF that would
be suitable for the collocation of SBCW's  Communications  Equipment ("Potential
Collocation  Sites").  SBCW shall either accept the proposed  site, or at SBCW's
option,  in the event  that  SBCW  reasonably  believes  that such site does not
satisfy the minimum  standards set forth in Annex M, reject such site by sending
notice of such election in writing to Vendor within  fifteen (15) days after the
notice thereof.  In addition,  SBCW may reject a Potential  Collocation  Site in
writing within fifteen (15) days after SBCW's receipt of Vendor's notice thereof
if there then exists an alternative site within such search area that, in SBCW's
judgment,  is  also  suitable  for  the  collocation  of  SBCW's  Communications
Equipment but that is available to SBCW upon economic terms and conditions  that
are, in SBCW's  judgment,  more  favorable to SBCW.  In the event SBCW pursues a
Potential  Collocation  Site,  Vendor shall provide SBCW with Compliance Data, a
Site Data Package and a Due  Diligence  Package with respect to such site within
fifteen  (15) days after  receipt of SBCW's  notice.  If SBCW elects to become a
tenant on a TowerCo  Existing  Site,  Vendor  shall  sublease  the Leased  Space
thereon  to SBCW or its  Affiliate  pursuant  to the BTS  Sublease  and SBCW and
Vendor shall execute a Site  Designation  Supplement  for such TowerCo  Existing
Site.  If SBCW  rejects a Potential  Collocation  Site as provided  above in the
event there  exists a suitable  alternative  site within the  applicable  search
area,  Vendor shall have no further  obligation  with respect to that  Potential
Collocation  Site and SBCW shall be  entitled to pursue  such  alternative  site
without  reference to this Agreement.  Furthermore,  if SBCW rejects or does not
pursue a Potential  Collocation  Site,  Vendor shall keep  performing all of its
obligations hereunder, including, without limitation, performing search Services
in such search area as provided in Article 5.

(b) If SBCW is  interested  in a Potential  Collocation  Site,  Vendor may, upon
written  notice  thereof  to  SBCW,  offer  the  performance  of  certain  other
Collocation  Services  set forth in Annex I (the  "Collocation  Services")  with
respect to such Potential  Collocation Site; provided,  that Vendor acknowledges
that at any time during the Term, SBCW shall have the right to engage any Person
other than Vendor to perform such Collocation Services. If the terms, conditions
and fees in connection  with such  Collocation  Services are acceptable to SBCW,
SBCW may engage Vendor to perform such Collocation  Services upon written notice
to Vendor  within five (5) Business Days after receipt by SBCW of the offer from
Vendor.  If SBCW elects to engage  Vendor to perform such  Collocation  Services
pursuant to this Section 3.02(b),  such Collocation  Services shall be performed
in  compliance  with the  requirements  of this  Agreement,  including,  without
limitation,   compliance  with  quality  standards,  Governmental  Requirements,
Permits and  Environmental  Laws, in each case as applicable to such Collocation
Services.  Vendor  hereby  acknowledges  and  agrees  that  any and all  fees in
connection with performance of any Collocation Services shall be due and payable
only if SBCW installs its  Communications  Equipment on a Potential  Collocation
Site.
                                       10
<PAGE>

Section 3.03.     Term.

(a) Subject to Article 13, this Agreement  shall commence on the Effective Date,
and shall continue until the fifth (5th)  anniversary of the Effective Date (the
"Term"),  plus such  additional  time as may be  required  (i) for an  aggregate
number of new Towers to be  developed  and  Completed  by either  Vendor or SBCW
(either  itself or through a third party  pursuant to Section  3.10(c)) equal to
the number of Towers that SBCW elected,  pursuant to Section 3.10(d),  to become
"Substitute  Sites" under the  Agreement to Sublease and (ii) for the parties to
satisfy their  respective  obligations  hereunder to the extent such obligations
arose or accrued prior to such fifth (5th) anniversary.

(b)  Notwithstanding  anything to the  contrary  contained  herein,  the parties
acknowledge  and agree that upon  Completion  of any BTS Site and execution of a
Site  Designation  Supplement  therefor or the  execution of a Site  Designation
Supplement  with respect to any TowerCo  Existing  Site,  except with respect to
those  provisions of this Agreement  which survive the expiration or termination
hereof, the BTS Sublease, the applicable Site Designation Supplement and related
documents shall govern the respective rights and obligations of the parties with
respect to such BTS Site or TowerCo Existing Site.

Section 3.04.     Time for Commencement and Completion.

         Vendor and SBCW  acknowledge  that the time for Scheduled  Commencement
Date  and  Completion  of the BTS  Site  will be  determined  by the  applicable
Implementation  Plan  and the  Site  Schedule.  Vendor's  unexcused  failure  to
Complete  any BTS Site in  accordance  therewith  shall  subject  Vendor  to the
Liquidated Damages pursuant to Section 11.01.

Section 3.05.     Relationship.

         Vendor agrees to furnish its best skill and judgment in performing  its
obligations  hereunder,   and  to  cooperate  with  SBCW  in  furthering  SBCW's
interests.  Except as  expressly  provided  in Section  8.01,  SBCW,  Vendor and
TowerCo  Parent,  in the  performance  of this Agreement will be acting in their
individual capacities and not as employees, partners, joint venturers, agents or
associates of one another. In the performance of this Agreement,  Vendor is, and
shall  at all  times  during  the  term of this  Agreement  be,  an  independent
contractor.  Nothing  contained in this Agreement  creates the relationship of a
joint venture, partnership,  association or agency between the parties. No party
shall have any  authority  to bind or  otherwise  obligate  the  other.  Persons
retained by either  party as  employees  or agents  shall not,  solely by reason
thereof, be deemed to be employees or agents of the other party.

                                       11
<PAGE>

Section 3.06.     Project Personnel.

(a) Vendor shall,  at its own cost and expense,  employ only  competent and able
personnel for the  performance  of the Services and all of Vendor's  obligations
under  this   Agreement,   including,   without   limitation,   contractors  and
subcontractors that are properly licensed and legally qualified to construct the
Towers and  Improvements  and complete the Work on each BTS Site and/or  provide
the  Collocation  Services.  Vendor  shall make  available to SBCW a list of its
principal  contractors  and  subcontractors,  and SBCW  shall  have the right to
request a particular  contractor or  subcontractor  be removed from the list for
the  Project  so long as such  request  is based  upon  commercially  reasonable
criteria.  Vendor shall, at all times during the term of this Agreement,  keep a
sufficient number of qualified  personnel to the extent required to Complete the
Project  pursuant  to the  Implementation  Plan  and Site  Schedules,  including
without  limitation,  a  sufficient  number of suitable  experts in the areas of
engineering,  design,  construction,   installation,   management,   performance
enhancement and other operational specialties applicable to the Project. Subject
to Section  3.06(d),  Vendor shall have exclusive  control of and direction over
the  Persons  engaged in the  performance  of  Vendor's  obligations  under this
Agreement.

(b) If  reasonably  requested by SBCW,  Vendor shall make  available  additional
suitable   experts   in  the  areas  of   engineering,   design,   construction,
installation,   management,   performance   enhancement  and  other  operational
specialties  applicable  to the  Project,  and SBCW shall pay any  direct  costs
associated with any such suitable experts that are in addition to those required
pursuant to Section 3.06(a).

(c) Vendor  will be solely  responsible  for the  actions and conduct of all its
employees, agents, consultants, advisors, contractors and subcontractors. Vendor
will  ensure  that  anything  related  to its  employees,  agents,  consultants,
advisors,  contractors  or  subcontractors  shall be in strict  compliance  with
Governmental Requirements.

(d) SBCW reserves the right to require Vendor to immediately  remove and exclude
any Person or entity  employed by or otherwise  working for Vendor,  its agents,
consultants,  contractors,  subcontractors  or  advisors,  from  any BTS Site or
TowerCo Existing Site, at SBCW's reasonable  discretion,  who (i) engages in any
misconduct, (ii) is incompetent or (iii) is negligent in the performance of its,
his or her duties.  Vendor shall be responsible  for any additional  labor costs
arising in connection with any removal or exclusion  requested  pursuant to this
Section 3.06(d).

(e) Vendor shall assign key managers and personnel,  including Contract Managers
as  provided  below,  to manage,  supervise  and be  responsible  for the timely
performance of Vendor's obligations hereunder. Unless SBCW otherwise consents in
writing, as to each BTS Site, Vendor shall (i) allocate sufficient  personnel to
devote time and attention to such BTS Site,  and (ii) not remove any key manager
(including  Contract  Managers)  from any such position or reassign any such key
manager,  either within the Project or to another  project,  without a qualified
replacement.  In addition,  each party agrees to assign to the Project  contract
managers (the "Contract Managers") to provide overall supervision and management
of the Project. Each party may change its Contract Managers at any time and from
time to  time.  The  parties  further  agree to  cooperate  with  each  other in
implementing  the due  diligence  and  construction  process  set  forth in this
Agreement in order to Complete the Work on all BTS Site pursuant to the terms of
this  Agreement  and to use their  commercially  reasonable  efforts to amicably
resolve  any and all  issues  relating  to  performance  by  each  party  of its
respective  rights and obligations  hereunder.  The foregoing is intended to set
forth a general  approach to the day-to-day  conduct of the Project,  but is not
intended to qualify or limit the  obligations  of the parties  hereunder  or any
rights  hereunder  that any party may have in  respect  of a breach by the other
party of such obligations.

                                       12
<PAGE>

Section 3.07.     Familiarity with Project and BTS Sites.

         Vendor  represents  and warrants  that Vendor is familiar with projects
similar to the  Project,  is or will  become  familiar  with the  Specifications
applicable to the Towers and Improvements,  will visit and examine each BTS Site
and the surrounding locale, and knows or will know the working conditions in and
around each BTS Site.

Section 3.08.     Quality Standard.

         Vendor  agrees to perform its  obligations  and  furnish  its  Services
hereunder  properly,  diligently,  and in good  faith,  in  accordance  with the
standards of its profession,  and in accordance with all applicable Governmental
Requirements.  Vendor shall implement quality control procedures, which shall be
sufficient to ensure  compliance  with the  Specifications  and shall  otherwise
maintain quality standards for the Services at least equal to the normal quality
standards  applied by Vendor and entities  Controlled by TowerCo Parent prior to
the date of this Agreement.

Section 3.09.     Books and Records of Vendor, Right of Inspection by SBCW.

         Vendor  shall keep such  accounts  as may be  necessary  for its proper
financial  management  of the  Project  under  this  Agreement.  The  system  of
accounting  employed by Vendor shall be such as is  reasonably  satisfactory  to
SBCW.  SBCW  shall  be  afforded  access  to all  of  Vendor's  records,  books,
correspondence,   instructions,  drawings,  plans,  blueprints,  specifications,
receipts,  vouchers, memoranda and similar data relating to the Project and this
Agreement to the extent  relating to SBCW's  intended use,  Vendor's  compliance
with the terms hereof,  Vendor's and each BTS Site's and TowerCo Existing Site's
compliance  with  Governmental  Requirements,  the  structural  integrity of the
Improvements,  or if SBCW otherwise provides reasonable  justification therefor,
except for privileged  documents or where  disclosure is prohibited by law. Such
books and  records  shall be open for  inspection  and copying  upon  reasonable
written  notice by SBCW,  at its cost,  and its  authorized  representatives  at
reasonable  hours at Vendor's  principal  office and shall be retained by Vendor
for a period of three (3) years after the expiration of the BTS Sublease.

Section 3.10.     Scope of the Project.

(a) Subject to the terms and conditions of this Agreement,  SBCW, for itself and
as  agent  for the  SBCW  Parties,  hereby  grants  to  Vendor  for the Term the
exclusive  right to develop new Towers which SBCW elects to have  constructed in
the Territory; provided that the foregoing shall not apply with respect to Sites
subject to the  existing  contracts  listed in Part A of Annex N annexed  hereto
(the "Existing Contracts") and the "in-progress" Sites listed in Part B of Annex
N. The exclusive  rights  provided to Vendor  hereunder shall only apply to SBCW
and the SBCW Parties set forth on the  signature  pages to this  Agreement,  and
their  respective  successors  and assigns  (but only if and for so long as such
successors or assigns are Affiliates of SBC Communications Inc.)

(b)  Notwithstanding  anything to the contrary  contained  herein and subject to
Article  13, the  parties  agree that  during  the Term,  Vendor  shall have the
exclusive right and obligation to perform all Services on the BTS Sites pursuant
to this  Agreement  other than  Collocation  Services  and  except as  expressly
provided  in this  Agreement  to the  contrary,  and shall  have an  affirmative
obligation to Complete the Work on any such BTS Sites in strict  compliance with
the provisions of this Agreement;  provided, however, that if at any time during
the Term,  Vendor's right and obligation to perform Services on the BTS Sites is
suspended  or  terminates  (i) in  respect of any BTS Site  pursuant  to Section
13.01(b)(i),  then SBCW shall have the right to engage any Person to perform any
and all  Services on such BTS Site,  or (ii)  pursuant to Section  13.01(b)(ii),
then SBCW  shall  have the right to engage  any  Person to  perform  any and all
Services  on any or all BTS Sites.  SBCW  reserves  the right to  construct  and
install all of the Constructed  Improvements and its Communications Equipment on
the BTS Sites; provided, however, that SBCW shall have the right to request that
Vendor  construct  and install  one or more  concrete  equipment  pads or raised
platforms  capable of accommodating  SBCW's or SBCW Party's  buildings,  huts or
equipment  shelters.  SBCW  agrees to  negotiate  in good faith with  Vendor for
Vendor to construct and install SBCW's Communications Equipment.

                                       13
<PAGE>

(c) Notwithstanding anything to the contrary contained herein, SBCW reserves the
right,  either  directly or through a SBCW Party or any third party,  to acquire
Sites and  thereafter to develop and  construct  its own Towers  pursuant to the
terms  summarized  on Schedule  3.10(c)  hereof.  Following  Completion  of such
Towers,  such Towers shall be sold to Vendor (or to Southern  Towers,  Inc.,  an
Affiliate of Vendor) for an amount calculated in accordance with the schedule of
costs agreed to by the parties and attached to Schedule 3.10(c).  After the sale
of any such Tower to Vendor (or  Southern  Towers,  Inc.),  said Tower  shall be
deemed to be a BTS Site and SBCW or a SBCW Party shall  occupy the Leased  Space
subject  to  the  terms  of the  BTS  Sublease.  In  acquiring,  developing  and
constructing its own Towers as aforesaid,  SBCW or the applicable SBCW Party may
retain one or more third party  consultants  and/or  contractors  to perform the
work  associated  therewith,  but the  retaining  of  such  entities  shall  not
otherwise relieve SBCW from its obligations under this Agreement. The obligation
of SBCW to sell  Towers that it has  developed  to Vendor (or  Southern  Towers,
Inc.)  shall not  apply to (i) Sites  controlled  by SBCW or SBCW  Parties  with
respect  to  which,  as of  the  date  of  the  Agreement  to  Sublease,  actual
construction has commenced, defined as the issuance of building permits for such
Site, or (ii) the "in-progress" Sites listed in Part B of Annex N.

(d) At any time on or before the "Final  Closing  Date" under the  Agreement  to
Sublease,  SBCW may elect to have any Towers that are being  developed by either
Vendor or by SBCW  (either  itself or through a third party  pursuant to Section
3.10(c)) become  "Substitute Sites" pursuant to the Agreement to Sublease rather
than become BTS Sites under this Agreement and the BTS Sublease.  For such Tower
to so become a Substitute  Site,  such Tower must satisfy all of the  conditions
and criteria set forth in the Agreement to Sublease for Substitute Sites and, in
addition:

          (i)  if such Tower is being developed by Vendor,  no later than thirty
               (30) days  before  the  anticipated  date of  Completion  of such
               Tower,  Vendor shall  provide to SBCW  Vendor's  reasonable  good
               faith estimate of (A) Vendor's actual, direct out-of-pocket costs
               of acquiring the applicable Site and developing and  constructing
               such Tower (including all Site acquisition costs and other "hard"
               and "soft" costs),  plus ---- (B) Vendor's  personnel and related
               costs  reasonably  allocated  to such  Tower  based on the amount
               spent by such personnel on such Site  acquisition and development
               and  construction,  and,  if SBCW shall  elect to have such Tower
               become a Substitute Site (which election shall be made in writing
               no later  than  fifteen  (15)  days  after  receipt  of  Vendor's
               calculation),  upon Completion of such Tower,  SBCW shall acquire
               such Tower from Vendor for an amount equal to the actual  amounts
               under (A) plus (B) above  (calculated  as of ---- the  Completion
               date),  plus (C) a profit  margin  equal  to  Vendor's  customary
               profit margin for  arms-length  ---- agreements to develop Towers
               for third  parties.  Following the  acquisition  of such Tower by
               SBCW, such Tower shall be leased to Vendor's Affiliate,  Southern
               Towers,  Inc.  pursuant to the Agreement to Sublease and shall be
               governed  by the  Agreement  to  Sublease  and the SBCW  Sublease
               rather than by this Agreement; and

          (ii) if such  Tower is  being  developed  by SBCW  (either  itself  or
               through a third party pursuant to Section  3.10(c)),  and if SBCW
               shall elect to have such Tower  become a  Substitute  Site (which
               election shall be made in writing no later than fifteen (15) days
               before the  anticipated  date of Completion of such Tower),  then
               upon   Completion,   such  Tower  shall  be  leased  to  Vendor's
               Affiliate,  Southern  Towers,  Inc.  pursuant to the Agreement to
               Sublease  and shall be governed by the  Agreement to Sublease and
               the SBCW Sublease rather than by this Agreement.

         Transaction  and  transfer  costs  associated  with a Tower  becoming a
"Substitute  Site" as set forth in this  Section  3.10(d)  shall be  governed by
paragraph 7 of Schedule 3.10(c).

                                       14
<PAGE>

Section 3.11.     Available BTS Sites in Event of Condemnation.

         If prior to the execution of a Site  Designation  Supplement  for a BTS
Site, any  condemnation  occurs as to any BTS Site so as to render such BTS Site
unsuitable for the Permitted Use, Vendor shall, at the request of SBCW,  perform
all its  obligations  hereunder  in  respect  of a  replacement  site  for  such
condemned BTS Site  satisfactory  to SBCW  consistent  with the  requirements of
Article  5, as if such  replacement  site were a BTS Site  hereunder,  including
without limitation,  Acquisition of such replacement site, the construction of a
Tower and  Improvements  on any selected BTS Site  pursuant to and in accordance
with Article 6 and the further  subleasing of a portion of such BTS Site to SBCW
or its Affiliate pursuant to the BTS Sublease and a Site Designation Supplement.
The monthly  amounts  payable in respect of such  replacement  BTS Site shall be
equal to the amount of the BTS Rent that  would have been  payable in respect of
the replaced condemned BTS Site. The Site Schedule,  Scheduled Commencement Date
and Completion Date for any such  replacement site shall be determined by Vendor
and SBCW consistently with the construction schedules applicable to BTS Sites in
general.  This  Agreement  shall  survive  the Term  indefinitely  to the extent
necessary to give effect to this Section 3.11.

                                   Article IV
                             Vendor's Undertakings.

Section 4.01.     Vendor's Undertakings.

(a) Commencing on the Effective Date of this Agreement, Vendor agrees to furnish
the  Services  for and on  behalf of SBCW and to  perform  such  Services  in an
expeditious  manner consistent with the interests of SBCW. In the performance of
the Services, Vendor shall furnish its best skill and judgment (i) in accordance
with the  standards  established  by the  industry,  (ii)  consistent  with good
development and construction  practices and efficient business practices,  (iii)
utilizing  skill and  judgment  available  throughout  its  organization  in the
performance  of this  Agreement to provide its  professional  knowledge,  ideas,
experience and abilities  relating to the design,  scheduling,  development  and
construction  of  the  Towers  and  Improvements,   and  (iv)  in  a  competent,
professional and efficient manner.

(b) Vendor shall keep SBCW fully informed of all Governmental  Requirements that
affect,  in any material  respect,  the Services to be performed  hereunder  and
shall  promptly  notify in writing SBCW of any part of the Project that does not
comply with any  Governmental  Requirements  to the extent  Vendor is or becomes
aware of such noncompliance.

(c) In addition to the Services,  as described in this  Agreement,  Vendor shall
have such other duties and responsibilities  reasonably and customarily required
for developments  similar to the development of each BTS Site as may be required
or  necessary  from time to time during the design,  development,  construction,
equipping   and   Completion   of  each  BTS  Site,   which  other   duties  and
responsibilities  shall be  deemed to be  within  the  scope of this  Agreement;
provided,  however,  that SBCW shall not incur any costs or  expenses  for or in
connection with any such services for BTS Sites.

Section 4.02.     Governmental Requirements and Permits.

(a) Vendor shall obtain, or cause to be obtained, the consent or approval of all
Governmental Authorities.  and all Permits necessary for the Development of each
BTS Site.  Vendor  shall  advise  SBCW in  writing  of any  potential  issues or
problems,  including without  limitation any delays in connection with obtaining
any approvals from Governmental Authority.

(b) Vendor shall coordinate and manage all  professional and technical  services
required in connection with the  preparation and filing of applications  for and
obtaining all Permits Vendor shall be responsible  for diligently  preparing and
filing all applications for, and pursuing and obtaining, the Permits.

(c) Permits will be filed by Vendor in its own name,  except where prohibited by
applicable laws, and SBCW shall assist Vendor in securing all such Permits.

                                       15
<PAGE>

(d)  Vendor  shall use its best  efforts  to obtain  any  Permits  necessary  to
commence  construction of the Tower and  Improvements on or before the Scheduled
Commencement Date with respect to each BTS Site, and shall, unless otherwise set
forth in the Site  Schedule,  prepare and file an  application  for the required
Permit or Permits  with the  applicable  Governmental  Authority  not later than
thirty (30) days after the date of the  applicable  Notice to Proceed.  Vendor's
efforts relating to obtaining any Permits shall include, without limitation, the
approval  of any  necessary  rezoning of such BTS Site,  grant of any  variance,
vacating of any right-of-way,  issuance of any order or other action that may be
necessary,  or  approve  any other  land use  approval  necessary,  to  commence
construction  of the Tower and  Improvements  on such BTS Site. If, despite such
efforts, any Permits required to be obtained before commencement of construction
have not been  obtained  or could not have  been  obtained  as of the  Scheduled
Commencement  Date, then Vendor shall continue,  if SBCW agrees, to exercise its
best efforts,  for a period of at least one (1) year, to obtain any such Permits
as  promptly  as  possible,  and,  subject to  Section  4.02(e),  the  Scheduled
Commencement  Date will be adjusted to reflect all additional time which will be
required for the performance of any of the duties or obligations of Vendor under
this Agreement as a result of the delay in obtaining the Permits. The failure to
obtain  any such  Permit  shall  not in and of  itself  constitute  a breach  of
Vendor's obligations hereunder. However, the failure of Vendor to perform any of
its  obligations  set forth in this  Section  4.02 shall  constitute a breach of
Vendor's  obligations under this Agreement,  which, if not cured as contemplated
by Section 13.01(a)(i), would constitute an event of default hereunder.

(e) If Vendor has not obtained any Permit  required for the  Construction of the
Tower and  Improvements on any BTS Site, or for the Permitted Use thereof or any
other required Permit by the applicable Scheduled Commencement Date set forth in
the applicable Site Schedule,  but in no event later than ninety (90) days after
SBCW issues a Notice to Proceed for any BTS Site,  then, at any time thereafter,
SBCW will have the right,  at SBCW's sole option,  to (i) assume  responsibility
for  obtaining  such  Permit by  written  notice to  Vendor,  and  Vendor  shall
reimburse SBCW for any costs, fees, or expenses (including reasonable attorneys'
fees and  expenses)  incurred in pursuing and obtaining  such Permit;  provided,
however,  that any  reimbursement  in  excess of  $20,000  shall be  subject  to
Vendor's  pre-approval;  provided,  further,  however,  that if Vendor  fails to
approve any  reimbursement in excess of $20,000,  then SBCW shall have the right
to pursue  obtaining  such  Permits and shall be liable for any costs,  fees and
expenses  incurred in connection  therewith in excess of $20,000,  and provided,
further,  however,  that any  election  under  this  clause (i) shall be without
prejudice  to SBCW's right to elect later one of the options set forth in clause
(ii) or (iii) below with  respect to such BTS Site;  (ii) reject the BTS Site at
no cost or  expense to SBCW,  whereupon  SBCW shall have the right to engage any
Person to perform  Services in respect to such BTS Site or an  alternative  site
within the  applicable  SARF;  or (iii)  reject the BTS Site and cause Vendor to
propose  additional  potential cell sites as  alternatives,  in accordance  with
Section 5.01. If SBCW makes the election in clause (ii) above and shall,  either
itself or through a third  party,  acquire a site and develop a tower within the
applicable  SARF, then the provisions of Section 3.10(c) hereof shall govern the
acquisition  of such site,  the  development  of such tower and the sale of such
tower to Vendor.

                                       16
<PAGE>

(f) Vendor shall comply with all  Governmental  Requirements  in performing  its
obligations  under this  Agreement,  the BTS Sublease and each Site  Designation
Supplement. Vendor shall indemnify, and hold harmless, each SBCW Indemnitee from
and  against  any Claims  (including  without  limitation  any fine,  penalty or
damage)  arising  out of  Vendor's  failure  to  comply  with  any  Governmental
Requirements  including,  without  limitation,  zoning  laws  and  FAA  and  FCC
regulations.

(g) If SBCW  determines  that  Vendor's  proposed  Tower  height  would cause an
extension  of time to obtain  any  Permit  beyond  the  period  set forth in the
applicable Site Schedule,  Vendor shall, at SBCW's written  request,  revise the
Due  Diligence  Package to provide a Tower height which,  while  meeting  SBCW's
requirements,  will,  in  SBCW's  judgment,  be  permitted  in a timely  fashion
consistent  with  the  applicable  Site  Schedule;  provided,  however,  that in
revising the Due  Diligence  Package,  Vendor shall have the right to pursue (i)
Permits  for  a  Tower  which  meets  SBCW's   requirements  but  which  can  be
subsequently  modified  to  increase  the  height  of the Tower in order to meet
Vendor's  requirements and/or (ii) simultaneous  Permits for the construction of
(1) a temporary  structure which satisfies SBCW's  requirements,  if all Permits
for such  temporary  structure  can be obtained  within the time provided in the
applicable  Site Schedule,  and (2) a permanent  Tower with greater height which
meets both SBCW's and Vendors requirements.  In the event that SBCW installs its
Communications  Equipment on any  temporary  tower  structure  prior to Vendor's
completion  of obtaining  permits and  constructing  a higher  permanent  Tower,
following  completion  of such higher  permanent  Tower,  SBCW's  Communications
Equipment  shall be relocated to the  permanent  Tower at Vendor's sole cost and
expense, and under the direction of SBCW

(h) Notwithstanding  anything to the contrary contained herein,  Vendor may, but
shall not be required to file or pursue any appeal or other similar action to be
filed  with a court  of  competent  jurisdiction  ("Permit  Appeal  Action")  in
connection  with obtaining  Permits;  provided,  however,  that Vendor shall not
pursue a Permit  Appeal Action that in any way involves SBCW or uses SBCW's name
or  represents  any  interest of SBCW absent  prior  consultation  with SBCW and
express  written  consent from SBCW to take such Permit  Appeal  Action.  Vendor
shall  notify  SBCW if Vendor  desires to  initiate  Permit  Appeal  Action with
respect to any BTS Site and,  following  the giving of such  notice,  SBCW shall
promptly  respond in writing  whether it has any objection to Vendor  initiating
such Permit Appeal Action. If SBCW shall so object, then SBCW shall no longer be
obligated  under  Section  3.10 to  exclusively  engage  Vendor to  perform  the
Services  on such BTS  Site and SBCW  shall  be free to  engage  any  Person  to
construct Tower,  Improvements and Constructed Improvements on such BTS Site and
perform any Services in connection therewith.

                                       17
<PAGE>

                                   Article V
                             Pre-Construction Phase

Section 5.01.     Proposal of BTS Sites; Development Plan.

(a) From time to time during the Term in  connection  with SBCW's need for a new
Tower,  SBCW shall issue a search area request form ("SARF") to Vendor  pursuant
to Attachment A to Annex C attached hereto. Promptly after receipt of each SARF,
but in no event  later than  thirty  (30) days after the giving of such  notice,
Vendor shall perform  searching  services in the search area  designated in such
SARF by using  diligent,  good faith efforts,  consistent with the standards set
forth in  Section  4.01,  to  identify  at least  three (3)  potential  BTS Site
locations,  unless  otherwise  agreed,  within each radio frequency  search area
identified  in such SARF and to prepare a  preliminary  Site Schedule and a Site
Data Package  collecting the information set forth in Annex G-1 attached hereto,
to the extent  required  by SBCW prior to  issuance of the Notice to Proceed for
presenting  such potential sites to SBCW for final  selection.  No site shall be
proposed (or shall be required to be proposed) unless Vendor reasonably believes
that such site meets the  requirements for proposed BTS Sites set forth in Annex
L to this  Agreement  (the "Minimum  Standards for BTS Sites") of this Agreement
for BTS Site in all material  respects  and that it will be  possible,  with the
exercise of diligent  efforts,  to obtain the Permits necessary to construct the
Tower and  Improvements.  Within  fifteen  (15) days after  receipt of  Vendor's
proposal,  SBCW shall in writing either accept or, if SBCW  reasonably  believes
that such sites do not satisfy the Minimum  Standards for BTS Sites,  reject one
or more of the proposed  BTS Sites and, in the event SBCW accepts such  proposed
site, such site shall become a BTS Site. If none of the sites proposed by Vendor
for any search area are accepted by SBCW, Vendor shall have an additional thirty
(30) days in which to propose additional  potential BTS Sites. SBCW shall accept
one or more of the additional  proposed BTS Sites or, at SBCW's  option,  in the
event that SBCW  reasonably  believes that such sites do not satisfy the Minimum
Standards for BTS Sites, reject the proposed BTS Sites in writing within fifteen
(15) days after  receipts of Vendor's  proposal.  If SBCW shall accept more than
one proposed BTS Site or additional  proposed BTS Site,  then Vendor may, in its
reasonable  judgment,  select one such Site and pursue that Site rather than the
others  accepted by SBCW. If none of the proposed BTS Sites are accepted by SBCW
or if Vendor is unable, notwithstanding diligent efforts, to propose a site that
meets the  requirements  of this  Section  5.01 within the time period set forth
herein, Vendor shall have no further obligation to search for potential sites in
response to such SARF,  and SBCW shall be  entitled to pursue such site  without
reference to this Agreement.

(b) Vendor will provide SBCW with methodology for each search ring and keep logs
demonstrating  reasons for rejecting  potential BTS Sites,  including why viable
alternative  locations were  rejected.  SBCW has the right to inspect these logs
upon reasonable notice.

                                       18
<PAGE>

(c) SBCW's right to select any proposed BTS Site as a BTS Site shall not relieve
or release Vendor from performing any of its obligations hereunder in respect of
such  BTS  Site or  otherwise  affect  any of  Vendor's  obligations  hereunder.
Together with SBCW's  written  notice of the  acceptance of a proposed site as a
BTS Site, SBCW shall deliver to Vendor a Notice to Proceed with respect such BTS
Site in the form of Annex D attached  hereto,  to be  completed  and returned to
SBCW in accordance  with Section 5.02.  Acceptance of the proposed BTS Site does
not constitute final  acceptance of the construction  which shall be governed by
Section 6.12 hereof.

(d) Not later  than ten (10) days  after  receipt of the Notice to Proceed as to
any BTS Site,  Vendor  shall  prepare for the  Development  of each BTS Site and
shall submit to SBCW for its approval,  which approval shall not be unreasonably
withheld or  delayed,  an  Implementation  Plan and a final Site  Schedule  with
respect to such BTS Site,  which  shall  include,  among  other  things,  design
services,  preparation of a development  plan, and  coordination of construction
activities.

Section 5.02.     Due Diligence

         During the pre-construction  phase, Vendor shall, on its own or through
one or more qualified  consultants  approved by SBCW: (i) compile and review all
reasonably  available  existing data with respect to each BTS Site from an owner
or a ground  lessor  of such BTS Site and any and all  Governmental  Authorities
having  jurisdiction  thereof,  and any  other  Persons  who may  have  relevant
information necessary to develop each BTS Site; (ii) for TowerCo Existing Sites,
within ten (10) days following  acceptance by SBCW pursuant to Section  3.02(a),
Vendor shall provide  Compliance Data to SBCW,  (iii) on new construction of BTS
Sites,  Vendor  shall  within  ten (10) days  from  initial  acceptance  by SBCW
pursuant to Section 5.01,  provide the 1A survey and proposed heights and power/
emissions  data to SBCW for  requisite  filing with the FAA and within three (3)
months provide  environmental  compliance data which will be required before FCC
Form 854 can be filed to register the  structure;  (iv) Vendor shall cause to be
performed  any  and  all  analyses,  examinations,   investigations,  tests  and
inspections  of each BTS Site,  including,  but not  limited  to,  environmental
studies,  surveys,  geotechnical studies, soil borings and the like and cause to
be accurately  completed and returned to SBCW with respect to each BTS Site, the
Due Diligence  Package in the form attached  hereto as Annex G-2  containing all
necessary or reasonably  available  information;  (v) make, or cause to be made,
inquiries of all Governmental  Authorities and Persons who will furnish electric
power, telephone service or any other utility to each BTS Site as to any matters
which may affect or be necessary to the  Development  of each BTS Site; and (vi)
determine all  Governmental  Requirements  necessary for the Development of each
BTS Site, including, but not limited to, the Tower and Improvements, zoning laws
or  regulations.  Vendor shall perform or supervise the activities  described in
items (i) through (vi) above,  and,  shall deliver to SBCW copies of all written
reports,  memoranda  or material  correspondence  prepared by or for Vendor with
respect to the  foregoing.  SBCW and Vendor  shall each have the right to reject
any BTS Site that in the respective  party's  reasonable  belief fails to comply
with the Minimum Standards for BTS Sites or other requirements of this Agreement
based  on the  results  of the  information  contained  in  Site  Data  Package,
Compliance  Data,  Due  Diligence  Package or other due  diligence  performed by
Vendor.

                                       19
<PAGE>

         If,  notwithstanding  Vendor's  diligent  efforts,  Vendor is unable to
acquire  or  negotiate  a Ground  Lease for any site  which  meets  the  Minimum
Standards for BTS Sites and which is otherwise reasonably  acceptable to Vendor,
the Vendor  shall not be required  to acquire or enter a Ground  Lease for or to
construct  or complete  such site.  In such event,  SBCW shall have the right to
engage  any  Person  to  perform  Services  in  respect  to such  BTS Site or an
alternative site within the applicable  SARF;  provided,  however,  that if SBCW
shall  exercise  such right and shall,  either  itself or through a third party,
acquire  a Site  and  develop  a tower  within  the  applicable  SARF,  then the
provisions of Section  3.10(c) hereof shall govern the acquisition of such Site,
the development of such tower and the sale of such tower to Vendor.

Section 5.03.     Utilities.

         Vendor shall  negotiate with the utility  companies  servicing each BTS
Site a plan for the  provision  of services to such BTS Site  including  without
limitation  electricity,  and other shared utilities  required on each BTS Site.
Vendor shall make applications for such utility companies to furnish services to
such BTS Site as may be adequate for the  Permitted  Use of the BTS Site by SBCW
and all Space  Subtenants.  Vendor shall cause such utility companies to provide
connections  to such BTS  Site.  In the  case of  telephone  company  connection
facilities,  all  obligations  shall  remain with  Vendor to effect  connections
required  for the  Permitted  Use of the BTS Site under the BTS  Sublease,  with
exception  that Vendor  shall  utilize  SBCW as its agent to work with the local
telephone company on the development of the servicing plan. SBCW shall reimburse
Vendor for the cost of procuring  and  installing  the  connections  referred to
herein,  such  reimbursement  to be allocated  on an equitable  basis with other
lessees of space on the Tower.

                                   Article VI
                               Construction Phase

Section 6.01.     General.

(a) The parties shall hold progress  meetings,  and Vendor shall submit progress
reports to SBCW, in accordance  with the  Implementation  Plan or otherwise on a
weekly,  bi-weekly or monthly basis as may be agreed between  parties.  Progress
reports will show for each BTS Site, at a minimum, and not by way of limitation,
all dates and  schedules  referred  to in the  Implementation  Plan and the Site
Schedule,   any  anticipated  delays,  other  relevant   information,   and  the
corresponding activity period. Included in the information provided by Vendor to
SBCW shall be an estimate of when the  equipment  shelter can be placed and when
the equipment can be activated.  In addition,  SBCW may request and Vendor shall
facilitate  progress  meetings  with  Vendor's key managers and  subcontractors,
including the establishment of oversight  committees to monitor specific work in
progress on BTS Sites at times and  locations  agreed upon by SBCW and Vendor in
writing  no less than seven (7) days prior to such  meetings.  Progress  reports
shall be for planning purposes and monitoring compliance with this Agreement.

(b) Should any information or approval be required from SBCW as Work progresses,
Vendor shall  request such  information  or approval in writing.  Said  requests
shall  be  submitted  sufficiently  in  advance  of  the  date  upon  which  the
information  or approval  is needed,  but in no event less than five (5) days in
advance of such date,  to permit SBCW to act without  affecting  the progress or
sequence  of the  Work.  Such  request  shall  provide a  reasonable  time for a
response by SBCW.

(c) Vendor shall,  on a periodic  basis (but not less  frequently  than weekly),
review the progress of the  construction,  evaluate the percentage of completion
of each BTS Site as indicated in the Implementation Plan and the applicable Site
Schedule.  The  construction  schedule report shall be distributed not less than
weekly  during  the  construction  phase of the  Project  indicating  the actual
progress  compared to the scheduled  progress of the Work in accordance with the
applicable  Site  Schedule.  The reports shall  compare the actual  construction
dates to scheduled construction dates for each BTS Site.

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<PAGE>

(d)  Following  completion  of the Tower and  Improvements,  Vendor has five (5)
Business Days in which to provide  Completion  Data to SBCW.  Upon acceptance of
the Completion Data, SBCW shall, within five (5) Business days of receipt of the
Completion  Data,  either issue  approval of this  Completion  Data or provide a
written  explanation  of the  deficiency if SBCW does not accept the  Completion
Data.

Section 6.02.      Performance of the Work

         Vendor shall have the responsibility and obligation to perform the Work
in  accordance  with  Annex A.  Vendor  shall  provide  a  management  team or a
representative on each BTS Site to provide supervision and administration of the
Completion  of the Work for each  such BTS  Site.  Vendor  shall  establish  and
implement  coordination and  communication  procedures  between Vendor and SBCW.
Vendor shall  establish and implement  procedures  for reviewing and  processing
requests  for   clarifications  and   interpretations  of  the   Specifications,
including, without limitation,  drawings and technical specifications,  schedule
adjustments,  and such other  procedures  as may be  required  to  Complete  the
Project. Vendor shall receive operation and maintenance manuals,  warranties and
guarantees for materials and equipment used in the Completion of the Project and
shall deliver this information to SBCW upon Completion of the Project.

Section 6.03.     Implementation Plan.

         The Implementation  Plan will set forth in detail the various tasks for
construction   and  completion  of  the   construction  of  the  Tower  and  the
Improvements for each BTS Site. Any material changes in the Implementation  Plan
shall be subject to written approval by SBCW, not to be unreasonably withheld or
delayed.  Vendor shall  commence the Work pursuant to the  Implementation  Plan,
using such means and methods of  construction  as will  maintain the progress of
the Work  substantially  in accordance  with the Site Schedule for each BTS Site
and shall cause  Completion of each BTS Site in accordance with the requirements
of the Site Schedule for such BTS Site.

Section 6.04.     Site Schedule.

(a) To enable the Towers  and the  Improvements  to be  planned,  scheduled  and
Completed in an orderly and expeditious  manner,  Vendor acknowledges and agrees
that each Site Schedule  shall be consistent  with the  Specifications  and each
stage of the Implementation Plan. As shall be provided in each Site Schedule for
a BTS Site, following finalization of construction plans and receipt of required
regulatory  approvals,  Vendor  has eight (8) weeks to  construct  the BTS Site.
Vendor and SBCW may agree to extend  this date for a BTS Site in the  applicable
Site Schedule or otherwise in a writing between the parties.

(b) Upon the occurrence of an event of Force Majeure,  the Site Schedule for any
affected BTS Site shall be adjusted to reflect all additional time which will be
required for the performance of any of the duties or obligations of Vendor under
this Agreement as a result of such event,  which  adjustment shall be subject to
the prior written approval of SBCW, not to be unreasonably withheld or delayed.

(c) Except as set forth in Section 6.04(b) as to an individual BTS Site, no Site
Schedule for any BTS Site shall  change,  and Vendor will have no right to cause
any such change,  without prior written reasonable approval by SBCW. Within five
(5)  Business  Days after the receipt of any request from Vendor for a change to
any Site  Schedule,  SBCW shall  notify  Vendor in writing  of its  approval  or
disapproval of such proposed change. Failure of SBCW to respond within said five
(5) Business Day period shall  constitute  and be deemed an  acceptance  of such
requested  change  unless  the change  is, or  results  in an  extension  of the
Scheduled  Completion Date by more than thirty (30) days with respect to any BTS
Site,  in which case SBCW must approve such change in writing  before it becomes
effective, such approval not to be unreasonably withheld.

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<PAGE>

(d) Vendor  acknowledges  and agrees that it has an  affirmative  obligation and
responsibility  promptly to notify SBCW of any circumstance which affects or may
affect any Site  Schedule in any  material  respect and the extent to which such
Site Schedule may be affected as a result of such circumstance.

Section 6.05.     Quality Review.

         Vendor shall  establish  and implement a program to monitor the quality
of the construction, as set forth in the Implementation Plan. The purpose of the
program  shall be to assist in guarding  against  defects and  deficiency in the
Work.  At any time and from  time to time,  SBCW  may,  in its  discretion,  and
without need to demonstrate cause, conduct an independent program to monitor the
quality  of the  construction  and  Vendor's  compliance  with  its  obligations
hereunder.

Section 6.06.     Compliance with Requirements, Permits, Bonds and Insurance
during Construction

                                       22
<PAGE>

         Vendor  shall  comply  with  all   Environmental,   Health  and  Safety
Requirements  as  they  relate  to  the  construction  of  the  Towers  and  the
Improvements  or the provision of  Collocation  Services in connection  with the
Project.  Vendor  shall,  at its own cost and expense,  procure and maintain all
licenses and permits required by local, state or federal regulatory agencies and
authorities with respect to the  construction,  and shall comply with all local,
state and federal laws,  ordinances,  rules and  regulations  applicable to this
Agreement.  SBCW has the right to audit Vendor's  compliance with Environmental,
Health and Safety  Requirements upon reasonable  notice.  Vendor shall indemnify
and hold  harmless  each of the SBCW  Indemnitees  from and  against  any  fine,
penalty or damage arising out of the failure by Vendor, its Affiliates or any of
their respective employees,  agents,  contractors,  subcontractors,  advisors or
consultants  to comply  with any such  laws,  ordinances,  rules or  regulations
including,  without  limitation,  zoning  laws and FAA  regulations  unless such
failure arises from SBCW's willful or negligent conduct. Vendor shall obtain, or
cause to be  obtained,  all  required  bonds and  insurance,  including  without
limitation the insurance  required under Article 10,  necessary or advisable for
the commencement of construction and Completion of the Work with respect to each
BTS Site or the provision of Collocation Services.

Section 6.07.     Work Permits.

         Vendor shall be the applicant for any and all necessary Permits for the
applicable  Work.  Vendor  shall  coordinate  and  manage all  professional  and
technical  services  required in connection  with the  preparation and filing of
applications  for and obtaining  all Permits.  Vendor shall be  responsible  for
ensuring  that all  applications  for the Permits are  diligently  prepared  and
filed, and pursued and obtained.

Section 6.08.     Construction by Vendor.

(a) Vendor,  at Vendor's  sole cost and expense,  shall cause the Towers and the
Improvements to be constructed and installed diligently and in a timely fashion,
with workmanship and materials in accordance with standards generally prevailing
in the industry and in any event,  in accordance  with the  Specifications,  the
Implementation  Plan for each BTS Site and all applicable  laws.  SBCW will have
the right to approve  or reject the  quality  of all  materials,  equipment  and
systems to be used in the  Completion  of the Towers and  Improvements  that are
different  from or not in  conformity  with  the  Specifications.  Vendor  shall
supervise the work and activities of the contractors,  subcontractors, engineers
and  other  Persons  engaged  in  the  design,  development,   construction  and
installation of the Towers and Improvements. Vendor shall obtain, or cause to be
obtained,  all  warranties.  Vendor shall cause the  construction of a Tower and
other Improvements on each BTS Site in accordance with this Agreement, including
the applicable Site Schedule and on or before the Site Completion Date.

                                       23
<PAGE>

(b) If SBCW  reasonably  requests  changes to the  Specifications,  Vendor shall
promptly  make such  changes to the  Specifications  and SBCW  shall  adjust the
Implementation  Plan,  the  Site  Schedule  for  any  affected  Site,  as may be
necessary or  required,  in SBCW's  reasonable  judgment  provided  that (i) the
change in the  Specifications  would not have a material  adverse  effect on the
Permitted Use under the BTS Sublease;  and (ii) SBCW pays any  reasonable  costs
incurred by Vendor and directly attributable to implementation of such changes.

Section 6.09.     Site Data.

         In performing Services hereunder,  Vendor shall compile data concerning
each  BTS  Site and  furnish  such  data to  SBCW,  all in  accordance  with the
procedures set forth in Annex C and Annex G,  including all Compliance  Data and
Completion Data.

Section 6.10.     Warranty.

         Vendor  does  hereby   warrant  and   guarantee   that  the  Tower  and
Improvements  on each BTS Site and all  workmanship  and materials  incorporated
therein will be constructed in accordance  with the  Specifications  and will be
free from  defects in  workmanship  and  materials:  (i) as to the Tower,  for a
period  commencing on the Completion  Date for such BTS Site and ending upon the
expiration of the term of the Site Designation  Supplement,  after giving effect
to  any  and  all  extensions  thereof,  and  (ii)  as to the  Improvements  and
Constructed  Improvements (to the extent made by Vendor as opposed to SBCW), for
a period  of one (1) year  commencing  on the  Completion  Date  (the  "Warranty
Period").  In  addition,  at  SBCW's  request,  Vendor  shall  assign  to SBCW a
nonexclusive right to enforce all warranties respecting materials used by Vendor
in  Completing  each BTS Site and shall  secure  any and all  consents  from the
suppliers  of such  materials to make such  assignment  effective or enforce any
such  warranties  on behalf of SBCW.  If any defect or deviation  should  exist,
develop, be discovered or appear within the Warranty Period, Vendor, at its sole
cost and expense,  immediately upon demand,  shall fully and completely  repair,
correct and eliminate  such defect or deviation.  The foregoing  warranties  and
guarantees  are  cumulative of and in addition to, and not  restrictive of or in
lieu of, any and all other warranties and guarantees provided for or required by
the  Specifications,  any other provision of this Agreement or applicable  laws,
and shall survive the expiration or termination of this Agreement.

                                       24
<PAGE>

Section 6.11.     Access and Inspection.

(a) The construction  shall be performed in such a manner as will permit SBCW to
inspect each BTS Site. SBCW may, at its election, conduct or have conducted such
inspections as it deems  necessary at each BTS Site. If SBCW notifies  Vendor of
any observed defects or nonconformities  with the  Specifications,  Vendor shall
promptly  correct  any defect or  nonconformity  in such time and manner as will
permit Completion of each BTS Site in accordance with the Site Schedule for such
BTS Site. The failure of SBCW to inspect any BTS Site, however,  will not in any
way limit,  waive, or otherwise affect the rights of SBCW with respect to any of
Vendor's warranties or obligations under this Agreement.

(b) SBCW will have  access to any BTS Site during all  working  hours,  and will
have the right to observe the Work performed; provided, however, that SBCW shall
not  delay,  hinder  or  interfere  with the  performance  of the  Work.  SBCW's
inspection  of any Work will not  relieve  Vendor of any of its  obligations  to
perform the Work in accordance with this Agreement, including without limitation
the  Specifications,  except  to  the  extent  a  specific  deviation  from  the
Specifications  at any BTS Site is or has been accepted in writing by SBCW. Work
found not to be in  accordance  with the  Specifications  shall be  replaced  or
re-performed  by  Vendor,  except to the extent a  specific  deviation  from the
Specifications  is or has been  accepted in writing by SBCW.  SBCW will have the
right  to  reject  materials  and  workmanship  which  are  defective  or not in
conformance  with the  Specifications.  Rejected  Work at any BTS  Site  must be
promptly  removed  from  such BTS  Site.  Failure  on the part of SBCW to reject
defective or nonconforming  Work will not be construed to imply an acceptance of
such  Work;  provided,  however,  to the extent a  specific  deviation  from the
Specifications  is or has been accepted in writing by SBCW, such deviation shall
not be deemed to be defective or nonconforming Work.

(c) Should SBCW consider it necessary or advisable at any time before Completion
to examine Work already  completed  therein,  Vendor shall,  on request of SBCW,
promptly furnish all necessary facilities, labor, and material for that purpose.
If such Work is found to be defective in any material respect,  Vendor shall pay
all  expenses of such  examination.  If,  however,  such Work is not found to be
defective  in any  material  respect,  SBCW  shall  pay  all  expenses  of  such
examination  and  restoration  of the Work. The Site Schedule as to affected BTS
Site shall be equitably adjusted.

Section 6.12.     Completion.

(a) Promptly  following the Completion of the Work at any BTS Site in accordance
with  the  requirements  of the  Specifications  and  the  requirements  of this
Agreement,  including  without  limitation the construction of the Tower and the
Improvements on such BTS Site and the performance of the final cleanup  thereon,
Vendor  shall give SBCW  written  notice of its good faith  belief that such BTS
Site is Completed. Not later than twenty (20) days after receipt of such written
notice,  SBCW shall provide  Vendor with written  notice stating (i) SBCW agrees
that the Work as to such BTS Site is  Completed,  whereupon  the  parties  shall
execute  a  Completion  Certificate  with  respect  to such  BTS Site as soon as
reasonably  practicable after SBCW gives such notice, (ii) SBCW rejects such BTS
Site as not  Completed;  provided  SBCW  includes an  explanation  in reasonable
detail of the  respects in which such BTS Site is not  Completed,  or (iii) SBCW
exercises  the  option set forth in  Section  6.12(c)  to  execute a  Completion
Certificate together with a Punch List.

                                       25
<PAGE>

(b) In addition to any right SBCW may have under  Section  6.11,  SBCW will have
the  right to (i)  inspect  any BTS Site at any time  after  SBCW  receives  the
notification under Section 6.12(a) and prior to any date on which the Completion
Certificate is executed and (ii) notify Vendor in writing if such  inspection by
SBCW reveals  that  Completion  has not  occurred  with respect to any BTS Site.
Promptly after receipt of any such notification, Vendor shall promptly cause any
unperformed Work to be performed.

(c) Upon issuance of the Completion Certificate with respect to a BTS Site, such
BTS Site shall  constitute a completed and accepted BTS Site (a  "Completed  BTS
Site"). If at any time prior to issuance of Completion Certificate such BTS Site
does not comply with the  Specifications or other requirements of this Agreement
in any  material  respect,  SBCW may,  at its sole  option,  elect to  execute a
Completion Certificate with respect to such BTS Site together with a punch list,
in the form of Annex E  attached  hereto  (the  "Punch  List"),  indicating  the
particulars  of  the  alleged   deviation  from  the   Specifications  or  other
requirements  of Vendor  hereunder.  Vendor shall  promptly,  but not later than
within  thirty  (30) days of the date of the Punch  List and at its own cost and
expense,  correct any such  non-compliance  or  deviation.  Upon  execution of a
Completion Certification and a Site Designation Supplement with respect to a BTS
Site,  SBCW shall commence  payment to Vendor of the BTS Rent applicable to such
BTS Site pursuant to the BTS Sublease.

(d) Notwithstanding Section 6.12(c), if (i) any BTS Site becomes a Substantially
Completed  Site and (ii) at any time  before  the  execution  of the  Completion
Certificate  or the Site  Designation  Supplement  with respect to any BTS Site,
SBCW installs and begins  operation of SBCW's  Communications  Equipment on such
BTS  Site in a  revenue  generating  mode,  such BTS Site  shall  be  deemed  to
constitute a Substantially  Completed BTS Site, and from and after the date such
BTS  Site is  deemed a  Substantially  Completed  Site  and such  Communications
Equipment  has been in  service,  SBCW  shall be  obligated  to pay  Vendor  (or
Southern  Towers,  Inc. an  Affiliate  of Vendor) the  applicable  BTS Rent with
respect to such BTS Site; provided, however, that in either case SBCW shall have
the right to defer,  accrue,  and withhold  payment of, the  applicable BTS Rent
until such BTS Site is Completed. Not later than thirty (30) days after any such
BTS Site is Complete, SBCW shall pay such accrued BTS Rent, without interest.

                                  Article VII
                             Guaranty Of Obligations

Section 7.01.     TowerCo Parent's Guaranty.

(a) TowerCo Parent hereby unconditionally guarantees to SBCW the full and timely
performance  and  observance  of all of the  terms,  provisions,  covenants  and
obligations of Vendor under this Agreement (the  "Obligations").  TowerCo Parent
agrees that if Vendor  defaults at any time during the term of this Agreement in
the  performance  of any of the  Obligations,  TowerCo  Parent shall  faithfully
perform and fulfill all Obligations  and shall pay to SBCW all attorneys'  fees,
court costs,  and other expenses,  costs and  disbursements  incurred by SBCW on
account of any  default by Vendor  and on  account  of the  enforcement  of this
guaranty.

                                       26
<PAGE>

(b) If Vendor  defaults  under this  Agreement  and SBCW  elects to enforce  the
provisions of this Section 7.01, SBCW shall promptly give TowerCo Parent written
notice  thereof,  which notice  shall  constitute  an exercise of SBCW's  rights
against TowerCo Parent  pursuant to this Section 7.01.  Following the receipt of
such notice by TowerCo Parent, TowerCo Parent shall have the same period of time
as is afforded to Vendor  under this  Agreement to cure such default but no such
cure period shall diminish the  obligations of TowerCo Parent under this Section
7.01.

(c) This guaranty  obligation of TowerCo  Parent shall be enforceable by SBCW in
an action against TowerCo Parent without the necessity of any suit,  action,  or
proceedings by SBCW of any kind or nature whatsoever against Vendor, without the
necessity  of any notice to TowerCo  Parent of Vendor's  default or breach under
this  Agreement  and  without  the  necessity  of any other  notice or demand to
TowerCo  Parent to which TowerCo  Parent or Vendor might  otherwise be entitled,
all of which notices  TowerCo  Parent hereby  expressly  waives.  TowerCo Parent
hereby agrees that the validity of this guaranty and the  obligations of TowerCo
Parent hereunder shall not be terminated,  affected,  diminished, or impaired by
reason of the  assertion or the failure to assert by SBCW against  Vendor any of
the rights or remedies  reserved  to SBCW  pursuant  to the  provisions  of this
Agreement  or any other  remedy or right which SBCW may have at law or in equity
or otherwise.

(d)  TowerCo  Parent  covenants  and agrees that this  guaranty is an  absolute,
unconditional,  irrevocable  and continuing  guaranty.  The liability of TowerCo
Parent hereunder shall not be affected, modified, or diminished by reason of any
assignment,  renewal,  modification  or  extension  of  this  Agreement  or  any
modification  or waiver of or change in any of the  covenants  and terms of this
Agreement by agreement of SBCW and Vendor, or by any unilateral action of either
SBCW or Vendor, or by an extension of time that may be granted by SBCW to Vendor
or any indulgence of any kind granted to Vendor, or any dealings or transactions
occurring between SBCW and Vendor, including, without limitation, any adjustment
compromise,  settlement, accord and satisfaction, or release, or any bankruptcy,
insolvency,   reorganization,   arrangement,   assignment  for  the  benefit  of
creditors,  receivership,  or trusteeship affecting Vendor.  TowerCo Parent does
hereby  expressly  waive  any  suretyship  defense  it may have by virtue of any
statute, law, or ordinance of any state or other governmental authority.

(e) All of SBCW's  rights and  remedies  under this  guaranty are intended to be
distinct,  separate,  and  cumulative  and no such  right and  remedy  herein is
intended to be the exclusion of or a waiver of any other.

(f) TowerCo Parent hereby waives presentment  demand for performance,  notice of
nonperformance,  protest,  notice of protest,  notice of dishonor, and notice of
acceptance.  TowerCo Parent further waive any right to require that an action be
brought  against  Vendor or any other person or to require that resort be had by
SBCW to any security held by SBCW.

                                       27
<PAGE>

                                  Article VIII
                 Vendor's Additional Obligations As To Bts Sites

Section 8.01.     Hazardous Waste and Contamination Investigation.

(a) Prior to the Ground  Lease  Effective  Date for any BTS Site,  Vendor  shall
cause the  Environmental  Assessment  on such BTS Site to be  performed.  Vendor
shall provide SBCW with copies of any and all such Environmental Assessments.

(b)  Within  five  (5)  Business  Days  after  discovery  of  any  Environmental
Conditions  on any BTS Site not  disclosed  by, or in  excess of the  conditions
disclosed by, the Environmental Assessment,  Vendor shall advise SBCW in writing
of such condition and its effect upon the Site Schedule. SBCW reserves the right
to reject any proposed BTS Site if, in SBCW's sole discretion, it determines the
environmental condition creates an unreasonable risk or liability. All costs and
expenses  incurred by Vendor arising out of or by reason of the discovery of any
such  condition  on the BTS  Site  (including,  without  limitation,  costs  and
expenses paid or incurred to rectify such  condition)  shall be borne by Vendor.
The applicable  Site Schedule  shall be adjusted to reflect all additional  time
which will be required for the  performance  of any of the duties or obligations
of Vendor under this Agreement as a result of any such condition.

Section 8.02.     Geotechnical Subsurface and Soil Investigation.

(a)  Vendor  shall  obtain,  perform  and  analyze  all  reasonably  appropriate
geotechnical  data, soil and subsurface tests and other soil  engineering  tests
and reports necessary to the design,  engineering,  permitting, and construction
of the Tower and the  Improvements  (except that the  provisions of this Section
8.04 shall not apply to the Environmental Assessment).

(b) If Vendor shall have timely obtained all reasonably  appropriate tests, but,
nonetheless, concealed and unknown conditions that affect the performance of the
Work are  encountered  below ground or in an existing  structure  other than the
Work,  then (i) Vendor  shall bear all costs and  expenses  arising out of or by
reason of the  existence  of any such  condition  on the BTS Site (except to the
extent that (x) Vendor  notifies SBCW that its good faith estimate of such costs
and expenses exceeds $100,000 and Vendor is unwilling to bear any such costs and
expenses  in excess of such  amount,  in which  event SBCW will have the option,
exercisable in its sole discretion, either to (A) agree to pay the amount of any
such  reasonably  incurred  costs and  expenses  in excess of such amount or (B)
terminate  this  Agreement  as to such BTS Site,  in which  event  SBCW shall no
longer be obligated  under Section 3.09 to engage Vendor to perform  Services on
such BTS Site,  and shall be free to engage  any other  Person to  perform  such
Services),  and (ii) the  applicable  Site Schedule shall be adjusted to reflect
all  additional  time which will be required for the  performance  of any of the
duties or  obligations  of Vendor under this  Agreement as to such BTS Site as a
result  of any  such  condition,  subject  to  Vendor's  receipt  of  the  prior
reasonable approval of SBCW.

Section 8.03.     Additional Environmental Requirements

         Prior to commencement of construction in respect of any BTS Site and as
part of the Compliance  Data provided to SBCW,  Vendor shall perform an analysis
to  determine  whether (i) the  proposed  site will be located in an  officially
designated wilderness area or preserve; (ii) the facility may affect federally

                                       28
<PAGE>

listed,  threatened or endangered species or designated critical habitats; (iii)
the facility may affect districts, site buildings, structures, objects, or other
cultural resources listed, or eligible for listing,  in the National Register of
Historic  Places;  (iv) the facility may affect Indian  religious sites; (v) the
potential site is located within a 100-year floodplain; (vi) the construction of
the  facility  will  involve a  significant  change in surface  features  (e.g.,
wetland fill,  deforestation,  or water diversion);  (vii) the structure will be
equipped  with  high  intensity  white  lights  and  be  located  in or  near  a
residential  neighborhood;  including any future  modifications  to the rules as
directed by the FCC.  Vendor shall  deliver the results of each such analysis to
SBCW upon completion of such analysis,  together with a written certification to
the  results  thereof  based  on the  consulting  reports  received  by  Vendor,
including  Vendor's  certification  that  there  is no  condition  of  the  type
described in clauses (i); (ii); (iii); (iv); (v); (vi); or (vii). This data will
also include letters and/or other  documentation from the governmental  agencies
with  responsibility  for these matters,  including but not limited to the State
Historical Preservation Officer, U.S. Fish and Wildlife, and the U.S. Army Corps
of Engineers.  If it is found that any condition  listed in this Section 8.03 is
present at any BTS Site,  an  Environmental  Assessment  must be prepared by the
Vendor  and  provided  to  SBCW.   SBCW  will  be  responsible  for  filing  the
Environmental Assessment,  upon approval of the data contained therein, with the
FCC. If any of conditions  listed  herein are present,  no  construction  may be
commenced on a BTS Site until the required  FCC  applications  have been granted
and  notice  of  such  grant  is  provided   to  Vendor  by  SBCW's   authorized
representative,  and the applicable Site Schedule shall be adjusted accordingly.
All costs and  expenses  incurred  by Vendor in  connection  with or relating to
Vendor's compliance with the requirements of this Section 8.03 shall be borne by
Vendor. If,  notwithstanding  anything to the contrary contained herein,  Vendor
discovers  that any of the  conditions  described  in clauses  (i)-(vii) of this
Section  8.03 exist and any of these  conditions  shall have a material  adverse
effect on the construction, operation or value of such Site, Vendor shall not be
obligated to construct or complete such Site.

Section 8.04.     FAA/FCC Compliance.

         Vendor  hereby  expressly  agrees  to  comply  with any and all  rules,
policies,  regulation and  interpretations  of SBCW relating to or in connection
with SBCW's  compliance  with the  applicable FAA and FCC  regulations,  as such
rules, policies, regulations and interpretations are described in Schedule 8.04.

Article IX
                              Agreement To Sublease

Section 9.01.     Execution of the Site Designation Supplement.

         Subject to Section 6.12(c), upon issuance of the Completion Certificate
with respect to a BTS Site or the final acceptance of a TowerCo Existing Site by
SBCW,  and  subject to Section  3.10(c),  upon the  issuance  of the  Completion
Certificate  with respect to a Tower developed by SBCW or an SBCW Party pursuant
to  Section  3.10(c)  and upon the sale of such  Tower  to  Vendor,  SBCW  shall
sublease the Leased Space of such BTS Site or TowerCo  Existing Site from Vendor
pursuant  to  the  BTS  Sublease  and  SBCW  and  Vendor  shall  execute  a Site
Designation  Supplement  for such BTS Site or  TowerCo  Existing  Site,  thereby
supplementing  the BTS Sublease so as to cause such BTS Site or TowerCo Existing
Site to be covered  thereby.  SBCW shall designate the specific  location of the
Leased Space on each BTS Site or TowerCo Existing Site to be initially  occupied
by SBCW or its Affiliate and the Site Designation  Supplement shall reflect such
location.

                                       29
<PAGE>

Section 9.02.     Effect of Sublease and Site Designation Supplement.

         The parties  acknowledge  and agree that upon the  Completion  of a BTS
Site or the final acceptance of an TowerCo Existing Site by SBCW, in addition to
any  obligations  of Vendor  hereunder that survive,  the respective  duties and
responsibilities  of the parties  pertaining to the sublease of such BTS Site or
TowerCo  Existing Site by Vendor (or by Southern  Towers,  Inc., an Affiliate of
Vendor) to SBCW shall be set forth and  governed by the BTS  Sublease and a Site
Designation Supplement for such BTS Site or TowerCo Existing Site.

Article X
                                    Insurance

Section 10.01.    Vendor's Insurance Requirements.

         Throughout the term of this Agreement,  Vendor shall carry and maintain
in force the following insurance:

(a) Commercial  General  Liability  Insurance  (including  protective  liability
coverage on  operations  of  independent  contractors  engaged in  construction,
blanket  contractual  liability  coverage,   products  liability  coverage,  and
explosion, collapse and underground hazards coverage) for the benefit of Vendor,
against claims for personal injury,  bodily injury and property  damage,  with a
limit of not less  than  $1,000,000  in the event of  personal  injury or bodily
injury to any number of persons or of damage to property  arising out of any one
occurrence,  and not less than  $2,000,000 in the  aggregate  applicable to this
Project.  Such  insurance  (which may be furnished  under a primary policy or an
"umbrella"  policy or policies with a limit of not less than  $5,000,000)  shall
also include  coverage  against  liability for bodily injury or property  damage
arising  out of use by or on behalf of Vendor of any owned,  non-owned  or hired
automotive  equipment  for a limit  not less  than that  specified  above.  Such
insurance shall include a cross-liability/severability of interest provision and
shall otherwise comply with the requirements applicable to such insurance.

(b) Worker's compensation and related insurance covering all employees of Vendor
employed in, on or about the Project in order to provide  statutory  benefits as
required  by  the  applicable   laws  and  otherwise  in  compliance   with  the
requirements  applicable  to  such  insurance,  including  employer's  liability
insurance with limits of not less than $1,000,000 each  accident/$1,000,000 each
employee by decease/1,000,000 policy limits and otherwise in compliance with the
requirements applicable to such insurance

(c) Comprehensive  automobile  liability  insurance with limits of not less than
$1,000,000  per  occurrence  and in the aggregate for bodily  injury,  including
death and property  damage and  otherwise in  compliance  with the  requirements
applicable to such insurance.

                                       30
<PAGE>

(d)  Vendor's  all risk  insurance  policy  with  limits  of not less  than full
replacement  cost of each  Tower and the  Improvements  of each BTS Site and all
TowerCo Existing Sites on which SBCW or its Affiliates are a tenant.  So long as
such self insurance is reasonable in light of the financial  condition of Vendor
form time to time, SBCW agrees that Vendor may, at Vendor's option,  self insure
with respect to all or a portion of the risks required to be insured  against by
Vendor under this Section 10.01(d).

Section 10.02.    Evidence of Insurance.

         Promptly  following SBCW's reasonable  requests made from time to time,
Vendor shall furnish SBCW with appropriate certificates evidencing the insurance
required to be maintained by Vendor hereunder. If Vendor for any reason fails to
obtain  and/or  maintain in force any of the  insurance  required  under Section
10.01,  then Vendor shall,  and Vendor does hereby agree to, indemnify each SBCW
Indemnitee  against,  and hold,  save, and defend each SBCW Indemnitee  harmless
from,  any  and  all  claims,   demands,   actions,  causes  of  action,  suits,
liabilities,  damages,  losses,  costs  and  expenses  of  any  kind  or  nature
whatsoever (including, without limitation,  reasonable attorneys' fees and court
costs  incurred in  enforcing  this  indemnity  and  otherwise)  which such SBCW
Indemnitee  may  suffer or incur,  or which may be  asserted  against  such SBCW
Indemnitee, whether meritorious or not, against which such SBCW Indemnitee would
or should have been insured under any required  insurance  which Vendor does not
for any reason obtain or maintain in force.

Section 10.03.    Waiver of Subrogation.

         Each insurance policy  maintained by Vendor with respect to the Project
shall  contain  a waiver  of  subrogation  clause,  or shall  name both SBCW and
against Vendor as insured parties thereunder,  so that no insurer shall have any
claim over or against SBCW, by way of subrogation or otherwise,  with respect to
any  claims  which  are  insured  under  any such  policy,  except  for  workers
compensation insurance.

                                   Article XI
                              Liability; Indemnity

Section 11.01.    Liquidated Damages.

(a)  Except  as  expressly  provided  in this  Agreement,  if, as a result of an
Excusable Delay, Vendor delays in performing any of its obligations  pursuant to
any Site Schedule,  then SBCW shall adjust any Site Schedule pursuant to Section
6.04(b) so as to allow Vendor to perform the obligations  which Vendor could not
perform due to such Excusable  Delay.  If Vendor delays in performing any of its
obligations pursuant to any Site Schedule for any reason other than an Excusable
Delay,  then SBCW will have the option,  exercisable in its sole discretion,  to
allow  Vendor to perform the  obligations  which Vendor could not perform due to
such delay to a later time; provided,  however, that no such adjustment shall be
effective unless evidenced by a writing executed by SBCW.

(b) If Vendor fails to meet its  obligation  to  Substantially  Complete any BTS
Site  in  accordance  with  the  applicable   Site  Schedule,   in  addition  to
constituting a breach by Vendor,  SBCW will have the right to liquidated damages
in  respect  of each BTS Site that has not been  Substantially  Completed  in an
amount equal to $7,500 per month (prorated for partial  months),  for each month
or partial month that such failure continues (the "Liquidated Damages"),  not to
exceed  $15,000 for any single BTS Site.  If Vendor owes  Liquidated  Damages in
respect of any BTS Site, such  Liquidated  Damages shall be payable by Vendor in
cash,  within thirty (30) days from the date of the written notice  thereof.  If
after sixty (60) days the BTS Site is still not completed,  SBCW shall no longer
be obligated to engage  Vendor to perform the Services on such BTS Site and SBCW
shall be free to engage  any Person to  complete  the  Tower.  Improvements  and
Constructed Improvements on such BTS Site.

                                       31
<PAGE>

(c) The payment of the  Liquidated  Damages  shall not  relieve  Vendor from its
obligations  to construct and install the Towers and  Improvements,  and perform
its  other  obligations   hereunder  in  accordance  with  the  respective  Site
Schedules.  The parties  hereto  acknowledge  that the amount of the  Liquidated
Damages payable by Vendor to SBCW under this Section 11.01 constitute liquidated
damages and not penalties,  that the injuries to SBCW caused by Vendor's  delays
described above are difficult or impossible to estimate accurately, and that the
sums payable herein are reasonable  estimates of the probable losses  associated
with such injuries.  The parties  further  acknowledge  that SBCW may not assert
other damages separate from and in addition to the Liquidated Damages for losses
related to delay.

Section 11.02.    Indemnity of SBCW.

(a) Vendor shall,  and Vendor does hereby agree to,  indemnify and hold harmless
each SBCW  Indemnitee  from and  against  any loss,  damage,  including  without
limitation any direct or indirect, special, incidental or consequential damages,
liability,  cost, expense, action or claim, including reasonable attorneys' fees
and amounts paid in settlement  ("Claims"),  by reason of or arising out of: (i)
personal injury,  death, and damage to tangible property  resulting from (A) the
intentional  or negligent  acts or omissions  of Vendor's  directors,  officers,
employees, agents, consultants, contractors or subcontractors in connection with
the Completion of each BTS Site and  performance of this  Agreement,  or (B) any
design  or  manufacturing  defect in any  Tower,  the  Improvements  or any part
thereof, whether manufactured by Vendor hereunder or otherwise or any defects in
construction  or   installation  of  any  Tower,   Improvements  or  Constructed
Improvements;  (ii)  Vendor's  breach of its  obligations  under this  Agreement
including without  limitation in respect of any Services;  (iii) the termination
or  removal of any  employee  or  subcontractor  of Vendor  pursuant  to Section
3.06(d);  (iv)  Vendor's  breach  of any  representation  or  warranty  in  this
Agreement,  including without  limitation its warranty pursuant to Section 6.10;
or (v) failure of Vendor to comply with any  obligation  under this Agreement as
to Governmental Requirements.

(b) SBCW  shall,  and SBCW does hereby  agree to,  indemnify  and hold  harmless
Vendor, Vendor's Affiliates, and the respective directors,  officers, employees,
agents,  contractors,  subcontractors,  advisors and  consultants  of Vendor and
Vendor's Affiliates (each, a "Vendor Indemnitee") from and against any Claim, by
reason of or  arising  out of  personal  injury,  death and  damage to  tangible
property  resulting from the intentional or negligent acts or omissions of SBCW,
but only to the  extent  (i) such  injury,  death or damage is caused by SBCW in
connection with (x) SBCW's  installation of any Constructed  Improvements or any
of SBCW Communications  Equipment,  (y) inspections  pursuant to Section 6.11 or
(z) the  provisions  of Section  6.12(d)  relating  to SBCW's  operation  of its
Communications  Equipment  prior to the execution of the Completion  Certificate
and (ii) Vendor is not responsible therefor under the terms of this Agreement.

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<PAGE>

Section 11.03.    Relationship to Insurance.

         In no event shall the indemnification provisions of Section 11.02 above
diminish,  affect impede or impair,  in any manner  whatsoever,  the benefits to
which any SBCW Indemnitee may be entitled under any insurance policy required by
this  Agreement or  otherwise  with respect to the Project or under the terms of
any waiver of any subrogation contained therein.

Section 11.04.    No Third-Party Beneficiaries.

         None of the duties and obligations of Vendor under this Agreement shall
in any way or in any manner be deemed to create any  liability  of Vendor to, or
any  rights in, any  person or entity  other than the SBCW  Indemnitees  and the
Vendor Indemnitees.

                                  Article XII
                    Additional Representations And Warranties

Section 12.01.    SBCW's Representations and Warranties.

(a) SBCW represents and warrants to Vendor that: (i) SBCW is a corporation, duly
organized,  validly existing and in good standing under the laws of the State of
Delaware;  and (ii) SBCW has the full and complete right, power and authority to
enter into this  Agreement  and perform its  respective  duties and  obligations
under  this  Agreement  in  accordance  with the  terms and  conditions  of this
Agreement.

(b) SBCW  represents  and  warrants to Vendor that SBCW and the SBCW Parties set
forth on the signature  pages to this Agreement are all of the Affiliates of SBC
Communications  Inc.  that control PCS or cellular  properties  in the Territory
(other than those certain  Affiliates that SBC  Communications  Inc. controls in
the Indianapolis, Indiana and New Orleans, Louisiana markets).

Section 12.02.    Vendor's Representations and Warranties.

(a) Vendor represents and warrants that Vendor is a corporation, duly organized,
validly  existing and in good standing  under the laws of the State of Delaware,
and has the full and  complete  right,  power and  authority  to enter into this
Agreement and perform  Vendor's duties and  obligations  under this Agreement in
accordance with the terms and conditions of this Agreement.

(b) Vendor  represents and warrants to SBCW that at all times during the term of
this  Agreement,  Vendor shall have  sufficient  funds available to Complete the
Project in accordance with this Agreement,  including,  without limitation,  the
Implementation Plan and Site Schedules.

                                       33
<PAGE>

Section 12.03.    TowerCo Parent's Representations and Warranties.

         TowerCo  Parent  represents  and  warrants  that:  TowerCo  Parent is a
corporation,  duly  organized,  validly  existing and in good standing under the
laws of the State of Delaware; and (ii) TowerCo Parent has the full and complete
right,  power  and  authority  to enter  into this  Agreement  and  perform  its
respective  duties and  obligations  under this Agreement in accordance with the
terms and conditions of this Agreement.

Article XIII
                             Default And Termination

Section 13.01.    Default by Vendor.

(a)      The following events shall constitute events of default by Vendor:

 (i)      If Vendor,  in any material  respect:  violates or breaches,  or fails
          fully and completely to observe, keep, satisfy, perform or comply with
          any terms, covenants, conditions, requirements, provisions, duties and
          obligations under this Agreement other than the breaches  described in
          clauses  (ii),  (iii) (iv),  (v) and (vi) below,  and does not cure or
          remedy such failure to perform  within ten (10) days after  receipt of
          written  notice from SBCW with  respect  thereto  (which  notice shall
          describe  with  reasonable  particularity  such  failure);   provided,
          however,  that if such failure to perform shall necessitate  longer to
          cure than  such ten (10) day  period,  and SBCW does not  unreasonably
          object to an  extension,  then such cure period  shall be extended for
          such period of time as is reasonably necessary to cure such failure to
          perform, provided, further, that Vendor commences such cure within ten
          (10) days after  receipt of written  notice  from SBCW and  thereafter
          proceeds  diligently  and in good  faith  to cure the  default  within
          thirty (30) days from the date of receipt of notice of such default;

(ii)     If, (x) in any  consecutive  twelve  (12) month  period,  SBCW  becomes
         entitled to the  Liquidated  Damages  pursuant  to Section  11.01(b) in
         excess of  $200,000  in  respect  of any BTS Sites or (y) SBCW  becomes
         entitled to  Liquidated  Damages  pursuant  to Section  11.01(b) in the
         amount of $15,000 in respect of any BTS Site;

(iii)    If any  representation  or warranty made by Vendor in this Agreement or
         the BTS Sublease was false or misleading in any material respect on the
         date as of which made (or deemed made);

(iv)     if Vendor breaches the provisions of Section 5.01(a);

(v)      if Vendor breaches the provisions of Section 5.02 hereof;

(vi)      If (A) a trustee  or  receiver  is  appointed  to take  possession  or
          control  of all or  substantially  all of  Vendor's  assets,  and such
          receiver or trustee shall fail,  within sixty (60) days of appointment
          to affirm or assume this Agreement,  to provide adequate  assurance as
          to its  ability to  perform  all of the terms and  conditions  of this
          Agreement as a receiver or trustee of Vendor, to cure all other events
          of default and to pay all damages  incurred by SBCW as a result of all
          events of default;  (B) Vendor shall commence any voluntary proceeding
          under  present or future  Federal  bankruptcy  laws or under any other
          bankruptcy,  insolvency or other laws respecting  debtor's rights;  or
          (C) an "order for relief" or other  judgment or decree by any court of
          competent  jurisdiction  is entered  against Vendor in any involuntary
          proceeding  against Vendor under present or future Federal  bankruptcy
          laws  or  under  any  other  bankruptcy,   insolvency  or  other  laws
          respecting  debtor's rights, or any such involuntary  proceeding shall
          be  commenced  against  Vendor  and  shall  continue  for a period  of
          forty-five (45) days after commencement
          without dismissal.

                                       34
<PAGE>

(b) Upon the occurrence of any event of default by Vendor under this  Agreement,
SBCW may pursue any and all rights and remedies  available under  applicable law
and  any one or  more  of the  following  rights  and  remedies,  separately  or
concurrently or in any combination, without further notice or demand whatsoever:

     (i)  upon the occurrence of any event of default with respect to a BTS Site
          under Sections 13.01(a)(i),  (ii)(y), (iii), (iv) or (v), SBCW may, at
          its option,  either (x) suspend its  obligations  with respect to such
          BTS Site  until  such  default  is cured by  Vendor or  terminate  its
          obligations  to engage  Vendor to perform  Services in respect of such
          BTS Site pursuant to Section 3.10,  by giving  Vendor  written  notice
          thereof, and thereafter SBCW shall have the right to engage any Person
          to perform Services in respect of such BTS Site or an alternative site
          within the applicable  SARF or (y) terminate this Agreement as to such
          BTS  Site  by  giving  Vendor  written  notice  of  termination   and,
          thereafter  SBCW  shall have the right to engage any Person to perform
          Services in respect to such BTS Site or an alternative site within the
          applicable SARF; or

     (ii) upon the occurrence of any event of default:  (A) under Sections 13.01
          (a)(ii)(x) or (vi), or (B) with respect to more than ten percent (10%)
          or more of the  proposed  cell  sites  accepted  by SBCW  pursuant  to
          Section  5.01 during any twelve (12)  consecutive  month  period under
          Sections  13.01(a)(i),  (ii)(y),  (iii), (iv) or (v), SBCW may, at its
          option,  either:  (x) suspend its  obligations  until such  default is
          cured by Vendor  or  terminate  its  obligations  to engage  Vendor to
          perform Services (including,  without limitation,  with respect to any
          or all BTS Sites)  pursuant to Section 3.10, by giving Vendor  written
          notice thereof, and thereafter SBCW shall have the right to engage any
          Person to perform  Services  on any or all BTS Sites or (y)  terminate
          this  Agreement in its  entirety by giving  Vendor  written  notice of
          termination,  and this  Agreement  shall be  terminated  as to all BTS
          Sites at the time  designated by SBCW in its notice of  termination to
          Vendor.
(c) SBCW will have the  right to  recover  from  Vendor  all costs and  expenses
incurred  by SBCW in  enforcing  its rights and  remedies  hereunder,  including
attorneys'  fees  and  expenses  paid or  incurred  by SBCW in  connection  with
enforcement measures,  including the filing of any action at law or in equity or
the filing of any appeal of any  decision or judgment  with  respect to any such
action.

(d) The  termination  of this  Agreement  by SBCW by reason of default by Vendor
shall  not  relieve  Vendor of any of its  duties  and  obligations  theretofore
accrued under this Agreement prior to the effective date of such  termination or
any representations or warranties theretofore made by Vendor.

                                       35
<PAGE>

Section 13.02.    Obligations upon Termination.

         Upon the termination of this Agreement, Vendor shall promptly:

(a) Upon  request  by SBCW,  deliver  to SBCW or such  other  person as SBCW may
designate all materials,  supplies, equipment keys, contracts and documents, all
books of account and records maintained pursuant to this Agreement pertaining to
this Agreement and the Project.

(b) Upon SBCW's request,  assign all existing  contracts relating to the Project
to SBCW or such other person or entity as SBCW shall designate.

(c) Furnish all such information, take all such other action, and cooperate with
SBCW as SBCW shall  reasonably  require in order to  effectuate  an orderly  and
systematic  termination of Services and Vendor's other, duties,  obligations and
activities hereunder.

Section  13.03.  Termination  of  Agreement  by  Vendor  in  Respect  of  SBCW's
Bankruptcy.

         Vendor may terminate  this  Agreement with respect to all BTS Sites for
cause in the event of  occurrence  of any of the  following,  after which Vendor
shall continue performing its duties and obligations  hereunder accrued prior to
the  effective  date of such  termination,  but  shall  cease  searching  for or
attempting to acquire any additional cell sites:

(a) A trustee or receiver is appointed to take  possession  or control of all or
substantially  all of SBCW's  assets,  and such  receiver or trustee shall fail,
within  sixty (60) days of  appointment,  to affirm or assume this  Agreement to
provide  adequate  assurance  as to its  ability to perform all of the terms and
conditions of this Agreement as a receiver or trustee of SBCW, to cure all other
events of default,  and to pay all damages incurred by Vendor as a result of all
events of default.

(b) SBCW shall commence any voluntary proceeding under present or future Federal
bankruptcy  laws or  under  any  other  bankruptcy,  insolvency  or  other  laws
respecting debtor's rights.

(c) An "order for relief" or other  judgment or decree by any court of competent
jurisdiction is entered against SBCW in any involuntary  proceeding against SBCW
under present or future Federal  bankruptcy laws or under any other  bankruptcy,
insolvency or other laws respecting  debtor's  rights,  or any such  involuntary
proceeding  shall be commenced  against SBCW and shall  continue for a period of
forty-five (45) days after commencement without dismissal.

                                       36
<PAGE>

                                  Article XIV
                                  Force Majeure

Section 14.01.    Force Majeure.

         An  event  of  "Force  Majeure"  shall  mean the  following  events  or
circumstances,  to the extent that they delay the  Completion of any BTS Site or
the  performance  of Vendor of its  other  duties  and  obligations  under  this
Agreement in respect of a BTS Site:

(a)      Condemnation or other exercise of the power of eminent domain;

(b) Material changes in Governmental Requirements applicable to the construction
of the Towers and  Improvements  and Completion of the BTS Site effective  after
the Effective Date, and the material orders of any Governmental Authority having
jurisdiction over a party;

(c) acts of God, including, without limitation,  tornadoes,  hurricanes, floods,
sinkholes, landslides, earthquakes, epidemics, quarantine and pestilence;

(d)      fire and other casualties, such as explosions and accidents;

(e)  acts of a  public  enemy,  acts  of  war,  terrorism,  effects  of  nuclear
radiation,  blockades,  insurrections,  riots, civil disturbances or national or
international calamities; and

(f) strikes,  walkouts, labor disputes or other third party events or conditions
to the extent there is no alternative  available to comply with the  obligations
of this Agreement; provided that Vendor is using commercially reasonable efforts
to mitigate the effect of such event or condition,  and, provided,  further that
if such event or condition  causes a delay in  performance  for a period greater
than  forty five (45) days,  then SBCW  shall have the right to  terminate  this
Agreement as to the affected BTS Site.

Section 14.02.    Effect of Force Majeure.

         Vendor  shall be entitled to an  adjustment  of the Site  Schedule  for
Force  Majeure,  but only for the number of days due to such  causes and only to
the extent that such occurrences actually delay the Completion of such BTS Site.
The extent of any such  adjustment is subject to the prior  written  approval of
SBCW, not to be unreasonably withheld or delayed. Under no circumstances shall a
Force Majeure event result in any extension of the Term.

                                   Article XV
                      Fire or Other Casualty; Condemnation

Section 15.01.    Obligation to Reconstruct; Use of Insurance Proceeds.

         In  the  event  of   destruction  or  damage  to  any  Tower  or  other
Improvements  by fire or  other  casualty  prior  to  Completion,  Vendor  shall
restore,  reconstruct and repair any such destruction or damage by fire or other
casualty such that the Tower and the  Improvements  shall be in accordance  with
the  Specifications.  Vendor  shall use all  available  insurance  proceeds  for
restoration,  reconstruction or repair, as required by this Agreement,  and SBCW
shall consent to such use of insurance  proceeds as required.  The parties agree
to adjust the Site Schedule in order to extend the timetable for the  Completion
of Work with respect to any destroyed or damaged Towers or Improvements.

                                       37
<PAGE>

Section 15.02.    Condemnation of the Tower or Site; Application of Compensation

         In the event that a Tower or a BTS Site,  or both, or any part thereof,
is damaged or taken by the  exercise of the power of eminent  domain at any time
prior to the Completion Date, SBCW shall apply the  compensation  awarded to and
received by it to restoration, reconstruction and repair of the Tower; provided,
however, that the Tower can (i) be restored, reconstructed or repaired, and (ii)
be  commercially  feasible  for its  Permitted  Use as  contemplated  by the BTS
Sublease after the Taking (as defined in the BTS Sublease). The parties agree to
adjust the Site Schedule in order to extend the timetable for the  Completion of
Work with respect to the taken Tower or BTS Site.

                                  Article XVI
                                  Miscellaneous

Section 16.01.    Notices

         Whenever any notice, demand,  request, advice or other communication is
required or permitted under this Agreement such notice,  demand or request shall
be in  writing  and  shall be sent by  registered  or  certified  mail,  postage
prepaid,   return  receipt  requested,  or  be  sent  by  nationally  recognized
commercial  courier for next  Business Day  delivery so long as such  commercial
courier  requires the recipient to sign a receipt  evidencing  delivery,  to the
addresses set forth below or to such other addresses as are specified by written
notice given in accordance herewith:

         SBCW or SBCW Party:          SBC Wireless, Inc.
                                      17330 Preston, #100A
                                      Dallas, Texas 75252
                           Attention: General Counsel
                          Facsimile No.: (972) 733-2021

                                      with a copy to:

                                      SBC Communications Inc.
                                      175 E. Houston
                                      San Antonio, Texas 78205
             Attention:            Vice President and Assistant General Counsel
                                   Facsimile No.: (210) 351-3488

         TowerCo Parent:              SpectraSite Holdings, Inc.
         --------------
                       100 Regency Forest Drive, Suite 400
                           Cary, North Carolina 27511
                           Attention: General Counsel
                          Facsimile No.: (919) 468-8522

                                      with a copy to:

                    Paul, Weiss, Rifkind, Wharton & Garrison
                           1285 Avenue of the Americas
                          New York, New York 10019-6064
                      Attention: Mitchell L. Berg, Bruce A
                                    Gutenplan
                          Facsimile No.: (212) 757-3990

         Vendor:                      SpectraSite Communications, Inc.
                       100 Regency Forest Drive, Suite 400
                           Cary, North Carolina 27511
                           Attention: General Counsel
                          Facsimile No.: (919) 468-8522

                                      with a copy to:

                    Paul, Weiss, Rifkind, Wharton & Garrison
                           1285 Avenue of the Americas
                          New York, New York 10019-6064
                      Attention: Mitchell L. Berg, Bruce A
                                    Gutenplan
                          Telephone No.: (212) 373-3000
                          Facsimile No.: (212) 757-3990

                                       38
<PAGE>

All notices, demands,  requests, advice or communications given by mailing shall
be deemed given on the date of receipt in the United States Mail; those given by
commercial  courier  shall be  deemed  given on the date  such  notice,  demand,
request,  advice or  communication  is delivered to the  recipients  address set
forth above or to such other address as is specified by written  notice given in
accordance herewith.  Any notice, demand,  request,  advice or communication not
received  because of changed address or facsimile  number of which no notice was
given or because of refusal to accept  delivery shall be deemed  received by the
party to whom addressed on the date of hand  delivery,  on the date of facsimile
transmittal, on the first calendar day after deposit with commercial courier, or
on the third  calendar day  following  deposit in the United States Mail, as the
case may be.

Section 16.02.    Assignment, Binding Effect.

         The rights of the  parties  under this  Agreement  are  personal to the
parties and may not be assigned  without the prior written  consent of the other
party,  except that (i) Vendor may retain third party contractors to perform its
obligations  hereunder  and may  delegate  any of its  obligations  hereunder to
wholly-owned  direct or indirect  subsidiaries  of TowerCo Parent and assign any
rights  relating  thereto to such  subsidiaries,  provided that the retaining of
such third parties or such delegation or assignment shall not relieve or release
Vendor from its  obligations  hereunder  and (ii) TowerCo  Parent and Vendor may
collaterally assign,  mortgage,  pledge,  hypothecate or otherwise  collaterally
transfer  their  interest  in  this  Agreement  to  any  Permitted  Subleasehold
Collateral  Assignee (as defined in that certain Lease and  Sublease,  dated the
date  hereof,  by  and  between  SBCW  and  Southern  Towers,  Inc.  (the  "SBCW
Sublease")), and any such Permitted Subleasehold Collateral Assignee (as defined
in the SBCW Sublease)  shall have the right to exercise  remedies under any such
mortgage,  pledge,  hypothecation  or other  collateral  transfer  in the manner
consistent with the provisions of this and every other agreement between TowerCo
Parent, Vendor and SBCW made in connection with this transaction. This Agreement
shall be binding upon and  enforceable  against,  and shall inure to the benefit
of, the parties hereto and their  respective legal  representatives,  successors
and permitted assigns.

                                       39
<PAGE>

Section 16.03.    Authorized Representatives.

         Any  consent,  approval,  authorization  or other  action  required  or
permitted to be given or taken under this  Agreement  by SBCW or Vendor,  as the
case may be, shall be given or taken by one or more of the Contract  Managers or
other  authorized  representatives  of each party.  The written  statements  and
representations of the Contract Managers or any other authorized  representative
of SBCW or  Vendor  shall be  binding  upon the  party  for whom the  applicable
Contract Managers or such other person is an authorized representative,  and the
other party hereto shall have no obligation  or duty  whatsoever to inquire into
the authority of any Contract  Managers or such other authorized  representative
to take any action which he proposes to take.

Section 16.04.    Headings.

         The use of headings,  captions and numbers in this  Agreement is solely
for the convenience of identifying  and indexing the various  provisions in this
Agreement  and  shall in no event  be  considered  otherwise  in  construing  or
interpreting any provision in this Agreement

Section 16.05.    Annexes, Exhibits and Schedules.

         Each and every  annex,  exhibit and  schedule  referred to or otherwise
mentioned in this  Agreement is attached to this  Agreement  and is and shall be
construed to be made a part of this Agreement by such reference or other mention
at each point at which  such  reference  or other  mention  occurs,  in the same
manner and with the same effect as if each annex and  exhibit  were set forth in
full and at length every time it is referred to or otherwise mentioned.

Section 16.06.    Publicity.

         Neither party will advertise or publish any information related to this
Agreement  without the prior written approval of the other party,  except to the
extent  previously  disclosed by a party in  accordance  with the then  existing
agreements of the parties.

Section 16.07.    Severability.

         If any term, covenant, condition or provision of this Agreement, or the
application  thereof to any person or circumstance,  shall be held to be invalid
or unenforceable, then in each such event the remainder of this Agreement or the
application of such term,  covenant,  condition or provision to any other person
or any other  circumstance  (other than those as to which it shall be invalid or
unenforceable) shall not be thereby affected, and each term, covenant, condition
and provision  hereof shall remain valid and  enforceable  to the fullest extent
permitted by law.

                                       40
<PAGE>

Section 16.08.    Waiver.

         Failure  by either  party to  complain  of any  action,  non-action  or
default  of the other  party  shall  not  constitute  a waiver of any  aggrieved
party's rights  hereunder.  Waiver by either party of any right arising from any
default of the other  party  shall not  constitute  a waiver of any other  right
arising  from a  subsequent  default  of the same  obligation  or for any  other
default, past, present or future.

Section 16.09.    Rights Cumulative.

         All  rights,  remedies,  powers  and  privileges  conferred  under this
Agreement  on the parties  shall be  cumulative  of and in addition  to, but not
restrictive of or in lieu of, those conferred by law or equity.

Section 16.10.    Time of Essence, Prompt Responses.

         Time is of the  essence of this  Agreement.  Anywhere a day  certain is
stated for  payment or for  performance  of any  obligation,  the day certain so
stated enters into and becomes a part of the  consideration  for this Agreement.
The parties  recognize and agree that the time limits and time periods  provided
herein are of the  essence of this  Agreement.  The  parties  mutually  agree to
exercise their mutual and separate good faith reasonable efforts to consider and
respond promptly and as expeditiously as is reasonably possible  notwithstanding
any time period provided in this Agreement.

Section 16.11.    Applicable Law.

         This Agreement  shall be governed by,  construed  under and interpreted
and  enforced  in  accordance  with the laws of the State of New  York,  without
regard to its conflicts of laws provisions.

Section 16.12.    Waiver of Jury Trial.

         To the maximum extent  permitted by law, the parties hereby  knowingly,
voluntarily and  intentionally  waive the right to a trial by jury in respect of
any litigation  based hereon,  arising out of, under or in connection  with this
Agreement,  or any course of  conduct,  course of  dealing,  statement  (whether
verbal or  written)  or action of either  party or any  exercise by any party of
their respective rights under this Agreement (including, without limitation, any
action to terminate this Agreement, and any claim or defense asserting that this
Agreement  was  fraudulently  induced or is otherwise  void or  voidable).  This
waiver is a material inducement for the parties to enter into this Agreement.

Section 16.13.    Entire Agreement.

         This  Agreement  contains the entire  agreement of SBCW and Vendor with
respect  to the  engagement  of Vendor as the Vendor  for the  Project,  and all
representations,  warranties,  inducements,  promises  or  agreements,  oral  or
otherwise,  between the parties not  embodied in this  Agreement  shall be of no
force or effect.

                                       41
<PAGE>

Section 16.14.    Modifications.

         This  Agreement  shall not be modified or amended in any respect except
by a written agreement executed by both parties.

Section 16.15.    Counterparts.

         This Agreement may be executed in several  counterparts,  each of which
shall  be  deemed  an  original,  and all of such  counterparts  together  shall
constitute one and the same instrument.

Section 16.16.    No Brokers.

         SBCW and Vendor hereby  represent,  agree and acknowledge  that no real
estate broker or other person is entitled to claim or to be paid a commission as
a result of the  execution and delivery of this  Agreement  including any of the
Exhibits, or any proposed improvement use, disposition or lease of any or all of
the BTS Site.

Section 16.17.    Power of Attorney by SBCW Parties; Authorization.

(a) SBCW Parties and each of them,  hereby  irrevocably  constitute  and appoint
SBCW (the  "Agent") as their  agent to modify,  amend or  otherwise  change this
Agreement or any of its terms or provisions,  to take all actions and to execute
all documents necessary or desirable to effect the terms of this Agreement,  and
to take all actions  and to execute  all  documents  which may be  necessary  or
desirable in connection therewith,  to give and receive consents and all notices
hereunder, to negotiate and settle claims for identification, and to perform any
other act arising  under or  pertaining  to the  Agreement  (including,  without
limitation, issuing an SARF to Vendor and accepting or rejecting any BTS Site or
TowerCo  Existing  Site  proposed  by  Vendor  for use by such SBCW  Party,  the
issuance of a Completion  Certificate  with respect  thereto or any other matter
pertaining to a BTS Site or the Project).  SBCW Parties, and each of them, agree
that service of process upon the Agent in any action or proceeding arising under
or pertaining  to the  Agreement  shall be deemed to be valid service of process
upon SBCW Parties.

(b) Nothing  contained  herein  shall be deemed to make the Agent liable to SBCW
Parties  because of service in its capacity as agent.  In performing  any of its
duties  hereunder,  the Agent shall not incur any  liability to SBCW Parties for
losses, damages, Liabilities or expenses, except for its willful default.

(c) It is  expressly  understood  and agreed that this power of attorney and the
agency  created  hereby is coupled  with an interest of the  respective  parties
hereto  and shall be binding  and  enforceable  on and  against  the  respective
successors  and  assigns of SBCW  Parties,  and each of them,  and this power of
attorney shall not be revoked or terminated and shall continue to be binding and
enforceable in the manner provided herein.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                       42
<PAGE>

<PAGE>

                    [Signatures continued from previous page]

                                  SBCW PARTIES
                                       44

<PAGE>

                                     ANNEX A

                                [To be inserted]

<PAGE>

                                     ANNEX B

                                [To be inserted]

<PAGE>

                                     ANNEX C

                                [To be inserted]

<PAGE>

                                     ANNEX D

                                [To be inserted]

<PAGE>

                                     ANNEX E

                                [To be inserted]

<PAGE>

                                     ANNEX F

                                [To be inserted]

<PAGE>

                                     ANNEX G

                                [To be inserted]

<PAGE>

                                     ANNEX H

                                [To be inserted]

<PAGE>

                                     ANNEX I

                                SBC WIRELESS INC.
                              Build to Suit Program

                              Collocation Services
                            on TowerCo Existing Sites
                                     Summary

Program Management (All Phases)

o    Coordination,   selection  and  management  of  subcontractor  professional
     services as requested/necessary,  such as: FAA study, survey,  geotechnical
     study,  environmental site assessment,  structural  analysis,  interference
     study, appraisals, expert witnesses, expert reports, legal assistance, site
     plans and other reasonable requests.

Site Leasing

o    Coordination of title curative activities and preparation of required title
     curative documents,  including negotiation and follow-up on satisfaction of
     title exceptions and coordination of commitment for title insurance (actual
     title insurance policy cost by SBCW).

Zoning and Permits (if applicable)

o Preparation,  coordination and submittal of zoning applications,  drawings and
other required documents.

o    Attendance at all pre-hearing meetings, community meetings, coordination of
     all lobbying and zoning efforts with all involved parties.

o        Attendance at all planning and zoning hearings.

o Procurement of zoning  approval and building permit  application  preparation,
coordination and submittal.

Construction Project Management

Vendor's General Construction Service shall include:

General Construction Services          Vendor personnel will coordinate
                                       construction consistent with the
                                       applicable Site Schedule and the Project
                                       Schedule.

<PAGE>

Support Site Acquisition Activity      Vendor's qualified  construction
                                       personnel will schedule and coordinate
                                       site visits for construction  feasibility
                                       in order to  develop  preliminary  site
                                       data to  include photographic
                                       documentation,  pertinent site
                                       information, general measurements,
                                       locations of viable utilities and
                                       notation  of unusual  conditions.  In
                                       addition,  Vendor will provide
                                       construction documents and zoning quality
                                       exhibits in a timely manner.

Finalize                               Construction Drawings  Building Permit
                                       Vendor will contract a SBCW approved
                                       Architectural/Engineering firm to produce
                                       all necessary plans and specifications
                                       within the required, scheduled time
                                       frame.  Vendor will   process  the
                                       Building Permit Application and submit
                                       for permit issuance.

Prepare                                Construction  Budget and Schedule  Vendor
                                       will complete schedule of values for each
                                       site to be constructed,  and will prepare
                                       schedules  for  Architectural/Engineering
                                       and site construction.

Procurement of Construction Materials  Vendor will procure and install permanent
                                       construction materials   and  leave  the
                                       base station site in a
                                       ready-for-equipment  condition.  Vendor's
                                       personnel will be  responsible  for  the
                                       coordination   of   Vendor equipment,
                                       antennas,  cables and all ancillary
                                       mounting hardware   installation.   In
                                       addition,   Vendor  will provide
                                       procurement  services by ordering and
                                       scheduling delivery of wireless equipment
                                       and materials.

Pre-Bid                                Meeting Vendor coordinates and meets with
                                       all   construction   disciplines   on   a
                                       scheduled   site-walk   to  review   site
                                       details,    answer   general   questions,
                                       discuss  ways and means of  construction,
                                       etc.

                                       2
<PAGE>

Obtain three (3) Competitive           Vendor will obtain three (3) competitive
                                       bids from each contractor,  subcontractor
                                       and vendor for all outsourced items or
                                       services purchased that are expected to
                                       exceed $25,000.

Bid                                    Packages Analyzed/Contract Awarded Vendor
                                       will  review  all bid  packages  and will
                                       negotiate    contracts   with   qualified
                                       contractors.

Prepare                                Construction Schedule Vendor will prepare
                                       a complete construction schedule for each
                                       site.

Pre-Construction  On-Site  Meeting  with  Selected           Vendor  will  meet
Contractor/Subcontractors                                    with all outsourced
                                  Contractor to
                                discuss scope of
                                  work, answer
                                                             general questions
                                 and confirm all
                                                             ways and means of
                                  construction.

Sub-Contractor                                               Management   Vendor
                                                             will be responsible
                                                             for  facilitating,
                                                             coordinating and
                                                             managing all
                                                             sub-contractors
                                                             used  to  complete
                                                             the  construction
                                                             phase.

Commence Construction                                        Vendor will  ensure
                                                             that General
                                                             Contractor has
                                                             commenced
                                                             construction in a
                                                             timely manner.

Coordinate for BTS Equipment Delivery/Anchored  (if          Vendor will monitor
Bids on Outsourced Services                                  vendor's  delivery
                                and installation
                                of SBCW equipment
                                (if applicable).

Grounding System Installed and Certified                     Vendor will  ensure
                                                             that the Grounding
                                                             System  is
                                                             installed and
                                                             inspected by a
                                                             certified
                                                             electrician,  to
                                                             meet SBCW specified
                                                             standard.

Certify                                                      Foundation (if
                                                             applicable)  Vendor
                                                             will arrange for an
                                                             independent
                                                             inspection and
                                                             certification of
                                                             the  foundation (if
                                                             necessary).

General Construction Landscaping, Etc.                       Vendor will monitor
                                                             the  completion of
                                                             any other General
                                                             Construction,
                                                             landscaping, etc.

Punchlist                                                    Prepared     Vendor
                                                             will    prepare   a
                                                             Punchlist   to   be
                                                             utilized   at   the
                                                             final          site
                                                             inspection.

Final                                                        Site Inspection and
                                                             Acceptance   Vendor
                                                             will  review   the
                                                             Punchlist  and  to
                                                             ensure  site
                                                             construction is
                                                             complete  and
                                                             coordinate with
                                                             respective
                                                             personnel  at  time
                                                             of construction
                                                             completion to
                                                             assure
                                                             specification
                                                             compliance.

Submit Close-Out Documentation                               Vendor will prepare
                                                             and deliver a
                                                             comprehensive
                                                             construction binder
                                                             that  will  include
                                                             all applicable
                                                             documentation.

                                       3
<PAGE>

Update                                                       Reports Vendor will
                                                             provide cost
                                                             tracking and
                                                             progress reports as
                                                             indicated by
                                                             respective
                                                             personnel.

Construction Documentation                                   Change Order
                                                             Request Lien
                                                             Release Checklist
                                                             Daily Daily
                                                             Construction Report
                                                             Weekly Project
                                                             Status Summary Form
                                                             Weekly Time Report
                                                             Site Pictures
                                                             Cost Tracking
                                                             As Built Survey
                                                             All other required
                                                             documentation

                                       4
<PAGE>

                                     ANNEX J

                               BTS SUBLEASE TERMS

Parties:

Landlord - Vendor or Southern Towers, Inc., an Affiliate of Vendor

Tenant - SBCW or any SBC Operating Company

Term:

         25 year initial term with Tenant  withdrawal  rights  described  below.
SBCW will have the right to  withdraw  from each BTS Site at any time  following
the  tenth  (10th)  anniversary  of the  commencement  date for such BTS Site by
giving ninety (90) days prior written notice to Vendor of the  withdrawal  date.
From and after such  withdrawal  date,  SBCW shall not be  obligated to pay Rent
with  respect to such BTS Site and shall  vacate the BTS Site on or prior to the
withdrawal date.

Permitted Use:

         The leased  premises  shall include space on the tower for the location
of  Tenant's  communications  equipment,  together  with  access  and use of the
surrounding  land for  installation  of Tenant's  equipment  shelter,  equipment
building  or  hut,  generators  and  associated  fuel  tanks,  grounding  rings,
connections for utilities,  one or more foundations,  concrete equipment pads or
raised platforms and similar improvements.

Rental Rate:

         Initial rent of $1,400 per month per BTS Site, (subject,  as to any BTS
Site leased to SBCW or its Affiliates  after the first (1st)  anniversary of the
date hereof,  to increase in accordance with the following  sentence,  but using
CPI changes  beginning  with the CPI for  January 1,  2000).  Rent is subject to
increase  annually on the anniversary of the rent commencement date for each BTS
Site in an amount equal to the lesser of (i) the  applicable CPI change plus 4%,
or (ii) 5.0% per year (but never less than zero percent (0%)).

Landlord Covenants:

         The BTS Sublease will contain covenants  regarding  Landlord's and each
BTS Site's  legal  compliance  (including  environmental  laws and FAA and FCC),
insurance,  non-interference  with  Tenant's  operations  and  transmissions  by
Landlord and other subtenants, tower lighting, repair and maintenance of the BTS
Site and similar covenants similar in scope and content to the provisions of the
SBCW Sublease.

<PAGE>

Taxes; Ground Lease Rent; Utility:

         Landlord shall be required to pay all taxes, ground rents and utilities
applicable to the BTS Site provided the Tenant shall pay for utilities necessary
to operate its equipment.

Representations:

         Landlord  shall  represent as to absence of hazardous  materials on the
BTS Site,  compliance of the BTS Site with legal  requirements and other similar
matters.

Termination Upon Certain Events:

         Tenant may terminate with respect to any BTS Site without any liability
on 30 days prior  written  notice  following  (i) a default by  Landlord  of any
covenant which is not cured within 10 days after notice thereof;  (ii) if Tenant
does not obtain or maintain licenses,  permits or other approvals  necessary for
the operation of Tenant's  equipment;  or (iii) if Tenant is unable to occupy or
utilize the leased  premises  due to a ruling or  directive  of the FCC or other
governmental or regulatory agency, including, but not limited to, a take back of
channels or change in frequencies.

Assignment:

         Tenant may assign  its  subleasehold  interest  pursuant  to  covenants
similar in scope and content to the applicable provisions of the SBCW Sublease.

<PAGE>

                                     ANNEX K
                                [To be inserted]

<PAGE>

                                     ANNEX L

                         Minimum Standards for BTS Sites

o     Tower and foundation designed to accommodate four (4) broadband equivalent
      carriers1 o Will use  commercially  reasonable  efforts to lease and fence
      minimum of 100' x 100' premise o Lease premise and fenced stoned  compound
      minimum of 2,400 usable  square feet for monopole  towers and guyed towers
      and 3,600 usable  square feet for self support  towers.  Guyed towers will
      have additional  ground and airspace  rights to accommodate  guyed anchors
      and provide appropriate access thereto.
o     Minimum twelve (12') wide stoned access road to compound
o     Fencing, and initial equipment grounding
o     Underground  (unless not economically  constructable)  electric  and telco
      conduit  facilities  to compound, sized  properly  for four (4)  broadband
      carriers
o     No  restrictions  on assignment to Vendor or Southern  Towers,  Inc.
      and subletting a portion of tower and
      premises to third party tenants
o     Best efforts on compound layout to efficiently utilize ground space to
      maximize collocations

--------
1 Broadband  equivalent carrier equals the greater of twelve (12) panel antennas
(e.g.  DB878)  and  related  equipment   including  one  (1)  8'  diameter  high
performance microwave dish or SBCW  configuration(s)  described in Annex K along
with  appropriate  loading to  accommodate a sector frame for the panel antennas
(e.g. mount). Each antenna and dish to have 1 5/8" coax (total of 13).

<PAGE>

                                     ANNEX M

                                [To be inserted]

<PAGE>

                                     ANNEX N

         A.       Existing Contracts

         1. Master Build to Suit Lease Agreement, dated __________,  1998 by and
between SBA Towers,  Inc., as landlord,  and  Southwestern  Bell Mobile  Systems
d/b/a Cellular-One-Chicago, as tenant.

         2.  Master  Build to Suit Lease  Agreement  dated  April 6, 2000 by and
between SBA Towers,  Inc., as landlord,  and Buffalo Telephone  Company,  Albany
Telephone  Company,  Genesee Telephone  Company,  Syracuse Telephone Company and
Regasus  Cellular  Telephone  Company  No. 3 (NY-4),  Inc.  d/b/a  Cellular-One,
collectively, as tenant.
 <TABLE>
<S>                                <C>                           <C>                          <C>

Midwest Sites

      Site #                    Site Name                      Vendor                     Market Area
      ------                    ---------                      ------                     -----------
      251                       Hartland                       SBA                        Chicago
      266                       52nd & Keeler                  SBA                        Chicago
      445                       Northbrook                     SBA                        Chicago
      488                       Griffith                       SBA                        Gary-Hammond, IN
      499                       Frankfurt                      SBA                        Chicago
      505                       Morris NW                      SBA                        Joliet, IL
Upstate NY

      Site #                    Site Name                      Vendor                     Market Area
      ------                    ---------                      ------                     -----------
      A00004                    Queensbury                     SBA                        Albany
      B00020                    Evans                          SBA                        Buffalo
      B00002                    Roll Road                      SBA                        Buffalo
      R00003                    Parma                          SBA                        Rochester
      S99002                    Onondaga West                  SBA                        Syracuse
      S00001                    Albion                         SBA                        Syracuse
      S00003                    Oswego                         SBA                        Syracuse
      S00004                    Fairhaven Village              SBA                        Syracuse
      I00003                    Virgil                         SBA                        Ithaca
      I00006                    Weedsport                      SBA                        Ithaca
      R00010                    Junius Pond                    SBA                        Ithaca
      W00001                    Orleans                        SBA                        Watertown
      W00002                    Pamelia                        SBA                        Watertown
      W00003                    Dekalb                         SBA                        Watertown
      U00003                    Schuyler                       SBA                        Utica

</TABLE>
<PAGE>

         B.       Additional "In-Progress" Sites

[SBCW to schedule up to 35 additional "in-progress" sites prior to Initial
Closing]

                                       2

<PAGE>

                                  SCHEDULE 8.04
                                [To be inserted]

<PAGE>

                                SCHEDULE 3.10(c)

         SBCW shall have the right,  in lieu of requiring  Vendor to perform the
Services  with  respect  to any  search  area,  to locate  and secure a BTS Site
therein,  to complete the site  acquisition  work with respect to such BTS Site,
and to develop  and  construct a wireless  transmission  tower on such BTS Site.
Upon SBCW's completion of such construction,  Vendor (or Southern Towers,  Inc.,
an Affiliate of Vendor) shall  purchase  such BTS Site from,  and lease space at
such BTS Site to,  SBCW or a SBCW  Party on the terms of the BTS  Sublease.  The
following  terms and conditions  shall apply to SBCW's rights and obligations in
respect of any such BTS Site:

1. Quality of BTS Sites: Any BTS Site identified  and/or developed by SBCW shall
satisfy the Minimum Standards for BTS Sites set forth on Annex L attached to the
Agreement.

2.  Construction  and Site  Acquisition:  SBCW, at SBCW's sole cost and expense,
shall  construct and install the towers (a) diligently and in a timely  fashion,
with workmanship and materials in accordance with standards generally prevailing
in the  industry  and,  in any  event,  in  accordance  with the  Specifications
attached to the Agreement as Annex A and all  applicable  laws and (b) generally
in a manner consistent with the provisions of the Agreement  governing  Vendor's
construction  obligations.  All site acquisition work performed by SBCW shall be
performed in a manner consistent with the provisions of the Agreement  governing
Vendor's  performance of such work, and all Ground Leases acquired by SBCW shall
(i) be acquired at rates  consistent  with SBCW's  average ground rent as of the
date of such site  acquisition  work,  (ii) not contain any  restrictions on the
ground lessee's ability to sublet its interests thereunder,  (iii) not allow the
applicable  ground  lessor  to  share  in  any  revenue  of  the  ground  lessee
thereunder, and (iv) be, in all other respects, on terms reasonably satisfactory
to Vendor.  SBCW shall deliver to Ground Lessor Vendor's standard form of ground
lease.

3. Completion:  Whether  "Completion" of a tower  constructed by SBCW shall have
occurred shall be determined in a manner  consistent  with the provisions of the
Agreement governing Completion of the towers by Vendor.

4. Title:  Title to BTS Sites  (including  SBCW's interest as ground lessee) and
towers transferred to Vendor (or Southern Towers,  Inc.) shall be free and clear
of all liens and encumbrances  except for any  encumbrances  permitted under the
definitive Section 3.10, which permitted  encumbrances shall be limited to those
that are customary in the sale of wireless transmissions tower structures and do
not materially impair the use, operation and value of the towers.

5. General  Conditions:  Vendor's (or Southern  Towers,  Inc.'s)  obligation  to
purchase the BTS Sites and towers shall be subject to conditions  precedent that
are customary in the case of a sale of wireless  transmissions tower structures,
including  obtaining all governmental  and third party consents,  receipt of all
permits,  certificates and approvals  required to operate the towers, no adverse
environmental  conditions  at  the  BTS  Site,  and  no  pending  litigation  or
arbitration  affecting the towers.  In connection  with each tower  developed by
SBCW hereunder,  SBCW shall deliver or cause to be delivered to Vendor the items
set forth on Annex 1 to this Schedule 3.10(c).

<PAGE>

6. Price:  Vendor shall reimburse SBCW for the towers in an amount determined in
accordance with the Fixed Price Schedule attached to this Schedule 3.10(c).  Any
costs incurred, during any phase of the site acquisition,  design,  engineering,
construction  or  development  of a Tower by SBCW, as a result of  extraordinary
activities  that are not  usually  considered  part of standard  costs,  are not
included in the Fixed Price Schedule. Such extraordinary costs must be discussed
between the parties before they are incurred, if possible.

7.  Transaction  Structure:  SBCW and  Vendor  shall use good  faith  efforts to
structure the sale and acquisition of the BTS Sites and towers by SBCW to Vendor
(or Southern Towers,  Inc.) in a manner that will minimize the transaction costs
associated with such sale and acquisition,  including  without  limitation,  any
real property transfer taxes.  Vendor and SBCW shall each be responsible for 50%
of such costs (other than each party's legal and other  professional fees, which
shall be responsibility of such party).

<PAGE>

                                     Annex 1
                                       to
                                Schedule 3.10(c)

          Deliverables for Sites Constructed by SBCW or its Affiliates

o        Proposed Tenant
o        Site ID
o        Site Name
o        Corridor (if applicable)
o        Site City, County, State
o        Site Latitude and Longitude
o  Lat/Long  Source  (NAD 27 or NAD 83;  Survey  or GPS) o Site  Location  Map &
Directions o Executed Ground Lease Agreement (required) and Amendments
         (if applicable)
o        Ground Lease Commencement Letter
o        Easement of contractual right of access and any utility right of way
         not included in lease
o        Underlying Prime Agreement Lease and Amendments (if applicable)
o        Title Report or Title Commitment
o        NonDisturbance Agreement (if required)
o        Registered Land (Site) Survey (within 6 months
o        Phase 1 Report
o        Phase II Reports, as applicable
o        FCC Applications and Approvals, as applicable
o        Geotechnical Report
o        Photos (Min. 6)
o        Site Plan [part of Site Acquisition Work]
o        NEPA Checklist
o        SHPO
o        AM Tower Study
o        ASAC Type Opinion Letter
o        Site Layout Exhibit
o        Tower Profile Exhibit
o        Architectural & Engineering Drawings
o        Zoning and Permitting Approvals/Verification Letter from Local
         Government Official
o        Telephone and Electrical Service Providers
o        General Information on Tower
o        Tower Type (Self Support, Monopole, Guyed)
o        Tower Height (AGL)
o        Tower Capacity
o        FAA Filing Application (FAA Form 7460)
o        FAA Determination

<PAGE>

o        FCC Authorization
o        FCC Antenna Registration Worksheet (FCC Form 854)
o        Foundation Drawing
o        Foundation Certification Letter
o        FAA 1A Reporting Letter (if required)
o        Tower Structural Engineering Drawings
o        Tower Foundation Design Plans and Design Calculations
o        Tower Design Plans and Wind Load Calculations
o        Site Construction Plans & Documentation
o        Building Permit and Electrical Permit or Permit No.
o        Contractor's Notice to Proceed Letter
o        Equipment and/or Workmanship Warranties
o        Contractor's and Subcontractor's Waivers of Lien
o        AsBuilt Documentation
o        AsBuilt Materials List Complete with Serial Numbers
o        AsBuilt Drawings (RedLined Construction Plans)
o        Certificate of Occupancy (if/when available)
o        Site Specific Tower Photos (After Construction)
o        Materials Purchase Orders
o        Full Accounting of All Invoices Paid
o        Collocation Application that defines Initial Installation Requirements
         including:
o        Call Sign
o        RX and TX Frequencies
o        Radiation Center (AGL)
o        Antenna Types(s), Quantities and Orientation
o        Transmission Line
o        Equipment Type
o        Ground Space Requirements
o        Microwave Requirements (if applicable)
o        Dish Size
o        Dish Mounting Heights (AGL)
o        Cabling

                                       2

<PAGE>

                                    EXHIBIT E

                           FORM OF LEASE AND SUBLEASE

<PAGE>

                                    EXHIBIT E

                                      FORM

                                       of

                                  SBCW SUBLEASE

                                    LEASE AND
                                    SUBLEASE

                                  by and among

                   SBC WIRELESS, INC., a Delaware corporation,
                   for itself and as Agent for the SBCW GROUP,

                                       and

                              SOUTHERN TOWERS, INC.

                             Dated October __, 2000

<PAGE>

                                TABLE OF CONTENTS

                                                                            Page

SECTION 1. Definitions........................................................1
SECTION 2. Sublease Documents................................................13
SECTION 3. Subleased Property................................................14
SECTION 4. Existing Subleases and Colocation Agreements......................19
SECTION 5. Reserved Space....................................................19
SECTION 6. Permitted Use.....................................................21
SECTION 7. Access............................................................22
SECTION 8. Term.  22
SECTION 9. Withdrawal........................................................23
SECTION 10. Rent and SBCW Leaseback Charge...................................23
SECTION 11. Condition of the Sites and Obligations of TowerCo................25
SECTION 12. Requirements for Alterations; Title to Alterations; Addition of
            Equipment; Work on the Site..........27
SECTION 13. Damage to the Site, Tower or the Improvements....................29
SECTION 14. Space Subtenants; Interference...................................30
SECTION 15. Taxes and Assessments............................................32
SECTION 16. Utilities........................................................33
SECTION 17. Governmental Permits.............................................33
SECTION 18. No Liens.........................................................35
SECTION 19. Condemnation.....................................................36
SECTION 20. Waiver of Subrogation; Indemnity.................................37
SECTION 21. Subordination and Attornment.....................................38
SECTION 22. Environmental Covenants..........................................39
SECTION 23. Insurance........................................................42
SECTION 24. Right of Substitution; Right of First Refusal....................44
SECTION 25. Assignment and Subletting........................................47
SECTION 26. Estoppel Certificate.............................................49
SECTION 27. Holding Over.....................................................49
SECTION 28. Rights of Entry and Inspection...................................49
SECTION 29. A Party's Right to Act for the Other Party; SBCW Set-Off Right...50
SECTION 30. Defaults and Remedies............................................50
SECTION 31. Quiet Enjoyment..................................................55
SECTION 32. No Merger........................................................55
SECTION 33. Broker and Commission............................................55
SECTION 34. Recording of Site Designation Supplement.........................56
SECTION 35. Purchase Options.................................................56
SECTION 36. Net Lease........................................................58
SECTION 37. Compliance with Specific FCC Regulations.........................58
SECTION 38. TowerCo Parent's Guaranty........................................59
SECTION 39. Tax Indemnities..................................................61
SECTION 40. General Provisions...............................................69

<PAGE>

                               LEASE AND SUBLEASE

         THIS  LEASE  AND  SUBLEASE  is made and  entered  into this ____ day of
__________,  2000 (this "Sublease"), by and among SBC WIRELESS, INC., a Delaware
corporation  (for itself and as Agent for the SBCW Group Members whose names are
set forth on Exhibit D hereof or which become parties to this Sublease after the
date  hereof,  "SBCW"),  SPECTRASITE  HOLDINGS,  INC.,  a  Delaware  corporation
("TowerCo  Parent"),   and  SOUTHERN  TOWERS,  INC.,  an  indirect  wholly-owned
subsidiary of TowerCo Parent and a Delaware corporation ("TowerCo").

         In   consideration   of  the  premises  and  other  good  and  valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
Parties to this Sublease agree as follows:

SECTION 1.        Definitions.

         For purposes of this Sublease, the following capitalized terms have the
following respective meanings:

                  "Additional Rent" has the meaning set forth in Section 3(i)
hereof.

                  "Affiliate"  of a  Person  means  any  Person  which,  whether
         directly or indirectly,  Controls, is Controlled by, or is under common
         Control with the subject Party.

                  "After-Tax Basis" has the meaning set forth in Section 39(a)
(3)(i) hereof.

                  "Agreement  to  Sublease"  means  the  Agreement  to Lease and
         Sublease, by and among TowerCo Parent, TowerCo, and the SBCW Group.

                  "Alterations"   means  the  construction  or  installation  of
         Improvements   on  any  Site  or  any  part  thereof   after  the  Site
         Commencement  Date  for  such  Site,  or the  alteration,  replacement,
         modification  or addition to all or any  component  of a Site after the
         Site   Commencement   Date  for  such  Site,   whether   Severable   or
         Non-Severable.

                  "Assumed Rate" has the meaning set forth in Section 39(a)(1)
(v) hereof.

                  "Available  Space" means, as to any Site, a Tower location,  a
         portion  of the  Land,  a  portion  of the  Improvements  or any  other
         portion,  space or area of such Site that is available  for sublease by
         TowerCo to any Space Subtenant  (including SBCW and its Affiliates,  in
         such  capacity) and all rights  appurtenant  to such portion,  space or
         area.

                  "Award" means any amounts paid,  recovered or  recoverable  as
         damages, compensation or proceeds by reason of any taking on account of
         a Taking,  including all amounts paid  pursuant to any  agreement  with
         such entity  which has been made in  settlement  or under threat of any
         such  action or  proceeding,  less the  reasonable  costs and  expenses
         incurred in collecting such amounts.
<PAGE>

                  "Build to Suit  Agreement"  means  the  Agreement  to Build to
         Suit  dated as of the date  hereof by and among  SBCW, SpectraSite
         Communications, Inc. and SpectraSite Holdings, Inc.

                  "Capital  Stock"  means:  (i) in the  case  of a  corporation,
         corporate stock; (ii) in the case of an association or business entity,
         any  and  all  shares,  interests,  participations,   rights  or  other
         equivalents  (however designated) of corporate stock; (iii) in the case
         of  a  partnership  or  limited  liability   company,   partnership  or
         membership  interests (whether general or limited);  and (iv) any other
         interest or participation that confers on a Person the right to receive
         a share of the  profits and losses of, or  distributions  of assets of,
         the issuing Person.

                  "Cash Flow"  means,  as to any  Person,  the  earnings  before
         interest expense,  depreciation,  amortization and taxes of such Person
         and its Subsidiaries on a consolidated basis,  determined in accordance
         with GAAP.

                  "Claims"   means  any   claims,   demands,   actions,   suits,
         proceedings,   disbursements,  judgments,  damages,  penalties,  fines,
         losses,   liabilities,   costs  and  expenses,   including   reasonable
         attorneys' fees and amounts paid in settlements.

                  "Code"  means the Internal  Revenue  Code of 1986,  as amended
         from time to time.

                  "Colocation   Agreements"   means  any  existing   contractual
         arrangements and agreements pursuant to which any SBCW Affiliate shares
         any Site with other providers of wireless telecommunications  services,
         local public safety  organizations,  governmental entities such as post
         offices and law  enforcement  organizations,  and  operators  of remote
         monitoring  systems  for  commercial  purposes,  and to which such SBCW
         Affiliate is a party,  as set forth in Schedule A to Exhibit A attached
         hereto.

                  "Communications Equipment" means, as to any Site, transmitting
         and/or  receiving  equipment  and  other  equipment  installed  at  the
         Reserved  Space (as to SBCW or any Affiliate  thereof) or any Available
         Space  (as to a Space  Subtenant),  which  is or will be  necessary  in
         providing current and future wireless communication services, including
         without  limitation,  switches,  antennas,  microwave  dishes,  panels,
         conduits,  flexible  transmission  lines,  cables,  radio,  amplifiers,
         filters and other transmission or communications  equipment  (including
         interconnect  transmission equipment,  transmitter(s),  receiver(s) and
         accessories) and such other equipment and associated software as may be
         necessary in order to provide  such  wireless  communication  services,
         including without limitation,  voice or data.  Communications Equipment
         shall  include  any  existing,  replaced  and  upgraded  Communications
         Equipment.

                  "Communications  Facility" means, as to any Site, the Reserved
         Space (as to SBCW or an SBCW Affiliate) or any Available Space (as to a
         Space Subtenant), together with the applicable SBCW Affiliate's or such
         Space Subtenant's Improvements.

                  "Control"  means the  ownership,  directly or  indirectly,  of
         sufficient  voting shares of an entity,  or otherwise  the  possession,
         directly or  indirectly,  of the power to direct or cause the direction
         of the management and policies of an entity, or the power to veto major
         policy  decisions of any such entity,  whether through the ownership of
         voting securities, by contract or otherwise.

                                       2
<PAGE>

                  "CPI" means the Consumer Price Index for all Consumers,  U.S.,
         City Average  (1982-84 = 100) All Items Index,  published by the Bureau
         of Labor  Statistics,  United States  Department  of Labor.  If the CPI
         shall cease to be compiled and published at any time during the term of
         this  Sublease,  but a  comparable  successor  index  is  compiled  and
         published by the Bureau of Labor  Statistics,  United States Department
         of Labor,  the adjustments to the SBCW Leaseback Charge provided for in
         Section  10, if any,  shall be  computed  according  to such  successor
         index,  with  appropriate  adjustments  in the  index  to  reflect  any
         differences in the method of computation  from the CPI. If, at any time
         during  the term of this  Sublease,  neither  the CPI nor a  comparable
         successor  index is  compiled  and  published  by the  Bureau  of Labor
         Statistics,  the index for "all items"  compiled  and  published by any
         other branch or department of the federal government shall be used as a
         basis  for  calculation  of the  CPI-related  adjustments  to the  SBCW
         Leaseback Charge provided for in this Sublease, and if no such index is
         compiled  and  published  by any branch or  department  of the  federal
         government,  the  statistics  reflecting  cost of living  increases  or
         decreases,   as   applicable,   as  compiled  by  any   institution  or
         organization  or  individual  generally  recognized  as an authority by
         financial and insurance institutions shall be used.

                  "CPI Change" means an increase or decrease, if any, (expressed
         as a positive or negative  percentage)  in the most recently  published
         CPI as of  January 1  immediately  preceding  the  commencement  of the
         applicable Site Term Year (the "Index Date"), from the CPI published as
         of January 1 immediately preceding the Index Date.

                  "Date of  Taking"  means the  earlier  of the date upon  which
         title to applicable Site, or any portion  thereof,  subject to a Taking
         is  vested  in  the  condemning  authority,  or  the  date  upon  which
         possession of such Site or portion  thereof is taken by the  condemning
         authority.

                  "Default Notice" has the meaning given to such term in Section
          3(h) hereof.

                  "Effective Date" means the date of this Sublease, as set forth
         in the caption of the Sublease.

                  "Emergency" has the meaning given to such term in Section 29
         (b) hereof.

                  "Estimated Cost" has the meaning given to such term in Section
         17(f) hereof.

                  "Existing  Sublease"  means,  with  respect  to any Site,  any
         sublease, license, lease or other agreement for use of a Tower location
         and other space on such Site  between a SBCW Group Member and any other
         Person that is in effect as of the applicable Site Commencement Date.

                                       3
<PAGE>

                  "Fair  Market  Value"  as to any Site,  means the fair  market
         sales  value of such Site that  would be  obtained  in an  arm's-length
         transaction  between an informed and willing  buyer and an informed and
         willing seller, under no compulsion,  respectively,  to buy or sell the
         Site in question.

                  "FAA" means the United States Federal Aviation Administration.

                  "FCC" means the United States Federal Communications
         Commission.

                  "Federal Depreciation Deductions" has the meaning set forth in
         Section 39(a)(1)(ii) hereof.

                  "Federal Income Tax Benefits"  means the Federal  Depreciation
         Deductions and the federal  income tax deductions  described in Section
         39(a)(1)(iii) hereof.

                  "Ground  Lease" means,  as to a Leased Site, the ground lease,
         easement,  license or other  agreement,  pursuant  to which a Sublessor
         Entity holds a leasehold interest,  leasehold estate, easement, license
         or other real property interest.

                  "Ground  Lessor"  means,  as to a Leased Site, the "lessor" or
"landlord" under the related Ground Lease.

                  "Ground  Rents"  means,  as to any Site,  all rents,  fees and
         other charges payable by a SBCW Group Member to the Ground Lessor under
         the Ground Lease for such Site.

                  "Improvements"  means,  as to  each  Site,  (i)  one  or  more
         concrete  equipment pads or raised  platforms  capable of accommodating
         exterior cabinets,  electrical service and access for the placement and
         servicing of SBCW's or its Affiliate's  and, if applicable,  each Space
         Subtenant's  Improvements;  (ii) buildings,  huts, shelters or exterior
         cabinets;  (iii)  generators and associated fuel tanks;  (iv) grounding
         rings  (other  than  those  for  SBCW's  or its  Affiliate's  equipment
         shelters);  (v) fencing;  (vi) signage;  (vii)  connections for utility
         service up to the meter; (viii) hardware  constituting a tower platform
         to hold  SBCW's or its  Affiliate's  and,  if  applicable,  each  Space
         Subtenant's  Communications  Equipment;  (ix) access road improvements;
         (x)  common   shelters,   if  any;  and  (xi)  such  other   equipment,
         alterations, replacements,  modifications,  additions, and improvements
         as may be  installed  on or  made  to  all or any  component  of a Site
         (including  the  Land  and  the  Tower).  Improvements  do not  include
         Communications Equipment.

                  "Inclusion"  means  the  inclusion  in the  income of any SBCW
         Group Member of any amount realized in connection with the transactions
         effected by this Sublease or related  documents  other than the amounts
         described in Section 39(a)(1)(iv) hereof.

                  "Initial Site" has the meaning set forth in the definition of
         "Site."

                  "Investment  Grade" means  outstanding  senior  unsecured debt
         securities rated BBB or higher by Standard & Poor's or Baa or higher by
         Moody's.

                                       4
<PAGE>

                  "Land" means, as to each Site, the land constituting a portion
         of such Site,  together with all easements and other rights appurtenant
         thereto.

                  "Laws" means all federal,  state, county,  municipal and other
         governmental constitutions,  statutes,  ordinances, codes, regulations,
         resolutions,  rules,  requirements  and  directives  and all decisions,
         judgments,  writs,  injunctions,  orders, decrees or demands of courts,
         administrative  bodies  and  other  authorities   (including,   without
         limitation, the FAA and FCC) construing any of the foregoing.

                  "Leased  Site"  means a Site as to  which a  Sublessor  Entity
         holds a leasehold  interest,  leasehold  estate,  easement,  license or
         other  possessory  interest  in the  Land  which  is part of such  Site
         pursuant to a Ground Lease.

                  "Liens"  means,  as to each Site,  an interest or a claim by a
         Person other than SBCW or any of its Affiliates,  whether such interest
         or claim is based on the common law,  statute or  contract,  including,
         without  limitations,   liens,  charges,   Claims,  leases,   licenses,
         Mortgages,   conditional   agreements,   title  retention   agreements,
         preference,  priority  or other  security  agreements  or  preferential
         arrangements  of any  kind,  reservations,  exceptions,  encroachments,
         covenants,  conditions,  restrictions  and other title  exceptions  and
         encumbrances  affecting  all or any  part of the  Land,  the  Tower  or
         Improvements thereof.

                  "Market  Capitalization"  means,  as to any Person,  as of any
         date of determination,  either (i) the number of issued and outstanding
         shares of such  Person's  Capital  Stock (as set forth in such Person's
         most recent filings with the U.S.  Securities and Exchange  Commission)
         multiplied  by the closing price of the Capital Stock of such Person on
         any  exchange  on which such stock is listed or (ii) in the case of any
         Person  as to which the  information  specified  in  clause  (i) is not
         available,  the  total  market  value  of the  equity  of such  Person,
         determined by a commercially reasonable appraisal process.

                  "Mortgage" means, as to any Site, any mortgage, deed to secure
         debt, deed of trust,  trust deed or other conveyance of, or encumbrance
         against,  the Land or  Improvements  on such Site as  security  for any
         debt, whether now existing or hereafter arising or created.

                  "Mortgagee" means, as to any Site, the holder of any Mortgage,
         together with the heirs, legal representatives, successors, transferees
         and assigns of the holder.

                  "NDA" means a  non-disturbance,  subordination  and attornment
         agreement executed between a Mortgagee and TowerCo.

                  "Net Worth" means, with respect to a Person,  the total assets
         minus the total  liabilities of such Person and its  Subsidiaries  on a
         consolidated basis, as determined in accordance with GAAP.

                  "Non-Conforming Alterations" has the meaning given to such
         term in Section 3(i) hereof.

                                       5
<PAGE>

                  "Nonseverable" shall mean, with respect to any Alteration, any
Alteration that is not a Severable Alteration.

                  "Option  Purchase  Price Amount"  means,  with respect to each
         Site,  the fixed  purchase  price  for such  Site in the event  TowerCo
         exercises  its purchase  option with respect  thereto  under Section 35
         hereof as specified  in Exhibit A with respect to the Initial  Sites or
         in the Site Designation Supplements with respect to all other Sites.

                  "Option  Trigger  Window" has the  meaning  given to such term
         under Section 35(a).

                  "Owned  Site" means a Site with  respect to which a SBCW Group
         Member owns fee simple title in the Land which is part of the Site.

                  "Party" means each of the SBCW Group Members,  TowerCo and
         TowerCo Parent,  as appropriate.  "Parties" means the SBCW
         Group Members, TowerCo and TowerCo Parent together.

                  "Permitted Liens" has the meaning given to such term in
         Section 18(a).

                  "Permitted  Subleasehold  Mortgage" means a mortgage,  deed of
         trust,  trust  deed,  deed  to  secure  debt  or  other  like  security
         instrument  for the  benefit  of a  Permitted  Subleasehold  Collateral
         Assignee.

                  "Permitted  Subleasehold  Pledge" means a pledge or collateral
         assignment  as  security  for any  indebtedness  for the  benefit  of a
         Permitted Subleasehold Collateral Assignee.

                  "Permitted Subleasehold Collateral Assignee" means a holder of
         (i) a collateral assignment of this Sublease, the Agreement to Sublease
         or the Build to Suit Agreement,  and/or (ii) a mortgage, deed of trust,
         trust deed, deed to secure debt or other like security  instrument with
         respect to TowerCo's leasehold and subleasehold interests in all or any
         portion of the Sites, pursuant to that certain Credit Agreement,  dated
         as of April 20, 1999,  as amended,  among  SpectraSite  Communications,
         Inc., as borrower,  SpectraSite  Holdings,  Inc.,  as  guarantor,  CIBC
         Oppenheimer  Corp.,  Credit  Suisse First Boston and the other  parties
         thereto, as the same may be amended, supplemented,  extended, restated,
         refinanced or refunded (collectively,  the "Credit Agreement"), or that
         will be a recipient or beneficiary of a pledge or collateral assignment
         by  TowerCo  of  TowerCo's  interests  hereunder  or  the  holder  of a
         mortgage,  deed of trust, trust deed, deed to secure debt or other like
         security   instrument   with   respect  to  TowerCo's   leasehold   and
         subleasehold  interests  in all or any  portion  of the Sites  that has
         assets  at the  time of the  execution  of the  Permitted  Subleasehold
         Pledge or Permitted Subleasehold  Mortgage, as applicable,  of not less
         than $2  billion,  and is:  (i) a  national  bank;  (ii) a  commercial,
         national or state savings bank or trust company; (iii) an investment or
         merchant  bank;  (iv) a foreign  bank  qualified  to do business in the
         states in which the Sites are located and  authorized  to make loans in
         the United  States;  (v) a  charitable  foundation;  (vi) a real estate
         investment fund; (vii) an insurance  company;  (viii) a credit company;
         (ix) a pension or retirement  fund or a fund which,  in turn, is funded
         substantially  by a  pension  or  retirement  fund;  (x) a real  estate
         investment trust; (xi) a venture capital firm; (xii) a mortgage banking
         house; (xiii) an international bank or investment company; or (xiv) any
         other institutional  lender performing lending functions similar to any
         of the foregoing.  Notwithstanding  the foregoing,  in no event shall a
         Permitted Subleasehold Collateral Assignee be a SBCW Competitor.

                                       6
<PAGE>

                  "Permitted Transferee" means: (i) a Person who has outstanding
         debt that is  Investment  Grade;  (ii) with  respect  to a  transaction
         involving  twenty  percent  (20%) or more of all Sites now or hereafter
         subject to this Sublease and less than forty percent (40%) of all Sites
         now or hereafter subject to this Sublease, a Person reasonably believed
         by SBCW to have a  current  Net Worth or  Market  Capitalization  of at
         least $50  million or Cash Flow for the last full  fiscal  year of such
         Person of at least $10  million;  (iii) with  respect to a  transaction
         involving  forty  percent  (40%) or more of all Sites now or  hereafter
         subject to this Sublease and less than eighty  percent (80%) or more of
         all  Sites  now  or  hereafter  subject  to  this  Sublease,  a  Person
         reasonably  believed  by SBCW to have a  current  Net  Worth or  Market
         Capitalization  of at least $250 million or Cash Flow for the last full
         fiscal  year of such  Person  of at least  $50  million;  or (iv)  with
         respect to a transaction  involving eighty percent (80%) or more of all
         Sites now or hereafter  subject to this Sublease,  a Person  reasonably
         believed by SBCW to have a current  Net Worth or Market  Capitalization
         of at least $500  million or Cash Flow for the last full fiscal year of
         such Person of at least $100 million.

                  "Permitted  TowerCo  Transferee"  means:  (i) a Person who has
         outstanding  debt that is  Investment  Grade;  (ii) with  respect  to a
         Transfer of the Subleased  Property  involving more than twenty percent
         (20%) but less than forty  percent  (40%) of all Sites now or hereafter
         subject to this Sublease,  a Person  reasonably  believed by TowerCo to
         have a  current  Net Worth or Market  Capitalization  of at least  $100
         million or Cash Flow for the last full fiscal year of such Person of at
         least $5 million;  (iii) with  respect to a Transfer  of the  Subleased
         Property  involving  forty  percent  (40%) or more of all  Sites now or
         hereafter  subject to this Sublease and less than eighty  percent (80%)
         or more of all Sites  now or  hereafter  subject  to this  Sublease,  a
         Person  reasonably  believed  by TowerCo to have a current Net Worth or
         Market  Capitalization  of at least  $250  million or Cash Flow for the
         last full fiscal year of such Person of at least $50  million;  or (iv)
         with  respect  to a Transfer  of the  Subleased  Property  or any other
         transaction of the types referred to in Section 25(a), involving eighty
         percent  (80%) or more of all Sites now or  hereafter  subject  to this
         Sublease, a Person reasonably believed by TowerCo to have a current Net
         Worth or Market  Capitalization  of at least $500  million or Cash Flow
         for the last full fiscal year of such Person of at least $100 million.

                  "Permitted  Use" means use of the  Subleased  Property of each
         Site for the  purposes  of: (i)  constructing,  installing,  operating,
         managing,  maintaining and marketing the Tower and Improvements thereof
         and making further  Improvements  to such Site as permitted  hereunder,
         and (ii) for further use of such Subleased Property by Space Subtenants
         (including  SBCW  and its  Affiliates  with  respect  to any  Available
         Space),  and the right to use by Space  Subtenants  (including SBCW and
         its Affiliates with respect to any Available  Space) of any portions of
         the  Land,  Tower  and  Improvements  of each  Site  as are  reasonably
         necessary for operation of the Communications  Facilities of such Space
         Subtenants.

                                       7
<PAGE>

                  "Person"  means an  individual,  partnership,  joint  venture,
         limited liability company, association, corporation, trust or any other
         legal entity.

                  "Proceeds" means all insurance moneys recovered or recoverable
         by  TowerCo or SBCW as  compensation  for  casualty  damage to any Site
         (including the Tower and Improvements thereof).

                  "Reimbursable Cost" has the meaning given such term in Section
         17(f) hereof.

                  "Rent" has the meaning given such term in Section 10(b).

                  "Reserved  Space" means,  as to each Site:  (i) the portion of
         the  Land  and  Improvements  of  such  Site  used  by  SBCW or an SBCW
         Affiliate as of the date of the applicable Site  Commencement  Date, or
         as may be used by SBCW or its Affiliate as "Reserved Space" pursuant to
         this Sublease,  as reserved for the exclusive use and occupancy by SBCW
         or any of its Affiliates, including without limitation, MTSOs and other
         switches and SBCW's Improvements located on the Land, but not including
         parking spaces and associated  loading docks (which facilities shall be
         shared by SBCW,  its  Affiliates,  TowerCo and Space  Subtenants  on an
         equitable  basis);  (ii) the  portion of the Tower of such Site used by
         SBCW  or an  SBCW  Affiliate  for  Communications  Equipment  as of the
         applicable  Site  Commencement  Date,  or as may be used by SBCW or its
         Affiliate as "Reserved  Space"  pursuant to this Sublease,  as reserved
         for the exclusive  use and occupancy by SBCW or any of its  Affiliates,
         including  without  limitation,  any  antennas  (depicting  any antenna
         arrays  and,  if  reasonably  available,   setting  forth  their  model
         numbers),  transmission  lines,  amplifiers and filters  located on the
         Tower; and (iii) any and all rights pursuant to Section 5(b) and 24 and
         all appurtenant  rights  reasonably  inferable to permit SBCW's and its
         Affiliates'  full use and  enjoyment of the Reserved  Space,  including
         without limitation, the appurtenances specifically described in Section
         5, all in accordance with Section 5.

                  "Restoration"  means, as to a Site that has suffered  casualty
         damage, such restoration,  repairs,  replacements,  rebuilding, changes
         and  alterations,  including  the  cost of  temporary  repairs  for the
         protection of such Site,  or any portion  thereof,  pending  completion
         thereof,  required to restore the applicable  Site (including the Tower
         and  Improvements  thereon) to a condition which is at least as good as
         the condition which existed  immediately prior to such damage, and such
         other changes or alterations as may be reasonably acceptable to SBCW or
         the applicable Sublessor Entity and TowerCo or required by Law.

                  "Right of First Refusal" means the right of SBCW,  exercisable
         in its sole  discretion,  to sublease for its own use or the use of its
         Affiliates any Available Space from TowerCo pursuant to Section 24.

                                       8
<PAGE>

                  "Right of Substitution"  means the right of SBCW,  exercisable
         in its sole discretion, to substitute for its own use or the use of its
         Affiliates  the Reserved  Space of any Site for an  Available  Space on
         such Site by relocation of its Communications  Facility on such Site to
         such Available Space, all pursuant to Section 24.

                  "SBCW" has the meaning given to such term in the preamble.

                  "SBCW Affiliates" means,  collectively,  any Sublessor Entity,
         Affiliates of SBCW, the SBCW Group Members, and any Person in which SBC
         Communications  Inc.,  a  Delaware   corporation,   owns,  directly  or
         indirectly,  at least fifty  percent  (50%) of the Voting Stock of such
         Person or which SBC Communications Inc. otherwise Controls.

                  "SBCW  Competitor"  means any Person whose revenues,  together
         with any of its Affiliate's revenues, generated from providing wireline
         local    exchange    carrier    or    wireless    telephone    provider
         telecommunications  services,  constitute at least twenty percent (20%)
         of the total consolidated revenues of such Person and its Affiliates.

                  "SBCW Group" means collectively,  SBCW and the SBCW Affiliates
         whose names are set forth in the signature pages hereof. Each member of
         the SBCW Group is herein a "SBCW Group Member".  Solely for purposes of
         Section 39, the term "SBCW Group" shall include each SBCW Group Member,
         the affiliated group of corporations and each member thereof within the
         meaning of Code section 1504 of which any SBCW Group Member is or shall
         become a member if such group shall have filed a  consolidated  return;
         if  applicable,  each member in any entity  classified as a partnership
         for federal  income tax purposes  and such entity  itself if and to the
         extent  such  entity is treated as the tax owner of any of the Sites or
         portions  thereof  or such  entity is a direct or  indirect  partner in
         another  entity  classified  as a  partnership  which is so treated (in
         either case, an "SBCW  Partnership");  and, if  applicable,  any entity
         owned by a SBCW Group  Member or an SBCW  Partnership  that for federal
         income tax  purposes  is  disregarded  as an entity  separate  from its
         owner.

                  "SBCW's  Improvements"  means each of the  following,  in each
         case located on the Land portion of the Reserved Space, installed by or
         for  the  benefit  of SBCW or its  Affiliates  and  used by SBCW or its
         Affiliates:  (i) such Person's Communications  Equipment;  and (ii) (v)
         equipment shelters,  equipment buildings, and other constructions,  (w)
         generators  and  associated  fuel tanks,  (x) grounding  rings for such
         Person's equipment shelters, (y) connections for utilities service from
         the  meter  to  such  Communications  Equipment,  and  (z)  one or more
         foundations,  concrete  equipment  pads or  raised  platforms  for such
         Communications   Equipment,    equipment   shelters,    buildings   and
         constructions.

                  "SBCW  Indemnitee"  means  SBCW,  SBCW  Affiliates,   and  the
         respective directors,  officers,  employees, and agents of SBCW or SBCW
         Affiliates (except TowerCo and any agents of TowerCo).

                  "SBCW Leaseback Charge" has the meaning given to such term in
         Section 10(b).

                                       9
<PAGE>

                  "SBCW Partnership" has the meaning set forth in the definition
         of "SBCW Group".

                  "Severable"  shall mean, with respect to any  Alteration,  any
         Alteration  that can be readily  removed from a Site or portion thereof
         without damaging it in any material  respect or without  diminishing or
         impairing the value, utility, useful life or condition that the Site or
         portion  thereof  would have had if such  Alteration  had not been made
         (assuming  the Site or portion  thereof  would have been in  compliance
         with this Sublease  without such  Alteration),  and without causing the
         Site or portion  thereof to become  "limited use  property"  within the
         meaning of Rev.  Proc.  76-30,  1976-2 C.B.  647.  Notwithstanding  the
         foregoing,  an  Alteration  shall not be  considered  Severable if such
         Alteration is necessary to render the Site or portion thereof  complete
         for its intended use by TowerCo (other than  Alterations  consisting of
         ancillary items of equipment of a kind customarily furnished by lessees
         of property comparable to the Site or portion thereof).

                  "Site"  means  any  site  now or  hereafter  subject  to  this
         Sublease,  including without limitation:  (i) any initial Site which is
         subject to this  Sublease as of the date hereof as described in Exhibit
         A (the  "Initial  Sites");  and (ii) any  Site  added to this  Sublease
         pursuant  to  a  Site  Designation  Supplement  with  respect  thereto.
         Reference to a Site shall include the Land, the Tower, the Improvements
         (excluding Severable  Alterations) and Non-Severable  Alterations,  but
         shall not include Communications Equipment thereon.

                  "Site  Commencement  Date" means the date on which the Term of
         this  Sublease  commences  as to such Site,  which shall be the date of
         this  Sublease  with  respect to the Initial  Sites and the date as set
         forth in the applicable Site Designation Supplement with respect to all
         other Sites.

                  "Site  Designation  Supplement"  means,  as  to  any  Site,  a
         supplement to this  Sublease,  in  substantially  the form of Exhibit B
         attached  hereto and  otherwise in recordable  form,  pursuant to which
         such Site is made subject to this Sublease,  and the subleased portions
         thereof  added  to the  Subleased  Property.  All  representations  and
         warranties  made by SBCW with respect to a Site shall be deemed made as
         of the date such Site is made subject to this Sublease.

                  "Site  Expiration  Date" means,  (i) as to any Owned Site, the
         Site Expiration Outside Date and (ii) as to any Leased Site, the sooner
         to occur of one day  prior to the  expiration  of the  relevant  Ground
         Lease (as the same may be  extended  or renewed  pursuant  to the terms
         hereof, including Section 3(f) hereof), and the Site Expiration Outside
         Date.

                  "Site Expiration Outside Date" means, as to any Site, the date
         certain set forth in Exhibit A or the Site  Designation  Supplement  as
         the "Site Expiration Outside Date".

                  "Site Term  Year"  means,  as to each  Site,  the one (1) year
         period commencing on the Site Commencement  Date, and ending on the day
         immediately  preceding the first  anniversary of the Site  Commencement
         Date,  and each  succeeding one (1) year period during the term of this
         Sublease.

                                       10
<PAGE>

                  "Space Subtenant" means, as to any Site, any Person (including
         SBCW and its Affiliates in respect of any Available Space),  which: (i)
         is a "sublessee"  under an Existing  Sublease  affecting  such Site; or
         (ii) subleases,  licenses or otherwise  acquires from TowerCo the right
         to use Available Space on such Site.

                  "Space  Subtenant's  Improvements"  means,  as  to  any  Space
         Subtenant at any Site, such Space Subtenant's Communications Equipment,
         together  with  equipment  buildings,   equipment  shelters  and  other
         constructions  located on the Land of the Available  Space of such Site
         and owned by such Space Subtenant.

                  "Sublease"  means this Lease and  Sublease,  together with any
         and all Exhibits,  Schedules and  attachments  hereto,  as the same may
         hereafter  be modified  and  amended,  including,  without  limitation,
         pursuant to Site Designation  Supplements.  References to this Sublease
         in respect of a  particular  Site shall  include  the Site  Designation
         Supplement therefor;  and references to this Sublease in general and as
         applied to all Sites shall include all Site Designation Supplements.

                  "Sublease   Year"  means  each   succeeding  one  year  period
         commencing on the date hereof.

                  "Subleased  Property" means each Site that is now or hereafter
         subject to this Sublease,  including the Land,  Tower and  Improvements
         thereof, less and except in each instance,  the Reserved Space thereof,
         Space Subtenant's Improvements, and SBCW's Improvements on such Site.

                  "Subleasehold Estate" means: (i) the rights, title,  interest,
         powers, privileges, benefits and options of TowerCo under this Sublease
         (whether as lessee of an Owned Site or as sublessee of a Leased  Site);
         and (ii) all of the right,  title and interest of TowerCo in and to the
         Sites  under this  Sublease  (whether  as lessee of an Owned Site or as
         sublessee of a Leased Site).
                  "Sublessor"  means,  as to each Site,  the SBCW Affiliate that
         either:  (i) owns fee simple title  thereto;  or (ii) holds a leasehold
         interest,  leasehold  estate,  easement,  license  or other  possessory
         interest therein pursuant to a Ground Lease.

                  "Sublessor Alteration"  has the meaning set forth in Section
         24(a) hereof.

                  "Sublessor Entities" has the meaning given to such term in the
         Agreement to Sublease.

                  "Subsidiary"   means,   with   respect  to  any  Person,   any
         corporation,  partnership,  joint venture or other entity in which such
         Person owns,  either  directly or  indirectly,  more than fifty percent
         (50%) of the  outstanding  Capital  Stock or other  ownership or equity
         interests  therein,  as the case may be,  or has the power to direct or
         cause the direction of the management and policies thereof.

                                       11
<PAGE>

                  "Substantial  Portion of Site" means, as to a Site, so much of
         such Site (including the Land, Tower and Improvements  thereof,  or any
         portion  thereof) as, when subject to a Taking or damage as a result of
         a casualty,  leaves the untaken  portion  unsuitable  for the continued
         feasible and economic operation of such Site for the Permitted Use.

                  "Substitution" means the relocation by SBCW or its Affiliate
         on a Site, pursuant to its Right of Substitution.

                  "Taking" means,  as to any Site, any  condemnation or exercise
         of the power of eminent domain by any public authority vested with such
         power,  or any taking in any other  manner for public use,  including a
         private purchase, in lieu of condemnation, by a public authority vested
         with the power of eminent domain.

                  "Tax Assumptions" has the meaning set forth in Section 39(a)
         (1) hereof.

                  "Tax Claim" has the meaning set forth in Section 39(d) hereof.

                  "Tax Indemnitee" has the meaning set forth in Section 39(a)(3)
         (i) hereof.

                  "Tax Indemnity Notice" has the meaning set forth in Section 3
         (a)(3)(i) hereof.

                  "Tax Loss" has the meaning set forth in Section 39(a)(3)(i)
         hereof.

                  "Tax" and "Taxes" has the meaning set forth  in Section 39(b)
         (1) hereof.

                  "Taxes and Assessments" means, as to each Site, any and all of
         the following levied, assessed or imposed upon, against or with respect
         to the  Site  (including  the  Reserved  Space),  any  part of the Site
         (including  the Reserved  Space),  or the use and occupancy of the Site
         (including  the Reserved  Space) at any time during the Term as to such
         Site:  (i) real  property  and personal  property ad valorem  taxes and
         assessments,   except  as  relates   specifically   to  SBCW's  or  its
         Affiliates'  Communications  Equipment  or  SBCW's  Improvements;  (ii)
         charges made by any public or quasi-public  authority for  improvements
         or  betterments  related to the Site (other than SBCW's  Improvements);
         (iii) sanitary taxes or charges,  sewer or water taxes or charges; (iv)
         any tax levied,  assessed or imposed upon or against the Rent  reserved
         hereunder or upon SBCW's or an SBCW Affiliates' interest in the Site or
         this  Sublease  (other  than  income  taxes or any  future tax which is
         established in lieu of income taxes); and (v) any other Governmental or
         quasigovernmental   impositions,    charges,   encumbrances,    levies,
         assessments,  fees or taxes of any  nature  whatsoever  related  to the
         Site,  whether general or special,  whether ordinary or  extraordinary,
         whether  foreseen or unforeseen and whether  payable in installments or
         not,  except as it relates  specifically  to  Communications  Equipment
         owned by SBCW or its Affiliates or the SBCW's Improvements.

                  "Term" means:  (i) as to this Sublease,  the term set forth in
         Section  8(a) hereof;  and (ii) as to each Site,  the term during which
         this Sublease is applicable to such Site.

                  "Total  Sites"  means  the  aggregate  number  of Sites now or
         hereafter subject to this Sublease.

                                       12
<PAGE>

                  "Tower" means a wireless transmissions tower structure or
         structures on a Site.

                  "TowerCo" has the meaning given to such term in the Preamble.

                  "TowerCo  Indemnitee" means TowerCo,  its Affiliates,  and the
         respective directors, officers, employees, and agents of TowerCo or its
         respective Affiliates.

                  "TowerCo Parent" has the meaning given to such term in the
         Preamble.

                  "TowerCo Work" has the meaning given to such term in Section
         12(b) hereof.

                  "Valuation Process" has the meaning set forth in Section 3(i)
         hereof.

                  "Voting  Stock" of any Person as of any date means the Capital
         Stock  of such  Person  that  is at the  time  entitled  to vote in the
         election of the Board of Directors of such Person.

                  "Withdrawal  Date" means the  effective  date of SBCW's or its
         Affiliate's election to terminate its reservation of the Reserved Space
         and add such  Reserved  Space to the  Subleased  Property  of such Site
         pursuant to Withdrawal Notice.

                  "Withdrawal  Notice"  means  a  notice  given  by  SBCW or its
         Affiliate pursuant to Section 9 exercising the Withdrawal Right.

                  "Withdrawal Right" means the right of SBCW or its Affiliate to
         elect to terminate its  reservation  of the Reserved Space with respect
         to a Site and add such Reserved Space to the Subleased Property of such
         Site as described in Section 9 hereof.

         Any  other  capitalized  terms  used in this  Sublease  shall  have the
respective meanings given to them elsewhere in this Sublease.

SECTION 2.        Sublease Documents.

(a) This Sublease shall consist of the following documents, as amended from time
to time as provided herein:

(i)      this Lease and Sublease;

(ii) the following Exhibits, which are incorporated herein by this reference:

                 Exhibit A        List of Sites Subject to Sublease
                 Exhibit B        Form of Site Designation Supplement
                 Exhibit C        Site Maintenance Obligations with respect to
                      Subtenants' Communications Equipment
               Exhibit D SBCW Group Members Bound by the Sublease
                          Exhibit E Standard Procedures
             Exhibit F Form of Notice of TowerCo Work or Additional
                                  Equipment
                 Exhibit G        Estimated Costs

                                       13
<PAGE>

(iii) Schedules to the Exhibits, which are incorporated herein by reference; and

(iv) such additional documents as are incorporated by reference.

(b) If any of the foregoing are  inconsistent,  this Sublease shall prevail over
the Exhibits, the Schedules and additional incorporated documents.

SECTION 3.        Subleased Property.

(a) Subject to the terms and conditions of this Sublease,  each Sublessor hereby
lets,  leases and demises  unto  TowerCo,  and except as  otherwise  provided in
Sections 3(h) and 22(b), TowerCo hereby leases, takes and accepts from Sublessor
the Subleased Property of all of the Sites owned or leased by such Sublessor, in
its "AS IS" condition,  without any  representation,  warranty or covenant of or
from SBCW or any SBCW Affiliate of SBCW  whatsoever as to the condition  thereof
or the  suitability  thereof for any particular  use, except as may be expressly
set forth in the  Agreement to  Sublease.  To SBCW's  knowledge,  the Towers are
satisfactory in all material respects for SBCW's and its Affiliates'  continuing
use consistent with its Permitted Use of such Towers. Except as set forth above,
TowerCo hereby acknowledges that neither SBCW nor any Affiliate or agent of SBCW
has made any representation or warranty, express or implied, with respect to any
of the Subleased Property, or any portion thereof, or the suitability or fitness
for the conduct of TowerCo's  business or for any other  purpose,  including the
Permitted  Use,  and  TowerCo  further  acknowledges  that  it has had or by its
execution  and  delivery  of  a  Site  Designation  Supplement,  will  have  had
sufficient  opportunity  to inspect and approve the  condition of the  Subleased
Property of the Sites.

(b) Each Site in  addition to the  Initial  Sites shall be made  subject to this
Sublease by the execution  and delivery of a Site  Designation  Supplement  with
respect thereto between Sublessor and TowerCo.  SBCW and TowerCo acknowledge and
agree that this  Sublease is intended to constitute a single  sublease  covering
the Subleased  Property of all of the Sites and a single agreement  covering all
the Sites, and not a separate sublease and agreement covering individual Sites.

(c) This Sublease is a grant of a leasehold  interest in each Owned Site subject
to all matters affecting  Sublessor's  right,  title and interest in and to each
Owned Site (including without  limitation,  Existing Subleases and the interests
of third  parties  as to any Owned  Sites  that are  subject  to any  Colocation
Agreements); and, as to Leased Sites, this Sublease is a grant of a subleasehold
interest  in  each  Leased  Site  subject  to all  matters  affecting  title  to
Sublessor's  leasehold  interest,  leasehold estate or other possessory interest
therein (including without  limitation,  Existing Subleases and the interests of
third parties as to any Leased Sites that are subject to Colocation Agreements).

(d) TowerCo  hereby  acknowledges  that,  as to the  Subleased  Property of each
Leased Site,  this Sublease is a sublease by Sublessor  under the provisions of,
and is  subject  and  subordinate  to all of the terms and  conditions  of,  the
applicable  Ground Lease of such Leased Site.  As to any Leased Site,  Sublessor
shall not be deemed to have assumed any duty or obligation of the Ground Lessor

                                       14
<PAGE>

under the applicable  Ground Lease and shall not be liable or responsible in any
manner whatsoever for any failure of such Ground Lessor to perform any such duty
or obligation.  TowerCo agrees that it will promptly pay or cause to be paid the
Ground Rent under each of the Ground  Leases of the Leased Sites during the Term
of this  Sublease  when such  payments  become due and payable and, in the event
TowerCo  fails to pay  Ground  Rent under any  Ground  Lease on a timely  basis,
TowerCo shall be responsible for any late charges,  fees or interest  payable to
the Ground  Lessor as a result  thereof.  Except as provided in Section  3(f) or
3(h),  TowerCo shall (and with respect to its activities on the Reserved  Space,
each  Sublessor  Entity shall) abide by, comply in all respects  with, and fully
and completely perform all other terms, covenants, conditions, and provisions of
each Ground Lease (including, without limitation, terms, covenants,  conditions,
and provisions relating to maintenance, insurance and alterations) as if TowerCo
were  the  "ground  lessee"  thereunder  and,  to the  extent  evidence  of such
performance  must be  provided  to the Ground  Lessor of the  applicable  Ground
Lease,  TowerCo  shall  provide such  evidence to  Sublessor.  TowerCo shall not
engage in or permit  any  conduct  that  would:  (i)  constitute  a breach of or
default  under any  Ground  Lease;  or (ii)  result in the Ground  Lessor  being
entitled to terminate the  applicable  Ground Lease or to terminate  Sublessor's
right as ground lessee under such Ground Lease,  or to exercise any other rights
or remedies to which the Ground  Lessor may be entitled  for a default or breach
under the applicable Ground Lease. During the Term of this Sublease, and subject
to Section  3(f) below,  Sublessor  agrees to exercise  prior to the  expiration
thereof and in accordance  with the provisions of the  applicable  Ground Lease,
any and all renewal options existing as of the applicable Site Commencement Date
and as may be further extended or renewed by Sublessor  pursuant to the terms of
this Sublease, for any Leased Site under the Ground Leases of such Leased Sites;
provided,  however, that Sublessor shall not, be obligated to renew or otherwise
extend the term of any  applicable  Ground  Lease in the event  such  renewal or
extension  would extend the term of the Ground Lease beyond the Site  Expiration
Outside  Date for  such  Leased  Site  unless  TowerCo  requests  otherwise  and
Sublessor  consents to such request  (which  consent  shall not be  unreasonably
withheld).  The applicable  Sublessor shall (i) forward to the applicable Ground
Lessor all requests for consents and other notices relating to the Permitted Use
which  TowerCo  reasonably  wishes to  deliver  to such  Ground  Lessor and (ii)
deliver to TowerCo all material  notices and  communications  received  from the
applicable Ground Lessor.

(e) TowerCo  shall not be entitled to act as agent for, or  otherwise  on behalf
of, SBCW or any SBCW  Affiliate or to bind SBCW or any SBCW Affiliate in any way
whatsoever in connection with any Ground Lease or otherwise  except as otherwise
provided in this Section 3.

(f) With respect to any  negotiations  with a Ground Lessor for the extension or
terms of renewal of a Ground Lease  (other than a renewal or extension  pursuant
to an option  contained  in such Ground  Lease which  Sublessor  is obligated to
exercise  pursuant  to  Section  3(d)),   TowerCo  shall,  in  cooperation  with
Sublessor,  at  TowerCo's  sole cost and  expense,  be  responsible  for and use
commercially  reasonable efforts to negotiate and obtain an extension or renewal
of the  Ground  Leases of the Leased  Sites on behalf of and for the  benefit of
Sublessor,  and Sublessor shall make commercially  reasonable  efforts to assist
TowerCo in obtaining such extension or renewal,  provided that such extension or
renewal  does not impose any  liability on  Sublessor  for which  TowerCo is not
responsible (or subsequently agrees to be responsible) under the terms of this

                                       15
<PAGE>

Sublease  during  the  Term as to each  Site.  With  respect  to any  amendment,
renewal, extension or other change to the Ground Lease desired by TowerCo during
the term pursuant to this Section 3, (i) Sublessor  shall be entitled to consent
to any such change  (such  consent  not to be  unreasonably  withheld)  and (ii)
subject to the foregoing,  Sublessor shall execute any such amendment,  renewal,
extension  or change  within ten (10) days of its receipt  thereof  from TowerCo
without  condition and shall bear any and all costs  associated with its review.
In the event TowerCo  determines  that it is unable or deems it  undesirable  to
negotiate  the terms of renewal or extension of the Ground Lease  directly  with
the Ground Lessor,  Sublessor may attempt to negotiate such renewal or extension
and TowerCo shall reimburse Sublessor for its reasonable  out-of-pocket expenses
relating to such  negotiation  unless TowerCo  exercises its  termination  right
provided  in the  following  sentence  within the  applicable  time  period.  If
Sublessor  completes the foregoing  negotiations  for such extension or renewal,
the Site Expiration  Date shall be extended to the Site Expiration  Outside Date
set  forth in the Site  Designation  Supplement  provided,  however,  that if in
connection  with such  renewal or extension  Sublessor,  without the approval of
TowerCo, agrees to any increase in Ground Rent over the then-current Ground Rent
or  agrees  to any  revenue  sharing  in  excess  of  existing  revenue  sharing
arrangements, TowerCo shall have the option, exercisable within thirty (30) days
of  receipt  of  notice  of  the  extension  or  renewal,   of  terminating  its
subleasehold  interests  in such Site as of the date the Ground Lease would have
expired had Sublessor not extended or renewed such Ground Lease. If Sublessor or
TowerCo is not able, after using commercially  reasonable  efforts, to extend or
renew any Ground Lease in accordance  with this Section  3(f),  then the Parties
shall permit such Ground Lease to expire on the applicable  expiration  date and
this  Sublease  shall  have no  further  force and  effect  as to the  Subleased
Property of the Leased Site to which such Ground Lease applies.  Each of TowerCo
and TowerCo Parent agrees that neither it, nor any of its  Affiliates,  may seek
to obtain,  obtain or hold,  any interest in any Ground Lease or its  underlying
fee interest that is superior or prior to  Sublessor's  interests in such Ground
Lease.  SBCW or an SBCW Affiliate shall have the right to acquire the fee simple
interest in the Site from the Ground Lessor  whereupon such Site shall be deemed
an Owned Site, in which event  TowerCo  shall have a leasehold  interest in such
Owned Site. Except as provided in this Section 3(f), or as TowerCo may otherwise
agree or direct, during the Term Sublessor shall not take any action to amend or
supplement  any Ground  Lease,  other than to  exercise  renewals  as  expressly
provided  herein  which each  Sublessor  covenants to do as provided  above.  In
addition  to the  foregoing,  Sublessor  agrees that it shall use its good faith
efforts to cooperate  with  TowerCo's  exercise of (or right to exercise any of)
its rights under this  Sublease  with respect to the Ground Lease and the Ground
Lessor, including, without limitation, pursuant to this Section 3.

(g)  Subject to Section 24 and Section 25,  Sublessor's  right to sell,  convey,
transfer, assign or otherwise dispose of Sublessor's interest in and to any Site
(including  Sublessor's  interest in and to the Subleased Property of such Site)
shall be unrestricted.

(h)  Notwithstanding  anything to the contrary contained herein, SBCW represents
to TowerCo that, as of the applicable Site Commencement  Date, each Ground Lease
for a Leased Site is or will be in full force and effect and Sublessor is not or
will not be in default under any such Ground Lease in any material  respect as a
result of  Sublessor's  acts or  omissions.  Each  Sublessor  shall  perform any
obligations  under and comply with the terms of each of the Ground  Leases,  but
only if such obligations are expressly reserved to Sublessor for its performance
under the terms of this  Sublease.  Upon  receipt by  Sublessor of any notice of
default or notice of an act or  omission  which  could with the  passing of time
and/or the giving of notice  constitute an event of default under a Ground Lease
or  non-compliance  with a term of a Ground Lease (the "Default  Notice"),  SBCW
shall, within five (5) business days after receipt of the Default Notice or such
shorter time as is reasonably  necessary to avoid a  termination  of such Ground
Lease,  provide  TowerCo with a copy of the Default  Notice.  If such default or
non-compliance  with a term of a Ground  Lease is caused by TowerCo or any Space
Subtenant,  TowerCo shall,  and shall cause the applicable  Space  Subtenant to,
cure or otherwise remedy such default or noncompliance. Notwithstanding anything
in this Sublease to the contrary,  unless an obligation  under a Ground Lease is
expressly  reserved  under this  Sublease for  performance  by a Sublessor,  any
default  referred to in the Default Notice shall constitute a default by TowerCo
under this Sublease.

                                       16
<PAGE>

(i) Unless an event of default by TowerCo shall have occurred and be continuing,
TowerCo, at its own cost and expense, may from time to time make, subject to the
requirements of Section 12, such Alterations  that are not required  pursuant to
Section  11(a) as  TowerCo  may deem  desirable  in the  proper  conduct  of its
business,  so long  as (i)  such  Alteration  shall  not  disrupt  or  otherwise
adversely affect SBCW's or its Affiliate's  Permitted Use of the Site or portion
thereof and is made in accordance with the  requirements set forth in Section 12
hereof, (ii) such Alteration shall not result in any material respect in (y) the
value  of the  Site or  portion  thereof  being  less  than  the  value  thereof
immediately  prior to such  Alteration,  or (z) the economic life of the Site or
portion thereof being less than the economic life of the Site or portion thereof
immediately prior to such Alteration,  (iii) such Alteration shall not cause the
Site or portion thereof to constitute  "limited use property" within the meaning
of Rev. Proc. 76-30, 1976-2 C.B. 647, and (iv) no Alterations, taken together or
separately, shall fail to comply with the provisions of Rev. Proc. 75-21, 1975-1
C.B. 715 or 79-48, 1979-1 C.B. 529.

         Notwithstanding  anything to the  contrary  contained  in this  Section
3(i),  TowerCo,  at its own  cost  and  expense,  may  from  time  to time  make
Alterations (including,  without limitation,  Nonseverable Improvements that may
be required by Law),  which do not comply with subclause (iv) of the immediately
preceding  sentence   ("Non-Conforming   Alterations")  provided  that  (i)  the
Non-Conforming  Alterations  otherwise  satisfy the terms and provisions of this
Section 3(i), and (ii) the applicable Sublessor does not make TowerCo's proposed
Non-Conforming  Alterations  in  accordance  with the  remainder of this Section
3(i).  In the event that  TowerCo  desires to make  Non-Conforming  Alterations,
TowerCo shall submit written notice to the applicable  Sublessor describing such
proposed  Non-Conforming  Alterations in reasonable detail. Such Sublessor shall
elect whether to make or cause to be made, at such Sublessor's cost and expense,
the Non-Conforming  Alterations by written notice provided to TowerCo within ten
(10) days after  receipt of  TowerCo's  proposal  regarding  the  Non-Conforming
Alterations. Such Sublessor's failure to respond to TowerCo within such ten (10)
day  period  shall be deemed to be such  Sublessor's  election  not to make such
Non-Conforming  Alterations.  In the  event  such  Sublessor  elects to make the
Non-Conforming  Alterations  and such  Sublessor  and TowerCo agree on terms and
conditions,  including,  but not  limited to, the amount and timing of rent with
respect  to such  Non-Conforming  Alterations  ("Additional  Rent"),  then  such
Sublessor shall make the Non-Conforming Alterations in accordance with plans and
specifications,  and  according  to a time  schedule,  provided  by TowerCo  and
reasonably  acceptable  to such  Sublessor.  In the event  that  such  Sublessor
elects, or is deemed to have elected, not to make the Non-Conforming Alterations

                                       17
<PAGE>

or such  Sublessor  and TowerCo  shall not have agreed on terms and  conditions,
TowerCo may make such Non-Conforming  Alterations and,  notwithstanding anything
to the contrary  contained  in this  Sublease  (other than the other  conditions
contained in this Section 3(i)), title to the  Non-Conforming  Alterations shall
without  further act or instrument act or instrument  vest in TowerCo.  Upon the
expiration  or  earlier  termination  of this  Sublease  as to a Site  at  which
Non-Conforming Alterations have been made, the following provisions shall apply:
(i) if TowerCo has not  exercised  its option to purchase  such Site and TowerCo
has made any Non-Conforming  Alterations,  the applicable Sublessor may purchase
such  Non-Conforming  Alterations from TowerCo at a price equal to the then fair
market value of such Non-Conforming  Alterations,  (ii) if TowerCo has exercised
its option to purchase such Site, TowerCo shall purchase such Site at a purchase
price equal to the Option Purchase Price Amount, plus the then fair market value
of the Non-Conforming Alterations and/or Sublessor Alterations,  if any, made to
such Site,  and (iii) if TowerCo has not  exercised  its option to purchase such
Site, TowerCo has made Non-Conforming Alterations,  and the applicable Sublessor
does not purchase such  Non-Conforming  Alterations from TowerCo,  TowerCo shall
continue  to hold such  Non-Conforming  Alterations,  and all rent and any sales
proceeds  attributed  to such Site  thereafter  shall be  allocated  between the
applicable  Sublessor and TowerCo in accordance with their relative interests in
such  Site (as  determined  below).  In each of  subclauses  (i) and (ii) of the
immediately  preceding  sentence,  the  applicable  party shall pay the purchase
price in cash or immediately  available funds. In each of the subclauses (i) and
(ii),  the then  fair  market  value of the  Non-Conforming  Alterations  and/or
Sublessor  Alterations  shall equal the excess of the then fair market  value of
such Site including such Non-Conforming Alterations and/or Sublessor Alterations
over  the   estimated   then  fair  market  value  of  such  Site  without  such
Non-Conforming   Alterations  and/or  Sublessor   Alterations.   The  applicable
Sublessor and TowerCo shall  attempt,  in good faith,  to agree on the then fair
market value of the Non-Conforming  Alterations and/or Sublessor Alterations (or
the relative interests of the applicable  Sublessor and TowerCo,  if applicable)
or,  alternatively,  shall  attempt,  in good faith,  to agree on an independent
qualified  appraiser  to  determine  such fair market  value and the fair market
values of the Non-Conforming  Alterations  and/or the Sublessor  Alterations (or
the relative interests of the applicable  Sublessor and TowerCo, if applicable).
Absent  agreement on value or on an appraiser  within thirty (30) days,  each of
such  Sublessor and TowerCo shall identify an  independent  qualified  appraiser
within ten (10) days  thereafter.  If either party fails to appoint an appraiser
within  such ten (10) day period,  the  appraiser  appointed  by the other party
shall alone  determine  such fair market value.  If two appraisers are appointed
and such appraisers  cannot agree on the then fair market value (or the relative
interests of the applicable  Sublessor and TowerCo,  if  applicable),  each such
appraiser  shall  identify a third  independent  qualified  appraiser  who shall
determine the then fair market value of the  Non-Conforming  Alterations  and/or
Sublessor  Alterations and the relative fair market values of the Non-Conforming
Alterations  and/or the  Sublessor  Alterations  (or the  relative  interests of
Sublessor and TowerCo, if applicable)  (collectively,  the "Valuation Process");
provided that if such two appraisers  cannot agree on the identity of such third
appraiser  within ten (10) days after the  appointment of the second  appraiser,
either  party  may  apply  to  the  American  Arbitration  Association  for  the
appointment of such appraiser.  If TowerCo  exercises its option to purchase the
Site, the fair market value of the  Non-Conforming  Alterations  and/or the fair
market value of the Sublessor  Alterations shall be paid to the party which made
such Alterations.

                                       18
<PAGE>

SECTION 4.        Existing Subleases and Colocation Agreements.

(a) Without limiting the generality of Section 3, TowerCo expressly acknowledges
that,  as to each Site,  this  Sublease  is subject  to all  Existing  Subleases
affecting such Site, including, without limitation,  Existing Subleases executed
prior to the  applicable  Site  Commencement  Date  pursuant  to any  Colocation
Agreement.  In respect of each Site,  by  execution  of this  Sublease or a Site
Designation Supplement the applicable Sublessor does transfer, assign and convey
over unto TowerCo, for the Term of this Sublease in respect of such Site, all of
its rights,  title and interest as  "sublandlord" or "sublessor" in, to or under
any  Existing  Subleases  affecting  such Sites and does hereby  delegate all of
Lessor's duties,  obligations and responsibilities  under the Existing Subleases
to TowerCo.  TowerCo does hereby  assume and agree to pay and perform all of the
duties,   obligations,   liabilities  and   responsibilities   of  Sublessor  as
"sublandlord" or "sublessor"  under the Existing  Subleases  affecting each Site
arising from and after the date of the Site Designation Supplement for such Site
and commencing on the Site  Commencement  Date for such affected  Site,  TowerCo
shall receive all rents payable thereunder.

(b) From time to time,  SBCW shall give TowerCo  written notice of the intent of
third  parties to  Colocation  Agreements  to occupy any  Available  Space,  and
promptly following receipt of such notice, TowerCo shall cooperate with SBCW and
the applicable  third party so as to facilitate such third party's  occupancy of
such Available Space on commercially reasonable terms.

(c) TowerCo shall, and does hereby agree to, indemnify, defend and hold the SBCW
Indemnitees  harmless from, against and in respect of any and all Claims,  paid,
suffered, incurred or sustained by any SBCW Indemnitee and in any manner arising
out of,  by  reason  of,  or in  connection  with  any  failure  of the  duties,
obligations, liabilities and responsibilities of a Sublessor as "sublandlord" or
"sublessor" under any of the Existing Subleases  affecting each Site and arising
from and  after  the Site  Commencement  Date for  such  Site,  to be fully  and
completely  performed pursuant to the Existing  Subleases,  except to the extent
caused by an SBCW Indemnitee.

(d) Unless  TowerCo  exercises the purchase  option with respect to a Site under
Section 35 hereof,  the  assignment by each Sublessor to TowerCo of the Existing
Subleases in respect of each Site shall automatically terminate and expire, such
Existing  Subleases shall  automatically  be reassigned to each Sublessor or its
designee,  and each  Sublessor or its designee  shall accept such  reassignment,
upon the expiration of the Term of, or earlier  termination of, this Sublease in
respect of such Site.

SECTION 5.        Reserved Space.

(a) TowerCo expressly  acknowledges that, as to any Site, the Subleased Property
of such Site does not include, and that each Sublessor has reserved and excepted
from  this  Sublease,  the  Reserved  Space  of such  Site  for  SBCW's  and its
Affiliates'  exclusive  possession  and use,  regardless  of whether or not such
Reserved Space is now or hereafter  occupied;  and,  TowerCo  further  expressly
acknowledges that, as between each Sublessor and TowerCo, the Reserved Space of

                                       19
<PAGE>

each Site shall, at all times during the Term of this Sublease,  be deemed to be
leased or subleased to TowerCo  pursuant hereto and leased back to SBCW (for the
benefit of SBCW or any of its Affiliates)  pursuant  hereto.  As an appurtenance
to, and a part of, the  Reserved  Space of each Site,  each  Sublessor  (for the
benefit of SBCW or any of its Affiliate) also reserves: (i) the right of ingress
to and egress  from the  entire  Site,  and  access to the entire  Tower and all
Improvements to such Site and Tower  (including any and all easements),  at such
times (on a 24-hour,  seven (7) day per week basis unless  otherwise  limited by
the Ground Lease or other  restrictions  of record that have  priority  over the
Sublease),  to such  extent,  and in such means and manners (on foot or by motor
vehicle, including trucks and other heavy equipment), as SBCW deems necessary or
desirable in connection  with its or its  Affiliates'  full use and enjoyment of
the  Reserved  Space,   including,   without   limitation,   the   construction,
installation,  use,  operation,  maintenance,  repair  and  replacement  of  its
Communications  Facility  thereon;  and (ii) the right to use any portion of the
Subleased Property of a Site,  including the Land and Improvements  thereof, for
purposes  of  temporary  location  and  storage  of  any  equipment   (including
Communications Equipment) and any part thereof in connection with performing any
repairs or replacements of such Person's Improvements;  provided,  however, that
such  storage  shall not have a  material  adverse  effect on Space  Subtenants'
Permitted Use.

(b) Subject to the  availability of Available  Space on the applicable  Tower at
the time of the  proposed  expansion,  SBCW may at any time expand the  Reserved
Space on up to three  hundred  (300)  Towers by the addition or  replacement  of
Communications Equipment on such Tower up to an additional fifteen percent (15%)
of the total  tower  loading  on such  Tower;  provided  that as a result of the
exercise of such expansion  right SBCW shall not be entitled to occupy more than
two (2)  platforms on any Tower.  (For the  avoidance  of doubt,  if SBCW or its
Affiliate  occupy  one  (1)  platform  at the  time  of  expansion,  SBCW or its
Affiliate may expand to occupy only one additional platform,  and if SBCW or its
Affiliates  occupy two (2) platforms at the time of such expansion,  SBCW or its
Affiliate  may expand on one or both of the  platforms it then  occupies but may
not expand to occupy an  additional,  third  platform.)  SBCW may  exercise  the
foregoing  expansion  right for itself or for the use and  benefit of any of its
Affiliates.

(c) Without limiting SBCW's rights under Section 24(a) hereof and subject to the
availability  of  Available  Space  on the  applicable  Tower at the time of the
proposed  expansion,  SBCW shall have the further  right to expand the amount of
equipment on the Towers beyond the first three  hundred  (300) Towers,  provided
that SBCW shall pay TowerCo as  additional  Leaseback  Charge $100 per month per
panel/antenna  or space equivalent of one  panel/antenna,  but in no event in an
amount to exceed  $1600  per  platform,  or if SBCW  locates  any such  expanded
equipment on a platform  which is not already  occupied by SBCW's  Communication
Equipment,  not to be less than $1200 per any such additional  platform  (except
with respect to microwave  dishes and related  equipment),  such amount to be in
addition to the SBCW  Leaseback  Charge due and  payable to TowerCo  pursuant to
Section 10. Such  amounts  shall  increase  each year after the date hereof five
percent  (5%) per year,  until  the tenth  anniversary  of the  applicable  Site
Commencement  Date and thereafter  pursuant to Section 10(f).  SBCW may exercise
the  foregoing  expansion  right for itself or for the use and benefit of any of
its Affiliates.

(d)  Notwithstanding  anything to the  contrary  contained  herein,  the Parties
acknowledge and agree that the Reserved Space of each Site will include, without
limitation, all portions of such Site utilized or occupied by SBCW or its

                                       20
<PAGE>

Affiliate as of the applicable Site Commencement Date for such Site for the use,
enjoyment,  operation or maintenance of Communications Facility on such Site for
the  Permitted  Use. If at any time  between the date hereof and the  applicable
Site  Commencement  Date, SBCW or its Affiliate elects to increase the amount of
equipment on a Tower on a Site,  then SBCW shall have an option,  exercisable at
its sole  discretion upon written notice to TowerCo prior to the applicable Site
Commencement  Date, to (i) count such Tower toward three hundred (300) Towers in
accordance  with  Section  5(b)  and pay the  amount  of SBCW  Leaseback  Charge
determined in  accordance  with Section 10(b) with respect to such Site, or (ii)
pay TowerCo,  the amount of SBCW Leaseback Charge  determined in accordance with
Section 5(c).

(e) The parties acknowledge and agree that antenna mounting hardware constitutes
a portion  of the  Improvements  and does not  constitute  part of the  Reserved
Space. If, as to any Sites,  SBCW or any SBCW Affiliate  desires to exercise its
Right  of   Substitution   pursuant  to  Section  24(b),  to  move  any  of  its
Communications Equipment on such Tower to any Available Space, and such exercise
would  require   relocation  of  the  existing  antenna  mounting   hardware  to
accommodate  such move,  TowerCo  shall move such antenna  mounting  hardware as
requested by SBCW or such SBCW Affiliate,  unless (i) other Space Subtenants are
sharing the same antenna mounting hardware, (ii) such relocation would adversely
affect  the  rights  of  other  Space  Subtenants  or  (iii)  TowerCo  otherwise
determines that such  relocation is not feasible or beneficial.  If TowerCo does
relocate SBCW or such SBCW Affiliate's  antenna mounting hardware in response to
the exercise of the Right of  Substitution,  SBCW or such SBCW  Affiliate  shall
reimburse  TowerCo  for  the  reasonable  costs  directly  attributable  to such
relocation.  If as  contemplated  by the  foregoing,  TowerCo does not or cannot
relocate the existing antenna mounting hardware, TowerCo shall, at its sole cost
and expense,  install  suitable  mounting  hardware at the location on the Tower
designated by SBCW or the applicable  SBCW  Affiliate,  so as to accommodate the
requested  relocation;  provided that SBCW or such SBCW  Affiliate  shall remain
responsible for the payment of all costs and expenses associated with moving its
antennas to the antenna mounting hardware supplied by TowerCo.

(f) If SBCW or any SBCW Affiliate desires to add or relocate any antennas to the
Tower  location of any Site,  the  provisions  of Sections  24(a)(i) and (a)(ii)
shall  apply.  Upon the  request of either  Party,  the Parties  shall  promptly
execute such instruments as may be reasonably  required to further evidence such
addition  or  relocation,  including  without  limitation  an  amendment  to the
applicable  Site  Designation  Supplement,  and shall cause such amendment to be
recorded at SBCW's or such SBCW Affiliate's cost and expense, unless the Parties
otherwise agree.

SECTION 6.        Permitted Use.

(a) TowerCo  shall use, and shall permit the use of, the  Subleased  Property of
each Site only for the Permitted Use.

(b) TowerCo shall not use, or permit to be used,  the Subleased  Property of any
Site,  or any portion  thereof,  by TowerCo,  any Person (other than SBCW or its
Affiliates)  or the  public in such  manner as might  reasonably  tend to impair
Sublessor's  title to or interest in such Site,  or any portion  thereof,  or in
such manner as might reasonably make possible a Claim or Claims of adverse usage

                                       21
<PAGE>

or adverse  possession by the public, as such, or any Person (other than SBCW or
its  Affiliate),  or of implied  dedication of such Subleased  Property,  or any
portion thereof. Nothing contained in this Sublease and no action or inaction by
SBCW or its  Affiliates  shall be deemed or construed to mean that Sublessor has
granted to  TowerCo  any right,  power or  permission  to do any act or make any
agreement  that may create,  or give rise to or be the  foundation  for any such
right,  title,  interest,  lien,  charge or other encumbrance upon the estate of
Sublessor in any Site.

(c) SBCW shall not use, or permit to be used, the Reserved Space of any Site, or
any portion  thereof,  by SBCW, any Affiliate  thereof,  any other Person (other
than  TowerCo  and  Space  Subtenants)  or the  public  in such  manner as might
reasonably  tend to impair  TowerCo's  right as a sublessor with respect to such
Site,  or any  portion  thereof,  or in such  manner  as might  reasonably  make
possible a Claim or Claims of adverse usage or adverse possession by the public,
as such, or any Person (other than TowerCo and Space Subtenants),  or of implied
dedication of such Reserved Space, or any portion thereof.  Nothing contained in
this  Sublease and no action or inaction by TowerCo shall be deemed or construed
to mean that  TowerCo  has granted to SBCW or any  Affiliate  thereof any right,
power or permission to do any act or make any agreement that may create, or give
rise to or be the foundation for any such right, title,  interest,  lien, charge
or other encumbrance upon the leasehold estate of TowerCo in any Site.

SECTION 7.        Access.

         The Subleased Property of a Site includes,  as an appurtenance thereto,
a  non-exclusive  right for access to the  Subleased  Property of each Site on a
24-hour,  seven  (7) day per week  basis,  on foot or motor  vehicle,  including
trucks and other heavy  equipment,  for the  installation and maintenance of the
Tower  and  Improvements  thereof  and the  Communications  Facilities  of Space
Subtenants.  The  Parties  acknowledge  and agree  that the right to access  the
Subleased  Property of each Site, or any portion  thereof,  granted  pursuant to
this  Section 7 shall be  granted  to TowerCo  and its  authorized  contractors,
subcontractors,  engineers, agents, advisors, consultants,  representatives,  or
other persons authorized by TowerCo and, under TowerCo's direct supervision, and
to Space  Subtenants,  subject to any  restrictions  contained in the applicable
Ground Lease.

SECTION 8.        Term.

(a) The term of this  Sublease,  as to each  Site,  shall  commence  on the Site
Commencement  Date set forth in the Site  Designation  Supplement  with  respect
thereto and shall expire on the Site Expiration Date therefor.

(b) No surrender by TowerCo to the  Sublessor of the  Subleased  Property of any
Site or any portion thereof, prior to the expiration of the Term as to such Site
shall be valid or  effective  unless  agreed to and  accepted in writing by such
Sublessor,  and no act by such Sublessor,  other than such a written acceptance,
shall constitute an acceptance of any such surrender.

(c) As to any Site,  upon  expiration or earlier  termination  of this Sublease,
TowerCo  shall,  at its cost and expense and upon  instructions  from SBCW,  (i)
within a reasonable period of time, but in no event less than thirty (30) days,

                                       22
<PAGE>

stop and cease,  and cause the Space  Subtenants on such Site to stop and cease,
the operation of its Communications Facilities on such Site and shall remove all
of  TowerCo's  Severable  Alterations  from  such  Site and  restore  each  Site
substantially  to the condition it was in on the  applicable  Site  Commencement
Date, subject to the addition of any permitted  Non-Severable  Alterations.  Any
Severable  Alterations not removed by TowerCo within said 15-day period shall be
deemed  abandoned  by TowerCo and title  thereto  shall  automatically,  without
further action, vest in the Sublessor of such Site.

SECTION 9.        Withdrawal.

(a)  Notwithstanding  anything to the contrary contained herein,  SBCW will have
the Withdrawal Right for the benefit of itself or its Affiliates, exercisable in
respect of any Site on the tenth anniversary of the applicable Site Commencement
Date and on each five-year anniversary of such date thereafter.  To exercise any
such Withdrawal  Right,  SBCW shall give TowerCo written notice of such exercise
not less than ninety  (90) days,  in the case of the  exercise  of a  Withdrawal
Right in respect of less than twenty percent (20%) of all Sites now or hereafter
under this  Sublease  and one  hundred  eighty  (180)  days,  in the case of the
exercise of a Withdrawal Right in respect of twenty percent (20%) or more of all
Sites now or hereafter under this Sublease,  prior to any such  anniversary (the
"Withdrawal  Notice").  If SBCW exercises the  Withdrawal  Right as to any Site,
SBCW shall not be required to pay the SBCW Leaseback Charge with respect to such
Site for the period  occurring after the Withdrawal Date and the Withdrawal Date
as to such Site shall be the date specified in the applicable Withdrawal Notice.
Not later than the  Withdrawal  Date of any Site,  SBCW or its  Affiliate  shall
vacate  the  Reserved  Space of such  Site if such  Reserved  Space is  occupied
whereupon  SBCW's or its  Affiliate's  sublease of such Reserved  Space pursuant
hereto and SBCW's or its Affiliate's  right to occupy and use the Reserved Space
of such Site as a sublessee  hereunder  shall be  terminated.  At the request of
either SBCW or TowerCo,  the appropriate parties shall enter into documentation,
in form and substance  reasonably  satisfactory to such parties,  evidencing any
withdrawal effected hereunder.

(b) In  addition  to and not in  limitation  of any right of SBCW under  Section
9(a), SBCW will have the right,  exercisable at any time during the Term of this
Sublease,  to cease  occupying  the Reserved  Space of any Site,  and retain its
right to such  Reserved  Space and may permit a SBCW  Affiliate  to occupy  such
Site, so long as SBCW continues to pay the SBCW  Leaseback  Charge in respect of
such Site.

SECTION 10.       Rent and SBCW Leaseback Charge.

(a) TowerCo  shall  prepay Rent (other than  Additional  Rent) in respect of the
Subleased  Property of each Site,  for the entire Term on the Site  Commencement
Date for each Site.  TowerCo shall pay Additional Rent in such time,  manner and
amounts as  determined  pursuant to Section 3(i)  hereof.  Each month during the
Term as to each Site,  SBCW shall pay, or cause its  Affiliate  to pay, the SBCW
Leaseback Charge in respect of the Reserved Space for such Site which is subject
to this Sublease,  in advance on or prior to the tenth (10) day of such calendar
month, beginning on the Site Commencement Date for such Site.

(b) The following terms shall have the following definitions:

                                       23
<PAGE>

                  "Rent"  means,  as to any Site the  rental  amount  prepaid by
         TowerCo for the leasing of the Sites  pursuant to this  Sublease as set
         forth in Annex A to the  Agreement  to Sublease  and to be set forth on
         the Site Designation Supplement and any Additional Rent with respect to
         such Site.

                  "SBCW Leaseback  Charge" means, as to any Reserved Space,  the
         monthly  rental  amount  payable to TowerCo  for the  leaseback  of the
         Reserved  Space on such Site to SBCW or its Affiliate  pursuant to this
         Sublease equal as to any Site in any Site Term Year, an amount equal to
         $1,400  per  month  subject  to an  increase  of the  lesser of (x) the
         applicable  CPI Change plus four  percent (4%) or (y) five percent (5%)
         per year (but never less than zero percent (0%)) on each anniversary of
         the Effective Date.

(c) TowerCo  shall pay a late charge of five percent (5%) of any amount  payable
by TowerCo under the provisions of this Sublease, which shall be paid within ten
(10)  days  after  the date the same is due;  provided,  however,  that the late
charge shall not be assessed in respect of the first late  payment  occurring in
any Site Term Year.

(d) If the Site Commencement Date for any Site is a day other than the first day
of a calendar month,  the applicable  SBCW Leaseback  Charge for the period from
such Site  Commencement  Date through the end of the calendar month during which
such Site Commencement Date occurs shall be prorated on a daily basis, and shall
be included in the  calculation of the SBCW Leaseback  Charge for the first full
calendar  month of the  Term,  on the  first  day of the  first  calendar  month
following such Site Commencement Date.

(e) SBCW or its  Affiliate  shall pay a late charge of five  percent (5%) of any
SBCW Leaseback  Charge payable by SBCW or its Affiliate  under the provisions of
this Sublease,  which shall be paid within ten (10) days after the date the same
is due; provided, however, that the late charge shall not be assessed in respect
of the first late payment occurring in any Site Term Year.  Notwithstanding  the
foregoing, if SBCW or its Affiliate fails to pay any portion of a SBCW Leaseback
Charge because SBCW or its Affiliate,  acting in good faith,  reduced the amount
of SBCW Leaseback Charge payable to TowerCo due to a mistaken belief that it was
entitled to  Reimbursable  Maintenance  Expenses  under Section  29(a),  no late
charge shall be payable in respect thereof.

(f)  Notwithstanding  anything to the contrary  contained  herein,  if after the
tenth (10th)  anniversary of the  applicable  Site  Commencement  Date, the then
current  SBCW  Leaseback  Charge  payable to TowerCo with respect to any Site is
below the market rate  agreed upon by the Parties at the time of  determination,
then such  SBCW  Leaseback  Charge  shall  automatically  be  increased  on such
anniversary  and  on  each  anniversary  thereafter,  based  on the  CPI  Change
effective as of date of such anniversary.  If, however,  the then SBCW Leaseback
Charge  payable to TowerCo  with  respect to such Site is above the market rate,
then such SBCW Leaseback Charge shall be  automatically  reset at ninety percent
(90%)  of such  agreed  upon  market  rate  effective  as of such  tenth  (10th)
anniversary of the applicable Site  Commencement Date and shall increase on each
following  anniversary  at the then current  annual  market rate of increase for
comparable  properties.  Notwithstanding  anything  to  the  contrary  contained
herein,  the Parties shall agree as to the market rate not later than sixty (60)
days prior to such tenth anniversary of the applicable Site  Commencement  Date.
If the Parties are unable to agree upon the market rate, then SBCW shall have an
option,  exercisable  by written  notice to TowerCo,  to exercise its Withdrawal
Right in accordance with Section 9(a).

                                       24
<PAGE>

SECTION 11.       Condition of the Sites and Obligations of TowerCo.

(a) TowerCo  acknowledges  that, as between TowerCo and SBCW, in respect of each
Site,  TowerCo  has the  obligation,  right and  responsibility  to  repair  and
maintain such Site, including without limitation,  an obligation to monitor each
Tower to maintain the  structural  integrity of the Tower and the ability of the
Tower to hold and  support  all  Communications  Equipment  then  mounted on the
Tower, in accordance with all applicable Laws and standard  industry  practices.
Subject to the other provisions contained in this Sublease, TowerCo, at its sole
cost and  expense,  except if such cost or expense  arises out of a negligent or
wrongful act or omission of SBCW or its Affiliates,  shall monitor, maintain and
repair  each  Site such that SBCW or its  Affiliates  and Space  Subtenants  may
utilize such Site to the extent permitted herein, including, without limitation,
each Tower  lighting  system  (to the extent  required  by  applicable  Law) and
markings and the structural integrity of each Tower.  Installation,  maintenance
and repair of each Site must comply with all Laws applied in a manner consistent
with standard industry practices.  TowerCo's duties include, without limitation,
subject to the other  provisions  contained  in this  Sublease,  maintenance  of
appropriate records and notification to the FAA of any failure on TowerCo's part
and repairs and correction of same. TowerCo assumes all responsibilities,  as to
each Site, for any fines, levies,  and/or other penalties imposed as a result of
non-compliance   with  said   requirements  of  said  authorities   unless  such
non-compliance  occurs  on or prior to the Site  Commencement  Date for any such
Site (in which event SBCW or the applicable  SBCW Affiliate shall be responsible
for such  fines,  levies  and/or  other  penalties).  TowerCo  shall cause Space
Subtenants to maintain and repair all Communications  Equipment on each Site, in
accordance with the requirements of this Sublease  including without  limitation
as set forth in Exhibit C;  provided,  however,  that  nothing in this  Sublease
shall  require  TowerCo to  maintain  SBCW's or its  Affiliate's  Communications
Equipment.  Without limiting the foregoing, TowerCo at its own cost and expense,
shall make (or cause to be made) all Alterations to the Sites as may be required
from time to time to meet in all respects the  requirements  of applicable  Laws
(regardless  of the Person  upon whom such  requirements,  by their  terms,  are
nominally imposed).

(b) For each Site, TowerCo, at its sole cost and expense, shall provide SBCW all
necessary and appropriate  information requested by SBCW for SBCW to obtain (and
SBCW will obtain  within a reasonable  amount of time) all of the  certificates,
permits, and other approvals which may be required in connection with FCC or FAA
regulations.  TowerCo  shall  also  provide  SBCW  all  appropriate  information
requested by SBCW  pertaining  to any  easements or consents  which are required
from any third parties with respect to the operation of such Site, including the
lighting  system  serving  such  Site,  SBCW  shall  cooperate  with  TowerCo in
connection  therewith,  as  contemplated by Section 17. Nothing in this Sublease
shall require  TowerCo to provide any  information  necessary for SBCW to obtain
any  certificate,  permit or other approval  relating  specifically  and only to
SBCW's Communications Equipment. If, as to any Site, or any portion thereof, any
certificate, permit, license, easement, or approval relating to the operation of
such Site is canceled,  expires, lapses, or is otherwise withdrawn or terminated
or, if TowerCo has breached its obligation  under this Section 11(b),  then SBCW
shall have the right, in addition to its other remedies pursuant to this

                                       25
<PAGE>

Sublease,  at law, or in equity,  to take appropriate  action to remedy any such
noncompliance  and demand  reimbursement for any expenses incurred in connection
therewith  from  TowerCo,  and/or to  terminate  this  Sublease  as to such Site
subject to Sections 29 and 30.

(c) For each Site,  TowerCo  agrees to monitor the lighting  system serving such
Site and will notify the appropriate FAA service office of any lighting  failure
within thirty (30) minutes of  discovering  such failure.  In addition,  TowerCo
agrees, as soon as practicable,  to begin a diligent effort to repair the failed
lighting on an Emergency basis, and to notify SBCW upon successful completion of
the repair.  Notwithstanding  anything to the contrary  contained in Section 30,
TowerCo's  failure to (i) successfully  schedule such repair and notify SBCW, in
each  case as  soon  as  practicable  but in any  event  no  later  than  within
twenty-four  (24) hours of  receiving  such  notice  and (ii)  repair the failed
lighting  within  five (5) days,  constitutes  default  by  TowerCo  under  this
Sublease.  Notwithstanding  anything to the contrary  contained herein,  TowerCo
agrees to  indemnify,  defend and hold each SBCW  Indemnitee  harmless  from and
against any Claims arising out of or by reason of any failed lighting whether or
not TowerCo shall have complied with the provisions of this Section 11(c) unless
such Claims arise out of or by reason of SBCW  Indemnitee's  gross negligence or
willful  misconduct.  In addition to and not in limitation of Sections 30(d) and
(e), if TowerCo  defaults  under this Section  11(c),  SBCW,  in addition to its
other  remedies  pursuant to this Sublease,  at law, or in equity,  may elect to
take  appropriate  action to repair or replace  lights and invoice  TowerCo.  In
addition,  SBCW may terminate  this Sublease as to such Site within fifteen (15)
days of the occurrence of such default; provided, that such default is not cured
within the aforementioned fifteen (15) days period. Without in any way affecting
TowerCo's  obligations  relating  to  lighting:  (i)  in  order  to  accommodate
TowerCo's  needs  during the  transition  period,  SBCW  agrees to  monitor  the
lighting  system  serving the Towers or the  Improvements  of the Sites from the
respective dates of the Site Designation Supplements until the expiration of two
calendar  months after the Final  Closing  Date (as defined in the  Agreement to
Sublease);  (ii)  during the  entire  Term,  SBCW  shall have the right,  at its
expense, to install and maintain equipment for the purpose of monitoring (x) the
lighting system serving the Tower or the  Improvements of each Site,  and/or (y)
any device of TowerCo's used to monitor the lighting  system serving each Tower;
and (iii) TowerCo shall have the right, at its expense,  to install and maintain
equipment for the purpose of monitoring any device of SBCW's or SBCW Affiliate's
used to monitor the lighting system servicing any Tower. At TowerCo's  election,
SBCW shall (i)  provide  TowerCo a data feed for a fee and on terms to be agreed
(x) from all appropriate  security monitoring devices now at the Tower (it being
understood  that these  devices will be leased or subleased to TowerCo with each
Tower,  and that TowerCo will be responsible  for the repair and  maintenance of
the  devices  and their  wiring up to the point of  hand-off to SBCW's T1 at the
Site) and (y) from any additional  devices which TowerCo  wishes to install,  at
TowerCo's sole cost and expense; (ii) permit TowerCo access to the contact point
box at each Tower where TowerCo may install, at TowerCo's sole cost and expense,
its own direct links to such devices; or (iii) permit TowerCo,  where available,
access to the contact point for each Tower through SBCW's regional switching (it
being  understood  that  TowerCo  shall be  responsible  for  providing  its own
dedicated  telephone  lines to the Site,  that  these  monitoring  devices  will
generally  be  subleased  to TowerCo  with each Tower,  and that TowerCo will be
responsible for the repair and maintenance of the devices and their wiring up to
the point of hand-off to TowerCo's dedicated lines).

                                       26
<PAGE>

(d) Without limiting  TowerCo's  obligations under this Section 11 and the other
provisions  of this  Sublease,  the Parties  acknowledge  that SBCW and the SBCW
Affiliates  are licensed by the FCC to provide  telecommunications  services and
that the Sites are used to provide  those  services.  Nothing  in this  Sublease
shall be construed to transfer control of any FCC authorization  held by SBCW or
the  SBCW  Affiliates  to  TowerCo  or to limit  the  right of SBCW and the SBCW
Affiliates to take all necessary  actions to comply with their obligations as an
FCC licensee or with any other legal obligations to which they are or may become
subject.

SECTION 12.       Requirements for Alterations; Title to Alterations; Addition
of Equipment; Work on the Site.

(a) All Alterations that are made to a Site (whether required or optional) shall
comply with the  requirements  of clauses (i),  (ii),  (iii) and (iv) of Section
3(i) hereof.  Subject to Section 3(i),  title to each  Alteration  shall without
further act or  instrument  vest in the  Sublessor of such Site and be deemed to
constitute a part of the Site and be subject to this Sublease  provided that any
such  Alteration  is required  pursuant  to Section 11 (a) or is a  Nonseverable
Alteration.  Title to all other  Alterations  shall  vest in  TowerCo.  Any such
Alteration may be removed by TowerCo,  at its own cost and expense,  at any time
prior to the end of the Term for the  applicable  Site if such  removal will not
cause the Site to be in violation of any applicable Law. Any such Alteration may
also be  removed  at the  expiration  of the Term so long as the  Site  restored
substantially  to its  condition  (normal wear and tear  excepted)  prior to the
making of such Alteration;  provided,  however,  that any Severable  Alterations
that  are not  removed  from a Site  within  15-days  after  at the  time of its
surrender by TowerCo  shall become the property of the  Sublessor of the Site as
provided in Section 8(c) hereof.

(b) Whenever  TowerCo is permitted or required to make  Alterations to any Site;
construct,  replace,  maintain or repair the Tower and Improvements of any Site;
maintain  or repair,  or cause  Space  Subtenants  to  maintain  or repair,  any
Communications   Equipment,  or  reconstruct  or  restore,   Subleased  Property
(hereinafter called the "TowerCo Work"), the following provisions shall apply:

(i)      No TowerCo Work shall be commenced  until all  certificates,  licenses,
         permits,  authorizations,  consents  and  approvals  necessary  for the
         TowerCo Work, from all  governmental  authorities  having  jurisdiction
         with  respect  to any Site or the  TowerCo  Work as set out in  Section
         12(c) hereof have been obtained.  SBCW shall obtain,  and TowerCo shall
         reimburse  SBCW in  accordance  with  Section  17(f)  for  the  cost of
         obtaining, any FCC or FAA permits or approvals relating to TowerCo Work
         and all other such  certificates,  licenses,  permits,  authorizations,
         consents and approvals  shall be obtained by TowerCo at TowerCo's  cost
         and expense.

(ii)     TowerCo shall commence and perform the TowerCo Work in accordance  with
         standard operating procedures agreed upon by the parties  substantially
         in the form of Exhibit E attached hereto ("Standard Procedures").

(iii)    TowerCo  shall cause the  TowerCo  Work to be done and  completed  with
         industry standard materials and in a good,  substantial and workmanlike
         manner, free from faults and defects,  and in compliance with all Laws,
         and shall  utilize  only  industry  standard  materials  and  supplies.
         TowerCo shall be solely  responsible for construction  means,  methods,
         techniques,   sequences  and  procedures,   and  for  coordinating  all
         activities  related to the TowerCo Work, and SBCW shall have no duty or
         obligation to inspect the TowerCo Work,  but shall have the right to do
         so,  at  reasonable  times,  upon  reasonable  prior  notice  and  in a
         reasonable manner.

                                       27
<PAGE>

(iv)     TowerCo shall promptly  commence the TowerCo Work and, once  commenced,
         diligently  and  continually  pursue the TowerCo  Work and complete the
         TowerCo Work within a reasonable  time.  TowerCo  shall  supervise  and
         direct the TowerCo Work utilizing  commercially  reasonable efforts and
         reasonable  care,  and shall  assign such  qualified  personnel  to the
         TowerCo  Work as may be  necessary  to  cause  the  TowerCo  Work to be
         completed in an expeditious fashion.
(v)      All TowerCo Work shall be performed at TowerCo's sole cost and expense.
         TowerCo  shall  provide  and  pay  for  all  labor,  materials,  goods,
         supplies,  equipment,  appliances,  tools,  construction  equipment and
         machinery and other  facilities  and services  necessary for the proper
         execution and  completion of the TowerCo Work.  TowerCo shall  promptly
         pay when due all costs and  expenses  incurred in  connection  with the
         TowerCo  Work.  TowerCo  shall pay,  or cause to be paid,  all fees and
         taxes required by law in connection with the TowerCo Work.

(vi)     TowerCo shall be  responsible  for the acts and omissions of all of its
         employees,    contractors,    subcontractors,     engineers,    agents,
         representatives,  advisors and all other persons  performing any of the
         TowerCo Work. TowerCo shall be responsible for initiating,  maintaining
         and  supervising  all  necessary  safety  precautions  and  programs in
         connection  with the  TowerCo  Work,  and  shall  take  all  reasonable
         protection to prevent damage,  injury or loss to, the TowerCo Work, all
         persons  performing TowerCo Work on the Site, all other persons who may
         be  involved in or affected by the  TowerCo  Work,  all  materials  and
         equipment  to  be   incorporated   in  the  TowerCo  Work,   Tower  and
         Improvements of such Site.

(vii)    Unless  otherwise  permitted to  self-insure  in  accordance  with this
         Sublease,  TowerCo shall procure and maintain in full force and effect,
         and shall  cause its  contractors  and  subcontractors  to procure  and
         maintain in full force and effect,  with  respect to the TowerCo  Work:
         (x) full  replacement  cost  "all-risk",  "builder's  risk"  insurance,
         insuring  the  TowerCo  Work;  and (y) the  other  types  of  insurance
         required to be maintained pursuant to Section 23 of this Sublease. Such
         additional  insurance  policies shall meet the  requirements  set forth
         elsewhere  in this  Sublease  with  respect to the  insurance  policies
         otherwise  required to be obtained and maintained by TowerCo under this
         Sublease.

(c) Before any TowerCo Work is performed or any antennas or other  equipment are
added  to a Tower  by  TowerCo  or a Space  Subtenant  other  than  SBCW and its
Affiliates,  TowerCo  shall  provide  SBCW with a  "Notice  of  TowerCo  Work or
Additional  Equipment" in the form of Exhibit F attached  hereto  containing the
following  information  with  respect to any  antennas or other  equipment to be
added and the following information,  to the extent relevant with respect to any
TowerCo Work to be performed, together with any additional information required

                                     28
<PAGE>

by Law in  order  for  SBCW to make  any  necessary  or  appropriate  FAA or FCC
regulatory filings with respect thereto:  Proposed temporary construction height
(including  any  temporary  equipment),  Effective  Radiated  Power  ("ERP")  or
Equivalent  Isotropically  Radiated Power ("EIRP") (if  microwave);  analysis of
Radio Frequency  ("RF") Emissions  pursuant to FCC Rule 1.1307(b);  statement of
construction method to be used (crane, gin poke, other);  description of devices
installed (microwave,  cellular,  other (e.g. Part 15 device);  specification of
whether   antenna  is  side  mounted  or  top  mounted,   and  if  top  mounted,
certification that the antenna tip or other equipment is not taller than the top
of the existing  structure).  With respect to any TowerCo Work to be  performed,
TowerCo also shall provide in such Notice all relevant information regarding the
nature of such TowerCo Work. SBCW shall promptly make all FAA and FCC regulatory
filings as it deems necessary or appropriate in connection with such addition of
equipment or TowerCo Work.  SBCW shall notify TowerCo  promptly after the filing
of any and all  such  FAA and FCC  regulatory  filings  and the  passage  of any
additional time required by any  governmental  entity prior to  authorization to
add such equipment. After receipt of such notice from SBCW, TowerCo or the Space
Subtenant,  as the case may be, may add such  equipment  to the Tower or perform
such TowerCo Work, provided such addition or TowerCo Work is consistent with the
information set forth in the Notice of TowerCo Work or Additional Equipment.

(d) During the Term for each Site,  TowerCo  shall have access to the air rights
over SBCW's or the applicable SBCW Affiliate's  equipment  shelters at such Site
to install  or  construct  a stacked  equipment  shelter  or similar  structure;
provided  that such  stacked  shelter  or  similar  structure  shall not have an
adverse effect on, or interfere with,  SBCW's or the applicable SBCW Affiliate's
use  of or  access  to  the  Site  (including  the  Reserved  Space  and  SBCW's
Improvements  at such Site).  TowerCo may submit  plans and  specifications  for
stacked equipment shelters or similar  structures  designed for use with respect
to specific types of SBCW or SBCW Affiliate  equipment  shelters.  Provided SBCW
shall  have   approved  a   particular   design  and  the   related   plans  and
specifications,  TowerCo  shall have the right to install such  structure(s)  at
appropriate Sites to which such design applies.  TowerCo shall give SBCW no less
than (3) three  business days prior written  notice of the  commencement  of any
such installation.

SECTION 13.       Damage to the Site, Tower or the Improvements.

(a) If there occurs a casualty which damages or destroys of all or a Substantial
Portion of any Site,  then either Party shall have the right to  terminate  this
Sublease as to such Site by written notice to the other Party within thirty (30)
days of the occurrence of such casualty  whereupon the Term shall  automatically
expire as to such Site, on the date of such  casualty,  as if such date were the
Site Expiration Date as to such Site.

(b) If less than a  Substantial  Portion  of any Site  (including  the Tower and
Improvements thereon) is damaged or destroyed by casualty,  TowerCo, at its sole
cost and expense,  shall promptly and diligently  proceed with the adjustment of
TowerCo's  insurance Claims in respect thereof within a period of two (2) months
after the date of the damage and,  thereafter,  if and to the extent required by
this Section 13, promptly commence, and diligently prosecute to completion,  the
Restoration,  repair,  replacement  and rebuilding of the same. The  Restoration
shall  be  carried  on and  completed  in  accordance  with the  provisions  and
conditions of this Section 13.

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<PAGE>

(c) All Proceeds of TowerCo's  insurance shall be held by TowerCo for the mutual
benefit of TowerCo and Sublessor on account of such damage,  shall be applied to
the payment of the costs of the  Restoration  and shall be paid out from time to
time as the  Restoration  progresses.  Any portion of the  Proceeds of TowerCo's
insurance applicable to a particular Site remaining after final payment has been
made for work performed on such Site shall be retained by and be the property of
Sublessor.  If the  cost  of  Restoration  exceeds  the  Proceeds  of  TowerCo's
insurance, TowerCo shall pay the excess cost.

(d)  Without  limiting  TowerCo's  obligations  hereunder  in  respect of a Site
subject to a casualty, in the event TowerCo is required to cause the Restoration
of a Site that has suffered a casualty, TowerCo shall make available to SBCW (or
its Affiliate  occupying space on such Site) a portion of the Subleased Property
of such Site for the purpose of such Person locating a temporary  communications
facility,  such as a "cell on wheels",  and shall give such Person priority over
Space Subtenants at such Site as to the use of such portion; provided,  however,
that:  (i) the  placement of such  temporary  communications  facility  does not
interfere in any material respect with TowerCo's  Restoration and repair of such
Improvements or the operations of any Space Subtenant;  (ii) such Person obtains
any permits and approvals,  at such Person's cost,  required for the location of
such  temporary  communications  facility  on such  Site;  and  (iii)  there  is
available space on the Site for placing such temporary communications facility.

(e) The  foregoing  provisions  of this  Section 13 apply only to damage of each
Site by fire,  casualty  or other  cause  occurring  after the  applicable  Site
Commencement Date.

(f) If SBCW or its  Affiliate  damages  any Site as a result  of  SBCW's or such
Affiliate's  negligent or wrongful  act or  omission,  or failure to perform its
obligations  under  this  Sublease,  SBCW or its  Affiliate  will,  at its  sole
expense,  promptly repair and restore the Subleased Property of such Site to its
respective condition prior to such damage.

(g) If TowerCo fails to complete the Restoration of the Subleased  Property,  of
any Site required  under this  Sublease  within two (2) months after the date of
the damage,  SBCW may  terminate  this Sublease as to the  applicable  Site upon
giving TowerCo  written notice of its election to terminate  within fifteen (15)
days following the expiration of such time period,  provided,  however,  that if
TowerCo's failure to complete such Restoration  within such two (2)-month period
is caused by: (i) failure to obtain a new permit, or (ii) TowerCo's inability to
have  access  to the  affected  Site,  such  2-month  period  shall be  extended
accordingly in order to allow TowerCo to complete the Restoration.

(h) This Section 13(h) shall be deemed an express agreement governing any damage
or  destruction  of any Site by fire or other  casualty,  and Section 227 of the
Real Property Law of the State of New York  providing for such a contingency  in
the  absence of an  express  agreement  and any other law of like  import now or
hereafter in force, shall have no application.

SECTION 14.       Space Subtenants; Interference.

(a) TowerCo acknowledges and agrees that TowerCo will not permit the addition of
any Space  Subtenants  (other  than SBCW or its  Affiliates  in  respect  of any
Available  Space) at the  Subleased  Property  of any Site to  adversely  affect
SBCW's Reserved Space and its operation,  use or enjoyment of any Reserved Space
on  such  Site,  taking  into  account  customary  and  commercially  reasonable
practices for multi-tenant wireless communication sites and towers thereon.

                                       30
<PAGE>

(b) TowerCo shall not and shall not permit any Space Subtenants (other than SBCW
or its Affiliates in respect of any Available  Space) on the Subleased  Property
of any Site to (i) install or change, alter or improve the frequency,  power, or
type of the  Communications  Equipment that interferes with the operation of the
Reserved Space of such Site or is not authorized by, or violates, any applicable
Laws or is not made or installed in accordance with good  engineering  practices
(and  TowerCo  shall  require  any Space  Subtenant  who  subleases  or licenses
Available Space on any Tower to covenant to comply with the foregoing);  or (ii)
implement a configuration  which  interferes with the operation of SBCW's or its
Affiliate's Communications Equipment on such Site or the Reserved Space thereof.

(c) In the event any Space  Subtenant  installs or operates  any  Communications
Equipment  which is not  authorized  by, or in violation  of, any Laws,  TowerCo
shall  cause  such  Space  Subtenant  to remove  such  Communications  Equipment
promptly, failing which TowerCo shall remove such Communications Equipment.

(d) In the event of any interference occurring as a result of actions of TowerCo
or Space  Subtenants  described  in  Sections  14(b)  above as to the  Subleased
Property  of any  Site,  TowerCo  shall  be  responsible  for  coordinating  and
resolving any such  interference  problems caused by TowerCo or Space Subtenants
(other  than  SBCW  or  its  Affiliates  in  respect  of any  Available  Space),
including,  without limitation,  using its best efforts to correct and eliminate
the interference  within  forty-eight (48) hours of receipt of notification from
SBCW and perform an  interference  study in accordance  with the  procedures set
forth in Schedule 14(d). If the  interference  cannot be corrected or eliminated
within such 48-hour  period,  TowerCo shall cause, at TowerCo's  option,  any of
TowerCo's or Space Subtenants'  (other than SBCW or its Affiliates in respect of
any Available Space)  Communications  Equipment or Communications  Facility that
interferes  with the  operation  of  SBCW's  or its  Affiliate's  Communications
Facility  or  the  Reserved  Space,  authorized  frequency  spectrum  or  signal
strength,  to be immediately  powered down or turned off, with the right to turn
such interfering  equipment or facility back up or on only during off-peak hours
specified by SBCW in order to determine whether such  interference  continues or
has been eliminated;  provided,  however, that if any interference  continues at
the time the interfering equipment is powered down, the Communications Equipment
that  interferes  with the operation of SBCW's or its  Affiliates  Communication
Facility  or  Reserved  Space  shall be  turned  off.  If  TowerCo  or any Space
Subtenant  (other than SBCW or its Affiliates in respect of any Available Space)
cannot correct or eliminate,  to the  satisfaction  of SBCW,  such  interference
within twenty (20) days of receipt of written notice from SBCW, TowerCo shall or
shall cause such Space  Subtenant  (other than SBCW or its Affiliates in respect
of  the  Available   Space)  to  cease  the  operations  of  the   objectionable
Communications  Equipment and to stop  providing  services  from the  applicable
Communication  Facility or the Subleased  Property of the applicable Site in its
entirety until the interference problems are resolved.

(e) SBCW and its Affiliates  shall not: (1) install or change,  alter or improve
the frequency,  power, or type of the Communications  Equipment in a manner that
interferes   with  the   operation  of   TowerCo's  or  any  Space   Subtenant's
Communications Equipment on a Site or is not authorized by Law or is not made or
installed in accordance  with good  engineering  practices;  or (ii) implement a
configuration  which  interferes  with the  operation  of TowerCo's or any Space
Subtenant's Communications Equipment on such Site.

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<PAGE>

(f) In the event of any interference occurring as a result of actions of SBCW or
its  Affiliates  described in Section 14(d) above as to any Site,  SBCW shall be
responsible for coordinating and resolving any such interference problems caused
by SBCW or its Affiliates, including, without limitation, using its best efforts
to correct and  eliminate  the  interference  within  forty-eight  (48) hours of
receipt of notification from TowerCo. If the interference cannot be corrected or
eliminated  within such  48-hour  period,  SBCW shall cause any of SBCW's or its
Affiliate's  Communications Equipment or Communications Facility that interferes
with  the  operation  of  TowerCo's  or  any  Space  Subtenant's  Communications
Facility's  authorized frequency spectrum or signal strength,  to be immediately
powered down or turned off, with the right to turn such interfering equipment or
facility back up or on only during  off-peak  hours  specified by TowerCo or the
affected  Space  Subtenant  in  order to  determine  whether  such  interference
continues or has been eliminated;  provided,  that if any interference continues
at the time the  interfering  equipment  is  powered  down,  the  Communications
Equipment that  interferes  with the operation of TowerCo or any Space Subtenant
Communication  Facility  shall be turned  off. If SBCW or its  Affiliate  cannot
correct or  eliminate,  to the  satisfaction  of TowerCo or the  affected  Space
Subtenant,  such  interference  within  twenty  (20) days of  receipt of written
notice from  TowerCo,  SBCW or its Affiliate  shall cease the  operations of the
objectionable  Communications  Equipment  and stop  providing  services from the
applicable  Communications  Facility or the Subleased Property of the applicable
Site  in  its  entirety   (including  the  Tower  and  Improvements)  until  the
interference problems are resolved.

(g)  Notwithstanding  anything in this Section 14 to the contrary,  in the event
any interference occurs in respect of a Site and the source of such interference
is not  readily  determinable,  it  shall be  assumed  that  TowerCo  or a Space
Subtenant  and not SBCW or its  Affiliates  is the  cause of such  interference,
TowerCo  shall be  responsible  for the  performance  of its  obligations  under
Section 14(c) in respect of such interference, and SBCW shall be relieved of any
obligations  under  Section  14(e) in respect of such  interference,  unless and
until  it is  determined  that  SBCW  or its  Affiliates  is the  cause  of such
interference.

SECTION 15.       Taxes and Assessments.

(a)  TowerCo  shall pay all  Taxes and  Assessments  with  respect  to each Site
applicable to all periods  occurring after the Site  Commencement  Date for such
Site on or prior  to the  date on which  such  Taxes  and  Assessments  are due;
provided that TowerCo  shall have the right to contest,  by proper legal actions
or  proceedings  in good faith any Taxes and  Assessments  for which  TowerCo is
responsible  hereunder and, if permitted under  applicable law, to defer payment
of such Taxes and Assessments pending the outcome of such contest, provided that
at the time of the commencement of any such action or proceeding, and during the
pendency thereof,  (i) no event of default by TowerCo shall have occurred and be
continuing,  (ii) such contest  operates to suspend  collection of the contested
Taxes and  Assessments or claims and is maintained  and prosecuted  continuously
with  diligence,  (iii) the Site would not be subject to  forfeiture  or loss by
reason of the  institution or prosecution of such contest,  (iv) TowerCo,  shall
promptly pay or discharge such Taxes and Assessments and all additional charges,

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<PAGE>

interest,  penalties and expenses if such contest is terminated or  discontinued
adversely to TowerCo,  and (v) TowerCo shall keep Sublessor  reasonably informed
of any such  contest.  Each  Sublessor  shall  promptly  forward to TowerCo upon
receipt  copies of all bills,  invoices,  statements,  assessments  and  similar
notices  regarding Taxes and Assessments.  TowerCo shall receive any refunds for
Taxes and Assessments paid by TowerCo pursuant to this Sublease. Notwithstanding
the  foregoing,  TowerCo shall not be required to pay any Taxes and  Assessments
payable with respect to a Leased Site if the  applicable  Ground Lease  provides
that the Ground  Lessor is  responsible  therefor  without  pass-through  to the
ground  lessee  and  the  Ground  Lessor   actually  pays  any  such  Taxes  and
Assessments.  If the Ground  Lessor does not pay any such Taxes and  Assessments
and either Party becomes  aware of it, the Parties  will, at TowerCo's  expense,
cooperate and use commercially  reasonable efforts to cause the Ground Lessor to
pay such Taxes and Assessments.

(b)  Proration  of Taxes and  Assessments.  In the years that  include  the Site
Commencement  Date or the Site  Expiration Date of this Sublease as to any Site,
any  Taxes and  Assessments  (determined  without  regard to the Term) for which
TowerCo is responsible to any SBCW Affiliate under this section of this Sublease
and that are  calculated  or  assessed  on the  basis  of a time  period  (e.g.,
property  Taxes  assessed  annually)  shall be prorated  proportionately  by the
number of days in each such  period  during the time period of  assessment  that
includes the Site Commencement Date or Site Expiration Date, as the case may be.
TowerCo's  obligations under this Section 15 to SBCW Affiliates shall be limited
to that proportionate  amount of such Taxes and Assessments  attributable to the
period during which this Sublease is in effect with respect to such Site.

SECTION 16.       Utilities.

         TowerCo shall make all  arrangements  for, and thereafter shall pay, or
cause to be paid,  when due all  charges for  connection  of all  utilities  and
services  to such  Site  for the use of  Space  Subtenants,  including,  but not
limited to, electricity, telephone, power, and other utility used or consumed by
Space  Subtenants of such Site. As among SBCW (together with its Affiliates) and
all new Space  Subtenants,  TowerCo shall cause utility charges to be separately
metered,  and SBCW or its  Affiliate  (as the case may be)  shall be  separately
responsible for its own utility charges.

SECTION 17.       Governmental Permits.

(a) In addition to and not in limitation  of the  provisions of Section 11(a) of
this  Sublease,  TowerCo  shall,  at its own cost and expense,  provide SBCW all
necessary and appropriate  information  requested by SBCW for SBCW to obtain and
maintain  in effect all  certificates,  permits,  licenses  and other  approvals
relating  to FAA or FCC  regulations  and  TowerCo  shall,  at its own  cost and
expense, obtain and maintain in effect all certificates,  permits,  licenses and
other  approvals  (other  than those  relating to FCC and FAA  regulations)  and
comply with all Laws,  required or imposed by  governmental  authorities  (other
than those relating to FCC or FAA regulations), in connection with the operation
and  maintenance  of the Subleased  Property of each Site  (including  Tower and
Improvements  thereon).  As part of TowerCo's obligation to provide information,
TowerCo  shall  provide  SBCW  access  to data,  including  resistance  changes,
necessary to monitor the lighting systems at each Site.

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<PAGE>

(b) TowerCo shall  cooperate  with SBCW in SBCW's efforts to obtain and maintain
in effect any certificates,  permits, licenses and other approvals and to comply
with any Laws  required  or imposed on SBCW or its  Affiliates  by  governmental
authorities, applicable to the Reserved Space of each Site.

(c) SBCW shall,  at its own cost and expense,  obtain and maintain in effect all
certificates,  permits,  licenses and other  approvals and comply with all Laws,
required or imposed by  governmental  authorities,  in connection with operation
and  maintenance  of  the  Reserved  Space  of  each  Site,  including,  without
limitation, FCC regulations.  With the cooperation of TowerCo set out in Section
17(a)  hereof,  SBCW,  at  TowerCo's  cost and  expense,  also shall  obtain and
maintain in effect all  certificates,  permits,  licenses,  and other  approvals
required or imposed by  governmental  authorities in connection  with FAA or FCC
regulations  relating to the operation and maintenance of the Subleased Property
of each Site  (including  the  Towers  and  Improvements  thereon).  The cost of
obtaining  and  maintaining  such  FCC or FAA  permits  or  approvals  shall  be
reimbursed to SBCW in accordance with Section 17(f).

(d) SBCW shall cooperate with TowerCo in TowerCo's  efforts to provide  required
information  and to comply  with all Laws  required  or imposed by  governmental
authorities, applicable to each Site.

(e)  SBCW  shall  be  afforded  access  to  all  of  TowerCo's  records,  books,
correspondence,  instructions,  blueprints, permit files, memorandum and similar
data  relating to the  compliance of the Towers with all  applicable  Laws or if
SBCW otherwise provides reasonable  justification  therefore,  except privileged
documents or where  disclosure is prohibited by law.  TowerCo shall also provide
SBCW with an electronic  interface or other real time access to TowerCo's  Tower
administration  database  which  shall  enable  access to  detailed  information
concerning  collocations.  Such  information  shall be open for  inspection  and
copying  upon  reasonable  notice  by  SBCW,  at its  cost,  and its  authorized
representatives  at reasonable hours at TowerCo's  principal office and shall be
retained by TowerCo for period of three (3) years after the  expiration  of this
Sublease.

(f) The cost of SBCW's  obtaining  and  maintaining  all FCC and FAA permits and
approvals  relating to the operation and  maintenance of the Subleased Space and
TowerCo Work shall be borne by TowerCo in accordance with Sections  12(b)(i) and
17(c) (the "Reimbursable  Costs").  The Reimbursable Costs shall be based on (i)
actual reasonable out-of-pocket costs and (ii) SBCW's reasonable costs allocable
to  obtaining  and  maintaining  FCC and FAA  permits and  approvals,  including
personnel and office related costs  allocated  based on the amount of time spent
by such  personnel in obtaining  and  maintaining  such permits and approvals as
compared to such personnel's time spent on other matters.  SBCW and TowerCo have
agreed on an estimate of Reimbursable Costs (the "Estimated  Cost").  SBCW shall
periodically  provide TowerCo with an invoice for Estimated Costs,  which amount
shall be paid by TowerCo  to SBCW  within ten (10)  business  days of  TowerCo's
receipt of such invoice. In addition, SBCW shall use its commercially reasonable
efforts to deliver to TowerCo  within thirty (30) days following the end of each
calendar year, a statement  setting forth the actual costs (based on the formula
provided in  subclauses  (i) and (ii) above)  incurred by SBCW in obtaining  and
maintaining such FCC and FAA permits and approvals.  If actual costs are greater
than Estimated  Costs,  TowerCo shall  reimburse SBCW the difference  within ten
(10) Business Days of receipt of such end of the year statement. If Estimated

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<PAGE>

Costs are  greater  than  actual  costs,  SBCW shall  reimburse  TowerCo for the
difference  at the time such end of the year  statement is delivered to TowerCo.
For a period of sixty  (60) days  after  receipt  by  TowerCo  of SBCW's  annual
statement  setting forth actual costs,  TowerCo shall have the right, at its own
expense,  to  perform an audit of such  actual  costs by  requesting  reasonable
evidence  of the actual  costs and  expenses  incurred or  allocated  by SBCW to
Reimbursable   Costs  for  the  period  in  question.   In   addition,   if  the
organizational  structure of SBCW's FCC and FAA compliance department materially
changes or the cost of obtaining and maintaining FCC and FAA permits  materially
changes, the parties agree to use good faith efforts to negotiate  modifications
to  the  Reimbursable  Costs  agreement   described  above  and  the  respective
responsibilities of the parties with respect to FAA and FCC compliance work.

SECTION 18.       No Liens.

(a) TowerCo  shall not create or permit any Lien (other  than  Permitted  Liens)
against any Site, or any part thereof.  If any Lien (other than Permitted Liens)
is filed against all or any part of any Site, TowerCo shall cause the same to be
discharged by payment,  satisfaction  or posting of bond within thirty (30) days
after TowerCo has obtained knowledge of such Lien. If TowerCo fails to cause any
Lien (other than Permitted  Liens) to be discharged  within the permitted  time,
SBCW may cause it to be discharged  and may pay the amount of such Lien in order
to do so. If SBCW  makes any such  payment,  all  amounts  paid by SBCW shall be
payable by TowerCo to SBCW upon  demand.  "Permitted  Liens"  means,  as to each
Site: (i) Permitted Subleasehold Mortgages of TowerCo's subleasehold interest in
such Site and Permitted  Subleasehold  Pledges;  (ii) Space Subtenants' sublease
interests in the Subleased Space of such Site;  (iii) Liens existing on the Site
Commencement  Date for such Site;  (iv) Liens arising by, through or under SBCW,
its Affiliates or any other occupant of the Reserved Space;  (v) Liens for taxes
not yet due and payable or which are being contested in good faith in accordance
with the  provisions  of Section 15; (vi) Liens  created by the  underlying  fee
owners  of  the  Leased  Sites;  (vii)  easements,  rights  of way  and  similar
encumbrances  provided  that such  encumbrances  do not have a material  adverse
effect  on the use or  enjoyment  of such  Site or the  Reserved  Space  and are
approved by SBCW, such approval not to be unreasonably  withheld or delayed; and
(viii)  mechanics'  liens for  amounts  which are not more than thirty (30) days
overdue.

(b) TowerCo may, at TowerCo's sole cost and expense,  in its own name and on its
own  behalf  or in the name of and on behalf of the  Sublessor,  in good  faith,
contest any claim of Lien and, in the event of any such contest, may permit such
claim of Lien so contested to remain unpaid, unsatisfied and undischarged during
the period of such contest and any appeal therefrom; provided, however, that, if
any Site, the Subleased  Property of any Site or any part thereof are subject to
imminent danger of loss or forfeiture by virtue of or by reason of such claim of
Lien,  such claim of Lien shall be  complied  with  forthwith  or TowerCo  shall
deposit with the Sublessor a sum of money  reasonably  required by the Sublessor
as security to protect the Subleased Property of such Site from any such loss or
forfeiture.  The  Sublessor,  at the sole cost and  expense  of  TowerCo,  shall
cooperate fully with TowerCo in any such contest.

(c) Any Permitted  Subleasehold Mortgage or Permitted  Subleasehold Pledge shall
be subject to each and every term, covenant, condition, agreement,  requirement,
restriction  and provision set forth in this Sublease and subject to all rights,
title and interest of SBCW and each SBCW Affiliate.

                                       35
<PAGE>

(d)  Within  ten (10) days  after the  granting  of any  Permitted  Subleasehold
Mortgage or Permitted Subleasehold Pledge, TowerCo shall deliver to SBCW a true,
correct and fully  executed  copy of all  documents  pertaining  thereto and the
indebtedness  secured  thereby.  Promptly  upon  TowerCo's  receipt of copies of
recorded documents  evidencing the recordation thereof and bearing the recording
information  therefor,  TowerCo  shall  deliver to SBCW a copy of such  recorded
documents.

(e) The  Sublessor  shall  execute  any  necessary  easement or right of way for
utilities for any Site promptly following any request by TowerCo,  provided such
easement  or  right of way does not have an  adverse  effect  on  SBCW's  or its
Affiliate's  use or  enjoyment  of the  Reserved  Space  of such  Site or on the
ownership  by the  Sublessor  of the  Tower  on  such  Site,  including  without
limitation the operation of SBCW's Communications Equipment thereon.

(f) Other than as  provided  in Section  21, SBCW shall not create or permit any
Lien against the Subleased  Property of any Site,  or any part  thereof.  If any
Lien is filed  against  all or any part of the  Subleased  Property of any Site,
SBCW shall cause the same to be discharged by payment,  satisfaction  or posting
of bond within thirty (30) days after demand therefor by TowerCo.  If SBCW fails
to cause any Lien to be discharged within the permitted time,  TowerCo may cause
it to be  discharged  and may pay the  amount of such Lien in order to do so. If
TowerCo makes any such payment,  all amounts paid by TowerCo shall be payable by
SBCW to TowerCo upon demand.  Nothing in this Sublease shall prohibit SBCW or an
SBCW  Affiliate  from  permitting a Lien  against its interest  under the Ground
Lease or Reserved Space of any Site subject to (i) the  restrictions on Transfer
set forth in Section 25 and (ii) SBCW's  obligations  pursuant to Section  35(e)
hereof in the event TowerCo exercises its right to acquire all or portion of the
Sites. Notwithstanding the foregoing, any Lien against SBCW's interest under the
Ground  Lease  shall  only be  permitted  if such Lien is either  subject to and
subordinate to this Sublease and the purchase  option  contained  herein or such
lienholder  executes an NDA  substantially  similar to the NDA  provided  for in
Section 21.

(g) SBCW may,  at SBCW's sole cost and  expense,  in its own name and on its own
behalf or in the name of and on behalf of TowerCo,  in good  faith,  contest any
claim of Lien and,  in the event of any such  contest,  may permit such claim of
Lien so contested to remain  unpaid,  unsatisfied  and  undischarged  during the
period of such contest and any appeal therefrom; provided, however, that, if the
Subleased  Property  of any Site or any part  thereof  are  subject to  imminent
danger of loss or  forfeiture  by virtue of or by reason of such  claim of Lien,
such claim of Lien shall be complied  with  forthwith or SBCW shall deposit with
TowerCo a sum of money  reasonably  required  by TowerCo as  security to protect
TowerCo's  interest in the Subleased Property of such Site from any such loss or
forfeiture. TowerCo, at the sole cost and expense of SBCW, shall cooperate fully
with SBCW in any such contest.

SECTION 19.       Condemnation.

(a) If there occurs a Taking of all or a Substantial  Portion of any Site, other
than a Taking for  temporary  use,  then  either  Party  shall have the right to
terminate  this  Sublease  as to such Site by written  notice to the other Party
within  thirty (30) days of the  occurrence  of such Taking  whereupon  the Term
shall  automatically  expire as to such Site, on the Date of Taking,  as if such
date were the Site Expiration Date as to such Site.

                                       36
<PAGE>

(b) If there  occurs a Taking of less than a  Substantial  Portion  of any Site,
then this Sublease and all duties and obligations of TowerCo under this Sublease
in respect of such Site shall remain  unmodified,  unaffected  and in full force
and effect.  TowerCo shall promptly  proceed to reconstruct,  restore and repair
the  remaining  portion of the  Subleased  Property  of such Site (to the extent
feasible) to a condition substantially equivalent to the condition thereof prior
to the Taking.  TowerCo shall be entitled to apply the Award received by TowerCo
to the  reconstruction,  Restoration and repair of any Subleased Property of any
Site from time to time as such work  progresses.  If the cost of the repair work
exceeds the Award  recovered by TowerCo,  TowerCo  shall pay the excess cost. If
the Award  exceeds the cost of the repair work,  the excess shall be paid to the
Sublessor.

(c) If there  occurs  a  Taking  of any  Subleased  Property  of any Site or any
portion  thereof,  for temporary  use,  then this Sublease  shall remain in full
force and effect as to such Site for the  remainder  of the then  current  term;
provided,  however,  that during such time as TowerCo shall be out of possession
of such  Subleased  Property  by reason of such  Taking,  the  failure  to keep,
observe,  perform,  satisfy and comply with those terms and  conditions  of this
Sublease  compliance with which are  effectively  impractical or impossible as a
result of TowerCo's being out of possession of such Subleased Property shall not
be an event of  default  hereunder.  The  Award  for any such  temporary  Taking
payable  for any  period  prior to the  Site  Expiration  Date  shall be paid to
TowerCo and, for any period thereafter, to the Sublessor.

SECTION 20.       Waiver of Subrogation; Indemnity.

(a) Except as provided in this Sublease,  to the extent  permitted by applicable
Laws,  TowerCo  and SBCW  hereby  waive any and all rights of  recovery,  claim,
action or cause of action against each other, their respective agents,  officers
and employees,  for any loss or damage that may occur to the Subleased  Property
of each  Site,  by reason of fire,  the  elements,  or any other  cause  insured
against,  or  required  to be insured  against,  under the terms of  policies of
insurance maintained,  or required to be maintained,  for the Subleased Property
of such  Site,  by  TowerCo or SBCW (as the case may be) under the terms of this
Sublease, regardless of cause or origin.

(b)  Subject  to the  provisions  of  Section  20(a)  above,  TowerCo  agrees to
indemnify  and to hold each SBCW  Indemnitee  harmless  from any and all Claims,
with respect to bodily injury,  personal  injury or property  damage suffered or
incurred  by such SBCW  Indemnitee  by reason  of, or arising  out of  TowerCo's
sublease or lease,  as the case may be,  operation and  maintenance of each Site
(including the Tower and Improvements thereon),  including,  without limitation:
(i) any  default,  breach,  performance  or  nonperformance  by  TowerCo  of its
respective  obligations  and covenants under this Sublease,  including,  without
limitation,  Sections 12, 14 and 17,  hereof;  (ii) any Claims  against any SBCW
Indemnitee  arising  out of or  resulting  from (x)  TowerCo's  use,  operation,
maintenance or occupancy of any part of the Site or resulting from the condition
of the  Site  or (y)  any  Space  Subtenant's  use,  operation,  maintenance  or
occupancy of its Communications Facility; (iii) any failure of TowerCo to comply
with any  applicable  Laws or with the directives of FCC and FAA that TowerCo is
required to comply with pursuant to this Sublease or under applicable Laws; (iv)
any Claims arising out of or resulting  from TowerCo's or any Space  Subtenant's
acts or omissions or the negligence or  intentional  acts or omissions of any of
their respective agents, employees, engineers, contractors, subcontractors,

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<PAGE>

licensees,  or invitees in or about the Subleased Property of each Site, and (v)
any other provision of this Sublease which provides that TowerCo shall indemnify
and hold  harmless any SBCW  Indemnitee  in respect of the matters  contained in
such  provision.  If any  action  or  proceeding  is  brought  against  any SBCW
Indemnitee  by reason of any such  Claim,  TowerCo  upon  notice  from such SBCW
Indemnitee  covenants  and agrees to defend  such  action or  proceeding  at its
expense.

(c) Subject to the  provisions of Section 20(a) above,  SBCW agrees to indemnify
and to hold  each  TowerCo  Indemnitee  harmless  from any and all  Claims  with
respect  to bodily  injury,  personal  injury or  property  damage  suffered  or
incurred  by TowerCo by reason of, or arising  out of (i) any  default,  breach,
performance or  nonperformance  of SBCW's  obligations  and covenants under this
Sublease;  (ii) any Claims  against  TowerCo  arising out of or  resulting  from
SBCW's  use,  operation,  maintenance  or  occupancy  of  SBCW's  Communications
Equipment  or the  Reserved  Space,  to the extent  TowerCo  is not  responsible
therefor under the terms of this  Sublease,  (iii) SBCW's failure to comply with
any  applicable  Laws  or  with  the  directives  of FCC  and  FAA as to  SBCW's
Communications  Equipment;  (iv) any Claims  against  TowerCo  arising out of or
resulting from any acts or omissions or the negligence or intentional actions or
omissions  of  any  of  SBCW's  agents,   employees,   engineers,   contractors,
subcontractors,  licensees  or  invitees;  and (v) any other  provision  of this
Sublease which provides that SBCW shall  indemnify and hold harmless  TowerCo or
any Affiliate thereof in respect of the matters contained in such provision.  If
any action or proceeding is brought against TowerCo by reason of any such Claim,
SBCW upon  notice  from  TowerCo  covenants  and agrees to defend such action or
proceeding at its expense.

SECTION 21.       Subordination and Attornment.

(a) This Sublease and all rights of TowerCo therein,  and all interest or estate
of TowerCo in the Subleased Property of each Site, or any portion thereof, shall
be subordinate to any and all Mortgages,  which at any time during the Term, may
be placed upon the Subleased  Property,  or any portion thereof,  by SBCW or any
SBCW Affiliate, and to any replacements,  renewals,  amendments,  modifications,
extensions or refinancing  thereof, and to each and every advance made under any
Mortgage;  provided,  however,  that the subordination and attornment  contained
herein  shall not be  effective  unless the  existing  or any  future  Mortgagee
thereunder  shall  execute  and  deliver  an NDA in  favor of  TowerCo,  in form
reasonable  satisfactory  to TowerCo and its lenders  providing  that:  (i) such
Mortgagee  will  at all  times  fully  recognize  TowerCo's  rights  under  this
Sublease,  including the purchase option contained herein, and in the event of a
foreclosure  under any such Mortgage shall not disturb  TowerCo's  possession of
the Subleased  Property and will recognize such purchase  option,  so long as no
event of default shall have occurred and be subsisting hereunder, and so long as
TowerCo shall attorn to the purchaser upon such foreclosure;  and (ii) that upon
Mortgagee  acquiring  title to the  Subleased  Property,  TowerCo  shall  attorn
directly  to such  Mortgagee.  TowerCo  shall  agree  to such  other  terms  and
conditions in the NDA as may be reasonably required by such Mortgagee,  provided
that such terms and conditions do not affect TowerCo's  rights,  nor increase or
alter any of TowerCo's obligations, under this Sublease.

(b) Subject to the provision of Section 21(a), TowerCo shall execute in a timely
manner instruments that may be required to evidence this  subordination  clause,
in respect of the Subleased Property of each Site.

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<PAGE>

(c) The applicable  Sublessor shall enter into a subordination,  non-disturbance
and  attornment  agreement with any Space  Subtenants at such Space  Subtenant's
request.  Such  agreement  shall  be in  form  reasonably  satisfactory  to  the
applicable Sublessor and the applicable Space Subtenant and shall provide, among
other  things,  that  Sublessor  shall  not  terminate  such  Space  Subtenant's
subleasehold  interest in the  applicable  Site by reason of  TowerCo's  default
hereunder or the early  termination of this Sublease due to a default by TowerCo
or  otherwise,  so  long  as  the  Space  Subtenant  is not  in  default  in the
performance of the terms,  provisions and conditions contained in the applicable
sublease beyond notice and grace.

SECTION 22.       Environmental Covenants.

(a) For purposes of this Sublease,  the following terms shall have the following
meanings:  (i) "Hazardous Material" or "Hazardous  Materials" means and includes
petroleum products, flammable explosives, radioactive materials, asbestos or any
material containing asbestos, polychlorinated biphenyls, or any hazardous, toxic
or  dangerous  waste,  substance  or  material  defined  as such or defined as a
hazardous  substance  or any  similar  term,  by, in or for the  purposes of the
Environmental  Laws,  including,  without  limitation  Section 101(14) of CERCLA
(hereinafter  defined);  provided  that the  term  "Hazardous  Materials"  shall
exclude   quantities  of  materials  or  substances   maintained  by  SBCW,  its
Affiliates,  TowerCo and Space  Subtenants on or about any Site (including Tower
and  Improvements  thereon) in the ordinary course of business,  so long as such
materials are maintained in accordance with the applicable  Environmental  Laws:
(ii)  "Release"  shall have the meaning given such term, or any similar term, in
the Environmental Laws, including, without limitation Section 101(22) of CERCLA;
and (iii)  "Environmental  Law" or  "Environmental  Laws"  shall mean any "Super
Fund" or "Super Lien" law, or any other federal,  state or local  statute,  law,
ordinance, code, rule, regulation,  order or decree, regulating,  relating to or
imposing liability or standards of conduct concerning any Hazardous Materials as
may now or at any time hereafter be in effect,  including,  without  limitation,
the  following,  as same may be amended or replaced  from time to time,  and all
regulations  promulgated  thereunder or in connection  therewith:  the Superfund
Amendments  and  Reauthorization   Act  of  1986  ("SARA");   The  Comprehensive
Environmental Response,  Compensation and Liability Act of 1980 ("CERCLA");  The
Clean Air Act ("CAA"); the Clean Water Act ("CWA"); The Toxic Substances Control
Act ("TSCA");  The Solid Waste Disposal Act ("SWDA"), as amended by the Resource
Conversation and Recovery Act ("RCRA");  the Hazardous Materials  Transportation
Act: and the Occupational Safety and Health Act of 1970 ("OSHA").

(b) As to each Site,  SBCW  represents  and warrants to TowerCo  that, as of the
Site Commencement  Date for such Site, (i) to the best of SBCW's  knowledge,  no
portion of the Land of such Site is used for the storage, processing,  treatment
or disposal of  Hazardous  Materials,  except as set forth in any  environmental
report  heretofore  delivered to TowerCo;  (ii) to the best of SBCW's  knowledge
except for such  deminimus  quantities  that would not  trigger a  reporting  or
remediation  obligation  under any  applicable  Environmental  Law, no Hazardous
Materials have been released,  introduced,  spilled,  discharged or disposed of,
nor has there  been a threat  of  release,  introduction,  spill,  discharge  or
disposal  of a  Hazardous  Materials,  on,  in, or under the Land of such  Site,
except as set forth in any environmental report heretofore delivered to TowerCo;
(iii) to the best of SBCW's knowledge, there are no pending Claims,

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<PAGE>

administrative proceedings,  judgments,  declarations, or orders, whether actual
or threatened,  relating to the presence of Hazardous  Materials on, in or under
the Land of such Site;  (iv) to the best of SBCW's  knowledge,  the Land of such
Site is in compliance  with all  applicable  Environmental  Laws; and (v) to the
best of SBCW's  knowledge,  there are no pending or threatened  or  contemplated
condemnation  actions involving all or any portion of the Land of such Site. For
purposes of this Section, "to the best knowledge of," or words of similar import
with reference to SBCW means actual knowledge of the management of SBCW and such
actual  knowledge  will be imputed to the  management  of SBCW if the  Hazardous
Materials were brought to the Site by a SBCW Group Member.

(c) Except for any matters  for which SBCW  assumes  responsibility  pursuant to
this Sublease,  TowerCo covenants and agrees that: (i) TowerCo shall not conduct
or allow to be conducted upon any Site any business operations or activities, or
employ or use a Site, to generate, manufacture, refine, transport, treat, store,
handle, dispose of, transfer, produce, or process Hazardous Materials;  provided
that  TowerCo  shall  have the right to bring,  use and keep and allow any Space
Subtenant to bring and keep on the Subleased Property of each Site in compliance
with all applicable  Laws,  batteries,  generators and associated fuel tanks and
other substances  commonly used in the industry  necessary for the operation and
maintenance  of  each  Site;  (ii)  TowerCo  shall  carry  on its  business  and
operations at each Site in compliance in all respects  with,  and will remain in
compliance with, all applicable  Environmental  Laws and shall require all Space
Subtenants  to do the  same:  (iii)  TowerCo  shall  not  create or permit to be
created  any Lien  against  any Site for the costs of any  response,  removal or
remedial action or clean-up of Hazardous Materials;  (iv) TowerCo shall promptly
conduct and complete all investigations,  studies, sampling and testing, and all
remedial,  removal,  and other  actions  necessary  to clean up and  remove  all
Hazardous  Materials  on, from or  affecting  each Site in  accordance  with all
applicable Environmental Laws; (v) TowerCo shall promptly notify SBCW in writing
if TowerCo receives any notice,  letter,  citation,  order, warning,  complaint,
claim or demand that:  (w) TowerCo or any Space  Subtenant has  violated,  or is
about to violate,  any Environmental  Law, (x) there has been a Release or there
is a threat of Release,  of Hazardous  Materials at or from the applicable Site,
(y) TowerCo or any Space Subtenant may be or is liable, in whole or in part, for
the costs of cleaning up,  remediating,  removing or  responding to a Release of
Hazardous  Materials,  or  (z) a  Site  are  subject  to a  Lien  favor  of  any
governmental  entity for any liability,  cost or damages under any Environmental
Law.

(d) SBCW  covenants and agrees that as to each Site:  (i) SBCW shall not conduct
or  allow  to be  conducted  upon any  Reserved  Space of any Site any  business
operations  or  activities,  or employ or use a Reserved  Space of any Site,  to
generate,  manufacture,  refine,  transport,  treat, store, handle,  dispose of,
transfer, produce, or process Hazardous Materials; provided that SBCW shall have
the right to bring, use and keep on the Reserved Space of any Site in compliance
with all applicable  Laws,  batteries,  generators and associated fuel tanks and
other substances  commonly used in the industry  necessary for the operation and
maintenance  of each  Reserved  Space of any Site;  (ii) SBCW shall carry on its
business and  operations on the Reserved  Space of any Site in compliance in all
respects with, and will remain in compliance with, all applicable  Environmental
Laws;  (iii) SBCW shall not create or permit to be created any Lien  against any
Reserved  Space of any Site for the costs of any  response,  removal or remedial
action or clean-up of Hazardous Materials;  (iv) SBCW shall promptly conduct and
complete all investigations, studies, sampling and testing, and all remedial,

                                       40
<PAGE>

removal,  and other  actions  necessary  to clean up and  remove  all  Hazardous
Materials  on, from or affecting  the Reserved  Space of each Site in accordance
with all applicable  Environmental  Laws; (v) SBCW shall promptly notify TowerCo
in writing if SBCW  receives  any  notice,  letter,  citation,  order,  warning,
complaint,  claim or demand that: (w) SBCW has violated, or is about to violate,
any  Environmental  Law,  (x) there  has been a Release  or there is a threat of
Release,  of Hazardous  Materials at or from the Reserved Space of any Site, (y)
SBCW may be or is liable,  in whole or in part,  for the costs of  cleaning  up,
remediating,  removing or responding to a Release of Hazardous Materials, or (z)
the Reserved Space of any Site is subject to a Lien in favor of any governmental
entity for any  liability,  cost or damages  under any  Environmental  Law. SBCW
further covenants and agrees that the covenants  contained in this Section 22(d)
and the  indemnifications  provided  for in Section  22(f) shall also apply with
respect to any  operations or activities of SBCW  conducted upon space at a Site
other than the Reserved Space.

(e) Unless  resulting  or arising  solely from the  negligent or willful acts or
omissions  of  SBCW  or  SBCW's  Affiliates,   employees,   agents,   engineers,
contractors,  subcontractors,  licensees or invitees,  or from any other acts or
omissions  of such  parties in violation  of this  Sublease,  TowerCo  agrees to
indemnify  and hold SBCW and SBCW  Affiliates  harmless from and against any and
all Claims,  including Claims of any and every kind whatsoever  paid,  incurred,
suffered by, or asserted  against SBCW or SBCW  Affiliates or the Site for, with
respect to, or as a result of the  following:  (i) the  presence in, on, over or
under, or the escape, seepage, leakage, spillage, discharge, emission or Release
on or from the Site of any  Hazardous  Materials  prior to the  applicable  Site
Expiration  Date or  earlier  date of  termination  of this  Sublease;  (ii) the
violation of any  Environmental  Laws relating to or affecting the Site prior to
the  applicable  Site  Expiration  Date or earlier date of  termination  of this
Sublease;  (iii) a Release of any Hazardous Materials or the violation of any of
the  Environmental  Laws prior to the applicable Site Expiration Date or earlier
date of  termination  of this  Sublease in  connection  with any other  property
owned,  operated or used by or on behalf of TowerCo,  which violation or Release
gives or may give rise to any rights whatsoever in any Party with respect to the
Site  by  virtue  of  any  of the  Environmental  Laws;  (iv)  any  warranty  or
representation  made by TowerCo in this Section 22 is or becomes false or untrue
in any material  respect;  or (v) the  violation or breach of, or the failure of
TowerCo to fully and completely keep, observe, satisfy, perform and comply with,
any agreement, term, covenant, condition, requirement,  provision or restriction
of this Section 22.

(f) Unless  resulting or arising from the negligent or willful acts or omissions
of   TowerCo   or   TowerCo's   employees,   agents,   engineers,   contractors,
subcontractors,  licensees or  invitees,  or from any other acts or omissions of
such parties in violation of this  Sublease,  SBCW agrees to indemnify  and hold
TowerCo  harmless from and against any and all Claims,  including  Claims of any
and every kind  whatsoever  paid,  incurred,  suffered  by, or asserted  against
TowerCo or the Reserved  Space of any Site for,  with respect to, or as a result
of the  following:  (i) the  presence  in,  on,  over or under,  or the  escape,
seepage,  leakage,  spillage,  discharge,  emission  or  Release  on or from the
Reserved  Space of any Site of any Hazardous  Materials  prior to the applicable
Site Expiration  Date or earlier date of termination of this Sublease;  (ii) the
violation of any Environmental  Laws relating to or affecting the Reserved Space
of any Site prior to the  applicable  Site  Expiration  Date or earlier  date of
termination of this Sublease; (iii) a Release of any Hazardous Materials or the

                                       41
<PAGE>

violation  of  any of the  Environmental  Laws  prior  to  the  applicable  Site
Expiration  Date or earlier date of  termination  of this Sublease in connection
with any other property owned,  operated or used by or on behalf of SBCW,  which
violation  or  Release  gives or may give rise to any rights  whatsoever  in any
Party  with  respect to the  Reserved  Space of any Site by virtue of any of the
Environmental  Laws;  (iv) any warranty or  representation  made by SBCW in this
Section 22 is or becomes  false or untrue in any  material  respect;  or (v) the
violation  or breach of, or the  failure of SBCW to fully and  completely  keep,
observe,  satisfy,  perform and comply  with,  any  agreement,  term,  covenant,
condition, requirement, provision or restriction of this Section 22.

(g) Notwithstanding  anything to the contrary in this Sublease, in the event any
Claim of a type giving rise to  indemnification  obligations under Section 22 is
asserted against a TowerCo  Indemnitee and it cannot be readily  determined that
it was the act or  omission  of SBCW or its  Affiliate  that  gave  rise to such
Claim,  it shall be assumed for all purposes  hereof that it was  TowerCo's or a
Space  Subtenant's act or omission,  TowerCo shall indemnify SBCW Indemnitees in
respect  of such  Claim  pursuant  to  Section  22(e),  and SBCW  shall  have no
obligation  or  liability  to any  TowerCo  Indemnitee  in respect of such Claim
unless and until it is finally  determined that SBCW's or its Affiliate's act or
omission  gave rise to such  Claim.  The  provisions  of this  Section  22 shall
survive the  applicable  Site  Expiration  Date or earlier  termination  of this
Sublease.  The foregoing provisions of this Section 22 are not intended to limit
the generality of any of the other provisions of this Sublease.

SECTION 23.       Insurance.

(a) SBCW shall procure, and shall maintain in full force and effect at all times
during the Term as to the Sites,  the following  types of insurance with respect
to the Reserved  Space of the Sites,  and, if  applicable,  any of the Available
Space subleased to SBCW or its Affiliates  pursuant to Section 24(d),  paying as
the same become due all premiums therefor:

(i)      commercial  general public  liability  insurance  insuring  against all
         liability of SBCW and SBCW's officers, employees, agents, licensees and
         invitees  arising out of, by reason of or in connection with the use or
         occupancy of the Reserved Space of the Sites and, if applicable, any of
         the Available  Space  subleased to SBCW or its  Affiliates  pursuant to
         Section  24(d),  if any, in an amount of not less than  $1,000,000  for
         bodily injury or property damage as a result of one occurrence, and not
         less  than  $2,000,000  for  bodily  injury or  property  damage in the
         aggregate;

(ii) umbrella or excess liability insurance with limits not less than $5,000,000
per occurrence and in the aggregate: and

(iii)  workers'  compensation  insurance  covering all  employees of SBCW or its
Affiliates to the extent required by any Laws.

(b) SBCW  shall  pay all  premiums  for the  insurance  coverage  which  SBCW is
required to procure and maintain under this Sublease. Each insurance policy: (i)
shall name TowerCo as an  additional  insured;  provided  that such  requirement
shall only apply to liability  policy and shall have no  application to workers'
compensation policies; and (ii) shall provide that the policy cannot be canceled

                                       42
<PAGE>

as to TowerCo  except after the insurer  endeavors  to give TowerCo  thirty (30)
days' written  notice of  cancellation.  TowerCo agrees that SBCW may, at SBCW's
option and  election  self insure with  respect to all or a portion of the risks
required to be insured  against by SBCW under this Section 23. If SBCW elects to
be  covered  by and  participate  in its  self  insurance  and  risk  management
programs,  SBCW shall notify TowerCo of such election.  From time to time,  upon
reasonable  request by TowerCo,  SBCW shall  furnish to TowerCo the  information
concerning  its risk  management  and self  insurance  policies  and programs in
effect at the time of such request.

(c) For each Site,  TowerCo shall procure,  and shall maintain in full force and
effect at all times during the Term as to the  applicable  Site,  the  following
types  of  insurance  with  respect  to  each  Site,  including  the  Tower  and
Improvements thereon, paying as the same become due all premiums therefor:

(i)      commercial  general public  liability  insurance  insuring  against all
         liability  of  TowerCo  and  TowerCo's  officers,   employees,  agents,
         licensees  and invitees  arising out of, by reason of or in  connection
         with the use,  occupancy  or  maintenance  of each  Subleased  Property
         (including Tower and the  Improvements),  in an amount of not less than
         $1,000,000  for bodily injury or property  damage or as a result of one
         occurrence,  and not less than $2,000,000 for bodily injury or property
         damage in the aggregate.

(ii)     umbrella  or  excess  liability  insurance  with  limits  not less than
         $5,000,000 per occurrence and in the aggregate; and

(iii)    Insurance in an amount not less than full replacement cost of the Tower
         and  Improvements  of each Site,  against  direct and indirect  loss or
         damage by fire and all other  casualties  and risks  covered under "All
         Risk" insurance; and

(iv) workers'  compensation  insurance  covering all employees of TowerCo or its
Affiliates to the extent required by any Laws.

(d) TowerCo shall pay all premiums for the insurance  coverage  which TowerCo is
required to procure and maintain under this Sublease.  Each insurance policy (i)
shall name SBCW and the applicable  Sublessor as additional  insureds;  provided
that such  requirement  shall only apply to  liability  policy and shall have no
application to workers' compensation  policies;  and (ii) shall provide that the
policy cannot be canceled as to SBCW and the applicable  Sublessor  except after
the insurer gives SBCW ten (10) days' written notice of cancellation. If TowerCo
elects  to be  covered  by  and  participate  in its  self  insurance  and  risk
management  programs,  TowerCo shall notify SBCW of such election.  From time to
time,  upon  reasonable  request  by SBCW,  TowerCo  shall  furnish  to SBCW the
information  concerning  its risk  management  and self  insurance  policies and
programs in effect at the time of such request.

(e) All policy  amounts  set forth in this  Section 23 shall be reset every five
(5) years  during the Term to increase by an amount not less than the CPI Change
over the five (5) year period, except to the extent the Parties otherwise agree.

                                       43
<PAGE>

(f) TowerCo and SBCW shall not, on their own  initiative  or pursuant to request
or  requirement  of any Space  Subtenants  or other  Person,  take out  separate
insurance  concurrent  in form or  contributing  in the  event of loss with that
required in Section 23(c), unless the other Party thereto is named therein as an
additional  insured.  The Parties agree that, all policies of insurance required
by this Section 23 may contain such loss retention  provisions or deductibles as
is reasonable in light of financial conditions of the Parties from time to time.
In addition  and  notwithstanding  anything to the  contrary  contained  in this
Section  23(c),  TowerCo  shall be  permitted to satisfy its  obligations  under
Section  (c)(iii)  hereof by  self-insuring  such risk  coverage  to the  extent
reasonable  in light of the  financial  condition  of TowerCo from time to time.
TowerCo and SBCW shall  immediately  notify the other Party hereto  whenever any
such  separate  insurance  is  taken  out and  shall  deliver  to SBCW  original
certificates evidencing the same.

(g) As to the Subleased  Property and Reserved  Space of each Site, all policies
of  insurance  shall  be  written  on  companies  rated  A:VII  by AM  Best or a
comparable  rating  and  licensed  in the  State  where  such  Site is  located.
Certificates  evidencing  insurance shall be in a form reasonably  acceptable to
the recipient Party,  shall be delivered to such Party upon  commencement of the
Term and prior to expiration of such policy,  new  certificates  evidencing such
insurance, shall be delivered to such Party not less than twenty (20) days prior
to the  expiration of the then current  policy term.  The Parties agree that all
policies  of  insurance  required  by this  Section  23 may  contain  such  loss
retention  provisions  or  deductibles  as is  reasonable  in light of financial
conditions of the Parties.

(h) Nothing in this  Section 23 shall  prevent  SBCW or TowerCo  from  obtaining
insurance of the kind and in the amount provided for under this Section 23 under
a blanket insurance policy or policies (evidence thereof reasonably satisfactory
to the other Party shall be delivered to the other Party by the insuring  Party)
which may cover other properties owned or operated by the insuring Party as well
as the Subleased Property or the Available Space;  provided,  however,  that any
such policy of blanket  insurance  shall: (i) specify the amounts thereof to the
extent such  amounts are used to meet the initial  limits  required  pursuant to
this Section 23; and (ii) provide that such policies of blanket insurance shall,
as respects the Subleased  Property or Reserved Space of each Site,  contain the
various  provisions  required  of  such an  insurance  policy  by the  foregoing
provisions of this Section 23.

SECTION 24.       Right of Substitution; Right of First Refusal.

(a)  Notwithstanding  anything to the contrary contained herein, SBCW shall have
the right (for the  benefit of itself or any SBCW  Affiliate)  to modify  and/or
replace,  at SBCW's expense,  its Communications  Equipment at any Site provided
said replacement  Communications  Equipment does not increase the weight or sail
area of SBCW's Communications  Equipment (excluding the microwave dishes) on the
Tower as of the date hereof by more than ten percent  (10%) and  otherwise  does
not cause overall Tower capacity to be exceeded.  SBCW also shall have the right
to make any  Alterations  to the Site  that it  reasonably  deems  necessary  to
increase the capacity of or otherwise augment,  strengthen or enhance a Tower (a
"Sublessor  Alteration").  Except with respect to replacement or substitution of
identical or  substantially  identical  equipment in the  identical  space,  the
following provisions shall apply with respect to any modification, expansion,

                                       44
<PAGE>

replacement, addition or relocation of Communications Equipment by SBCW (in each
case, an "SBCW Alteration") and any Sublessor Alteration under this Sublease.

(i) Prior to commencing any such SBCW Alteration or Sublessor  Alteration,  SBCW
shall  obtain   TowerCo's   written   approval  (which  approval  shall  not  be
unreasonably withheld,  conditioned or delayed, so long as such modifications or
replacements  do not violate the  applicable  provisions  of this  Sublease)  of
detailed  plans and  specifications  accurately  describing  the  proposed  SBCW
Alteration or Sublessor  Alteration.  TowerCo shall either approve or disapprove
such plans and  specifications  in  writing  within  ten (10)  business  days of
TowerCo's receipt of such plans and  specifications  failing which TowerCo shall
be deemed to have approved SBCW's' proposed plans and specifications.

(ii) SBCW agrees to comply with the reasonable directions and requirements which
TowerCo,  in its good  faith  discretion,  may from  time to time  establish  in
connection  with such  modifications,  expansions,  replacements,  additions and
relocations  or Sublessor  Alterations,  as the case may be,  provided that such
directions  and  requirements  do not (i)  unreasonably  interfere  with  SBCW's
ordinary  course of business or  operations,  or (ii)  derogate or diminish  any
rights of SBCW or any SBCW Affiliate under this Sublease.  Such requirements may
include,  at  TowerCo's  request,  the  preparation,  at  SBCW's  cost  and by a
professional  engineer  licensed  in the state in which the Site is located  and
reasonably  satisfactory to TowerCo,  of a structural analysis which details the
effect of the SBCW Alteration on the Tower or the Sublessor  Alteration,  as the
case may be and TowerCo's operations.

(b)  Notwithstanding  anything to the contrary  contained  herein, if during the
Term,  there is any Available Space in respect of the Subleased  Property of any
Site, then SBCW shall have the Right of Substitution  (for the benefit of itself
or any SBCW  Affiliate) as to such Available  Space.  The Right of  Substitution
pursuant to this Section  24(b) may be  exercised by SBCW at any time,  and from
time to time,  without limit,  upon written notice to TowerCo,  provided that no
such  relocation  shall impair the  structural  integrity of the Tower.  If SBCW
elects to exercise  its Right of  Substitution,  then,  upon  completion  of the
relocation of the Communications Equipment of SBCW or its Affiliate on the Tower
and  Improvements  thereon,  the  previously  existing  Reserved  Space  of  the
applicable  Site shall  automatically  be released by SBCW or its  Affiliate and
become a part of the  Subleased  Property of such Site,  subject to the terms of
this Sublease, and concurrently  therewith,  the Available Space on such Site to
which the  Communications  Equipment of SBCW or its Affiliate has been relocated
shall  automatically  become  and  constitute  the  Reserved  Space of such Site
subject to Section 5. The terms of this Section  24(b) shall be  self-operative,
and no further  instrument  shall be  required  to  evidence  any  Substitution;
provided,  however, that upon the request of either SBCW or TowerCo, the Parties
shall promptly execute such instruments as may be reasonably required to further
evidence such Substitution, including without limitation an amendment to Exhibit
A or the applicable Site Designation Supplement. SBCW or its Affiliate shall, at
such Person's cost and expense,  complete the  relocation of its  Communications
Equipment  and return the  previously  existing  Reserved  Space to its original
condition, ordinary wear and tear excepted.

                                       45
<PAGE>

(c)  Notwithstanding  anything to the contrary  contained  herein, if during the
Term,  TowerCo intends to sublease any Available Space of the Subleased Property
of any Site to a  potential  Space  Subtenant,  TowerCo  shall  notify  SBCW and
Sublessor  by sending a copy of any  letter-offer,  letter of  intent,  or other
correspondence with the potential Space Subtenant together with a summary of the
economic terms of the proposed  sublease as contained in such  documents,  which
economic  terms  shall  include at least the number  and  location  of all Sites
subject to the proposed  lease or sublease,  the number,  type,  and location of
each antenna or other equipment on each Tower, the rent payable for such antenna
or other equipment on the Tower (including any escalation  provisions),  and the
term of each Space Subtenant sublease and any renewals thereof, which term in no
event shall bind Sublessor to a term  (including  renewals) which extends beyond
the Site Expiration  Outside Date of the Site in question unless Sublessor shall
have  consented  to  such  extended  term in  writing,  such  consent  not to be
unreasonably  withheld or delayed (the "Economic Offer").  SBCW may, in its sole
discretion,  by providing written notice thereof to TowerCo within ten (10) days
after  receipt of the  Economic  Offer from  TowerCo (x)  exercise  its Right of
Substitution  pursuant to Section 24(b) in respect of such Available  Space,  or
(y)  exercise  the Right of First  Refusal in respect  of such  Available  Space
pursuant to Sections  24(e) and (f), or (z)  exercise  both,  if with respect to
multiple  Sites.  If TowerCo  intends to  sublease  Available  Space at multiple
Sites,  SBCW shall not be entitled to exercise  either its Right of Substitution
and/or  its  Right  of First  Refusal  as to any  Available  Space  unless  SBCW
exercises  such Right in respect of a minimum of the greater of (i) five percent
(5%) or (ii) two (2) of the  total  number  of Sites  that  TowerCo  intends  to
sublease.

(d) If SBCW exercises the Right of Substitution as to any Available Space,  then
such  Available  Space shall  become  "Reserved  Space" for all purposes of this
Sublease and be subject to the  provisions  of Section 5. If SBCW  exercises the
Right of First Refusal as to such Available  Space,  then TowerCo shall sublease
the Available Space to SBCW (or its designated  Affiliate) for the sublease term
set forth in the applicable  Economic  Offer.  For the first three hundred (300)
times that SBCW  exercises its Right of First  Refusal  pursuant to this Section
24,  the rent  for such  space  shall  be  equal to the  lesser  of (i) the rent
provided for in the Economic Offer or (ii) an amount of rent that bears the same
proportion to the SBCW  Leaseback  Charge charged with respect to the Site(s) at
which such  Available  Space is located as the  Available  Space with respect to
which SBCW  exercises the Right of First Refusal bears to the Reserved  Space of
such Site(s). With respect to any exercise by SBCW of its Right of First Refusal
after the first three hundred  (300) times,  the rent for any  additional  space
leased  pursuant  to such  exercise of the Right of First  Refusal  shall be the
amount specified in the Economic Offer.  SBCW (or its designated  Affiliate) and
TowerCo shall execute a sublease agreement in the form substantially  similar to
the BTS Sublease  (as defined in the  Build-to-Suit  Agreement),  as modified to
reflect the rental rate as herein above  provided  for and the sublease  term in
the applicable  Economic  Offer,  or in any other form acceptable to TowerCo and
SBCW  and,  SBCW  shall,  for all  purposes  of this  Sublease,  become  a Space
Subtenant of such Available Space at the rate prescribed above.

(e) If SBCW fails to notify  TowerCo as to its election to exercise its Right of
Substitution  or its Right of First  Refusal under  Section  24(c),  then SBCW's
options  referred to in Section 24(c) with respect to such Available Space shall
expire and TowerCo  shall be entitled to sublease  such  Available  Space to the
potential  Space  Subtenant  within 90 days after SBCW's receipt of the Economic
Offer (which ninety (90) day period shall be extended so long as TowerCo is

                                       46
<PAGE>

diligently  endeavoring  to  conclude  such  sublease)  upon,  in  all  material
respects, the terms and conditions contained in the applicable Economic Offer.

(f) If TowerCo  subleases any Available Space of any Site to the potential Space
Subtenant as provided above,  TowerCo shall promptly  provide SBCW a copy of the
final definitive sublease with the Space Subtenant (the "Final  Agreement").  If
the  economic  terms  of the  Final  Agreement  are not the same or  better  for
TowerCo,  in all material  respects,  than those of the Economic Offer, then, in
addition to any other  remedies  SBCW may have,  SBCW may require  that the SBCW
Leaseback  Charge  for the Site in  question  and all  other  economic  terms be
reduced to and conformed with those of the Final Agreement.

(g) If such  Available  Space has not been so subleased to such Space  Subtenant
within 90 days after  SBCW's  receipt of the  applicable  Economic  Offer (which
ninety  (90) day period  shall be  extended  so long as  TowerCo  is  diligently
endeavoring to conclude such sublease),  then the restrictions  provided in this
Section 24 shall again apply with respect to such Available  Space,  and TowerCo
shall have no right to sublease any such Available  Space without again offering
such Available  Space to SBCW in accordance  with the provisions of this Section
24.

SECTION 25.       Assignment and Subletting.

(a)  Without  the prior  written  consent of SBCW,  TowerCo  may not assign this
Sublease or any of  TowerCo's  rights  hereunder in whole or in part except that
(A) TowerCo may assign all of its rights  under this  Sublease,  without  SBCW's
consent,  to any parent,  subsidiary  or Affiliate  of TowerCo;  (B) TowerCo may
sublease  Available Space as provided in Section 24 hereof; and (C) TowerCo may,
with SBCW's consent not to be unreasonably  withheld (provided that such consent
will not be  required in the case of a  transaction  described  in Clause  (A)),
assign this  Sublease in its  entirety to a successor  corporation  or entity to
TowerCo by way of merger, consolidation or other reorganization or to any Person
acquiring all or  substantially  all of TowerCo's  assets;  provided that in the
case of an  assignment  under  Subsection  (A) such  assignee  (i) is not a SBCW
Competitor and (ii) assumes all of TowerCo's obligations  hereunder;  and in the
case of an  assignment  under  Subsection  (C) such  assignee (i) is a Permitted
TowerCo  Transferee,  (ii) is not a SBCW  Competitor  and (iii)  assumes  all of
TowerCo's  obligations  hereunder;  provided  further  that  TowerCo  may make a
partial assignment of this Sublease upon the prior written consent of SBCW to be
provided in its sole and  absolute  discretion.  Upon any  permitted  assignment
under (A) or (C) , TowerCo  shall be released  from its  obligations  under this
Sublease  from  and  after  the  date of such  assignment.  Upon  any  permitted
assignment under  Subsection (C) above (other than to any parent,  subsidiary or
Affiliate of TowerCo),  TowerCo Parent shall, with SBCW's written consent not to
be unreasonably  withheld,  be released from its obligations under this Sublease
from and  after  the date of such  assignment.  Notwithstanding  the  foregoing,
TowerCo may enter into Permitted Subleasehold Pledges and Permitted Subleasehold
Mortgages,  in which case the Permitted  Subleasehold  Collateral  Assignee with
respect  thereto  shall  have the  right to  exercise  remedies  under  any such
mortgage,  pledge,  hypothecation  or  other  collateral  transfer  in a  manner
consistent with the provisions of this and every other agreement between TowerCo
and SBCW made in connection with this transaction.  TowerCo acknowledges that it
shall not be  permitted  to enter into a Permitted  Subleasehold  Mortgage  with
respect to all or any  portion  of a Site  prior to the  Closing of such Site in
accordance with Section 4.1 of the Agreement to Sublease.

                                       47
<PAGE>

(b) SBCW and each Sublessor Entity shall have the unrestricted  right during the
Term,  subject to any required  consent of any Ground Lessor,  to sell,  convey,
transfer,  assign or  otherwise  dispose (but not to sublease) of SBCW's or such
Sublessor  Entity's  interest  in and to any Site  (including  SBCW's  or a SBCW
Affiliate's interest in and to the Subleased Property of such Site), in whole or
in part (a "Transfer") to: (i) a SBCW Affiliate; (ii) a Permitted Transferee; or
(iii) any other Person (a "Non-Qualifying Transferee");  provided, however, that
with respect to subsections (ii) and (iii) above, neither SBCW or such Sublessor
Entity may assign its interest in the Reserved  Space except in connection  with
the sale or other transfer of all or a portion of SBCW's wireless  business on a
Site by Site basis,  and provided  further that SBCW may not assign its interest
in the Reserved Space without  transferring the corresponding  Ground Lease, and
vice  versa.  In the  event of any  Transfer  by SBCW or a SBCW  Affiliate  to a
Non-Qualifying  Transferee,  SBCW  shall  not be  relieved  of  its  obligations
hereunder.  In the event of any other Transfer by SBCW or a SBCW Affiliate,  all
obligations  under this Sublease of the Person  effecting  such  Transfer  shall
cease and terminate  with respect to the Site in question and TowerCo shall look
only and solely to the Person to whom SBCW's or such SBCW  Affiliate's  interest
in and to such Site (including  SBCW's or such SBCW Affiliate's  interest in and
to the Subleased  Property  thereof or any portion  thereof) (a "Transferee") is
Transferred  for  performance  of all of SBCW's or such  Affiliate's  duties and
obligations  under this  Sublease with respect to such Site  (provided  that the
Transferee assumes all of SBCW's or such Affiliate's obligations hereunder).

         Notwithstanding the foregoing,  in the event of a Transfer by SBCW or a
SBCW Affiliate to a Non-Qualifying Transferee, if either (x) such Non-Qualifying
Transferee  ultimately  becomes a  Permitted  Transferee  or (y)  subject to the
consent of TowerCo,  which consent may not be unreasonably withheld, no unwaived
event of default on the part of such Non-Qualifying Transferee occurs in respect
of such  Sites  for three (3)  years  after  the date of such  Transfer  to such
Transferee,  SBCW or such SBCW Affiliate, as applicable,  shall be released from
any and all  obligations  under this  Sublease  as to such  Sites,  pursuant  to
Section  25(c),  and upon SBCW's  request  TowerCo shall confirm such release in
writing.

         Except as expressly  provided in Section  25(b),  wherever  under or in
connection  with this  Sublease  SBCW or any SBCW  Affiliate  assigns its right,
title or interest, in whole or in part, in or to this Sublease or any Site, SBCW
or such SBCW Affiliate shall be released from performing any and all obligations
under this  Sublease in respect of the right,  title or interest so assigned and
under the applicable  Ground Lease,  from and after the date of such assignment,
and  TowerCo  hereby  acknowledges  such  release.  At or prior  to any  partial
assignment of this Sublease, SBCW or SBCW Affiliate and such assignee shall have
entered into one or more agreements,  including without  limitation,  a sublease
and site designation supplements  (collectively,  the "New Sublease Documents"),
that afford SBCW and such SBCW Affiliate  relative  rights  (including,  without
limitation,  provisions  relating  to the  right  of SBCW  to act for  TowerCo),
vis-a-vis SBCW's or such SBCW Affiliate's  rights and obligations  under the New
Sublease  Documents  no less  favorable to SBCW and SBCW  Affiliates  than those
afforded by the Sublease and the Site  Designation  Supplements  with respect to
the rights and obligation of SBCW and any SBCW  Affiliate,  and are otherwise in
form and substance reasonably satisfactory to SBCW.

                                       48
<PAGE>

(c) Without  limiting the  generality of the other  provisions of this Sublease,
any assignment of interest pursuant to this Sublease shall be effectuated by ten
(10) days'  written  notice of such  assignment,  which notice shall include the
name, address,  and telephone number of assignee.  Each Party hereby agrees that
any attempt of the other Party to assign its interest in this Sublease or any of
its rights  hereunder,  in whole or in part,  in  violation  of Section 25 shall
constitute a default under this Sublease and shall be null and void ab initio

(d) In the event that a Ground  Lease  restricts  TowerCo's  ability to sublease
space on the Leased Property,  the applicable Sublessor agrees that it shall use
commercially  reasonable  efforts  to  assist  and  cooperate  with  TowerCo  in
obtaining any such necessary consents,  at TowerCo's sole cost and expense, from
the Ground Lessor.

SECTION 26.       Estoppel Certificate.

         Either  Party,  from time to time upon ten (10) days' prior  request by
the other Party, shall execute, acknowledge and deliver to the requesting Party,
or to a person designated by such requesting  Party, a certificate  stating that
this  Sublease  is  unmodified  and in full  effect  (or,  if  there  have  been
modifications,  that this  Sublease is in full effect as  modified,  and setting
forth such  modifications)  and the dates to which  Rent and other sums  payable
under this Sublease have been paid,  and either stating that to the knowledge of
the signer of such  certificate no default exists  hereunder or specifying  each
such default of which the signer has knowledge.  The requesting  Party,  at such
Party's  cost and  expense,  shall cause such  certificate  to be  prepared  for
execution by the requested Party. Any such certificate may be relied upon by any
prospective  Permitted  Collateral  Assignee,  Mortgagee  or  purchaser  of  the
Subleased Property of each Site.

SECTION 27.       Holding Over.

         If TowerCo remains in possession of the Subleased  Property of any Site
after expiration or termination of the then current Term as to such Site without
any express written agreement by SBCW, then TowerCo shall be and become a tenant
at  sufferance,  and there shall be no renewal or extension of this  Sublease by
operation of law.  This section  shall be deemed to be an  "agreement  expressly
providing  otherwise"  within the meaning of Section  232-c of the Real Property
law of the State of New York.

SECTION 28.       Rights of Entry and Inspection.

(a) TowerCo shall permit SBCW and SBCW's  representatives,  agents and employees
to enter the  Subleased  Property  of any Site at all  reasonable  times for the
purposes of inspecting such Subleased Property,  showing the Site to prospective
purchasers,  tenants  and  Mortgagees,  making any  repairs or  replacements  or
performing  any  maintenance,  and performing any work on the Site that SBCW may
consider necessary to prevent or cure deterioration, waste or unsafe conditions.
Nothing in this  Section 28 shall  imply or impose any duty or  obligation  upon
SBCW to enter  upon any Site at any time  for any  purpose,  or to  inspect  the
Subleased  Property  at any time,  or to  perform,  or pay the cost of, any work
which TowerCo is required to perform under any provision of this  Sublease,  and
SBCW has no such duty or obligation.

                                       49
<PAGE>

(b) SBCW shall permit  TowerCo and TowerCo's  representatives  to inspect SBCW's
Communications Equipment for the purpose, in the event of an Emergency only, for
making repairs or replacements  to address such  Emergency.  The foregoing shall
not limit TowerCo's rights pursuant to Section 7 hereof.

SECTION 29. A Party's Right to Act for the Other Party; SBCW Set-Off Right.

(a) In addition to and not in limitation of any other remedy SBCW may have under
this Sublease,  if TowerCo fails to make any payment or to take any other action
(or to cause any Space  Subtenant to take any action) when and as required under
this Sublease, including without limitation Sections 11(a) and 17 and Exhibit C,
SBCW may,  without demand upon TowerCo and without waiving or releasing  TowerCo
from any duty,  obligation  or  liability  under  this  Sublease,  make any such
payment or take any such other  action  required  of TowerCo.  Unless  TowerCo's
failure results in or relates to an Emergency,  SBCW shall give TowerCo at least
ten (10) days prior written notice of SBCW's  intended  action and TowerCo shall
have the right to cure such failure  within such 10-day  period.  No such notice
shall be required in the event of an Emergency.  The actions which SBCW may take
shall include, but are not limited to, the performance of maintenance or repairs
and the making of replacements to the Towers and  Improvements on each Site (and
SBCW  shall  have full  access to the Sites for such  purpose),  the  payment of
insurance  premiums  which TowerCo is required to pay under this  Sublease,  the
payment of Ground Rents which TowerCo is required to pay under the Ground Leases
and the payment of Taxes and Assessments  which TowerCo is required to pay under
this  Sublease.  SBCW may pay all  incidental  costs and  expenses  incurred  in
exercising  its rights  hereunder,  including,  without  limitation,  reasonable
attorneys' fees and expenses, penalties,  re-instatement fees, late charges, and
interest.  An amount  equal to one hundred  twenty  percent  (120%) of the total
amount of the costs and expenses  (including salaries and benefits of employees)
incurred by SBCW or SBCW's  Affiliates  in  accordance  with this Section 29, is
referred to as the "Reimbursable Maintenance Expenses" of SBCW, shall be due and
payable by TowerCo upon demand and bear interest at the rate of eighteen percent
(18%) per annum from the date of demand  until paid by TowerCo.  SBCW shall have
the right to set off against  any SBCW  Leaseback  Charges due under  Section 10
hereof the amount of any Reimbursable Maintenance Expenses and any other amounts
due and  owing by  TowerCo  or  TowerCo  Parent  to SBCW or any SBCW  Affiliates
hereunder.

(b) For  purposes of this  Section,  the term  "Emergency"  means any event that
causes, has caused or is likely to cause, (i) any bodily injury, personal injury
or property damage;  (ii) the suspension,  revocation,  termination or any other
adverse  material effect as to any licenses  and/or  permits;  (iii) any adverse
effect on the  ability  of SBCW or its  Affiliates  or any Space  Subtenants  to
operate Communications  Equipment;  or (iv) any failure of any Site to comply in
any material respect with applicable Laws.

SECTION 30.       Defaults and Remedies.

(a)      The following events shall constitute events of default by SBCW:

(i)      If SBCW or a SBCW Affiliate  fails to perform any material  obligations
         pursuant to the applicable  Ground Lease for a Site that SBCW or a SBCW
         Affiliate is expressly required to perform pursuant to the terms of

                                       50
<PAGE>

         this  Sublease  and shall not cure such failure by the later of (x) the
         expiration of any applicable cure period, or (y) thirty (30) days after
         TowerCo gives SBCW written notice thereof; or

(ii) if SBCW shall  materially  violate or breach,  or shall  materially fail to
fully and  completely  observe,  keep,  satisfy,  perform and comply  with,  any
agreement, term, covenant, condition,  requirement,  restriction or provision of
this Sublease in respect of any Site (which violations, breaches or failures may
be  different  for each  Site),  and shall not cure  such  violation,  breach or
failure within thirty (30) days after TowerCo gives SBCW written notice thereof,
or, if such failure  shall be incapable of cure within thirty (30) days, if SBCW
shall not commence to cure such  failure  within such thirty (30) day period and
continuously  prosecute  the  performance  of the  same to  completion  with due
diligence; or

(iii) Subject to Section  30(i),  SBCW breached any material  representation  or
warranty in this Sublease as to any Site as of the date when made.

(iv) if SBCW becomes  insolvent as defined in the Uniform  Commercial Code under
the Laws  applicable to this Sublease or makes an assignment  for the benefit of
creditors;  or if any action is  brought  by SBCW  seeking  its  dissolution  or
liquidation  of its  assets or seeking  the  appointment  of a trustee,  interim
trustee,  receiver  or  other  custodian  for  any of its  property;  or if SBCW
commences a voluntary  proceeding  under the Federal  Bankruptcy Code; or if any
reorganization  or  arrangement   proceeding  is  instituted  by  SBCW  for  the
settlement, readjustment,  composition or extension of any of its debts upon any
terms; or if any action or petition is otherwise brought by SBCW seeking similar
relief  or  alleging  that it is  insolvent  or  unable to pay its debts as they
mature;  or if any action is brought  against  SBCW seeking its  dissolution  or
liquidation  of any of its  assets,  or seeking  the  appointment  of a trustee,
interim  trustee,  receiver or other custodian for any of its property,  and any
such action is consented to or acquiesced in by SBCW or is not dismissed  within
ninety  (90)  days  after  the  date  upon  which it was  instituted;  or if any
proceeding under the Federal  Bankruptcy Code is instituted against SBCW and (1)
an order for relief is entered in such  proceeding,  or (2) such  proceeding  is
consented to or  acquiesced  in by SBCW or is not  dismissed  within ninety (90)
days after the date upon which it was instituted;  or if any  reorganization  or
arrangement   proceeding  is  instituted   against  SBCW  for  the   settlement,
readjustment,  composition or extension of any of its debts upon any terms,  and
such  proceeding  is consented to or  acquiesced  in by SBCW or is not dismissed
within ninety (90) days after the date upon which it was  instituted;  or if any
action or petition is otherwise  brought  against SBCW seeking similar relief or
alleging  that it is  insolvent,  unable  to pay its  debts  as they  mature  or
generally  not paying its debts as they become due,  and such action or petition
is consented to or acquiesced in by SBCW or is not dismissed  within thirty (30)
days after the date upon which it was brought.

(b) Upon the occurrence of any event of default by SBCW under Section 30(a)(iv),
TowerCo  may  terminate   this  Sublease  by  giving  SBCW  written   notice  of
termination,  and this Sublease  shall be  terminated at the time  designated by
TowerCo in its notice of  termination  to SBCW whereupon SBCW shall be obligated
to refund to TowerCo all Rent for the rental periods occurring after the

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<PAGE>

effective date of such termination.  Upon the occurrence of any event of default
by SBCW under  Sections  30(a)(i)-(a)(iii)  as to the Reserved  Space of a Site,
TowerCo may  terminate  this  Sublease  as to such Site by giving  SBCW  written
notice  of  termination,  and  this  Sublease  shall  be  terminated  as to  the
applicable  Site at the time  designated by TowerCo in its notice of termination
to SBCW  whereupon  SBCW  shall be  obligated  to  refund  to  TowerCo  the Rent
allocable to such Site for the rental periods occurring after the effective date
of such  termination.  Notwithstanding  the foregoing,  if SBCW fails to pay any
portion of a SBCW Leaseback  Charge because SBCW or a SBCW Affiliate,  acting in
good faith,  reduced  the amount of SBCW  Leaseback  Charges  paid to TowerCo in
giving  effect  to a  mistaken  belief  that  it made  Reimbursable  Maintenance
Expenses  under Section 29(a) that SBCW or a SBCW Affiliate was not permitted to
make,  such failure  shall not  constitute an event of default  hereunder.  Upon
TowerCo's  demand after any  resolution  of any dispute as to the amount of such
Reimbursable  Maintenance Expenses,  SBCW shall pay such amount to TowerCo, with
interest thereon at the rate of eighteen percent (18%) per annum,  from the date
such amount was due until the date paid.

(c) TowerCo's remedy stated in Section 29(b) above shall not preclude pursuit of
any other  remedy or remedies  provided in this  Sublease or any other remedy or
remedies provided for or allowed by law or in equity, separately or concurrently
or in any combination.

(d) The following events shall constitute events of default by TowerCo:

(i) If TowerCo  fails to timely pay Ground Rent as  provided in Section  3(d) or
otherwise  fails to make  payment of any amount due  hereunder  and such failure
continues  for ten (10) days after the date such payment was due and payable or,
with respect to the payment of Ground Rent,  for such longer grace period as may
be provided for in the applicable Ground Lease, or

(ii) (x) TowerCo shall materially violate or breach, or shall materially fail to
fully and completely observe, keep, satisfy,  perform and comply with, any term,
covenant, condition, requirement, restriction or provision of this Sublease with
respect to any Site (which violations, breaches or failures may be different for
each Site),  and shall not cure such violation,  breach or failure within thirty
(30) days after SBCW gives TowerCo written notice  thereof,  or, if such failure
can be cured,  but not within thirty (30) days, if TowerCo shall not commence to
cure such failure within such thirty (30) day period and continuously  prosecute
the  performance  of the  same  to  completion  with  due  diligence  or (y) the
aggregate  amount of  Reimbursable  Maintenance  Expenses in respect of any Site
pursuant to Section 29(a) exceeds $4,000 on at least two occurrences  within the
same Sublease Year, whether or not reimbursed by TowerCo; or

(iii) Subject to Section 30(i), any  representation  or warranty made by TowerCo
in this Sublease  shall be false or  misleading  in any material  respect on the
date as of which made (or deemed made); or

(iv) TowerCo or TowerCo  Parent  shall  materially  violate or breach,  or shall
materially fail to fully and completely  observe,  keep,  satisfy or perform any
obligation for money borrowed involving not less than $5,000,000 in principal

                                       52
<PAGE>

amount  in  connection  with  this  Sublease,   including,  without  limitation,
Mortgages,  or any  obligation  under notes payable or drafts  accepted,  or any
obligation of any other agreement,  term or condition contained in any indenture
or agreement under which any such  obligation is created,  guaranteed or secured
if the effect of such default is to cause such obligation to become due prior to
its stated maturity; or

(v) If TowerCo becomes insolvent as defined in the Uniform Commercial Code under
the Laws  applicable to this Sublease or any Site or makes an assignment for the
benefit  of  creditors;  or if any action is  brought  by  TowerCo  seeking  its
dissolution  or  liquidation  of its  assets or  seeking  the  appointment  of a
trustee,  interim trustee,  receiver or other custodian for any of its property;
or if TowerCo  commences a  voluntary  proceeding  under the Federal  Bankruptcy
Code;  or if any  reorganization  or  arrangement  proceeding  is  instituted by
TowerCo for the settlement, readjustment, composition or extension of any of its
debts  upon any terms;  or if any action or  petition  is  otherwise  brought by
TowerCo seeking similar relief or alleging that it is insolvent or unable to pay
its debts as they mature;  or if any action is brought  against  TowerCo seeking
its dissolution or liquidation of any of its assets,  or seeking the appointment
of a  trustee,  interim  trustee,  receiver  or other  custodian  for any of its
property,  and any such action is consented to or acquiesced in by TowerCo or is
not  dismissed  within  ninety  (90)  days  after  the  date  upon  which it was
instituted; or if any proceeding under the Federal Bankruptcy Code is instituted
against  TowerCo and (1) an order for relief is entered in such  proceeding,  or
(2) such  proceeding  is  consented  to or  acquiesced  in by  TowerCo or is not
dismissed  within ninety (90) days after the date upon which it was  instituted;
or if any reorganization or arrangement proceeding is instituted against TowerCo
for the settlement,  readjustment,  composition or extension of any of its debts
upon any terms,  and such proceeding is consented to or acquiesced in by TowerCo
or is not  dismissed  within  ninety  (90) days after the date upon which it was
instituted;  or if any action or petition is otherwise  brought  against TowerCo
seeking similar relief or alleging that it is insolvent, unable to pay its debts
as they mature or  generally  not paying its debts as they become due,  and such
action or  petition  is  consented  to or  acquiesced  in by  TowerCo  or is not
dismissed within thirty (30) days after the date upon which it was brought.

(e) Upon the  occurrence of any event of default by TowerCo under Section 30(d),
Section 14(c),  Section 14(d) or Section 11(c) in respect of any Site,  SBCW may
terminate  this Sublease as to the  applicable  Site by giving  TowerCo  written
notice of termination, and this Sublease shall be terminated as to such Site, at
the time  designated  by SBCW in its notice of  termination  to TowerCo,  unless
otherwise provided herein.  Upon the occurrence of events of default (whether of
the same or different  types) by TowerCo  under Section 30(d) in respect of more
than fifty (50) Sites  during any  consecutive  five (5) year  period or portion
thereof,  SBCW may  terminate  this  Sublease as to all Sites by giving  TowerCo
written notice of  termination,  and this Sublease shall be terminated as to all
Sites at the time designated by SBCW in its notice of termination to TowerCo.

(f) SBCW and each  Sublessor may pursue any remedy or remedies  provided in this
Sublease,  including without limitation Section 30(e), or any remedy or remedies
provided for or allowed by law or in equity,  separately or  concurrently  or in
any combination, including, without limitation, (i) specific performance or

                                       53
<PAGE>

other equitable remedies;  (ii) money damages arising out of such default; (iii)
SBCW may exercise the Withdrawal  Right as to any Site  immediately  and without
further  act,  pursuant  to  Section 9; or (iv) SBCW may  perform,  on behalf of
TowerCo,  TowerCo's  obligations  under the terms of this  Sublease  pursuant to
Section 29, in which event SBCW shall have the right to set off all Reimbursable
Maintenance Expenses against the SBCW Leaseback Charges SBCW is required to pay.
If the amount of Reimbursable  Maintenance  Expenses  exceeds the SBCW Leaseback
Charges  payable by SBCW  hereunder and TowerCo does not reimburse SBCW the full
amount of such  excess  within ten (10) days  following  SBCW's  written  demand
therefor, SBCW may terminate this Sublease in respect of all or any of the Sites
pursuant to Section 30(e) and shall be reimbursed thereof.

(g) A  Party's  pursuit  of any  one or more of the  remedies  provided  in this
Sublease shall not constitute an election of remedies  excluding the election of
another  remedy or other  remedies,  or a  forfeiture  or waiver of any  amounts
payable under this Sublease as to the applicable Site by such Party or waiver of
any  relief or damages  or other  sums  accruing  to such Party by reason of the
other Party's failure to fully and completely keep,  observe,  perform,  satisfy
and  comply  with  all  of  the  agreements,   terms,   covenants,   conditions,
requirements,  provisions and  restrictions  of this  Sublease.  Notwithstanding
anything to the contrary contained herein,  neither Party shall be liable to the
other  parties  for  indirect,  incidental,  special or  consequential  damages,
including but not limited to lost profits,  however arising, even if a Party has
been advised of the possibility of such damages.

(h) Either  Party's  forbearance  in pursuing or  exercising  one or more of its
remedies shall not be deemed or construed to constitute a waiver of any event of
default or of any  remedy.  No waiver by either  Party of any right or remedy on
one  occasion  shall be  construed  as a waiver  of that  right or remedy on any
subsequent  occasion  or as a  waiver  of any  other  right  or  remedy  then or
thereafter existing. No failure of either Party to pursue or exercise any of its
powers,  rights or remedies or to insist upon strict and exact compliance by the
other  Party  with  any  agreement,  term,  covenant,  condition,   requirement,
provision or restriction of this Sublease, and no custom or practice at variance
with the terms of this  Sublease,  shall  constitute a waiver by either Party of
the right to demand strict and exact compliance with the terms and conditions of
this Sublease.

(i) Notwithstanding  the foregoing,  no event of default shall be deemed to have
occurred in respect of SBCW under  Section  30(a)(iii)  or in respect of TowerCo
under  Section  30(d)(iii),  if the other Party gives  notice after one (1) year
following:

(i)      the  applicable  Site  Commencement  Date with  respect  to the Site in
         question in the case of a  representation  or warranty  made under this
         Sublease or the applicable Site Designation Supplement, as to any Site;

(ii) the date hereof,  in the case of any other  representation or warranty made
under this Sublease; or

(iii) in the case of  representation  or warranty  made under the  Agreement  to
Sublease, as provided therein.

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<PAGE>

(j) Upon the occurrence of any event of default by TowerCo under this Section 30
in respect of any Site,  the  applicable  Sublessor  shall give every  Permitted
Subleasehold Collateral Assignee of which Sublessor has written notice a written
notice of, and an opportunity to cure within  forty-five (45) days after receipt
of such Sublessor's written notice of default,  all existing defaults hereunder.
In the  event  the  Permitted  Subleasehold  Collateral  Assignee  fails to cure
defaults as to any Site within such forty-five  (45) day period,  such Sublessor
may  terminate  this  Agreement as to such Site.  The parties  hereto agree that
prior to the date upon  which such  Sublessor  has the right to  terminate  this
Agreement as to such Site, any Permitted  Subleasehold  Collateral Assignee may,
at its option,  be substituted and replace  TowerCo as Sublessee  hereunder (and
TowerCo agrees to relinquish  all rights  hereunder) by assuming and agreeing to
be bound by each and every term, covenant,  condition,  agreement,  requirement,
restriction  and  provision  set forth in this  Agreement,  and  subject  to all
rights,  title, and interest of the applicable  Sublessor;  provided that in the
event there have been more than fifty (50) events of default within any five (5)
year period and SBCW gives notice under  Section 30(d) hereof of its election to
terminate this Sublease,  such Permitted  Subleasehold  Collateral Assignee may,
prior to termination of this Agreement by the applicable Sublessor, transfer its
interests  under  this  Agreement  in  its  entirety  after  providing  evidence
satisfactory  to SBCW that the proposed  assignee is not an SBCW  Competitor and
has appropriate industry experience, the capability and the financial ability to
perform the  obligations  of TowerCo  hereunder  and under any other  agreements
relating to or concerning the transactions between SBCW and TowerCo.

SECTION 31.       Quiet Enjoyment.

         TowerCo  shall,  subject to the terms and  conditions of this Sublease,
peaceably and quietly hold and enjoy the Subleased  Property of each Site during
the Term without  hindrance or  interruption  from SBCW,  so long as no event of
default has occurred and is continuing hereunder.

SECTION 32.       No Merger.

         There shall be no merger of this Sublease or the subleasehold  interest
or estate created by this Sublease in any Site with the superior  estate held by
the Sublessor thereof,  by reason of the fact that the same person or entity may
acquire, own or hold, directly or indirectly,  both the subleasehold interest or
estate created by this Sublease in any Site and such superior  estate;  and this
Sublease  shall  not be  terminated,  in  whole  or as to any  Site,  except  as
expressly provided herein.

SECTION 33.       Broker and Commission.

(a) All negotiations in connection with this Sublease have been conducted by and
between  TowerCo and SBCW without the  intervention of any person or other Party
as agent or broker  other than  Goldman,  Sachs & Co.  which is advising  SBCW's
parent,  SBC  Communications  Inc., in connection with this Sublease and related
transactions.

(b)  TowerCo  and SBCW  warrant  and  represent  to each other that there are no
broker's  commissions or fees payable in connection with this Sublease by reason
of their  respective  dealings,  negotiations or  communications  other than the
advisor's fee payable to Goldman, Sachs & Co. which shall be payable by SBC

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<PAGE>

Communications Inc. TowerCo and SBCW shall, and do hereby indemnify,  defend and
hold  harmless  each other from and against  the Claims of any and all  brokers,
agents and other intermediaries  alleging a commission,  fee or other payment to
be owing by reason of their respective dealings,  negotiations or communications
in connection with this Sublease.

SECTION 34.       Recording of Site Designation Supplement.

(a) Subject to the applicable provisions of the Agreement to Sublease,  upon the
execution of this  Sublease,  TowerCo may, at its cost and expense (i) cause the
Ground  Leases or  memorandum  of Ground Leases for the Sites to be filed in the
appropriate  County  property  records,  unless  such  Ground  Leases  expressly
prohibit such recording;  and (ii) promptly following the execution of each Site
Designation  Supplement,  cause such Site Designation  Supplement to be filed in
the  appropriate  County  property  records  unless  the  Ground  Lease  for the
applicable Site prohibits such recording.

(b) In  addition  to and  not in  limitation  of any  other  provision  of  this
Sublease,  the Parties shall have the right to review and make  corrections,  if
necessary, to any and all exhibits hereto or to the Site Designation Supplements
after the date hereof.  After making such  corrections,  TowerCo shall re-record
any such Site Designation Supplements to reflect such corrections,  if requested
by either Party. The Parties shall cooperate with each other to cause changes to
be  made  in the  documentation  for  any  Site,  and in  the  Site  Designation
Supplement  for such Site,  if such  changes are  requested  by either  Party to
evidence  any  permitted  changes  in  the  description  of the  Reserved  Space
respecting such Site,  including,  without  limitation changes in SBCW's or such
SBCW Affiliate's antennas or other parts of its Communications  Facility at such
Site. In addition to and not in limitation of the foregoing,  either Party shall
have  the  right,  at  its  sole  expense,  to  cause  any  amendment  to a Site
Designation   Supplement  to  be  recorded,   including  without  limitation  in
connection with such changes.

SECTION 35.       Purchase Options.

(a) Right to Purchase.  If this Sublease shall not have been earlier terminated,
or an event of default by TowerCo  shall not have  occurred and be continuing at
the date of option  exercise  or the date  fixed for  purchase  (as such date is
specified below), TowerCo shall have an option,  exercisable no earlier than one
hundred  eighty (180) days and no later than one hundred twenty (120) days prior
to each Site Expiration  Outside Date (the "Option Trigger  Window") to elect to
purchase  all (but not less than all) of the Sites  then  subleased  under  this
Sublease which have the same Site  Expiration  Outside Date, at a purchase price
equal to the aggregate of the Option  Purchase  Price Amounts and any additional
amounts determined  pursuant to Section 3(i) hereof for the applicable Sites and
on the other terms and subject to the conditions herein  specified.  TowerCo may
exercise such purchase  option by submitting to SBCW in writing an offer for all
of such Sites within the Option Trigger Window. The applicable  Sublessors shall
be obligated to sell, and TowerCo shall be obligated to buy, all such Sites at a
closing to be effective as of the relevant Site  Expiration  Outside Date.  SBCW
shall use  commercially  reasonable  efforts to obtain all consents to TowerCo's
purchase of Leased Sites pursuant to this Section 35 that may be required by the
Ground Leases  encumbering such Sites. In the event that SBCW cannot obtain such
consents on or prior to the closing date determined pursuant to Section 35(b),

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<PAGE>

then SBCW  shall,  at  TowerCo's  option,  enter into  alternative  arrangements
mutually  acceptable  to SBCW and TowerCo  which do not violate the terms of the
applicable  Ground  Leases and which  provide  TowerCo  with rights and benefits
comparable  to those  afforded  by an  assignment.  Except as  provided  in this
Section 35,  TowerCo shall have no right or option to purchase the Sites subject
to this Sublease.

(b) Payment of the Purchase  Price.  TowerCo shall pay to SBCW (as agent for the
applicable  Sublessors)  the Option  Purchase  Price Amounts and any  additional
amounts  determined  pursuant to Section 3(i) hereof for the applicable Sites in
cash or immediately  available funds on or prior to the closing of such sale. At
the closing of such sale, SBCW shall transfer the purchased  Sites, at TowerCo's
expense,  to TowerCo and the Term as to such Sites  shall end.  Risk of loss for
the Sites  purchased  pursuant  to  Section  35 shall  pass from the  applicable
Sublessor(s)  to TowerCo  upon  payment of the  purchase  price  therefor.  This
Sublease  shall remain in full force and effect with respect to Sites subject to
TowerCo's  binding  election  under  Section  35(a)  until the  applicable  Site
Expiration Outside Date.

(c)  Transfer by SBCW.  Any  transfer of Sites by SBCW or any SBCW  Affiliate to
TowerCo pursuant to this Section 35 shall include:

(i) an assignment of  Sublessor's  interest in any Ground Lease for such Site, a
transfer of fee simple  title to the Land for any Site which is an Owned Site, a
transfer of  Sublessor's  interest in the  applicable  Tower and related  assets
(other than SBCW Improvements, including SBCW's current or future Communications
Equipment)  and all  appurtenances  thereto;  provided  that  for so long as the
Ground Lease, as amended, modified, or extended, is still in effect, SBCW or any
SBCW Affiliate shall be entitled to continue to lease the Reserved Space on each
such Site from  TowerCo for  successive 1 year terms at rental rate equal to the
lesser of the then  current  market  rental  rates for  comparable  locations as
mutually  agreed  to by  SBCW  and  TowerCo  on an  annual  basis  prior  to the
commencement  of each lease year or the  Leaseback  Charge  then being  charged,
provided that the Leaseback Charge shall thereafter be subject to increase on an
annual basis at the  beginning of each 1-year term in an amount equal to the CPI
Change; provided, further however, if TowerCo and SBCW fail to agree on a rental
rate for one or more of the Sites, such rental rate shall be determined for each
applicable Site by Ernst & Young or another  nationally  recognized  independent
accounting  firm  mutually  acceptable  to SBCW  and  TowerCo.  The  cost of the
determination  of the rental rate shall be shared  equally by SBCW and  TowerCo.
SBCW shall have the right to elect to terminate any such lease with respect to a
Site as of the  expiration of each annual term by giving no less than sixty (60)
days prior written notice of such termination to TowerCo;

(ii) to the extent  legally  transferable,  all rights of SBCW or any  Sublessor
under  or  pursuant  to  warranties,  representations  and  guarantees  made  by
suppliers or  manufacturers  in  connection  with such Site,  but  excluding any
rights to receive amounts under such warranties,  representations and guarantees
representing reimbursements for items paid by SBCW or a Sublessor; and

(iii) to the extent legally transferable,  all known and unknown rights, claims,
credits,  causes of action, or rights to commence any causes of action or rights
of setoff of SBCW or a Sublessor against third parties relating to such Site

                                       57
<PAGE>

arising on or after the date of transfer,  including  unliquidated  rights under
manufacturers' and vendors'  warranties,  but excluding all amounts representing
reimbursements for items paid by SBCW or a Sublessor.

(d)  Evidence  of  Transfer.   The   Sublessor  and  TowerCo  shall  enter  into
assignments,  deeds (with  warranties of title as to Sublessor's  actions only),
bills of sale  and  such  other  documents  and  instruments  as the  other  may
reasonably request to evidence any transfer of such Sites.

(e) No Warranties.  Any transfer of a Site by a Sublessor or TowerCo pursuant to
this  Sublease  shall be "AS IS" and without any warranty  whatsoever by SBCW or
TowerCo,  except  that in any  transfer  of a Site  by a  Sublessor  to  TowerCo
pursuant to this  Sublease,  Sublessor  shall warrant that it has not previously
transferred title to such Site that is so transferred and that each such Site is
free of Liens created by or through SBCW or any Affiliate thereof.

SECTION 36.       Net Lease.

         This  Sublease   (along  with  the   corresponding   Site   Designation
Supplement)  is a net lease  and,  except as  otherwise  expressly  provided  in
Sections 13 and 19 hereof, shall not terminate, nor shall TowerCo be entitled to
any  abatement,  reduction,  setoff,  counterclaim,  defense or  deduction  with
respect  to any  Rent or  other  sum  payable  hereunder.  Except  as  otherwise
expressly  provided in Sections 12 and 19 hereof, the obligation of Lessee under
this Sublease or any Site Designation Supplement shall not be affected by reason
of:  (a) any  damage to or  destruction  of any Site or any part  thereof by any
cause whatsoever;  (b) any condemnation of any of the Site; (c) any prohibition,
limitation, restriction or prevention of TowerCo's use or enjoyment of a Site by
any person; (d) any matter affecting title to any Site or any part thereof;  (e)
any loss of possession  by TowerCo of a Site or any portion,  by reason of title
paramount or otherwise;  (f) the invalidity or unenforceability of any provision
hereof or the  impossibility  or illegality of performance by SBCW or TowerCo or
both;  (g) any  action of any  federal,  state,  local or  foreign  Governmental
Authority;  or (h) any other cause or occurrence whatsoever,  whether similar or
dissimilar to the foregoing.  The parties intend that the obligations of TowerCo
hereunder  shall continue  unaffected  unless such  obligations  shall have been
modified or terminated pursuant to an express provision of this Sublease.

SECTION 37.       Compliance with Specific FCC Regulations.

(a) TowerCo  understands and  acknowledges  that Space Subtenants are engaged in
the  business  of  operating  communications   equipment,   including,   without
limitation,  Communications Equipment at each Site. The Communications Equipment
is  subject  to  the  regulations  of  the  FCC,  including  without  limitation
regulations regarding exposure by workers and members of the public to the radio
frequency  emissions  generated  by  SBCW's  Communications  Equipment.  TowerCo
acknowledges that such regulations  prescribe the permissible exposure levels to
emissions  from the  Communications  Equipment  which  can  generally  be met by
maintaining  safe  distances  from such  Communications  Equipment.  In order to
comply  with  such  regulations,  TowerCo  shall  install,  or cause  the  Space
Subtenants  to  install,  at its or their  expense,  such  marking,  signage  or
barriers to restrict access to any Subleased Property of each Site as TowerCo

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<PAGE>

deems necessary in order to comply with the applicable FCC regulations.  TowerCo
further  agrees to post,  or to cause the Space  Subtenants  to post,  prominent
signage at all points of entry to the Subleased Property of each Site containing
instructions  as to any  potential  risk of exposure and methods for  minimizing
such risk.  TowerCo  shall  cooperate  in good faith with SBCW to  minimize  any
confusion or unnecessary  duplication that could result in similar signage being
posted with respect to any of SBCW's transmission  equipment at or near any Site
in respect of any Reserved Space on such Site.

(b) TowerCo further agrees to alert all personnel  working at or near each Site,
including  TowerCo's  maintenance  and  inspection  personnel,  to  heed  all of
TowerCo's  or Space  Subtenant's  signage or  restrictions  with  respect to the
Subleased  Property of a Site,  to maintain  the  prescribed  distance  from the
Communications  Equipment,  and to  otherwise  follow the  posted  instructions.
TowerCo further agrees to alert each Space Subtenant in advance of any repair or
maintenance  work to be  performance  on any Site which  would  require  work in
closer  proximity to the Subleased  Property  than  prescribed by the signage or
restrictions.

(c) TowerCo  agrees to cooperate  with each Space  Subtenant on a  going-forward
basis  with  respect to each Site in order to insure  that such Space  Subtenant
complies with the applicable FCC regulations.

(d) SBCW acknowledges and agrees that its Communications  Equipment at each Site
is  subject  to  the  regulations  of  the  FCC,  including  without  limitation
regulations regarding exposure by workers and members of the public to the radio
frequency  emissions  generated by SBCW's (and its  Affiliates')  Communications
Equipment.  SBCW  acknowledges  that such regulations  prescribe the permissible
exposure  levels  to  emissions  from its  Communications  Equipment  which  can
generally  be  met  by  maintaining  safe  distances  from  such  Communications
Equipment.  SBCW shall  cooperate  in good faith with  TowerCo to  minimize  any
confusion or unnecessary  duplication that could result in similar signage being
posted  with  respect  to any  of  SBCW's  (and  its  Affiliates')  transmission
equipment at or near any Site in respect of any Reserved Space on such Site.

(e) SBCW  further  agrees to alert all  personnel  working at or near each Site,
including  SBCW's  maintenance  and  inspection   personnel,   to  maintain  the
prescribed distance from the Communications  Equipment,  and to otherwise follow
the posted instructions of TowerCo.

SECTION 38.       TowerCo Parent's Guaranty.

(a) TowerCo Parent  unconditionally  guarantees to SBCW, the Sublessor Entities,
the   SBCW   Affiliates,   and   each   SBCW   Indemnitee   (collectively,   the
"beneficiaries",  individually a "beneficiary")  the full and timely payment and
performance  and  observance  of all of the  terms,  provisions,  covenants  and
obligations of TowerCo under this Sublease and each Site Designation  Supplement
(the "Obligations").  TowerCo Parent agrees that if TowerCo defaults at any time
during the Term of this  Sublease  and any Site  Designation  Supplement  in the
performance of any of the Obligations,  TowerCo Parent shall faithfully  perform
and fulfill all  Obligations  and shall pay to the  applicable  beneficiary  all
attorneys'  fees,  court  costs,  and other  expenses,  costs and  disbursements
incurred by the applicable  beneficiary on account of any default by TowerCo and
on account of the enforcement of this guaranty.

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<PAGE>

(b) If TowerCo defaults under this Sublease or any Site Designation  Supplement,
and the applicable  beneficiary elects to enforce the provisions of this Section
36, the applicable beneficiary shall promptly give TowerCo Parent written notice
thereof,   which  notice  shall   constitute  an  exercise  of  the   applicable
beneficiary's  rights  against  TowerCo  Parent  pursuant  to this  Section  36.
Following  the receipt of such notice by TowerCo  Parent,  TowerCo  Parent shall
have the same period of time as is afforded  to TowerCo  under this  Sublease or
the applicable  Site  Designation  Supplement to cure such default,  but no such
cure period shall diminish the  obligations of TowerCo Parent under this Section
36.

(c) This  guaranty  obligation  of TowerCo  Parent shall be  enforceable  by the
applicable beneficiary in an action against TowerCo Parent without the necessity
of any suit, action, or proceedings by the applicable beneficiary of any kind or
nature  whatsoever  against  TowerCo,  without  the  necessity  of any notice to
TowerCo  Parent of  TowerCo's  default  or breach  under  this  Sublease  or the
applicable Site Designation  Supplement,  and without the necessity of any other
notice or demand to TowerCo  Parent to which TowerCo  Parent might  otherwise be
entitled,  all of which notices TowerCo Parent hereby expressly waives.  TowerCo
Parent hereby agrees that the validity of this guaranty and the  obligations  of
TowerCo Parent  hereunder  shall not be  terminated,  affected,  diminished,  or
impaired by reason of the  assertion or the failure to assert by the  applicable
beneficiary  against  TowerCo  any of the  rights or  remedies  reserved  to the
applicable  beneficiary  pursuant  to the  provisions  of this  Sublease  or the
applicable  Site  Designation  Supplement or any other remedy or right which the
applicable beneficiary may have at law or in equity or otherwise.

(d)  TowerCo  Parent  covenants  and agrees that this  guaranty is an  absolute,
unconditional,  irrevocable  and continuing  guaranty.  The liability of TowerCo
Parent hereunder shall not be affected, modified, or diminished by reason of any
assignment,  renewal,  modification  or extension of this  Sublease and any Site
Designation  Supplement or any modification or waiver of or change in any of the
covenants  and terms of this  Sublease  or any Site  Designation  Supplement  by
agreement of a beneficiary and TowerCo,  or by any unilateral action of either a
beneficiary  or  TowerCo,  or by an  extension  of time that may be granted by a
beneficiary to TowerCo or any indulgence of any kind granted to TowerCo,  or any
dealings or transactions occurring between a beneficiary and TowerCo, including,
without  limitation,  any  adjustment,   compromise,   settlement,   accord  and
satisfaction,  or  release,  or  any  bankruptcy,  insolvency,   reorganization,
arrangements,   assignment  for  the  benefit  of  creditors,  receivership,  or
trusteeship  affecting  TowerCo.  TowerCo Parent does hereby expressly waive any
suretyship  defense it may have by virtue of any  statute,  law, or ordinance of
any state or other governmental authority.

(e) All of the  beneficiaries'  rights  and  remedies  under this  guaranty  are
intended to be distinct,  separate,  and cumulative and no such right and remedy
herein is intended to be the exclusion of or a waiver of any other.

(f) TowerCo Parent hereby waives presentment,  demand for performance, notice of
nonperformance,  protest,  notice of protest,  notice of dishonor, and notice of
acceptance. TowerCo Parent further waives any right to require that an action be
brought  against TowerCo or any other person or to require that resort be had by
a beneficiary to any security held by such beneficiary.

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<PAGE>

SECTION 39.       Tax Indemnities.

(a)      Income Tax Indemnity.

(1) Tax Assumptions.  In entering into this Sublease and related documents,  the
SBCW Group has made the following  assumptions regarding the characterization of
the  transactions  contemplated  hereunder for federal  income tax purposes (the
"Tax Assumptions"):

(i)      for federal  income tax  purposes,  the  Sublease  will be treated as a
         "true lease" with respect to all of the Subleased Property, the members
         of the SBCW Group will be treated,  directly or indirectly  through one
         or more entities that are  classified as  partnerships  or  disregarded
         entities for federal income tax purposes,  as the owners and Sublessors
         of the Subleased Property, and TowerCo will be treated as the lessee of
         the Subleased Property;

(ii)     following  the  execution  of this  Sublease,  the SBCW  Group  will be
         entitled  to  deduct,   pursuant   to  Section   168(b)  of  the  Code,
         depreciation  deductions  with respect to the adjusted tax basis in the
         Subleased  Property using the same depreciation  method(s) as in effect
         immediately   before  the   execution   of  this   Sublease   ("Federal
         Depreciation Deductions");

(iii)    prepaid Rent will be  characterized  as a loan under section 467 of the
         Code and Treasury Regulations issued thereunder and the SBCW Group will
         be entitled to deduct interest attributable thereto;

(iv)     the only amounts that any SBCW Group Member will be required to include
         in gross income with respect to the  transactions  contemplated by this
         Sublease  and  related  documents  will be (A)  Rent as it  accrues  in
         accordance  with the  terms of this  Sublease  and the  application  of
         Section 467 of the Code and Treasury Regulations issued thereunder; (B)
         any indemnity  (including any gross up) pursuant to this Sublease;  (C)
         any amounts paid or otherwise  recognized  pursuant to a voluntary sale
         or other  disposition  by any SBCW Group  Member  (other than a sale or
         disposition attributable to a default by TowerCo and/or the exercise of
         remedies  by SBCW or any SBCW  Affiliate  under this  Sublease)  of any
         Subleased  Property;  and (D) proceeds upon  TowerCo's  exercise of the
         purchase option pursuant to Section 35 of this Sublease; and

(v)      the combined effective federal and net state income tax rate applicable
         to each SBCW Group  Member  will be 39 percent  (the  "Assumed  Rate"),
         comprised  of 35 percent  for the  assumed  federal  rate and 4 percent
         (which is net of federal  income tax  benefits)  for the assumed  state
         rate.

(2)      TowerCo's Representations and Covenants.  TowerCo hereby represents and
         covenants to each SBCW Group Member as follows:

(i)      TowerCo,  any  Affiliate  of  TowerCo,  any  assignee or  sublessee  of
         TowerCo,  and any  user  (other  than  SBCW or its  Affiliates)  of any
         portion  of  the  Subleased   Property  will  not  claim   depreciation
         deductions as the owner of any of the Subleased Property for federal

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<PAGE>

         income tax  purposes  during the Term (and  thereafter  unless  TowerCo
         purchases such property pursuant to Section 35 hereof), with respect to
         such  Subleased  Property or portion  thereof,  except with  respect to
         Alterations financed by TowerCo or such assignee,  sublessee,  or other
         user,  nor will they take any other action in connection  with filing a
         Tax return or otherwise which would be inconsistent  with the treatment
         of the  SBCW  Group  Members  as the  direct  or  indirect  owners  and
         Sublessors of the Subleased Property for federal income tax purposes;

(ii)     none  of  the  Subleased  Property  will  constitute   "tax-exempt  use
         property"  as defined in Section  168(h) of the Code as a result of the
         status of TowerCo or any assignee,  sublessee, or user (other than SBCW
         or its Affiliates) of the Subleased Property;

(iii)    to the best of TowerCo's  knowledge,  on the Site Commencement Date, no
         Alterations to any of the Subleased  Property will be required in order
         to render any of the Subleased  Property  complete for its intended use
         by  TowerCo  except  for  ancillary  Severable   Alterations  that  are
         customarily  selected and  furnished by lessees of property  similar in
         nature to the Subleased Property;

(iv)     Except to the extent that TowerCo may make  Non-Conforming  Alterations
         pursuant  to  Section  3(i)  hereof,  TowerCo  has no  current  plan or
         intention of making any Alteration or repair with respect to any of the
         Subleased Property that would not be treated as severable  improvements
         or permitted  nonseverable  improvements  within the meaning of Revenue
         Procedure 75-21,  1975-1 C.B. 715, or Revenue  Procedure 79-48,  1979-2
         C.B. 599;

(v)      TowerCo has no current plan or intention  of making any  Alteration  or
         repair with respect to any of the Subleased Property the value of which
         as of the end of the Term with respect to such Subleased Property would
         compel TowerCo to exercise any of the purchase options under Section 35
         of this Sublease;

(vi)     TowerCo  is not  obligated  to  exercise  any of the  purchase  options
         provided in Section 35 of this Sublease,  it has not decided whether it
         will  exercise  any of the purchase  options  provided in Section 35 of
         this  Sublease,  and it has no  plans  to  enter  into  or  incur  such
         obligation or to make such decision in the immediate future;

(vii)    TowerCo  has no reason to  believe  that the fair  market  value of any
         Subleased  Property,  determined  at the  end of  the  applicable  Term
         (taking into account  inflation or  deflation),  is equal to or greater
         than the Option Purchase Price Amount of such Subleased Property; and

(viii)   TowerCo  believes that the Rent with respect to any Subleased  Property
         is no greater  than the fair rental  value of such  Subleased  Property
         throughout the Term.

(3)      Indemnity for Tax Losses.

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<PAGE>

(i)     If, as a result of

(A)      the  inaccuracy of any  representation  of TowerCo,  or the breach of
         any covenant of TowerCo,  set forth in Section  39(a)(2)
                  hereof;

(B)               any act of TowerCo, or any assignee or sublessee of TowerCo or
                  any user of the  Subleased  Property  (other  than SBCW or its
                  Affiliates) during the Term, other than any act required under
                  the Transaction Documents;

(C)      the failure by TowerCo to perform any act required of it under any of
         the Transaction Documents;

(D)               the failure by TowerCo to perform any act reasonably requested
                  by any SBCW  Group  Member  provided  that (1) such act is not
                  inconsistent   with  the  obligations  of  TowerCo  and  other
                  requirements  under the  Transaction  Documents,  (2) such act
                  does not have any adverse effect on TowerCo, and (3) such SBCW
                  Group  Member or SBCW  agrees  to  reimburse  TowerCo  for all
                  reasonable  costs incurred in connection  with performing such
                  act;

(E)               any  disposition  of  Subleased  Property  attributable  to  a
                  default by TowerCo  and/or the exercise of remedies under this
                  Sublease; or

(F)      the bankruptcy of TowerCo,

any SBCW Group Member (each a "Tax Indemnitee")  shall not claim on the relevant
income tax return  (based upon a written  opinion from  independent  tax counsel
that there is no reasonable basis that is consistent with the standards provided
for in ABA Formal  Opinion  85-352 as in effect on the date hereof for claiming)
all or any portion of the Federal  Income Tax Benefits,  shall lose the right to
claim all or any portion of the Federal Income Tax Benefits, shall suffer a loss
of,  disallowance  of, or delay in  obtaining  all or any portion of the Federal
Income Tax Benefits, or shall be required to recapture all or any portion of the
Federal  Income Tax Benefits,  or any Tax  Indemnitee  shall suffer an Inclusion
(any such event being  referred to as a "Tax Loss"),  then,  within  thirty (30)
days after receipt of a written  demand from or on behalf of the Tax  Indemnitee
describing in reasonable  detail the Tax Loss and the  computation of the amount
payable (a "Tax Indemnity Notice"),  TowerCo shall pay to such Tax Indemnitee as
an indemnity the amount specified in the Tax Indemnity Notice.  Subject to other
adjustments required by this Section  39(a)(3)(i),  such indemnity payment shall
be calculated in the Tax Indemnity  Notice to equal, on an After-Tax  Basis, the
sum of (y) the amounts of any additional  federal and state income taxes payable
by such Tax  Indemnitee  for the taxable year  calculated at the Assumed Rate as
the result of such Tax Loss and any  interest  thereon  (calculated  to the date
such payment is made using the actual  interest rates for  underpayments  of tax
applicable  to the relevant  periods),  plus (z) the amount of any penalties and
additions to tax actually  payable as a result of such Tax Loss and attributable
thereto.  At the option of such Tax Indemnitee,  the indemnity  payment shall be
determined  on a  periodic,  or "pay as you go," basis,  with each such  payment
reduced for any reduction in Taxes also calculated at the Assumed Rate resulting
from any Tax benefits  realized by such Tax  Indemnitee as a result of the event
giving rise to the indemnity payment.  Alternatively,  at the option of such Tax
Indemnitee,  the indemnity  payment shall be a net lump-sum amount,  taking into
account  all past and  anticipated  future  Tax  Losses  and Tax  savings at the
Assumed Rate, and using a discount rate equal to the Applicable Federal Rate (as

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<PAGE>

defined in Code section  1274(d)(1)  then in effect) to present value future Tax
Losses and Tax savings.  Any  indemnity  payment  made  pursuant to this Section
39(a)(3)(i)  shall be made on an  "After-Tax  Basis"  which  means that any such
payment  shall also include a  "gross-up"  for any federal or state income Taxes
(determined at the highest marginal  applicable  federal and state rates then in
effect) payable by such Tax Indemnitee with respect to the receipt or accrual of
such  indemnity  payment,  including such  gross-up.  Notwithstanding  any other
provision of this Section  39(a)(3)(i)  to the  contrary,  TowerCo  shall not be
required to make any payment under this Section 39(a)(3)(i) earlier than, (a) in
the case of a Tax Loss that is not being  contested  pursuant  to Section  39(d)
hereof,  the date such Tax Indemnitee (or the common parent of the  consolidated
group in which it is a member, as the case may be) files the applicable  federal
income Tax  return,  estimated  or final as the case may be,  which  would first
properly reflect the additional federal income Tax that would be due as a result
of the Tax  Loss  and (b) in the  case of a Tax  Loss  that is  being  contested
pursuant  to Section  39(d)  hereof,  thirty (30) days after the date on which a
Final Determination is made (or as otherwise provided in Section 39(d)).

(ii)  Verification  of  Calculations.  TowerCo may timely  request  that any Tax
Indemnity Notice be verified by Ernst & Young or another  nationally  recognized
independent  accounting  firm selected by TowerCo and  reasonably  acceptable to
such Tax Indemnitee. Such verification shall be at TowerCo's expense unless such
accounting  firm  determines that the amount payable by TowerCo is more than ten
percent less than the amount shown on the Tax Indemnity  Notice,  in which event
the Tax  Indemnitee  shall pay such costs.  In order to enable such  independent
accountants  to verify such amounts,  the Tax  Indemnitee  shall provide to such
independent  accountants (for their  confidential use and not to be disclosed to
TowerCo or any other  person)  all  information  reasonably  necessary  for such
verification.

(4)  Exceptions.  Notwithstanding  any  provision of this  Section  39(a) to the
contrary,  TowerCo  shall  not be  required  to  make  any  payment  to any  Tax
Indemnitee  in  respect  of any Tax  Loss to the  extent  that any such Tax Loss
occurs as a result of one or more of the following events:

(i)  Except to the extent of any  inaccuracy  of a  representation  or breach of
covenant  of  TowerCo  in  Section  39(a)(2)  hereof,  any act of TowerCo or any
assignee or sublessee of TowerCo or any user of the  Subleased  Property  (other
than  SBCW or its  Affiliates)  other  than any act  required  under  any of the
Transaction Documents,  or any failure by TowerCo to perform any act required of
it under any of the Transaction Documents or any act reasonably requested by any
SBCW  Group  Member  with  respect  to which the  three  conditions  in  Section
39(a)(3)(i)(D)  have been satisfied,  a determination that the Sublease is not a
"true lease" for federal  income tax purposes or such Tax  Indemnitee is not the
owner or Sublessor of the applicable Subleased Property;

(ii) Except to the extent caused by any inaccuracy of a representation or breach
of covenant  of TowerCo in Section  39(a)(2)  hereof,  any act of TowerCo or any
assignee or sublessee of TowerCo or any user of the  Subleased  Property  (other
than  SBCW or its  Affiliates)  other  than any act  required  under  any of the
Transaction Documents,  or any failure by TowerCo to perform any act required of
it under any of the Transaction Documents or any act reasonably requested by any
SBCW Group Member with respect to which the three conditions in Section

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<PAGE>

39(a)(3)(i)(D) have been satisfied, the voluntary sale, assignment, transfer, or
other  disposition  or the  involuntary  sale,  assignment,  transfer,  or other
disposition  attributable  to the  bankruptcy,  insolvency  or the breach of any
covenant  or  obligation  of the Tax  Indemnitee  set  forth in the  Transaction
Documents  of or by any such  Tax  Indemnitee,  in  either  case,  of any of the
Subleased  Property or portion  thereof by any such Tax Indemnitee  other than a
sale,  assignment,  transfer, or disposition (A) contemplated by the Transaction
Documents or otherwise;  (B) otherwise  resulting  from the exercise by any SBCW
Group  Member  of its  rights  or  performance  of  its  obligations  under  the
Transaction  Documents;  or (C)  attributable  to a default  by  TowerCo  and/or
exercise of remedies under this Sublease;

(iii) the gross negligence or willful misconduct of such Tax Indemnitee;

(iv)  penalties,  interest,  or additions to Tax to the extent based upon issues
unrelated  to  the  transactions   contemplated  by  the  Sublease  and  related
documents;

(v) the inclusion in income by any SBCW Group Member on its U.S.  federal income
tax return of any amount  attributable to an Inclusion unless (x) such Inclusion
is supported by a written  opinion of  independent  tax counsel that there is no
reasonable  possibility of success in taking the position that the amount is not
includable  in  income,  or (y) such  Inclusion  shall be due to the  failure of
TowerCo timely to provide Tax Indemnitee with information  reasonably  available
to  TowerCo  that is timely  requested  in  writing  by the Tax  Indemnitee  and
necessary for the Tax Indemnitee to exclude such amounts from income; and

(vi) any failure of the Tax  Indemnitee  to have taken all the actions,  if any,
required  of it by Section  39(d)  hereof to contest  the Loss and such  failure
materially prejudices the ability to contest, and TowerCo has a reasonable basis
for such  contest  (other  than a failure  attributable  in whole or part to the
failure of TowerCo to follow the procedures set forth in Section 39(d) hereof).

(b)      General Tax Indemnity.

(1)  Except  as  provided  in  Section  39(b)(2),  TowerCo  agrees to pay and to
indemnify, protect, defend, save, and keep harmless each SBCW Group Member on an
After-Tax Basis, from and against any and all taxes, impositions,  fees, levies,
assessments, duties, withholdings,  governmental claims, or other charges of any
nature whatsoever  (together with any related  interest,  fines,  penalties,  or
additions to tax), including without limitation,  rental,  income,  withholding,
sales, use,  transfer,  leasing,  personal or real property,  excise,  receipts,
franchise,  value-added,  stamp, filing,  recording,  documentation,  or license
taxes,  however  imposed  or  asserted,  by any  United  States  state  or local
government  or taxing  authority  (all the foregoing  being herein  collectively
called  "Taxes" or,  separately a "Tax",  upon or with respect to (A) any of the
Subleased  Property,  any  portion  thereof,  or any  interest  therein  (B) the
acquisition,   purchase,  sale,  financing,   leasing,  subleasing,   ownership,
maintenance, repair, redelivery,  alteration, insuring, control, use, operation,
delivery,  possession,  repossession,  location, storage,  refinancing,  refund,
transfer  of title,  registration,  reregistration,  transfer  of  registration,
return,  or other  disposition  thereof of any of the Subleased  Property or any
portion thereof, or interest therein, (C) the rental payments, receipts, or

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<PAGE>

earnings  arising  from the  Subleased  Property,  any portion  thereof,  or any
interest therein,  or payable pursuant to the Sublease,  or any other payment or
right  to  receive  payment  pursuant  to  any  related  document,  or  (D)  any
Alteration,  removal,  substitution,  maintenance,  or  repair  of  any  of  the
Subleased Property.

(i) Exclusions  from General Tax Indemnity.  The provisions of Section  39(b)(1)
shall not apply to, and TowerCo shall have no liability  under Section  39(b)(1)
with respect to:

(ii) Taxes on any SBCW Group Member (other than such Taxes that are sales,  use,
rental, property, stamp, document filing, license, or ad valorem Taxes, or value
added Taxes that are in the nature of or in lieu of such  Taxes)  imposed on any
such member that are franchise Taxes,  privilege Taxes, doing business Taxes, or
Taxes  imposed on,  based on or  measured  by,  gross or net  income,  receipts,
capital,  or net worth of any such member which are imposed by any state, local,
or other  taxing  authority  within  the  United  States  or by any  foreign  or
international  taxing  authority that would have been imposed  without regard to
the  execution  of this  Sublease  and related  documents  and the  transactions
contemplated thereunder;

(iii) Taxes on any SBCW Group Member,  including without  limitation,  sales and
transfer Taxes, that result from any transfer by any SBCW Group Member of any of
the Subleased Property other than a sale,  assignment,  transfer, or disposition
(I)  attributable to a default by TowerCo and/or exercise of remedies under this
Sublease or related  documents;  (II)  resulting from any  maintenance,  repair,
Alteration,  substitution,  relocation,  or removal of or any addition to any of
the Subleased  Property or portion thereof or interest therein,  (III) resulting
from any loss,  damage,  destruction,  theft,  taking,  casualty,  condemnation,
confiscation,  expropriation,  or seizure of any  Subleased  Property or portion
thereof or interest therein;  or (IV) resulting from any subleasing,  permitting
use thereof,  or relinquishing  possession of any Subleased  Property or portion
thereof or interest therein;

(iv) Taxes  imposed by any  jurisdiction  on any SBCW Group  Member  solely as a
result of its  activities  in such  jurisdiction  unrelated to the  transactions
contemplated by the Sublease and related documents;

(v) Taxes on any SBCW Group  Member that result from the willful  misconduct  or
gross negligence of any such member or an Affiliate thereof or the inaccuracy or
breach of any representation, warranty, or covenant of such Tax Indemnitee or an
Affiliate  thereof under the  Transaction  Documents  (except to the extent such
inaccuracy   or  breach  is  attributed  to  an  inaccuracy  or  breach  of  any
representation,  warranty  or  covenant  of  TowerCo or an  Affiliate  under the
Transaction Documents);

(vi) Taxes which are attributable to any period or circumstance  occurring after
the expiration or earlier  termination  of this  Sublease,  except to the extent
attributable to (I) a failure of TowerCo or any of its transferees or sublessees
or users of the Subleased  Property (other than SBCW or its Affiliates) to fully
discharge  its  obligations  under the Sublease and related  documents,  or (II)
Taxes  imposed  on or with  respect  to any  payments  that  are due  after  the
expiration or earlier  termination of the Sublease and which are attributable to
a  period  or  circumstance  occurring  prior  to or  simultaneously  with  such
expiration or earlier termination;

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<PAGE>

(vii) any Tax that is being  contested  in  accordance  with the  provisions  of
Section 39(d) during the pendency of such contest,  but only for so long as such
contest is  continuing  in  accordance  with  Section  39(d) and  payment is not
otherwise required pursuant to Section 39(d); or

(viii) Taxes imposed on any SBCW Group Member that are United States  federal or
state net income Taxes of any such member.

The provisions of this Section  39(b)(2) shall not apply to any Taxes imposed in
respect of the receipt or accrual of any payment made by TowerCo on an After-Tax
Basis.

(2) Reports. If any report, return,  certification,  or statement is required to
be filed with respect to any Tax that is subject to  indemnification  under this
Section  39(b),  TowerCo  shall  timely  prepare and file the same to the extent
permitted by law (except for (i) any report,  return,  or statement  relating to
any net income Taxes or, (ii) any report,  return, or statement  relating to any
other Taxes described in Section  39(b)(2)(i) or any Taxes in lieu of or enacted
in substitution  for any of the foregoing,  except that, in such cases,  TowerCo
shall timely  provide  information  necessary to file such  report,  return,  or
statement or (iii) any other report, return,  certification,  or statement which
any SBCW Group Member has notified  TowerCo that such member  intends to prepare
and file);  provided  that any such  member  shall have  furnished  TowerCo,  at
TowerCo's  expense,  with such information  reasonably  necessary to prepare and
file such returns as is within such member's control.  TowerCo shall either file
such report, return, certification, or statement and send a copy of such report,
return, certification, or statement to the member, or, where not so permitted to
file, shall notify the member of such requirement  within a reasonable period of
time  prior  to the due  date  for  filing  (without  regard  to any  applicable
extensions)  and prepare and deliver  such  report,  return,  certification,  or
statement to the member. In addition, within a reasonable time prior to the time
such report, return, certification,  or statement is to be filed, TowerCo shall,
to the extent  permitted by law,  cause all billings of such Taxes to be made to
each SBCW Group  Member in care of TowerCo,  make payment  thereof,  and furnish
written  evidence of such payment.  TowerCo shall furnish  promptly upon written
request such data, records and documents as any SBCW Group Member may reasonably
require of TowerCo to enable  such  member to comply  with  requirements  of any
taxing  jurisdiction   arising  out  of  such  member's   participation  in  the
transactions contemplated by this Sublease and related documents.

(3)  Payments.  Any Tax  indemnified  under  this  Section  39(b)  shall be paid
directly  when due to the  applicable  taxing  authority  if direct  payment  is
permitted, or shall be reimbursed to the appropriate SBCW Group Member on demand
if paid by such member in accordance  herewith.  Except as otherwise provided in
this Section 39(b),  all amounts payable to a SBCW Group Member  hereunder shall
be paid promptly in immediately  available funds, but in no event later than the
later of (i) ten (10)  Business  Days after the date of such  demand or (ii) two
(2) Business Days before the date the Tax to which such amount payable hereunder
relates is due or is to be paid and shall be accompanied by a written  statement
describing  in  reasonable  detail  the Tax and the  computation  of the  amount
payable.  Such written statement shall, at TowerCo's request, as long as payment
is not delayed,  be verified by Ernst & Young, or another nationally  recognized
independent  accounting firm selected by such member. Such verification shall be
at TowerCo's expense unless the accounting firm determines that the amount

                                       67
<PAGE>

payable by TowerCo is more than ten percent  less than the amount  shown on such
written  statement,  in which event,  the applicable SBCW Group Member shall pay
such costs. In the case of a Tax subject to  indemnification  under this Section
39(b) which is properly  subject to a contest in accordance  with Section 39(d),
TowerCo (i) shall be  obligated  to make any  advances  with respect to such Tax
whenever required under Section 39(d) and (ii) shall pay such Tax (in the amount
finally  determined to be owing in such contest) on an After-Tax  Basis prior to
the latest time  permitted by the relevant  taxing  authority for timely payment
after a final determination.

(c) Tax Savings.  If, by reason of any payment made to or for the account of any
Tax  Indemnitee  by  TowerCo  pursuant  to  Section  39(a)  or  39(b),  such Tax
Indemnitee  at any time  realizes a reduction  in any Taxes or receives a refund
which was not taken into account previously in computing such payment by TowerCo
to or for the account of the Tax Indemnitee,  then the Tax Indemnitee  shall pay
to TowerCo an amount  equal to such  actual  reduction  in Taxes or such  refund
(including  interest received),  plus the amount of any additional  reduction in
Taxes  of the  Tax  Indemnitee  attributable  to the  payment  made  by the  Tax
Indemnitee to TowerCo pursuant to this sentence; provided, however, that (A) the
Tax  Indemnitee  shall not be obligated to make such payment with respect to any
net Tax  savings or refund to the extent that the amount of such  payment  would
exceed  the  excess of (x) all prior  indemnity  payments  (excluding  costs and
expenses  incurred with respect to contests) made by TowerCo with respect to the
Tax being  refunded or reduced  pursuant to Section 39(a) or 39(b),  as the case
may be,  over (y) the  amount of all prior  payments  by the Tax  Indemnitee  to
TowerCo  hereunder  with respect to such Tax  provided  that any such excess tax
savings  realized (or deemed realized) by such Tax Indemnitee which are not paid
to TowerCo as a result of this subclause (A) shall be carried forward and reduce
TowerCo's  obligations  to  make  subsequent  payments  to such  Tax  Indemnitee
pursuant  to  Section  39  hereof;  and (B) if any such Tax  savings  or  refund
realized by such the Tax  Indemnitee,  or any tax savings taken into account for
purposes of determining  "After-Tax Basis" shall be lost or otherwise determined
to be  unavailable,  such lost or  otherwise  unavailable  Tax savings or refund
shall be treated as a Tax for which TowerCo must  indemnify  the Tax  Indemnitee
pursuant to Section  39(a) or 39(b),  as the case may be (without  regard to the
exceptions  in Section  39(a)(4) or 39(b) other than the Section  39(a)(4)(iii),
39(a)(4)(iv), or 39(b)(2)(iv)).

(d) Contest  Rights.  In the event that any Tax Indemnitee  receives any written
notice of any potential claim or proposed adjustment against such Tax Indemnitee
that  would  result in a Tax Loss  against  which  TowerCo  may be  required  to
indemnify  pursuant  to  Section  39(a)  or  39(b)  (a "Tax  Claim"),  such  Tax
Indemnitee  shall  promptly  notify  TowerCo  thereof and provide  TowerCo  with
relevant information  thereto;  provided,  however,  that the failure by the Tax
Indemnitee to provide any such information  shall not be treated as a failure to
comply with this Section  39(d)  unless the failure  materially  prejudices  the
conduct of the contest  hereunder.  TowerCo may  require the Tax  Indemnitee  to
contest  such  Tax  Claim at  TowerCo's  expense  and,  in that  event,  the Tax
Indemnitee  shall  consult  with TowerCo in good faith,  but the Tax  Indemnitee
shall retain ultimate control over such contest. Notwithstanding the immediately

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<PAGE>

preceding  sentence,  the Tax Indemnitee  shall not be obligated to contest such
Tax Claim  unless (1) prior to taking the first such  required  action,  TowerCo
shall  have  furnished  to the Tax  Indemnitee,  in the case of a  contest  with
respect to federal  income  Taxes,  with an opinion of a nationally  recognized,
independent  tax counsel chosen by TowerCo and reasonably  acceptable to the Tax
Indemnitee,  or, in the case of a contest with  respect to other Taxes,  with an
opinion of a qualified tax counsel chosen by TowerCo and  reasonably  acceptable
to the Tax  Indemnitee,  to the effect that there is a reasonable  basis that is
consistent  with the standards  provided for in ABA Formal  Opinion 85-352 as in
effect (on the date  hereof) for the position to be asserted in  contesting  the
matter in question, (2) no event of default by TowerCo under this Sublease shall
have  occurred and be  continuing,  (3) such contest does not involve a material
risk to the Tax Indemnitee of sale,  forfeiture,  or loss of, or the creation of
any lien  on,  any of the  Subleased  Property  or the  imposition  of  criminal
penalties, (4) TowerCo shall have acknowledged,  in writing, that the contest is
with respect to a liability  that is  indemnifiable  by TowerCo  pursuant to the
terms of this Section 39(d),  (5) if TowerCo  reasonably  requests,  and the Tax
Indemnitee  elects to pursue,  a contest that  requires  payment of the Tax as a
condition to pursuing  the  contest,  TowerCo  shall loan,  on an  interest-free
basis, sufficient funds to the Tax Indemnitee to pay the Tax and any interest or
penalties  due on the  date  of  payment,  and  shall  fully  indemnify  the Tax
Indemnitee for any adverse Tax consequences resulting from such advance. The Tax
Indemnitee  shall  not  make,  accept,  or  enter  into a  settlement  or  other
compromise  with respect to any Taxes  indemnified  pursuant to Section 39(a) or
forego or  terminate  any such  proceeding  with  respect  to Taxes  indemnified
pursuant to this Section  39(b),  without the prior written  consent of TowerCo,
which consent shall not be unreasonably withheld. If TowerCo requests in writing
that the Tax Indemnitee accept a settlement of a claim offered by the IRS (other
than an offer  conditioned upon the Tax  Indemnitee's  agreement with respect to
any issue wholly or partly  unrelated to the  transactions  contemplated  by the
Transaction  Documents),  the Tax Indemnitee shall either accept such settlement
offer or agree with  TowerCo  that  TowerCo's  liability  pursuant to Section 39
hereof shall be limited to an amount  calculated on the basis of such settlement
offer.  The Tax Indemnitee  shall not be required to appeal any adverse decision
of the United States Tax Court,  a Federal  District  Court,  or any  comparable
trial court.

SECTION 40.       General Provisions.

(a)  Notices.  Whenever  any notice,  demand or request is required or permitted
under this  Agreement,  such notice,  demand or request  shall be in writing and
shall be delivered by hand,  be sent by registered  or certified  mail,  postage
prepaid,   return  receipt  requested,  or  be  sent  by  nationally  recognized
commercial  courier for next business day  delivery,  to the addresses set forth
below,  or to such other  addresses as are specified by written  notice given in
accordance  herewith,  or shall be transmitted  by facsimile  (with a copy to be
sent by  nationally  recognized  courier for next  business day delivery) to the
number for each Party set forth below their respective  executions hereof, or to
such  other  numbers as are  specified  by written  notice  given in  accordance
herewith.  All  notices,  demands or requests  delivered by hand shall be deemed
given upon the date so delivered; those given by mailing as hereinabove provided
shall be deemed given on the date of deposit in the United  States  Mail;  those
given by commercial courier as hereinabove provided shall be deemed given on the
date of deposit with the commercial courier;  and those given by facsimile shall
be deemed  given on the date of  facsimile  transmittal.  Nonetheless,  the time
period, if any, in which a response, or action in response, to any notice,

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<PAGE>

demand or request  must be given shall  commence to run from the date of receipt
of the notice, demand or request by the addressee thereof. Any notice, demand or
request not received  because of changed address or facsimile number of which no
notice  was given as  hereinabove  provided  or  because  of  refusal  to accept
delivery shall be deemed  received by the Party to whom addressed on the date of
hand delivery, on the date of facsimile  transmittal,  on the first calendar day
after deposit with  commercial  courier,  or on the third calendar day following
deposit in the United States Mail, as the case may be.

         If to TowerCo:

                  Southern Towers, Inc.
                  c/o SpectraSite Communications, Inc.
                  100 Regency Forest Drive, Suite 400
                  Cary, North Carolina 27511
                  Attention:  General Counsel
                  Telecopy:  (919) 468-8522

                  with a copy to:

                  Paul, Weiss, Rifkind, Wharton & Garrison
                  1285 Avenue of the Americas
                  New York, New York  10019-6064
                  Attention:  Mitchell L. Berg
                               Bruce A. Gutenplan
                  Telecopy:  (212) 757-3990

         If to SBCW or any SBCW Affiliate:

                  SBC Wireless, Inc.
                  17330 Preston Road,  Suite #100A
                  Dallas, TX  75252
                  Attention: General Counsel
                  Telecopy: 972-733-2021

                  with a copy to:

                  SBC Communications Inc.
                  175 E. Houston
                  4th Floor
                  San Antonio, TX  78205
                  Attention:  Vice President and Assistant
                                    General Counsel
                  Telecopy: (210) 351-3488

         If to TowerCo Parent:

                  SpectraSite Holdings, Inc.
                  c/o SpectraSite Communications, Inc.
                  100 Regency Forest Drive, Suite 400
                  Cary, North Carolina 27511
                  Attention:  General Counsel
                  Telecopy:  (919) 468-8522

                  with a copy to:

                  Paul, Weiss, Rifkind, Wharton & Garrison
                  1285 Avenue of the Americas
                  New York, New York  10019-6064
                  Attention:  Mitchell L. Berg
                               Bruce A. Gutenplan
                  Telecopy:  (212) 757-3990

(b)  Facsimile as Writing.  The Parties  expressly  acknowledge  and agree that,
notwithstanding  any  statutory or decisional  law to the contrary,  the printed
product  of a  facsimile  transmittal  shall be  deemed  to be  "written"  and a
"writing" for all purposes of this Sublease.

(c) Binding Effect. This Sublease shall be binding upon and enforceable against,
and shall  inure to the  benefit  of, the  Parties  hereto and their  respective
heirs, legal representatives, successors and permitted assigns.

(d)  Headings.  The use of headings,  captions  and numbers in this  Sublease is
solely for the convenience of identifying and indexing the various provisions in
this  Sublease and shall in no event be  considered  otherwise in  construing or
interpreting any provision in this Sublease.

(e) WAIVER OF JURY TRIAL.  TO THE MAXIMUM  EXTENT  PERMITTED BY LAW, THE PARTIES
HEREBY KNOWINGLY,  VOLUNTARILY AND  INTENTIONALLY  WAIVE THE RIGHT TO A TRIAL BY
JURY IN RESPECT OF ANY  LITIGATION  BASED  HEREON,  ARISING OUT OF,  UNDER OR IN
CONNECTION  WITH THIS  SUBLEASE,  OR ANY COURSE OF  CONDUCT,  COURSE OF DEALING,
STATEMENT  (WHETHER VERBAL OR WRITTEN) OR ACTION OF EITHER PARTY OR ANY EXERCISE
BY ANY PARTY OF THEIR RESPECTIVE RIGHTS UNDER THIS SUBLEASE (INCLUDING,  WITHOUT
LIMITATION,  ANY ACTION TO  TERMINATE  THIS  SUBLEASE,  AND ANY CLAIM OR DEFENSE
ASSERTING THAT THIS AGREEMENT WAS  FRAUDULENTLY  INDUCED OR IS OTHERWISE VOID OR
VOIDABLE).  THIS WAIVER IS A MATERIAL  INDUCEMENT  FOR THE PARTIES TO ENTER INTO
THIS SUBLEASE.

(f) Exhibits.  Each and every exhibit referred to or otherwise mentioned in this
Sublease is attached to this Sublease and is and shall be construed to be made a
part of this Sublease by such  reference or other mention at each point at which
such  reference or other  mention  occurs,  in the same manner and with the same
effect as if each  exhibit were set forth in full and at length every time it is
referred to or otherwise mentioned.

                                       71
<PAGE>

(g)  Defined  Terms.  Capitalized  terms  used in this  Sublease  shall have the
meanings  ascribed  to them at the point where first  defined,  irrespective  of
where their use occurs, with the same effect as if the definitions of such terms
were set forth in full and at length every time such terms are used.

(h) Pronouns.  Wherever appropriate in this Sublease, personal pronouns shall be
deemed to include the other genders and the singular to include the plural.

(i)  Severability.  If any  term,  covenant,  condition  or  provision  of  this
Sublease,  or the application thereof to any person or circumstance,  shall ever
be held to be invalid or unenforceable, then in each such event the remainder of
this Sublease or the application of such term, covenant,  condition or provision
to any other person or any other  circumstance  (other than those as to which it
shall be invalid or unenforceable) shall not be thereby affected, and each term,
covenant,  condition and provision  hereof shall remain valid and enforceable to
the fullest extent permitted by law.

(j)  Non-Waiver.  Failure by any Party to complain of any action,  non-action or
breach of any other Party shall not constitute a waiver of any aggrieved Party's
rights  hereunder.  Waiver by any Party of any right  arising from any breach of
any other Party shall not  constitute a waiver of any other right arising from a
subsequent breach of the same obligation or for any other default, past, present
or future.

(k) Rights Cumulative.  All rights,  remedies,  powers and privileges  conferred
under this  Sublease on the Parties  shall be  cumulative of and in addition to,
but not restrictive of or in lieu of, those conferred by law.

(l) Time of  Essence.  Time is of the essence of this  Sublease.  Anywhere a day
certain is stated for  payment or for  performance  of any  obligation,  the day
certain so stated enters into and becomes a part of the  consideration  for this
Sublease.  If any date set  forth in this  Sublease  shall  fall on, or any time
period set forth in this  Sublease  shall  expire on, a day which is a Saturday,
Sunday or federal or state holiday,  such date shall  automatically  be extended
to, and the  expiration of such time period shall  automatically  to be extended
to, the next day which is not a Saturday,  Sunday,  federal or state  holiday or
other  non-business day. The final day of any time period under this Sublease or
any deadline  under this Sublease  shall be the specified day or date, and shall
include the period of time through and including such specified day or date.

(m)  Applicable  Law. This Sublease  shall be governed by,  construed  under and
interpreted  and enforced in accordance  with the laws of the State of New York,
without regard to conflicts of law.

(n) Entire Agreement. This Sublease contains the entire agreement of the Parties
with respect to the subject matter hereof, and all representations,  warranties,
inducements,  promises or agreements, oral or otherwise, between the Parties not
embodied in this Sublease shall be of no force or effect.

                                       72
<PAGE>

(o) Modifications. This Sublease shall not be modified or amended in any respect
except by a written agreement executed by the Parties in the same manner as this
Sublease is executed.

(p) Counterparts. This Sublease may be executed in several counterparts, each of
which shall be deemed an original,  and all of such counterparts  together shall
constitute one and the same instrument.

(q)  Attorneys'  Fees.  In the  event  of any  litigation  arising  under  or in
connection with this Sublease, the prevailing Party shall be entitled to recover
from the other Party the expenses of litigation (including reasonable attorneys'
fees, expenses and disbursements) incurred by the prevailing Party.

(r) Authority.  Each Party hereto  warrants and  represents  that such Party has
full and complete authority to enter into this Sublease and that each individual
executing  this  Sublease on behalf of such Party has been fully  authorized  to
execute  this  Sublease  on behalf of such Party and that such Party is bound by
the signature of such representative.

(s) Counsel.  Each Party hereto warrants and represents that such Party has been
afforded  the  opportunity  to be  represented  by  counsel  of  its  choice  in
connection with the execution of this Sublease and has had ample  opportunity to
read, review, and understand the provisions of this Sublease.

(t) No  Construction  Against  Preparer.  No provision of this Sublease shall be
construed  against or interpreted to the  disadvantage of any Party by any court
or other  governmental or judicial authority by reason of such Party's having or
being deemed to have prepared or imposed such provision.

(u) Power of Attorney by SBCW Group; Authorization.

(i) SBCW Group and each of them, hereby irrevocably  constitute and appoint SBCW
(the "Agent") as their agent to enter into,  modify,  amend or otherwise  change
this Sublease,  any Site Designation Supplement or any of their respective terms
or  provisions,  to take all actions and to execute all  documents  necessary or
desirable to effect the terms of this  Sublease,  and to take all actions and to
execution  all  documents  which may be necessary  or  desirable  in  connection
therewith,  to give and receive consents and all notices hereunder, to negotiate
and settle  Claims for  indemnification,  and to perform  any other act  arising
under or pertaining to the Sublease and the Site Designation  Supplements.  SBCW
Group,  and each of them,  agree that  service of process  upon the Agent in any
action or proceeding arising under or pertaining to the Sublease shall be deemed
to be valid service of process upon SBCW Group,  and each of them, and any claim
by TowerCo against SBCW Group, or any of them, in respect to the Sublease may be
asserted against, and settled with, the Agent. The Agent shall be deemed to have
accepted the appointment herein upon its execution of this Sublease.

(ii) Nothing  contained  herein shall be deemed to make the Agent liable to SBCW
Group  because of service in its  capacity as agent.  In  performing  any of its
duties hereunder, the Agent shall not incur any liability to SBCW Group for

                                       73
<PAGE>

losses, damages,  Liabilities or expenses, except for its fraud, willful default
or gross negligence.

(iii)    It is expressly  understood  and agreed that this power of attorney and
         the agency created hereby is coupled with an interest of the respective
         Parties hereto and shall be binding and  enforceable on and against the
         respective  successors and assigns of SBCW Group, and each of them, and
         this power of  attorney  shall not be revoked or  terminated  and shall
         continue to be binding and enforceable in the manner provided herein.

                   REMAINDER OF PAGE INTENTIONALLY LEFT BLANK

                                       74
<PAGE>

                                 SCHEDULE 14(d)

                          INTERFERENCE STUDY PROCEDURES

                      [To Be Provided for Initial Closing]

<PAGE>

                                    EXHIBIT A

                        LIST OF SITES SUBJECT TO SUBLEASE

                  [To Be Provided for Initial Closing and to be
                 modified at each Closing to reflect Sites added
                at each Closing pursuant to the Closing Schedule]

<PAGE>

                                                                      Schedule A
                                                                              to
                            Exhibit A (List of Sites)

                            Contractual Arrangements

<PAGE>

                                    EXHIBIT B

                       FORM OF SITE DESIGNATION SUPPLEMENT

<PAGE>

                                    EXHIBIT C

                          SITE MAINTENANCE OBLIGATIONS,
                        WITH RESPECT TO SPACE SUBTENANTS'
                            COMMUNICATIONS EQUIPMENT

                    [To Be Provided for the Initial Closing]

<PAGE>

                                    EXHIBIT D

                        SBCW GROUP BOUND BY THE SUBLEASE

                        [To Be Completed at Each Closing]

<PAGE>

                                    EXHIBIT E

                               STANDARD PROCEDURES

                    [To Be Provided for the Initial Closing]

<PAGE>

                                    EXHIBIT F

             FORM OF NOTICE OF TOWERCO WORK OR ADDITIONAL EQUIPMENT

                    [To Be Provided for the Initial Closing]

<PAGE>

                                    EXHIBIT G

                                 ESTIMATED COSTS

                    [To Be Provided for the Initial Closing]

<PAGE>

                                    EXHIBIT F

                            SITE MARKETING TERM SHEET

Parties

Marketer      - SpectraSite Communications, Inc.
Owner         - SBCW or any Sublessor Entity

Term

The  Agreement  shall  commence  on the Initial  Closing  Date and expire on the
earlier of (i) the date the Agreement to Sublease expires or is terminated, (ii)
the Final Closing Date or such later date as  contemplated by Section 3.3 of the
Agreement to Sublease; or (iii) with respect to a Site, at such time as the Site
becomes an Included Site or an Excluded Site.

Fees

Marketer  will  receive 20% of third party  rentals  until such time as the Site
with such tenant  sublease  becomes an Included  Site, and if such Site does not
become an Included  Site,  Marketer  shall be entitled to 20% of the third party
rental with respect to such tenant  sublease  for the term of such  sublease (as
the same may be  extended).  Owner will  receive 80% of the third  party  rental
until such time as the Site with such tenant sublease  becomes an Included Site,
at which time Owner's  right to receive third party rentals with respect to such
Included Site under the Site Marketing Agreement shall terminate.

Operational Procedures

Operational procedures will be similar to those contained in the SBCW Sublease.

Timing of Colocation

The parties will agree on a colocation  process that will allow for the diligent
processing and approval of colocation commitments.

Third Party Sublease and Rent

The  parties  will  mutually  agree on a standard  form of  sublease  reasonably
acceptable to both parties.

SBCW shall have the right to approve the third party tenant and sublease,  which
approval will not be unreasonably withheld or delayed.

The third party rent shall be at the then prevailing  marketing rates.  Marketer
shall collect such rents and shall pay Owner's portion of such rents to Owner on
a monthly basis.

<PAGE>

Access

SBCW will cooperate with Marketer to provide promptly to Marketer,  upon request
by Marketer,  reasonable  access to the Existing Sites and the books and records
of the Existing Sites.

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