EXHIBIT 10.1b















                     COMMUNICATION SYSTEMS DEVELOPMENT, LLC

                     AGREEMENT OF LIMITED LIABILITY COMPANY

                            Dated as of May 30, 1997













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                     COMMUNICATION SYSTEMS DEVELOPMENT, LLC
                     AGREEMENT OF LIMITED LIABILITY COMPANY

                                TABLE OF CONTENTS
                                                                                                                Page
<S>              <C>                                                                                            <C>
ARTICLE 1         DEFINITIONS.....................................................................................1

ARTICLE 2         FORMATION OF LIMITED LIABILITY COMPANY..........................................................1
                  2.1      Formation.  ...........................................................................1
                  2.2      Company Name...........................................................................1
                  2.3      The Certificate, Etc...................................................................2
                  2.4      Principal Business Office, Registered Office and Registered Agent......................2
                  2.5      Term of the Company....................................................................2
                  2.6      Purposes...............................................................................2
                  2.7      Powers.................................................................................2

 ARTICLE 3        CAPITALIZATION..................................................................................3
                  3.1      Initial Capital Contributions..........................................................3
                  3.2      ATS Construction Funding...............................................................3
                  3.3      Other Required Funds...................................................................4
                  3.4      Capital Accounts. .....................................................................5
                  3.5      Transfer of Capital Accounts...........................................................6
                  3.6      Deficit Capital Accounts...............................................................6
                  3.7      Additional Equity......................................................................6

ARTICLE 4         BOOKS; ACCOUNTING; TAX ELECTIONS; REPORTS ......................................................6
                  4.1      Fiscal Year............................................................................6
                  4.2      Method of Accounting and Taxation......................................................6
                  4.3      Books and Records and Inspection.......................................................6
                  4.4      Reports................................................................................7
                  4.5      Filing of Returns and Other Writings; Tax Matters Member.  ............................8

ARTICLE 5         ALLOCATIONS.....................................................................................8
                  5.1      Allocations of Profit and Loss.........................................................8
                  5.2      Section 754 Election...................................................................9
                  5.3      Allocations for Tax and Book Purposes..................................................9
                  5.4      Certain Accounting Matters.............................................................9
                  5.5      Tax Allocations; Code Section 704(c)...................................................9
                  5.6      Compliance With Section 704(b).........................................................9
                  5.7      Curative Allocations..................................................................10

 ARTICLE 6        DISTRIBUTIONS..................................................................................11
                  6.1      Distributions Other Than Proceeds of Any Liquidating Transaction......................11
                  6.2      Proceeds of Any Liquidating Transaction...............................................11
                  6.3      Liquidation of Member's Interest......................................................11

ARTICLE 7         RIGHTS AND OBLIGATIONS OF MEMBERS..............................................................12
                  7.1      Limited Liability.....................................................................12
                  7.2      Management and Control, Etc...........................................................12
                  7.3      Evidence of Authority, Etc............................................................13
                  7.4      Other Business, Etc...................................................................14

                                     

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                  7.5      Indemnification.......................................................................14
                  7.6      Agreements with Affiliates............................................................15
                  7.7      Payment of Expenses; Compensation.....................................................15

ARTICLE 8         TRANSFERS OF INTERESTS, ETC....................................................................15
                  8.1      Consent Required......................................................................15
                  8.2      Right of First Refusal................................................................16
                  8.3      Buy/Sell..............................................................................16
                  8.4      CSD Right/Obligation of Exchange.  ...................................................18
                  8.5      Obligations and Rights of Transferees and Assignees...................................19
                  8.6      Non-Recognition of Certain Transfers..................................................19
                  8.7      Required Amendments; Continuation.....................................................19
                  8.8      Resignation...........................................................................19

ARTICLE 9         TERMINATION....................................................................................20
                  9.1      Events of Dissolution.................................................................20
                  9.2      Application of Assets.................................................................20
                  9.3      Distributions in Liquidation..........................................................20

ARTICLE 10        MISCELLANEOUS..................................................................................20
                  10.1     Notices...............................................................................20
                  10.2     Specific Performance; Other Rights and Remedies.......................................21
                  10.3     Severability..........................................................................21
                  10.4     Counterparts..........................................................................21
                  10.5     Section Headings......................................................................21
                  10.6     Title to Company Property.............................................................21
                  10.7     Governing Law.........................................................................22
                  10.8     Further Acts..........................................................................22
                  10.9     Entire Agreement......................................................................22
                  10.10    Assignment............................................................................22
                  10.11    Parties in Interest...................................................................22
                  10.12    Mutual Drafting.......................................................................22
                  10.13    Amendments; Waivers...................................................................22
                  10.14    Schedule..............................................................................23
</TABLE>

Member Schedule - Initial Capital Contributions of the Members

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                     COMMUNICATION SYSTEMS DEVELOPMENT, LLC

                     AGREEMENT OF LIMITED LIABILITY COMPANY


         THIS AGREEMENT OF LIMITED LIABILITY COMPANY of Communication Systems
Development,  LLC,  dated  as of May 30,  1997,  is  entered  into by and  among
American Tower Systems,  Inc., a Delaware corporation ("ATS"), and Communication
Development Corporation, Inc., a California corporation ("CSD").

                                WITNESSETH THAT:

         WHEREAS,  the undersigned  desire,  by execution of this Agreement,  to
form a limited  liability  company  pursuant to the Delaware  Limited  Liability
Company  Act, 6 Del.  C.  ss.18-101  et seq.  (as from time to time  amended and
including any successor statute of similar import, the "Act");

         NOW,  THEREFORE,  in  consideration  of  the  mutual  covenants  herein
contained and other  valuable  consideration,  the receipt and adequacy of which
are hereby acknowledged, the parties hereto do hereby agree as follows:

                                    ARTICLE 1

                                   DEFINITIONS

         As used  herein,  unless  the  context  otherwise  requires,  the terms
defined in  Appendix A shall have the  respective  meanings  set forth  therein.
Terms defined in the singular  shall have a comparable  meaning when used in the
plural,  and vice  versa,  and the  reference  to any gender  shall be deemed to
include all genders.  Unless otherwise  defined or the context otherwise clearly
requires,  terms for which  meanings are provided in this  Agreement  shall have
such  meanings  when used in each  document  executed or required to be executed
pursuant hereto or thereto or otherwise  delivered,  from time to time, pursuant
hereto or  thereto.  The words such as  "herein",  "hereinafter",  "hereof"  and
"hereunder"  refer to this  Agreement as a whole and not merely to a subdivision
in which such words appear unless the context otherwise  requires.  The singular
shall include the plural and the masculine gender shall include the feminine and
neuter, and vice versa, unless the context otherwise requires.


                                    ARTICLE 2

                     FORMATION OF LIMITED LIABILITY COMPANY

         2.1  Formation.  The parties,  by execution of this  Agreement,  hereby
enter into and join  together in, and do hereby  form,  the Company as a limited
liability  company under and pursuant to the Act.  Each party hereto  represents
and warrants that it is duly  authorized to join in this  Agreement and that the
Person executing this Agreement on its behalf is duly authorized to do so.

         2.2  Company  Name.  The name of the  Company  shall  be  Communication
Systems  Development,  LLC. The business of the Company shall be conducted under
such name or such other names as may from time be established by a Determination
of the Members.
                                

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         2.3 The  Certificate,  Etc. One or more of the Members,  as  authorized
persons shall execute and file the  Certificate,  together with a duplicate copy
thereof, with the Secretary of State of the State of Delaware,  and upon receipt
from the  Secretary  of State of the  duplicate  copy (and any  certificates  of
amendment  thereto that may  subsequently be filed) marked "Filed",  the Members
executing  the  Certificate  shall  promptly  deliver  or mail,  or caused to be
delivered  or mailed,  a copy of the  Certificate  (or any such  certificate  of
amendment) to any Member not so executing the  Certificate  (or  certificate  of
amendment). The Members hereby agree (or to cause one or more of the individuals
designated  as managers  under  Section 7.2 hereof) to execute,  file and record
such other certificates and documents,  including amendments to the Certificate,
and to do such other acts as may be appropriate to comply with all  requirements
for the formation,  continuation and operation of a limited  liability  company,
the  ownership  of property,  and the conduct of business  under the laws of the
State of  Delaware  and any  other  jurisdiction  in which the  Company  may own
property or conduct business.

         2.4 Principal Business Office,  Registered Office and Registered Agent.
The principal  business office of the Company shall be located at 7488 Shoreline
Drive,  Suite 1-B,  Stockton,  California 95219 or at such other location as may
hereafter be designated by a Determination of the Members. The registered office
of the Company  shall be c/o  Corporation  Service  Company,  1013 Centre  Road,
Wilmington,  New Castle County, Delaware 19805. The registered agent for service
of process on the Company shall be Corporation Service Company, whose address is
1013 Centre Road, Wilmington,  New Castle County,  Delaware 19805. The principal
business office,  the registered  office and the registered agent of the Company
may be changed  from time to time upon a  Determination  of the  Members  and in
accordance  with  the  then  applicable  provisions  of the Act  and  any  other
applicable laws. The Members shall be promptly notified in writing of any change
in such principal  office,  registered office or registered agent for service of
process.

         2.5 Term of the Company.  The term of the Company shall commence on the
date of the initial filing of the  Certificate  with the office of the Secretary
of State of the State of Delaware (the  "Effective  Date"),  and shall  continue
until December 31, 2047 unless it is sooner dissolved pursuant to the provisions
of Section 9.1.

         2.6 Purposes. The purpose of the Company is to engage, whether directly
or  indirectly,  in  the  development,   ownership,  operation,  management  and
disposition of communication  towers and communication tower sites and to engage
in all actions necessary, convenient or incidental to the foregoing. The Company
shall not engage in any other business or activity  without a  Determination  of
the Members.

         2.7 Powers.  In furtherance of its purposes,  but subject to all of the
provisions  of this  Agreement,  the Company  shall have the power and is hereby
authorized to:

                  (a) acquire by purchase,  lease,  contribution  of property or
         otherwise and own, hold, sell,  convey,  transfer or dispose of real or
         personal  property which may be necessary,  convenient or incidental to
         the accomplishment of the purposes of the Company;

                  (b) act as a general  or  limited  partner  of any  general or
         limited  partnership  of which  the  Company  may be a  partner  and to
         exercise  all  of  the  powers,  duties,  rights  and  responsibilities
         associated therewith;

                  (c)  take  any  and  all  actions  necessary,   convenient  or
         appropriate  as the  holder of  partnership  interests,  including  the
         granting or approval of waivers,  consents or  amendments  of rights or
         powers relating  thereto and the execution of appropriate  documents to
         evidence such waivers, consents or amendments;

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                  (d) operate, purchase,  maintain, finance, improve, own, sell,
         convey, assign, mortgage, lease or demolish or otherwise dispose of any
         real  or  personal  property  which  may be  necessary,  convenient  or
         incidental to the accomplishment of the purposes of the Company;

                  (e)  borrow  money  and issue  evidences  of  indebtedness  in
         furtherance  of any or all of the purposes of the  Company,  and secure
         the  same by  mortgage,  pledge  or  other  lien on the  assets  of the
         Company;

                  (f) invest any funds of the Company  pending  distribution  or
         payment of the same pursuant to the provisions of this Agreement;

                  (g) prepay in whole or in part, refinance,  recast,  increase,
         modify or extend any  indebtedness  of the Company  and, in  connection
         therewith,  execute any extensions,  renewals or  modifications  of any
         mortgage or security agreement securing such indebtedness;

                  (h) enter into,  perform and carry out  contracts of any kind,
         including,  without  limitation,  contracts  with  any  Affiliate  of a
         Member,  necessary  to,  in  connection  with,  or  incidental  to  the
         accomplishment of the purposes of the Company;

                  (i)  establish  reserves  for  capital  expenditures,  working
         capital, debt service, taxes, assessments, insurance premiums, repairs,
         improvements,   depreciation,   depletion,  obsolescence,  and  general
         maintenance of buildings and other property out of the rents,  profits,
         or other income received;

                  (j) employ or otherwise engage employees, managers, directors,
         contractors, advisors and consultants (including without limitation any
         Member) and pay reasonable compensation for such services;

                  (k) enter  into  partnerships  or other  ventures  with  other
         Persons  (including  without limitation any Affiliate of any Member) in
         furtherance of the purposes of the Company; and

                  (l) do such other  things and engage in such other  activities
         related to the foregoing as may be  necessary,  convenient or advisable
         with respect to the conduct of the  business of the  Company,  and have
         and  exercise  all of the  powers  and rights  conferred  upon  limited
         liability companies formed pursuant to the Act.


                                    ARTICLE 3

                                 CAPITALIZATION

         3.1 Initial Capital Contributions. Each of the Members shall contribute
or cause to be contributed to the Company, on the Effective Date, as its Initial
Capital  Contribution,  the cash and  other  property  set  forth on the  Member
Schedule.

         3.2 ATS  Construction  Funding.  ATS agrees to make, from time to time,
Additional Capital Contributions for the purposes of constructing  communication
towers  and  other  improvements  on the  sites to be  acquired  by the  Company
pursuant to the consummation of the transactions contemplated by the

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Acquisition  Agreement  and,  in  addition  from  time to  time,  for  acquiring
additional sites and constructing  communication  towers and other  improvements
thereon, subject to the following conditions:

                  (i) ATS  shall  have  approved  the  acquisition  of any  such
         additional site for which the Additional Capital  Contribution is to be
         used, such approval not to be unreasonably withheld; and

                  (ii) CSD  shall  have  prepared  in good  faith,  based on the
         results  of  comparable  sites and towers  owned by the  Company or any
         Affiliates  of any of the Members,  and  furnished to ATS not less than
         thirty  (30)  days  prior  to the  proposed  acquisition  of the site a
         financial  analysis of the costs associated with such acquisition,  the
         construction  of  the  communication  tower  or  towers  thereon,   the
         estimated  revenue to be  obtained  and  expenses to be incurred in the
         operation and maintenance of such tower or towers.

         Upon receipt of such financial analysis,  and such other information as
it shall have reasonably requested,  ATS shall determine, in good faith, whether
it reasonably believes that the proposed project is in the best interests of the
Company.  In the  event it  agrees  that they will or is, as the case may be, it
shall be obligated to make the Additional  Capital  Contribution  referred to in
such  financial  analysis  in  a  timely  manner  in  order  to  facilitate  the
acquisition  of the  site and the  construction  of the  communication  tower or
towers.  Any  Additional  Capital  Contribution  made  by  ATS  pursuant  to the
provisions  of  this  Section  will  not  in  any  way  result  in a  change  or
modification as to any Member's  Company  Interest as initially set forth in the
Member  Schedule,  but shall only be  reflected  as an increase in ATS'  Capital
Account.  In the event ATS shall  not have  given  written  notice to CSD of its
objection (an "Objection Notice") to the acquisition within ten (10) days of the
receipt of such  financial  analysis  (and any other  information  with  respect
thereto which it has reasonably requested),  it shall be deemed to have approved
such  acquisition  and  shall  be  obligated  to make  such  Additional  Capital
Contribution. In the event ATS shall have given an Objection Notice (which shall
specify in reasonable detail the basis thereof),  CSD and ATS shall negotiate in
good faith in an effort to resolve their  differences  to the end that ATS would
be willing to make the Additional Capital Contribution. In the event ATS and CSD
are unable to resolve their differences  within twenty (20) days, CSD shall have
the  right,  in its sole and  absolute  discretion,  to (x) make the  Additional
Capital  Contribution  on the same terms and  conditions as ATS would  otherwise
have made such  Additional  Capital  Contribution,  (ii) to advance the required
funds in the form of a Member Loan, (iii) to obtain such funds as a loan from an
Unaffiliated  Person in accordance  with the provisions of Section 3.3 (in which
event no Determination of the Members will be required), or (iv) to acquire such
site and  construct  such tower or towers for its own account or for the account
of any Affiliate of CSD.

         Anything in this Section or elsewhere in this Agreement to the contrary
notwithstanding,  ATS shall  advance  all funds to finance the  construction  of
communication  towers on the  initial  sixty (60) sites  acquired by the Company
upon its formation and the consummation of the transactions  contemplated by the
Acquisition Agreement in the form of Additional Capital Contributions and not in
the form of Member Loans or loans from one or more Unaffiliated Persons.

         3.3 Other Required  Funds. In the event that in the judgment of Members
representing a Determination of the Members additional funds are required by the
Company for any Company  purpose  which ATS is not obligated to fund pursuant to
the provisions of Section 3.2, the Members may elect,  upon a  Determination  of
the  Members,  but  subject in any event to the  provisions  of Section  7.2, to
obtain  such funds as a loan from any  Unaffiliated  Person  upon such terms and
conditions as the Members, by Determination of the Members, deem appropriate or,
in the  alternative,  the Members may elect, by Unanimous  Determination  of the
Members, to cause each Member to advance, as an Additional Capital Contribution,
its proportionate  share, based upon the Company Interests of all Members, or in
such other  proportion  as shall be fixed by a  Unanimous  Determination  of the
Members, of the total amount so required,

                                       -4-

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it  being  expressly  understood  that  no  Member  may be  required  to make an
Additional  Capital  Contribution  and no such Additional  Capital  Contribution
shall be made by any  Member,  unless  the same  shall  have  been  approved  by
Unanimous  Determination of the Members. CSD shall also have the right, pursuant
to  the  provisions  of  Section  3.2,  to  obtain  funds  as a  loan  from  any
Unaffiliated Person.

         In the event that additional funds are required for any Company purpose
which ATS is not  obligated to fund  pursuant to the  provisions of Section 3.2,
and  provided  that the Members  are unable to obtain,  or agree upon terms with
respect to, a loan from an  Unaffiliated  Person of such funds or if the Members
fail to agree, by Unanimous Determination of the Members, to advance the same as
Additional Capital Contributions, then any Member may, by written notice to each
Member,  propose that the same be advanced as loans from the  Members.  Any such
loan (each a "Member  Loan") shall bear  interest at an annual rate of interest,
compounded quarterly, equal to the Prime Rate plus two (2) percentage points and
shall be payable,  on a priority  basis,  out of Cash Flow and at liquidation of
the Company,  all as further  provided in Article 6. Any such Member Loan may be
advanced by all of the Members, pro rata in proportion to Company Interests, or,
in the event that any Member  declines to participate in any such Member Loan by
advancing  its share  thereof  within ten (10) days  after  receipt of a written
proposal  with respect to such loan,  by any Member or Members who  determine to
participate  therein,  it being  expressly  understood and agreed that no Member
shall have any obligation to participate in any Member Loan so proposed.  To the
extent that any Member  declines to  participate in any Member Loan so proposed,
that Member's  portion of the Member Loan so proposed  shall be allocated to the
Member or Members who elect to participate  therein in such  proportions as such
other Members may agree or, in the absence of such agreement, pro rata among all
Members  electing  to  participate  therein in  proportion  to their  respective
Company Interests.

         3.4 Capital Accounts.  A separate capital account (a "Capital Account")
shall be  established  and  maintained  for each Member in  accordance  with the
following provisions:

                  (a) To each Member's  Capital  Account there shall be credited
         the  amount  of cash and fair  market  value of the  property  actually
         contributed to the Company  pursuant to Sections 3.1, 3.2 and 3.3, such
         Member's  allocable  share of  Profit  and the  amount  of any  Company
         liabilities  that are assumed by such Member or that are secured by any
         Company property distributed to such Member.

                  (b) To each  Member's  Capital  Account there shall be debited
         the amount of cash and the fair market  value of any  Company  property
         distributed to such Member pursuant to any provision of this Agreement,
         such Member's allocable share of Loss and the amount of any liabilities
         of such  Member  that are assumed by the Company or that are secured by
         any property contributed by such Member to the Company.

                  (c)  The  provisions  of  this   Agreement   relating  to  the
         maintenance  of Capital  Accounts  are  intended to comply with Section
         1.704-1(b)(2)(iv) of the Treasury Regulations, and shall be interpreted
         and applied in a manner consistent with such Treasury Regulations.

                  (d) A Member shall not be entitled to withdraw any part of its
         Capital Account or to receive any distributions from the Company except
         as  provided  in Article 6; nor shall a Member be  entitled to make any
         loan or Capital  Contribution  to the Company  other than as  expressly
         provided  herein.  No loan  made to the  Company  by any  Member  shall
         constitute a Capital Contribution to the Company for any purpose.

                  (e) Except as required  by the Act,  no Member  shall have any
         liability  for the  return  of the  Capital  Contribution  of any other
         Member. A Member who has more than one interest in the

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         Company  shall have a single  Capital  Account  that  reflects all such
         interests,  regardless of the class of interest owned and regardless of
         the time or manner in which the interests were acquired.

         3.5  Transfer  of  Capital  Accounts.   The  original  Capital  Account
established  for each  substituted  Member  shall be in the same  amount  as the
Capital Account of the Member which such  substituted  Member  succeeds,  at the
time such substituted Member is admitted to the Company.  The Capital Account of
any Member  whose  interest in the Company  shall be  increased  by means of the
transfer to it of all or part of the  interest in the Company of another  Member
shall be appropriately  adjusted to reflect such transfer. Any reference in this
Agreement to a Capital  Contribution  of or  distribution to a then Member shall
include a Capital  Contribution  or  distribution  previously  made by or to any
prior Member on account of the Company interest of such then Member.

         3.6 Deficit Capital  Accounts.  No Member with a deficit in his Capital
Account  shall be obligated  to restore  such deficit  balance or make a Capital
Contribution to the Company solely by reason of such deficit.

         3.7 Additional Equity. If the Members, by a Unanimous  Determination of
the Members,  conclude  that an additional  equity  investment in the Company is
necessary and desirable,  the Board shall determine the value of the outstanding
equity of the Company,  and based on such value,  shall  determine the price for
the additional  equity to be issued.  Each Member shall be entitled to subscribe
for such Member's  proportionate  share (based on its Company  Interest) of such
additional equity. If any Member shall subscribe for less than its proportionate
share, the excess shall then be offered to the  fully-subscribing  Members.  Any
portion not subscribed for by Members may then be offered to Persons who are not
Members.  If it is necessary to offer such equity to Persons who are not Members
on terms more favorable than the terms  originally  accepted by Members,  all of
the equity originally subscribed for by the Members shall be issued on the terms
the equity was offered to Persons who are not Members. The Board shall establish
procedures  for each  equity  issuance  that will assure that each Member has an
equitable and fair opportunity to subscribe for such equity,  exercise its right
to preserve  its  relative  Company  Interest  and  exercise  its right of first
refusal before any equity is offered to Persons who are not Members.

         3.8 Additional  Members.  No additional  Members may be admitted to the
Company without a Unanimous Determination of the Members, other than pursuant to
the provisions of Section 3.6 or Article 8.


                                    ARTICLE 4

                    BOOKS; ACCOUNTING; TAX ELECTIONS; REPORTS

         4.1 Fiscal Year.  The fiscal year of the Company  shall be the calendar
year (the "Year"), or such other year as shall be required under the Code.

         4.2  Method of  Accounting  and  Taxation.  The books of account of the
Company  (other  than books  required  to maintain  Capital  Accounts)  shall be
maintained on an accrual basis and otherwise in accordance  with GAAP. It is the
intention of the Members that the Company be taxed as a partnership  for Federal
income tax purposes and the Members shall take all action and make all elections
necessary to ensure that the Company is so taxed.

         4.3      Books and Records and Inspection.


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                  (a) Books of Account and Records.  Proper and complete records
         and books of  account of the  Company's  business,  including  all such
         transactions  and other matters as are usually entered into records and
         books of account  maintained  by Persons  engaged in businesses of like
         character  or as are  required by law,  shall be kept by the Company at
         the  Company's  principal  office and place of business.  To the extent
         required by law, the Company shall also keep,  at its principal  office
         and place of business, all records, required by the Act.

                  (b)  Inspection.  Each  Member  shall have the  right,  at all
         reasonable  times and upon  reasonable  notice  during  usual  business
         hours, to audit,  examine and make copies of or extracts from the books
         of account of the Company for any  purpose  reasonably  related to such
         Member's  interest  as a  member  of the  Company.  Such  right  may be
         exercised through any agent or employee of such Member designated by it
         or by a certified public accountant designated by such Member. A Member
         shall  bear all  expenses  incurred  in any  examination  made for such
         Member's account.

         4.4 Reports.

                  (a) Monthly Reports.  The Company shall prepare and deliver or
         cause to be delivered to each Member, within thirty (30) days after the
         end of each calendar month:

                           (i)  a  management-prepared   balance  sheet,  income
                  statement and cash flow statement for the Company with respect
                  to such  calendar  month just  ending  and the fiscal  year to
                  date;

                           (ii) a  management-prepared  statement  of income for
                  the Company comparing the actual results for the month and the
                  fiscal year to date with budgeted  amounts as set forth in the
                  most recently approved Annual Budget; and

                           (iii)  (A)  a   narrative   report   concerning   the
                  operations of the Company,  including the matters set forth in
                  the profit and loss and cash flow  statements and the variance
                  report described above; and (B) as of the end of each calendar
                  quarter, the balance of each Member's Capital Account.

                  The  monthly  financial   statements  and  other  reports  and
         information  shall be certified as accurate in all material respects by
         an officer of the Company to his best knowledge and belief.

                  (b) Annual  Report.  The Company  shall prepare and deliver or
         cause to be delivered to each Member, within eighty (80) days after the
         end of each fiscal year,  an annual  report for the Company  containing
         the following:

                           (i) a balance  sheet for the Company as of the end of
                  such Year,  and  statements  of income,  Members'  capital and
                  statement of cash flows for the Company for such year;

                           (ii)  a general description of the activities of the 
                  Company during the period covered by the report; and

                           (iii)  a  report  of  any  transactions  between  the
                  Company and any Member or  Affiliates  with  respect  thereto,
                  including  fees or  compensation  paid by the  Company and the
                  services  performed by the Members or any  Affiliates  thereof
                  for such fees or compensation.

                  The  annual  financial  statements  of the  Company  shall  be
         audited  (which audit shall be conducted in  accordance  with GAAP) and
         certified by the Accountants.

                                       -7-


<PAGE>

                  (c) Other  Information.  Forthwith upon request of any Member,
         the Company shall, at the cost and expense of the Company,  furnish (or
         cause to be furnished) to each Member such  information  bearing on the
         financial  condition  and  operations of the Company as any such Member
         may from time to time  reasonably  request.  Upon  obtaining  knowledge
         thereof, the Company shall furnish to each Member prompt written notice
         of any events or occurrences not otherwise provided for in this Section
         4.4 which may materially and adversely affect the Company.

         4.5 Filing of Returns and Other Writings; Tax Matters Member.

                  (a) The Tax Matters  Member  shall cause the  preparation  and
         timely  filing of all Company  tax returns and shall,  on behalf of the
         Company,  timely file all other writings  required by any  governmental
         authority having jurisdiction to require such filing.

                  (b) Unless and until the  Members  shall  otherwise  direct by
         Determination  of the  Members,  ATS will  serve  as the  "tax  matters
         partner"  (as such term is defined in Section  6231(a)(7)  of the Code,
         the "Tax Matters Member") for purposes of Section 6231 of the Code.

                  (c) The Company shall, to the fullest extent permitted by law,
         reimburse  and  indemnify  the Tax  Matters  Member for all  reasonable
         expenses,  including  reasonable  legal and  accounting  fees,  claims,
         liabilities,  losses and damages  incurred by the Tax Matters Member in
         connection with any administrative or judicial  proceeding with respect
         to the tax liability of the Members.

                  (d)  The   provisions   of  this  Section  shall  survive  the
         termination of the Company or the termination of any Member's  interest
         in the  Company and shall  remain  binding on the Members for as long a
         period of time as is necessary  to resolve  with the  Internal  Revenue
         Service any and all matters  regarding the Federal  income  taxation of
         the Company or the Members.

                  (e) The  Members  agree  to file all tax  returns  in a manner
         consistent with all Company tax returns.


                                    ARTICLE 5

                                   ALLOCATIONS

         5.1 Allocations of Profit and Loss.

                  (a) Profit. After giving effect to the special allocations set
         forth in Section 5.6 and taking into account any  curative  allocations
         in Section  5.7,  Profit of the  Company  for each fiscal year or other
         period shall be allocated among the Members as follows:

                  (i)      first,  to the Members in the amounts and proportions
                           necessary  to  reverse,  on a  cumulative  basis  and
                           without  duplication,  all allocations of Loss to the
                           Members pursuant to Section 5.1(b)(iii) over the life
                           of the Company;

                  (ii)     second, to the Members in the amounts and proportions
                           necessary  to  reverse,  on a  cumulative  basis  and
                           without  duplication,  all allocations of Loss to the
                           Members pursuant to Section  5.1(b)(ii) over the life
                           of the Company; and

                  (iii)    the balance, to the Members in accordance with their
                           Company Interests.

                                       -8-


<PAGE>


                  (b) Loss.  After giving effect to the special  allocations set
         forth in Section 5.6 and taking into account any  curative  allocations
         in Section  5.7,  Loss of the  Company  for each  fiscal  year or other
         period shall be allocated among the Members as follows:

                  (i)      first,  to the Members in the amounts and proportions
                           necessary  to  reverse,  on a  cumulative  basis  and
                           without duplication, all allocations of Profit to the
                           Members pursuant to Section 5.1(a)(iii) over the life
                           of the Company;

                  (ii)     second,  to the  Members  with  positive  balances in
                           their  Capital  Accounts,  in  accordance  with their
                           Company  Interests until the Capital  Accounts of all
                           Members are reduced to zero; and

                  (iii)    the balance, to the Members in accordance with their
                           Company Interests.

         5.2 Section 754 Election.  Upon the request of any Member,  the Company
shall elect, pursuant to Section 754 of the Code, to adjust the basis of Company
property as permitted  and  provided in Sections  734 and 743 of the Code.  Such
election shall be effective  solely for Federal (and, if  applicable,  state and
local)  income tax purposes and shall not result in any  adjustment  to the Book
Value of any  Company  asset or to the  Members'  Capital  Accounts  (except  as
provided  in  Treasury  Regulations  Section  1.704-1(b)(2)(iv)(m))  or  in  the
determination  or allocation of Profit or Loss for purposes  other than such tax
purposes.

         5.3 Allocations for Tax and Book Purposes. Except as otherwise provided
herein,  any  allocation  to a Member  for a fiscal  year or other  period  of a
portion  of the  Profit or Loss,  or of a  specially  allocated  item,  shall be
determined to be an allocation to that Member of the same  proportionate part of
each item of income,  gain, loss, deduction or credit, as the case may be, as is
earned, realized or available by or to the Company for Federal tax purposes.

         5.4 Certain  Accounting  Matters.  For purposes of determining  Profit,
Loss or any other items allocable to any period, Profit, Loss and any such other
items shall be determined on a daily,  monthly or other basis,  as determined by
the Managers using any permissible  method under Section 706 of the Code and the
Treasury Regulations promulgated thereunder.

         5.5 Tax  Allocations;  Code Section 704(c).  In accordance with Section
704(c) of the Code and the Treasury Regulations promulgated thereunder,  income,
gain,  loss,  and  deduction  with  respect to any property  contributed  to the
capital of the Company shall, solely for income tax purposes, be allocated among
the Members so as to take account of any variation between the adjusted basis of
such property to the Company for Federal income tax purposes and its fair market
value at the  time of  contribution.  In the  event  that the Book  Value of any
Company asset is  subsequently  adjusted in accordance with the last sentence of
the definition of Book Value, any allocation of income, gain, loss and deduction
with  respect to such  asset  shall  thereafter  take  account of any  variation
between the adjusted tax basis of the asset to the Company and its Book Value in
the same manner as under Section 704(c) of the Code and any Treasury Regulations
promulgated  thereunder.  Any  elections  or other  decisions  relating  to such
allocations  shall be made by the Managers in a manner that reasonably  reflects
the  purpose  and  intention  of this  Agreement.  Allocations  pursuant to this
section are solely for purposes of Federal, state, and local taxes and shall not
affect,  or in any way be taken into account in computing,  any Members' Capital
Account or share of Profit,  Loss or distributions  pursuant to any provision of
this Agreement.


                                       -9-

<PAGE>


         5.6 Compliance With Section 704(b).

                  (a)  Qualified  Income  Offset.  If  any  Member  unexpectedly
         receives  an  adjustment,   allocation  or  distribution  described  in
         Regulations Section 1.704-1(b)(2)(ii)(d)(4), (5) or (6) that causes the
         Member to have, or increases the amount of a Member's, deficit Adjusted
         Capital  Account  Balance,  items of  Company  income and gain shall be
         specially  allocated to such Member in accordance with the requirements
         of  Regulations  Section  1.704-1(b)(2)(ii)(d).  This Section 5.6(a) is
         intended to comply with the qualified  income offset  provision of such
         Regulations Section, and shall be interpreted consistently therewith.

                  (b) Gross Income  Allocation.  If any Member  would  otherwise
         have a deficit  Adjusted  Capital Account Balance as of the last day of
         any  fiscal  year or  other  period,  items of  income  and gain of the
         Company  shall be  specially  allocated  to such  Member (in the manner
         specified in Section  5.6(a)  hereof) so as to  eliminate  such deficit
         Adjusted Capital Account Balance as quickly as possible,  provided that
         an allocation pursuant to this Section 5.6(b) shall be made only if and
         to the extent that such Member  would have a deficit  Adjusted  Capital
         Account  Balance  after  all  other  allocations  provided  for in this
         Agreement have been tentatively made as if this Section 5.6(b) were not
         in this Agreement.

                  (c)  Limitation on Loss  Allocations.  No item of deduction or
         loss of the Company  shall be allocated to a Member if such  allocation
         would cause or increase a deficit Adjusted Capital Account Balance.  In
         the  event  that some but not all of the  Members  would  have  deficit
         Adjusted  Capital Account Balances as a result of an allocation of Loss
         pursuant to this  Article 5, the  limitation  set forth in this Section
         5.6(c)  shall be applied on a Member by Member  basis so as to allocate
         the maximum  permissible Loss to each Member under Regulations  Section
         1.704-1(b)(2)(ii)(d).

                  (d)  Minimum  Gain  Chargeback.   Notwithstanding   any  other
         provision of this Article 5, if there is a net decrease in "partnership
         minimum gain" or "partner nonrecourse debt minimum gain" of the Company
         (as such terms are defined in Regulations  Section  1.704-2) during any
         fiscal year or other  period,  prior to any other  allocation  pursuant
         hereto,  items of Company income and gain for such fiscal year or other
         period (and,  if  necessary,  for  subsequent  fiscal years or periods)
         shall be  specially  allocated  among the  Members in  accordance  with
         Regulations  Sections  1.704-2(f) and (i). The items to be so allocated
         shall  be   determined   in  accordance   with   Regulations   Sections
         1.704-2(f)(6) and (j)(2).

                  (e) Allocation of "Partner Nonrecourse  Deductions".  "Partner
         nonrecourse  deductions"  as defined in  Section  1.704-2(i)(1)  of the
         Treasury  Regulations  for any  fiscal  year or other  period  shall be
         specially  allocated to the Members who bear the economic  risk of loss
         for the "partner  nonrecourse debt" to which such "partner  nonrecourse
         deductions" are attributable,  as provided in Section  1.704-2(i)(1) of
         the Treasury Regulations.

                  (f)  Allocation  of  "Nonrecourse  Deductions".   "Nonrecourse
         deductions"  as such term is defined in  Section  1.704-2(b)(1)  of the
         Treasury  Regulations  for any  fiscal  year or other  period  shall be
         allocated to the Members in accordance  with their  respective  Company
         Interests.

         5.7 Curative Allocations. The allocations set forth in Section 5.6 (the
"Regulatory  Allocations")  are intended to comply with certain  requirements of
Sections  1.704-1(b)  and 1.704-2 of the Treasury  Regulations.  The  Regulatory
Allocations may not be consistent with the manner in which the Members intend to
divide Company Profits, Losses and similar items.  Accordingly,  Profits, Losses
and other items will be reallocated  among the Members (in the same year, and to
the extent necessary, in subsequent years) in a

                                      -10-


<PAGE>



manner consistent with Treasury  Regulation section 1.704-1(b) and 1.704-2 so as
to  prevent  the  Regulatory  Allocations  from  distorting  the manner in which
Company  Profits,  Losses and other items are intended to be allocated among the
Members pursuant to this Article 5.


                                    ARTICLE 6

                                  DISTRIBUTIONS

         6.1 Distributions  Other Than Proceeds of Any Liquidating  Transaction.
Subject to Section 18-607 of the Act, the Company shall  distribute Cash Flow to
each Member, on a monthly basis, in the following manner:

                  (a)  first,  up to  thirty  percent  (30%) of Cash Flow to the
         Members in payment of any Member Loans in proportion to the outstanding
         balances of such Member  Loans held by each Member  (amounts so paid to
         be  applied  first  to  interest  accrued  and  unpaid,   and  then  to
         outstanding principal); and

                  (b) the  balance,  to the  Members  in  accordance  with their
         respective Company Interests at the time of distribution.

         6.2 Proceeds of Any Liquidating Transaction. Upon the occurrence of any
transaction  (a   "Liquidating   Transaction")   involving  the  sale  or  other
disposition  of all or  substantially  all of the  assets  of the  Company,  all
proceeds  resulting  therefrom  (and all cash  available  from any other  source
during the period of winding up of the Company) shall be applied as follows:

                  (a) first,  to the payment of, or of the making of  reasonable
         provisions  for payment of, any debts or  liabilities of the Company to
         creditors (other than Members as holders of Member Loans);

                  (b) second,  to the Members in payment of any Member  Loans in
         proportion  to the  outstanding  balances of such Member  Loans held by
         each Member (with  amounts so paid to be applied  first to interest and
         then to principal); and,

                  (c) the balance,  to the Members in  proportion  to and to the
         extent of the positive  balances of the Capital Accounts of the Members
         (after  reflecting  in such Capital  Accounts all  adjustments  thereto
         necessitated by (i) all other Company  transactions for the Fiscal Year
         of the Company in which such Liquidating Transaction occurs prior to or
         simultaneously   with  such  Liquidating   Transaction  and  (ii)  such
         Liquidating Transaction).

         It is understood  and agreed that all payments under this Section shall
be made as soon as  reasonably  practicable  and in any  event by the end of the
Fiscal Year in which such Liquidating  Transaction  occurs or, if later,  within
ninety (90) days after the date of such Liquidating Transaction.

         6.3 Liquidation of Member's  Interest.  Upon  liquidation of a Member's
interest  in  the  Company,   other  than  in  connection   with  a  Liquidating
Transaction,   liquidating  distributions  to  such  Member  shall  be  made  in
accordance with Section 1.704-1(b)(2)(ii)(b)(2) of the Treasury Regulations.



                                      -11-


<PAGE>

                                    ARTICLE 7

                        RIGHTS AND OBLIGATIONS OF MEMBERS

         7.1 Limited  Liability.  Except as  otherwise  provided by the Act, the
debts,  obligations and liabilities of the Company, whether arising in contract,
tort or otherwise, shall be solely the debts, obligations and liabilities of the
Company,  and the Members shall not be obligated  personally  for any such debt,
obligation or liability of the Company solely by reason of being a member of the
Company.  The Members  shall not be  required to lend any funds to the  Company.
Each of the  Members  shall  only be liable to make  payment  of its  respective
contributions as and when due hereunder and other payments as expressly provided
in this Agreement.  If and to the extent a Member's  contribution shall be fully
paid, such Member shall not, except as required by the express provisions of the
Act regarding  repayment of sums wrongfully  distributed to Members, be required
to make any further contributions.

         To the extent that,  at law or in equity,  any Affiliate of a Member or
any manager, officer, stockholder, employee, agent or representative of a Member
or such Affiliate has duties (including fiduciary duties) and liabilities to the
Company or to the  Members,  no such Person shall be liable to the Company or to
any Member for its good faith  reliance  on the  provisions  of this  Agreement,
including  without  limitation  Section 7.4, which, in the event of any conflict
with any such duties, shall govern.

         7.2 Management and Control,  Etc. Management and control of the Company
shall be vested in the  Members  and all  material  decisions  with  respect  to
management, control, operation and disposition of the business and assets of the
Company shall, except as otherwise  specifically provided in this Agreement,  be
made by Determination of the Members.

         There  shall be  established  by the Members a Board of Managers of the
Company (the "Board"), composed of five managers,  designated as hereinafter set
forth.  The  Board  shall  meet on a regular  basis,  not less  frequently  than
quarterly, to review the operations of the Company, and any Determination of the
Members,  required  or  permitted  to be  taken  under  this  Agreement  may  be
accomplished  by action of a majority  of the  managers  (or, in the case of any
Unanimous  Determination  of the  Members,  by action  of all of the  managers),
either  at a  meeting  of the Board or by  written  consent.  The Board may also
appoint a Chairman,  President,  one or more Vice Presidents,  a Treasurer and a
Secretary and such other officers as the Board shall deem  appropriate,  each of
which  officers  may,  to the  extent  provided  by the  Board,  have the powers
attendant to a similar officer of a Delaware corporation.

         Each of ATS and CSD  shall  have  the  right,  from  time to  time,  to
designate  three  managers and two  managers,  respectively,  to the Board.  Any
manager may be removed,  with or without cause, and a successor appointed at any
time by the Member or Members  responsible  for  designation of such manager and
any Member  entitled to do so may also designate one or more alternates to serve
in the place of any manager  designated  by such Member who may  temporarily  be
unavailable to act with respect to Company matters. In the event of any transfer
by any Member or by any of its  successors  and assigns,  of any interest in the
Company in accordance  with Article 8, (a) the assigning  Member shall be deemed
to have assigned its right to designate a manager or managers under this Section
to its  assignee in the event that such  assignment  is of the  assignor's  then
entire  interest as a Member of the  Company  and the  assignee is admitted as a
Member in accordance with Article 8, and (b) the assigning Member shall have the
right to transfer  its right to  designate a manager,  by express  statement  of
exercise of such right in the  applicable  instrument of  assignment;  provided,
however,  that the assignee of such right is, or will be upon completion of such
transfer, the holder of not less than ten percent (10%) of the Company Interests
and the assignee is admitted as a Member in accordance with Article 8.


                                      -12-


<PAGE>

         The Company shall pay the reasonable out-of-pocket expenses,  including
travel and lodging, of each manager (including any manager-alternate)  acting in
connection with the business of the Company.

         From time to time upon request, the Company will furnish to each Member
such information  regarding the business,  properties,  financial  condition and
results  of  operation  of the  Company  in such  detail  as may  reasonably  be
requested;   and  the  Company   covenants   and  agrees  that  any   authorized
representative of any such Member shall have the right,  reasonably exercisable,
to visit and inspect any of the properties of the Company during normal business
hours and in a manner so as to not interfere with the operations and business of
the  Company,  to examine and to discuss  their  affairs,  finances and accounts
with, and be advised as to the same by, their  officers,  all at such reasonable
times and intervals as such Member may reasonably request.

         Notwithstanding anything to the contrary in this Agreement, the Company
shall  not  take  any of the  following  actions  without  first  obtaining  the
Unanimous  Determination  of the  Members,  which  approval  shall  be  given or
withheld at the absolute discretion of the Members:

         (a)      sell or exchange all or substantially all of the assets of the
                  Company;

         (b)      issue  any  additional   Company   Interests,   or  admit  the
                  transferee  of a Member's  Company  Interest  as a  substitute
                  Member under Section 8.2 hereof;

         (c)      dissolve  the  Company,  or  continue  the  Company  after its
                  dissolution due to the withdrawal of a Member (or if there are
                  none, of any Member) as provided in Section 9.1 hereof;

         (d)      merge or consolidate the Company with another  business entity
                  under the Act,  unless the Members of the Company  immediately
                  prior to such  merger  or  consolidation  own not less  than a
                  majority of the voting  interests in the survivor,  whether or
                  not the Company, of such merger or consolidation;

         (e)      file any voluntary petitions for the Company under Title XI of
                  the United States Code, the Bankruptcy  Act, or consent to the
                  filing of any involuntary petition for the Company thereunder,
                  or seek the protection of any other federal, state, bankruptcy
                  or insolvency law or debtor relief statutes;

         (f)      borrow any funds other than in the ordinary course of business
                  or if, as a result thereof,  the aggregate principal amount of
                  indebtedness   of  the  Company   outstanding   would   exceed
                  seventy-five  percent  (75%) of the fair  market  value of the
                  assets of the Company; or

         (g)      establish any  extraordinary  reserves  (i.e.,  reserves other
                  than those in the  ordinary  course of  business  which  shall
                  include,  without  limitation,  those with  respect to capital
                  expenditures).

         7.3 Evidence of Authority, Etc. Any Person dealing with the Company may
rely on a certificate signed by any Member:

                  (a) as to who are the Members or managers, officers, employees
         or agents of the Company;

                  (b) as to the existence or  nonexistence  of any fact or facts
         which  constitute  conditions  precedent  to acts by the Members or any
         such manager, officer, employee or agent or in any other manner germane
         to the affairs of the Company;

                                      -13-


<PAGE>


                  (c)  as to  who is  authorized  to  execute  and  deliver  any
         instrument or document on behalf of the Company;

                  (d) as to the  authenticity  of any copy of this Agreement and
         amendments hereto;

                  (e) as to any act or  failure  to act by the  Company or as to
         any other matter  whatsoever  involving the Company,  any Member or any
         manager, officer, employee or agent; or

                  (f) as to the authority of any Member or any manager, officer,
         employee or agent or other Person to act on behalf of the Company.

         7.4  Other  Business,  Etc.  Except  as  hereinafter  set forth in this
Section (or in any separate  agreement between the Company and any such Person),
any Member and any Affiliate of a Member may engage in or possess an interest in
other  business  ventures  (unconnected  with the  Company)  of  every  kind and
description,  independently  or with others and none of the Company or the other
Members shall have any rights in or to such  independent  ventures or the income
or profits therefrom by virtue of this Agreement.

         To the extent that,  at law or in equity,  any Affiliate of a Member or
any director,  officer,  stockholder,  employee,  agent or  representative  of a
Member or such Affiliate has duties (including fiduciary duties) and liabilities
to the Company or to the Members,  no such Person shall be liable to the Company
or to any  Member  for  its  good  faith  reliance  on the  provisions  of  this
Agreement.  The provisions of this Agreement,  to the extent that they expand or
restrict the duties and liabilities of any such Person otherwise existing at law
or in equity,  are  agreed by the  Members  to  replace  such  other  duties and
liabilities of such Person.

         Anything in this Section or elsewhere in this Agreement to the contrary
notwithstanding,  it is the intent and understanding of the Members, and each of
ATS and CSD covenant and agree as follows:

         (a)  except  as  set  forth  in the  Exceptions  Schedule,  all  future
acquisition  of  sites,  whether  in  fee  ownership,  pursuant  to a  leasehold
interest,  or otherwise,  for the construction of communication  towers, and all
future  construction of  communication  towers,  by CSD or any of its Affiliates
will be offered to the Company and neither CSD nor any of its  Affiliates  will,
directly or indirectly (as a stockholder, member, partner, trustee or otherwise)
own,  construct,  operate,  manage,  finance or otherwise  be involved  with any
communication towers, unless ATS shall have failed to approve the acquisition of
site pursuant to the provisions of Section 3.2; and

         (b)  the Company will enter into a Management Agreement with ATS.

         7.5 Indemnification. No Member, manager or officer of the Company shall
be liable to any other  Member or any other  Person who has an  interest  in the
Company for any loss,  damage or claim incurred by reason of any act or omission
performed or omitted by such Member,  manager of officer in good faith on behalf
of the Company and in a manner reasonably believed to be within the scope of the
authority conferred on such Member, manager or officer by this Agreement, except
that a Member,  manager of officer of the  Company  shall be liable for any such
loss,  damage or claim incurred by reason of such Person's  gross  negligence or
willful  misconduct.  To the full extent  permitted by applicable law, a Member,
manager or officer of the Company shall be entitled to indemnification  from the
Company for any loss, damage or claim by reason of any act or omission performed
or omitted by such Person in good faith on behalf of the Company and in a manner
reasonably  believed to be within the scope of the authority  conferred on it by
this Agreement,  except that no Member,  manager or officer shall be entitled to
be indemnified in respect of any loss,  damage or claim incurred by it by reason
of the Person's gross negligence or willful misconduct with respect to such

                                      -14-


<PAGE>

acts or omissions;  provided,  however,  that any  indemnity  under this Section
shall be provided out of and to the extent of Company assets only, and no Member
shall have personal liability on account thereof.

         7.6 Agreements with  Affiliates.  The Company may enter into agreements
with any Member or  Affiliate  of a Member for the  acquisition  of  property or
rendition of services,  provided that the  acquisition of such property from, or
the rendition of such services by, such Member or Affiliate has previously  been
approved by a Unanimous  Determination of the Members. The affected Member shall
in each case  disclose in advance the existence of any such  affiliation  to the
other Members.

         7.7 Payment of Expenses; Compensation. Promptly following the Effective
Date, or as the Members may, by Determination  of the Members,  otherwise agree,
the  Company  shall  reimburse  each Member for such  reasonable  fees and costs
incurred and reasonable out-of-pocket  expenditures relating to the formation of
the Company and the preparation of the associated documentation as may have been
approved by a  Determination  of the Members.  Except as expressly  set forth in
this Agreement,  or as otherwise approved by a Determination of the Members,  no
Member or manager  shall  receive any  compensation  for  performing  its duties
hereunder.


                                    ARTICLE 8

                          TRANSFERS OF INTERESTS, ETC.

         8.1 Consent Required.  Except as otherwise  contemplated by Section 8.2
or as permitted by the  succeeding  paragraphs of this Section,  no Member shall
suffer  or  permit  any  transfer,  whether  direct or  indirect,  voluntary  or
involuntary,  of all or any portion of such Member's Company Interest without an
approval given by  Determination  of the Members  representing a majority of the
Company Interests held by the  non-transferring  Members,  which approval may be
given or withheld  by the  non-transferring  Members in their sole and  absolute
discretion. Notwithstanding the foregoing, a Member may, without the approval of
the other Members, transfer an economic Company Interest pursuant to a Permitted
Transfer,  in which event the assignee  shall be entitled to the share of Profit
or Loss and any distribution or return of Capital  Contributions  and any credit
or other item  properly  allocable  to the Company  Interest to be  transferred.
However,  unless and until any such transfer of an economic  interest shall have
been  approved  by a  Determination  of the Members  representing  a majority in
interest of the Company Interests held by the non- transferring  Members,  which
approval may be given or withheld by the non-transferring  Members in their sole
and absolute discretion,  the assignee shall not be entitled to be admitted as a
Member of the Company and the assignor shall continue as a Member of the Company
for all other  purposes  of this  Agreement.  In  addition,  any  assignee of an
economic Company Interest pursuant to the foregoing provisions of this paragraph
who has not been admitted as a Member may further assign such interest  provided
that such  assignment  is  carried  out in  accordance  with and  subject to the
provisions of this Article,  in all respects as if or with the same effect as if
such assignee were a Member.

         The  foregoing  provisions  of this  Section  shall  not be  deemed  to
restrict  any  transfer  of an  interest  in ATS or  CSD,  except  as  otherwise
specifically provided.

         Anything in this  Section 8.1 or  elsewhere  in this  Agreement  to the
contrary  notwithstanding,  ATS may,  without the approval of the other Members,
pledge  all or any  portion  of its  interests  to one or more  banks  or  other
financial institutions pursuant to any bona fide borrowing arrangements,  which,
upon  foreclosure,  shall succeed to the interest of ATS and may become a Member
without the consent of any other Member being required.


                                      -15-


<PAGE>

         8.2 Right of First Refusal.

         (a) If any Member (the "Offeror") desires, at any time, to transfer all
or any part of its Company  Interest  other than as  permitted by Section 8.1 or
other  than  pursuant  to a  Permitted  Transfer,  it shall  submit to the other
Members  (the  "Offerees")  a true  copy of an offer to  purchase  such  Company
Interest (the "Offer"), which shall in any event disclose the price and terms of
such  proposed  sale and the name and  address of the  proposed  purchaser.  The
Offerees  shall have the absolute  right to purchase such Company  Interest upon
the terms and conditions as set forth in the Offer.  Each Offeree shall,  within
thirty (30) days of such receipt,  specify in a notice to the Offeror whether or
not it desires to accept the Offer,  and upon acceptance of the Offer,  the same
shall  constitute a binding  agreement of purchase and sale between the parties.
Failure to send such  notification  within thirty (30) days shall  constitute an
election to reject the Offer. The Offeror may sell its Company Interest,  to the
extent the Offer was not so accepted,  to the proposed  purchaser whose name and
address were disclosed in the Offer, but only upon the same terms and conditions
set forth therein and within sixty (60) days after the expiration of said thirty
(30) day  period  during  which the  Offeree  had the right to accept the Offer;
otherwise,  any such  sale  shall  be null  and  void and of no force or  effect
whatever.

         (b) In the event that two or more of the Offerees  desire to accept any
Offer,  and if such  Offerees  are unable to agree  among  themselves  as to the
apportionment  thereof,  each  accepting  Offeree shall be entitled to acquire a
portion of the offered  Company  Interest based upon the ratio which the Company
Interest of each such accepting Offeree bears to the aggregate Company Interests
of all such accepting Offerees.

         (c) No Offeree  shall have any  obligation,  by reason of acceptance or
rejection  of any Offer  pursuant  to this  Section  to  compensate  any  broker
retained by any Offeror or third party with respect to any proposed  transfer of
an Company Interest.

         (d) Each Member shall use reasonable  efforts to keep the other Members
apprised with respect to any  inquiries or proposals  regarding the sale of such
Member's Company Interest.

         8.3 Buy/Sell.  A Member (for  purposes of this Section the  "Initiating
Member")  may (a) in the  event  that  there  shall be a  transfer  of  majority
ownership or control of CSD to any Person in  competition  with the Company,  at
any time  within  ninety (90) days after  receipt of notice of such  transfer of
ownership or control (in which event only another  Member may be the  Initiating
Member),  or (b) in the event an Act of  Bankruptcy  occurs  with  respect  to a
Member (in which event only another  Member may be the  Initiating  Member),  by
notice to the other  Members (for  purposes of this  Section,  "Other  Members")
require  the Other  Members  to elect  either to sell  their  respective  entire
Company  Interests and any Member Loans to the Initiating  Member or to purchase
the entire interest of the Initiating Member in the Company and any Member Loans
for a price computed by reference to an amount stated in the Initiating Member's
notice (the "Stated  Amount").  The  purchase  price shall equal the amount such
Member  would  receive  as a  distribution  from the  Company in respect of such
Member's Company Interest and in repayment of any Member Loans if (i) all of the
assets of the Company  were sold on the closing  date under this Section for the
Stated Amount,  (ii) the Company were dissolved in accordance  with Section 9.1,
and (iii) the proceeds of sale were applied in  accordance  with Section 9.3, it
being  understood that the applicable  purchase price for such Company  Interest
and Member Loans shall be determined  by the affected  Members if they can agree
upon the same within ten (10) days prior to the closing date and  otherwise  the
same  shall  be  determined  on such  date by the  Accountants  (with  any  such
determination  by the  Accountants to be binding upon all Members in the absence
of  manifest  error).  Each of the Other  Members  shall have  thirty (30) after
receipt of the Initiating Member's notice within which to elect whether he shall
buy the  Initiating  Member's  Company  Interest  and  Member  Loans or sell his
Company  Interest and Member Loans based upon the Stated  Amount.  If any of the
Other

                                      -16-


<PAGE>


Members fails to make an election within such period, he shall be deemed to have
elected to sell his Company Interest and Member Loans to the Initiating Member.

         The closing pursuant to this Section shall occur on the sixtieth (60th)
day after the election  (or deemed  election) to purchase or sell has been made,
or at such earlier date as the purchasing Member(s) may specify on ten (10) days
prior written notice; provided,  however, that each of the following (unless and
except to the extent waived by the purchasing Member(s)) shall be a condition of
the  obligation of the  purchasing  Member(s) to proceed with any such purchase:
(a) that the Company shall have continued to be operated in accordance with this
Agreement  in all  material  respects  through  the date of  sale,  (b) that the
purchasing  Member(s)  shall have  obtained  all  lender  and other  third-party
consents,  if any,  required in  connection  with such sale,  and (c) that there
shall be no suit, action or proceeding  pending on the date of sale before or by
any court or  governmental  body  seeking to restrain or  prohibit,  or material
damages or other relief in connection with, the sale; provided further, however,
the Company  shall agree to  indemnify  and hold  harmless  the  seller(s)  with
respect to all Company obligations,  whether arising before or after the date of
such sale (other  than any such  obligations  resulting  from any breach of this
Agreement by a selling Member).

         The Company Interest and any applicable Member Loans shall be purchased
and the  purchase  price shall be paid at a closing to be held at the  principal
business office of the Company.  At the closing the Company  Interest and Member
Loans shall be duly conveyed, free of all liens and encumbrances on the same and
the  purchase  price  shall be paid by wire  transfer of  immediately  available
Federal funds. At the election of the purchasing Member(s), the Company Interest
and the Member Loans to be purchased  may be acquired in the name of one or more
nominees  (whether  or not any such  nominee  is an  Affiliate  of a  purchasing
Member),  provided,  however,  that any such  nominee is  designated  by written
notice given at least five (5) days prior to the date of Closing.

         Anything in this Section or elsewhere in this Agreement to the contrary
notwithstanding,  (a) in the event one, but not all, of the Other  Members shall
elect to purchase the  Initiating  Member's  Company  Interest and Member Loans,
such election shall take precedence over any election to sell Company  Interests
and Member Loans to the  Initiating  Member and any such elections to sell shall
be deemed to be an election to sell such Company  Interests  and Member Loans to
the Other Members who have elected to purchase the Company  Interests and Member
Loans of the Initiating  Member,  (b), such purchasing  Other Members shall have
the right but not the  obligation  to purchase the Company  Interests and Member
Loans of the non-  purchasing  Other  Members and,  after the closing under this
Section,  the purchasing  Other Members and, in the event the  purchasing  Other
Members do not elect to purchase all of the Company  Interests  and member Loans
of the  nonpurchasing  Other  Members,  the  non-purchasing  Other Members shall
continue the Company in accordance with this  Agreement,  and (c) if one or more
of the Other Members elect to purchase the Company  Interest and Member Loans of
the  Initiating   Member  and  are  unable  to  agree  among  themselves  as  to
apportionment  thereof, each Other Member shall be entitled to acquire a portion
of the  Initiating  Member's  Company  Interest  and Member Loans based upon the
ratio  which  the  Company  Interest  of each  such  Other  Member  bears to the
aggregate Company Interests of all of the purchasing Other Members.  In no event
shall the purchasing  Other Members be entitled to purchase less than all of the
Company Interest and Member Loans of any nonpurchasing  Other Member unless such
nonpurchasing  Other Member so agree in writing,  it being understood,  however,
that the purchasing  Other Members may elect to purchase  Company  Interests and
Member Loans from some but not all of the nonpurchasing Other Members.

         In the event of the  failure of a selling  Member to  proceed  with the
sale of its Company  Interest and Member Loans at the closing as herein provided
(other than any failure by reason of the non-occurrence of any condition to such
sale herein provided),  the same shall constitute a default by such Member under
this Agreement and any purchasing Member shall be entitled to pursue any and all
remedies available under this Agreement or at law or equity,  including specific
performance. In the event of the failure of a purchasing

                                      -17-


<PAGE>



Member (or its nominee) to proceed  with the purchase of a Company  Interest and
Member Loans at the closing as herein  provided  (other than because a condition
to such Member's obligation to make such purchase has not been satisfied),  each
selling  Member may elect,  by written  notice  given to the  purchasing  Member
within thirty (30) days after the date of such failure,  either (a) to cause the
purchasing  Member to sell its Company Interest and Member Loans to such selling
Member (or its nominee) at a purchase  price for such Company  Interest which is
ten percent  (10%) less than the price which the  defaulting  purchasing  Member
would have received if it had initially agreed to sell its Company Interest at a
price  determined by reference to the Stated Amount or (b) to pursue any and all
remedies  available  under  this  Agreement  or at law or in  equity,  including
specific  performance.  If a selling  Member elects within the aforesaid  thirty
(30) day period to cause such defaulting  purchasing  Member to sell the Company
Interest and Member Loans,  the closing  shall occur on the sixtieth  (60th) day
after the  election to purchase  has been given,  or at such earlier date as the
electing  Member may specify on ten (10) days prior  written  notice;  provided,
however,  that it shall be a condition of the electing  Member's  obligation  to
proceed,  in the case of the electing  Member as buyer,  that the conditions set
forth in the second  paragraph of this Section are satisfied and, in the case of
the former  purchasing  Member as seller,  that the  conditions set forth in the
immediately preceding paragraph are satisfied.

         8.4 CSD  Right/Obligation of Exchange.  In conjunction with the initial
public offering of the common stock of ATS (the "ATS IPO") (including an initial
public  offering  which  takes the form of a merger  with an  existing  publicly
traded  company),  CSD shall  have the  right,  and ATS shall  have the right to
require CSD, to exchange all but not less than all of CSD's Company Interest for
shares of common stock of ATS (of the class which is the subject of the ATS IPO,
the "ATS  Common  Stock")  on the terms and  subject to the  conditions  of this
Section. ATS agrees that it shall give prompt written notice (which notice shall
include the estimate  initial  public  offering  price or the range  thereof and
whether  ATS has elected to require CSD to  exchange  its Company  Interest  for
shares of ATS Common Stock pursuant to the provisions of this Section) to CSD of
its  determination  to proceed with the ATS IPO. In the event ATS shall not have
elected to require CSD to exchange its Company Interest for shares of ATS Common
Stock  pursuant to the  provisions  of this  Section,  CSD shall have the right,
exercisable  within  twenty  (20) days of  receipt of such  notice,  to elect to
exchange  all but not less than all of its  Company  Interest  for shares of ATS
Common  Stock.  Failure  of CSD to  deliver a timely  notice of  election  to so
exchange its Company  Interest shall be deemed to be an election not to exchange
its Company Interest.

         In the event CSD elects to exchange its Company  Interest,  ATS and CSD
shall  attempt in good faith to agree upon a fair market value for CSD's Company
Interest.  In the event ATS and CSD are unable to agree  upon such value  within
ten (10) days, CSD shall have the right, but not the obligation,  to submit such
matter to appraisal in accordance  with the  provisions of this Section.  In the
event ATS and CSD agree on such fair  market  value or CSD elects to submit such
matter to  appraisal,  ATS and CSD shall be obligated to effect the exchange and
shall be conclusively  bound to effect such exchange based on the results of the
appraisal.  In the event CSD shall have  elected  not to  submit,  or shall have
failed within such ten (10)-day period to have submitted, such matter to binding
appraisal in accordance with the provisions of the preceding sentence,  it shall
not have any further right to exchange its Company Interest for shares of common
stock  of ATS,  except  as  otherwise  provided  in the last  paragraph  of this
Section.  Any appraisal of the fair market value of the Company  Interest of CSD
shall be made by the managing  underwriter  of the ATS IPO (or, in the event the
ATS IPO shall be pursuant to a merger, by an investment banker  knowledgeable in
the communications tower business mutually reasonably  acceptable to ATS and CSD
or, in the absence of such agreement, by Credit Suisse First Boston). The number
of shares of ATS Common Stock to be issued in exchange for the Company  Interest
of ATS shall be  determined  by dividing the fair market value of CSD's  Company
Interest (as agreed upon by ATS and CSD or as  determined  by  appraisal) by the
amount paid by the underwriters to ATS (or the selling stockholders in the event
ATS does not sell any shares pursuant

                                      -18-


<PAGE>



thereto) in the ATS IPO (or the closing  price of the common  stock of the party
to the merger agreement on the date the merger agreement is executed).

         To the  extent  permitted  by the  Code,  ATS will  use its  reasonable
business  efforts to effect the exchange of CSD's Company Interest for shares of
ATS Common Stock pursuant to a tax-free reorganization under the Code so long as
doing so does not subject ATS or its subsidiaries or stockholders to any risk of
tax in connection with the exchange or any related transactions.

         CSD  hereby  appoints  ATS as its  agent  and  attorney-in-fact,  which
appointment  is coupled with an interest,  and is  irrevocable,  for purposes of
executing  and  delivering  all  such  agreements,   instruments  and  documents
necessary or desirable in order to  effectuate  the  provisions of this Section,
including  without  limitation  the  right  and power to  transfer  the  Company
Interest of CSD to ATS in accordance with the provisions of this Section, all in
the event CSD has elected to proceed with the  exchange of its Company  Interest
for shares of ATS Common Stock pursuant to the provisions of this Section.

         In the event CSD shall have  elected or been deemed to have elected not
to exchange its Company  Interest for shares of ATS Common Stock pursuant to the
ATS IPO and ATS subsequently determines not to proceed with such ATS IPO or such
ATS IPO is withdrawn or is otherwise not consummated,  CSD shall have the rights
set forth in this Section upon any  subsequent  determination  of ATS to proceed
with the ATS IPO.

         8.5 Obligations and Rights of Transferees and Assignees. Any Person who
acquires in any manner  whatsoever  the  interest  (or any part  thereof) of any
Member in the  Company,  irrespective  of whether  such Person has  accepted and
assumed in writing the terms and provisions of this Agreement,  shall be deemed,
by acceptance of the benefit of the acquisition  thereof,  to have requested and
agreed to be subject to and bound by all of the  obligations of this  Agreement,
with the same force and effect as any  predecessor  in Company  Interest,  shall
have only such rights as are provided in this Agreement,  and,  without limiting
the  generality  of the  foregoing,  such Person shall not have the value of his
interest ascertained or receive the value of such interest, or, in lieu thereof,
profits  attributable  to any right in the Company,  except as set forth in this
Agreement.

         8.6  Non-Recognition  of Certain Transfers.  Notwithstanding  any other
provision  of  this  Agreement,  any  transfer,  sale,  alienation,  assignment,
encumbrance or other  disposition in  contravention  of any of the provisions of
this Article shall be void and ineffective, and shall not bind, or be recognized
by, the Company.

         8.7  Required  Amendments;  Continuation.  If  and to  the  extent  any
transfer of a Company  Interest is permitted  hereunder  and the  transferee  is
admitted as a Member,  this Agreement shall be amended to reflect such admission
or transfer  and the  elimination  of the  transferor  Member and (if and to the
extent then required by the Act) a certificate  of amendment to the  Certificate
reflecting such admission and elimination  shall be filed in accordance with the
Act. The admission of any  substitute  Member  pursuant to this Article shall be
deemed effective immediately prior to the transfer of a Company Interest to such
substitute  Member.  If the transferor Member has transferred all of its Company
Interest pursuant to this Article,  then,  immediately  following such transfer,
the transferor Member shall cease to be a member of the Company.

         8.8  Resignation.  No Member  shall  have the right to resign  from the
Company without the prior written consent of the other Members.


                                      -19-

<PAGE>

                                    ARTICLE 9

                                   TERMINATION

         9.1 Events of Dissolution.

         (a) In accordance  with Section 18-801 of the Act, the Company shall be
dissolved and the affairs of the Company wound up upon the  occurrence of any of
the following events:

                  (i) a Unanimous  Determination  of the Members to dissolve the
         Company; or

                  (ii) death, retirement,  resignation, expulsion, bankruptcy or
         dissolution  of a Member or the  occurrence  of any other event  which,
         pursuant to the Act,  terminates the continued existence of a Member in
         the Company,  unless, if there is more than one Member  remaining,  the
         business  of the  Company  is  continued  by  the  consent  of all  the
         remaining  Members  within ninety (90) days following the occurrence of
         any such event; or

                  (iii)  the  sale,  transfer  or  other  disposition  of all or
         substantially all of the business and assets of the Company; or

                  (iv)  in any event, at 12:00 midnight on December 31, 2047.

         (b)  Dissolution  of the Company shall be effective on the day on which
the event  occurs  giving rise to the  dissolution,  but the  Company  shall not
terminate  until the  assets of the  Company  shall  have  been  distributed  as
provided  herein and a certificate of cancellation of the Company has been filed
with the Secretary of State of the State of Delaware.

         (c) If as a result of the occurrence of any event  described in Section
9.1(a)(ii), a Member is the only remaining member of the Company, to the fullest
extent  permitted by the Act, such Member shall have the right to admit a Person
as a new member of the Company,  effective as of the date of the  occurrence  of
the  event set forth in  Section  9.1(a)  (ii),  on terms  satisfactory  to such
remaining Member. Upon such admission, the Members are hereby authorized to, and
shall, continue the business of the Company without dissolution.

         9.2  Application of Assets.  In the event of  dissolution,  the Company
shall  conduct  only such  activities  as are  necessary  to wind up its affairs
(including  the sale of the  business  and  assets of the  Company in an orderly
manner),  and the assets of the Company  shall be applied in the manner,  and in
the order of priority, set forth in Section 6.2.

         9.3  Distributions  in  Liquidation.  No Member shall have the right to
request or require  the  distribution  of the assets of the Company in kind upon
the liquidation of the Company.


                                   ARTICLE 10

                                  MISCELLANEOUS

         10.1  Notices.  All  notices  and  other  communications  which  by any
provision of this Agreement are required or permitted to be given shall be given
in  writing  and shall be (a)  mailed by  first-class  or  express  mail,  or by
recognized  courier  service,  postage  prepaid,  (b) sent by  telex,  telegram,
telecopy or other form

                                      -20-


<PAGE>



of rapid transmission,  confirmed by mailing (by first class or express mail, or
by  recognized  courier  service,   postage  prepaid)  written  confirmation  at
substantially  the  same  time as such  rapid  transmission,  or (c)  personally
delivered to the receiving party (which if other than an individual  shall be an
officer or other responsible party of the receiving party). All such notices and
communications  shall be mailed,  sent or  delivered  as set forth on the Member
Schedule  (including any copies shown thereon) or to such other address  (within
the United  States of  America) as any party may have  designated  for itself by
written  notice to the  others in the  manner  herein  prescribed,  except  that
notices of change of address shall be effective only upon receipt.  All notices,
demands,  and requests to be sent  hereunder  shall be deemed to have been given
for all purposes of this Agreement upon the date of receipt or refusal.

         10.2  Specific  Performance;  Other  Rights  and  Remedies.  Each party
recognizes and agrees that in the event the other party should refuse to perform
any of its  obligations  under  this  Agreement,  the  remedy  at law  would  be
inadequate and agrees that for breach of such  provisions,  each party shall, in
addition to such other remedies as may be available to it at law or in equity or
as provided in Article 7, be  entitled to  injunctive  relief and to enforce its
rights  by an  action  for  specific  performance  to the  extent  permitted  by
Applicable  Law.  Each party hereby waives any  requirement  for security or the
posting  of any  bond or other  surety  in  connection  with  any  temporary  or
permanent  award of injunctive,  mandatory or other equitable  relief.  Noth ing
herein  contained shall be construed as prohibiting each party from pursuing any
other remedies available to it pursuant to the provisions of, and subject to the
limitations contained in, this Agreement for such breach or threatened breach.

         10.3 Severability.  If any term or provision of this Agreement shall be
held or deemed  to be, or shall in fact be,  invalid,  inoperative,  illegal  or
unenforceable  as  applied  to  any  particular  case  in  any  jurisdiction  or
jurisdictions,  or in  all  jurisdictions  or  in  all  cases,  because  of  the
conflicting of any provision with any  constitution or statute or rule of public
policy or for any other reason,  such circumstance  shall not have the effect of
rendering the provision or provisions in question invalid, inoperative,  illegal
or unenforceable in any other  jurisdiction or in any other case or circumstance
or of rendering any other  provision or  provisions  herein  contained  invalid,
inoperative,  illegal or  unenforceable to the extent that such other provisions
are not themselves actually in conflict with such constitution,  statute or rule
of public policy, but this Agreement shall be reformed and construed in any such
jurisdiction or case as if such invalid,  inoperative,  illegal or unenforceable
provision had never been contained herein and such provision reformed so that it
would be valid,  operative and  enforceable to the maximum  extent  permitted in
such jurisdiction or in such case.  Notwithstanding the foregoing,  in the event
of any such  determination  the  effect  of which is to  affect  materially  and
adversely any Member,  the Members shall  negotiate in good faith to modify this
Agreement  so as to effect  the  original  intent of the  Members  as closely as
possible to the fullest  extent  permitted by  Applicable  Law in an  acceptable
manner to the end that such intent is fulfilled to the maximum extent possible.

         10.4   Counterparts.   This   Agreement  may  be  executed  in  several
counterparts,  each of  which  shall be  deemed  an  original,  but all of which
together shall constitute one and the same  instrument,  binding upon all of the
Members. In pleading or proving any provision of this Agreement, it shall not be
necessary to produce more than one of such counterparts.

         10.5 Section Headings. The headings contained in this Agreement are for
reference  purposes  only  and  shall  not in any  way  affect  the  meaning  or
interpretation of this Agreement.

         10.6 Title to Company  Property.  All  property  owned by the  Company,
whether real or personal, tangible or intangible, shall be deemed to be owned by
the Company as an entity, and no Member, individually,  shall have any ownership
of such property. The Company may hold any of its assets in its own

                                      -21-


<PAGE>



name  or in the  name  of  its  nominee,  which  nominee  may  be  one  or  more
individuals, partnerships, trusts or other entities.

         10.7 Governing Law. In the event of a conflict between any provision of
this Agreement and any non-mandatory provision of the Act, the provision of this
Agreement  shall  control and take  precedence.  The  validity,  interpretation,
construction  and  performance  of this  Agreement  shall be  governed  by,  and
construed  in  accordance  with,  the  applicable  laws of the United  States of
America and the laws of the State of Delaware  applicable to contracts  made and
performed in such State and, in any event,  without  giving effect to any choice
or  conflict  of laws  provision  or rule that would  cause the  application  of
domestic substantive laws of any other jurisdiction.  Anything in this Agreement
to the contrary notwithstanding, in the event of any dispute between the parties
which  results in a Legal  Action,  the  prevailing  party  shall be entitled to
receive from the  non-prevailing  party  reimbursement for reasonable legal fees
and expenses incurred by such prevailing party in such Legal Action.

         10.8 Further Acts. Each party agrees that at any time, and from time to
time, before and after the consummation of the transactions contemplated by this
Agreement, it will do all such things and execute and deliver all such documents
and  other  assurances,  as any  other  party or its  counsel  reasonably  deems
necessary or desirable  in order to carry out the terms and  conditions  of this
Agreement  and  the  transactions  contemplated  hereby  or  to  facilitate  the
enjoyment of any of the rights created hereby or to be created hereunder.

         10.9  Entire  Agreement.  This  Agreement  (together  with  the  Member
Schedule)  constitutes  the entire  agreement of the parties and  supersedes all
prior agreements and undertakings,  both written and oral,  between the parties,
with respect to the subject matter hereof.

         10.10 Assignment. This Agreement shall not be assignable by any Member,
except as otherwise  provided in Section 8.1, and any such  assignment  shall be
null and void,  except that it shall inure to the benefit of and by binding upon
any  successor  to any party by  operation  of law,  including by way of merger,
consolidation  or sale of all or  substantially  all of its assets,  and ATS may
assign  its  rights  and  remedies  hereunder  to any  bank or  other  financial
institution which has loaned funds or otherwise extended credit to it.

         10.11  Parties in Interest.  This  Agreement  shall be binding upon and
inure  solely to the  benefit of each  party,  and  nothing  in this  Agreement,
express or implied,  is  intended to or shall  confer upon any Person any right,
benefit or remedy of any nature whatsoever under or by reason of this Agreement,
except as otherwise provided in Section 10.10.

         10.12  Mutual  Drafting.  This  Agreement  is the  result  of the joint
efforts of CSD and ATS, and each provision hereof has been subject to the mutual
consultation,  negotiation  and  agreement  of the parties and there shall be no
construction  against  either  party based on any  presumption  of that  party's
involvement in the drafting thereof.

         10.13 Amendments;  Waivers.. This Agreement may be amended from time to
time with  written  approval of all  Members.  At any time or from time to time,
except to the extent not permitted by Applicable Law, the Members may extend the
time for the  performance of any of the obligations or other acts of any Member,
and waive  compliance  by the other  with any of the  agreements,  covenants  or
conditions contained herein. Any such extension or waiver shall be valid only if
set forth in an instrument in writing signed by all Members.


                                      -22-


<PAGE>

         10.14  Schedule.   The  Member   Schedule   attached  hereto  shall  be
incorporated  into and shall be deemed a part of this  Agreement.  If the Member
Schedule  shall  not be  attached  hereto  at the  time  of  execution  of  this
Agreement,  or if it shall be incomplete,  it may be later attached or completed
in  accordance  with the  provisions of this  Agreement and the Member  Schedule
shall, as later attached or completed, for all purposes be deemed a part of this
Agreement  as if  attached  hereto  or  completed  at the time of the  execution
hereof.  Without  limiting the generality of the foregoing,  the Member Schedule
shall be amended  from time to time to reflect the  admission  of Members or the
transfer of interests of Members and the Company  shall,  from time to time,  so
cause the Member Schedule to be amended and shall promptly notify the Members in
writing of any change in the Member Schedule.

         IN WITNESS WHEREOF, the parties hereto have executed and delivered this
Agreement under seal as of the day and year first above written.

                                      American Tower Systems, Inc.


                                      By:_____________________________
                                          Name:
                                          Title:

                                      Communication Systems Development, Inc.


                                      By:_____________________________
                                          Name:
                                          Title:



                                      -23-


<PAGE>

                                                                      APPENDIX A

         "Accountant(s)"  shall mean such firm of independent  certified  public
accountants  as may be  engaged  from  time  to  time  by  the  Company,  upon a
Determination  of the  Members,  for  purposes  of  reviewing  or  auditing  the
financial  statements  of the Company and  performing  such other  duties as are
imposed upon the Accountants by the express provisions of this Agreement.

         "Act"  shall  have  the  meaning  set  forth  in the  recitals  to this
Agreement.

         "Act of Bankruptcy" shall mean, when used with reference to any Person,
any of the following events or occurrences:

                  (a) its  admitting in writing its  inability,  or being unable
         under  applicable  law,  or its  failing  generally,  to pay its  debts
         generally as they become due, or

                  (b) its filing a petition, answer or consent seeking relief as
         a debtor or otherwise  commencing a voluntary case under the Bankruptcy
         Code as from time to time in effect, or its authorizing, by appropriate
         proceedings of its board of directors or other governing body, any such
         petition, answer, consent or commencement of such a voluntary case; or

                  (c) the filing  against it or all or any  substantial  part of
         its property of a petition  commencing  an  involuntary  case under the
         Bankruptcy  Code which shall  remain  undismissed  for a period of more
         than  thirty (30) days or which is  consented  to by such Person or any
         order or decree  approving  relief  adverse to such  Person  thereunder
         shall remain unstayed and in effect for more than forty five (45) days;
         or

                  (d) its  commencement  of  proceedings  or filing a  petition,
         answer or consent  seeking relief as a debtor under any Applicable Law,
         other than the  Bankruptcy  Code, of any  jurisdiction  relating to the
         liquidation  or  reorganization  of debtors or to the  modification  or
         alteration  of  the  rights  of  creditors,  or  its  consenting  to or
         acquiescing  in such  relief  or its  admitting  or  acquiescing  in or
         failing promptly and in any event within thirty (30) days of the filing
         thereof, in an appropriate manner, to deny the material  allegations of
         any  petition  seeking  such  relief,  any  such  involuntary  petition
         remaining undismissed for more than thirty (30) days or an order in any
         involuntary proceeding adverse to such Person remaining unstayed and in
         effect for more than forty-five (45) days; or

                  (e) the entry of an order or decree  (whether or not final) by
         a court of  competent  jurisdiction  (i)  finding it to be  bankrupt or
         insolvent,  (ii) ordering or approving its liquidation,  dissolution or
         winding up, or  reorganization or any modification or alteration of the
         rights of its creditors,  or any  composition or readjustment of debts,
         (iii)  assuming   custody  of,  or  appointing  a  receiver,   trustee,
         sequestrator,  conservator,  assignee,  custodian,  liquidator,  fiscal
         agent or similar official for, such Person or all or a substantial part
         of its property and any such order or decree  shall  continue  unstayed
         and in effect for a period of forty-five (45) days; or

                  (f) its  convening a meeting of  creditors  for the purpose of
         consummating an out-of-court  arrangement,  or making an assignment for
         the benefit of, or entering  into a  composition,  extension or similar
         arrangement  with,  its  creditors  in respect of all or a  substantial
         portion of its debt; or

                  (g)  its  seeking  or  consenting  to or  acquiescing  in  the
         appointment  of  a  receiver,   trustee,   sequestrator,   conservator,
         liquidator,  fiscal agent or other custodian of itself or of all or any
         substantial part of its property; or

                  (h)  its winding-up, liquidation or dissolution; or

                                       A-1

<PAGE>



                  (i) its  authorization,  by appropriate action of its board of
         directors or other governing body, of any of the foregoing.

         "Additional Capital  Contribution" shall mean any Capital  Contribution
made in accordance with Section 3.2 or 3.3.

         "Adjusted  Capital  Account  Balance"  shall mean,  with respect to any
Member,  the balance in such Member's Capital Account after giving effect to the
following adjustments:

                  (a) credits to such Capital  Account of such Member's share of
         "partnership minimum gain" or a "partner nonrecourse debt minimum gain"
         or any amount which such Member would be required to restore under this
         Agreement or otherwise; and

                  (b) debits to such Capital  Account of the items  described in
         Section   1.704-1(b)(2)(ii)(d)(4),   (5)  and   (6)  of  the   Treasury
         Regulations.

         The  foregoing  definition  of  Adjusted  Capital  Account  Balance  is
intended to comply with the  provisions of Section  1.704-1(b)(2)(ii)(d)  of the
Treasury Regulations and shall be interpreted consistently therewith.

         "Affiliate" shall mean, with respect to any Person,  (i) in the case of
any such Person which is a Company,  any Member in such Company,  (ii) any other
Person which is a Parent, a Subsidiary, or a Subsidiary of a Parent with respect
to such  Person or to one or more of the Persons  referred  to in the  preceding
clause  (i),  (iii) any other  Person who is an  officer,  director,  trustee or
employee  of,  or  Member  in,  such  Person or any  Person  referred  to in the
preceding clauses (i) and (ii), and (iv) any other Person who is a member of the
Immediate  Family of such Person or of any Person  referred to in the  preceding
clauses (i) through (iii);  provided,  however, that such term shall not include
within its meaning the Company itself or a Subsidiary of the Company.

         "Agreement" shall mean this Agreement of Limited Liability Company,  as
it may be  amended,  restated  or  supplemented  from  time to  time  as  herein
provided.

         "Annual   Budget"  shall  mean  the  detailed   annual  budget  of  all
anticipated   revenues  and  other  cash   receipts  and  expenses  and  capital
expenditures   associated  with  ownership  and  operation  of  the  Company  as
heretofore furnished to each of the Members, as amended and updated from time to
time as provided herein.

         "Applicable Law" shall mean any Law of any Authority,  whether domestic
or  foreign,  including  without  limitation  the FCA and all  federal and state
securities and  Environmental  Laws, to which a Person is subject or by which it
or any of its business or operations is subject or any of its property or assets
is bound.

         "ATS" shall have the meaning given to such term in the Preamble.

         "ATS Common  Stock"  shall have the meaning  given such term in Section
8.4.

         "ATS IPO" shall have the meaning given such term in Section 8.4.

         "Authority"   shall  mean  any   governmental   or   quasi-governmental
authority, whether administrative, executive, judicial, legislative or other, or
any  combination  thereof,  including  without  limitation  any federal,  state,
territorial,   county,   municipal  or  other   government  or  governmental  or
quasi-governmental agency,

                                       A-2

<PAGE>



arbitrator,  authority,  board, body, branch, bureau, central bank or comparable
agency or Entity, commission,  corporation, court, department,  instrumentality,
master, mediator,  panel, referee, system or other political unit or subdivision
or other Entity of any of the foregoing, whether domestic or foreign.

         "Bankruptcy Code" shall mean 11 U.S.C. ss. 101 et seq., as from time to
time in effect,  and any  successor  law,  and any  reference  to any  statutory
provision  shall  be  deemed  to  be a  reference  to  any  successor  statutory
provision.

         "Board" shall have the meaning given such term in Section 7.2.

         "Book Gain" or "Book Loss"  shall mean the gain or loss  recognized  by
the  Company  for book  purposes  in any  Fiscal  Year by  reason of any sale or
disposition with respect to any of the assets of the Company.  Such Book Gain or
Book Loss shall be computed by reference  to the Book Value of such  property or
assets as of the date of such sale or  disposition,  rather than by reference to
the tax basis of such  property  or assets as of such  date,  and each and every
reference  herein to  "gain" or "loss"  shall be deemed to refer to Book Gain or
Book Loss,  rather than to tax gain or tax loss,  unless the context  manifestly
otherwise requires.

         "Book Value" of an asset shall mean,  as of any  particular  date,  the
value at which the asset is properly  reflected  on the books and records of the
Company as of such date in  accordance  with  Section  1.704-1(b)(2)(iv)  of the
Treasury  Regulations.  The initial  Book Value of each asset shall be its cost,
unless such asset was contributed to the Company by a Member,  in which case the
initial Book Value shall be the amount  stated as the fair market value for such
asset on the Member  Schedule  (or,  if no such value is stated,  as  reasonably
established  by a  Determination  of the Member),  and, in each case,  such Book
Value shall thereafter be adjusted for  Depreciation  with respect to such asset
rather than for the cost  recovery  deductions  to which the Company is entitled
for Federal  income tax purposes  with respect  thereto.  The Book Values of all
Company assets shall be adjusted to equal their  respective  fair market values,
as  determined  by the  Board  in its  reasonably  business  judgment  as of the
following  times:  (a) the acquisition of an additional  Company Interest by any
new or existing Member in exchange for more than a de minimis Additional Capital
Contribution;  (b) the distribution by the Company to a Member of more than a de
minimis  amount of  Company  assets,  including  money,  if, as a result of such
distribution, such Member's Company Interest is reduced; and (c) the termination
of the Company for Federal income tax purposes pursuant to Section  708(b)(1)(B)
of the Code.

         "Capital Account" shall have the meaning set forth in Section 3.4.

         "Capital  Contributions"  shall mean the total amount of cash and other
property  contributed to the Company by the Members,  whether as Initial Capital
Contributions or Additional Capital Contributions.

         "Cash Flow" shall mean, for any period, the amount,  computed on a cash
basis, of:

                  (i)      the sum of:

                           (A)      all gross receipts, all investment income of
                                    the  Company,  and all  cash  received  from
                                    other sources, and

                            (B)     any  amounts   released   from  reserves  as
                                    provided in the Annual Budget, reduced by:

                  (ii)     the sum of:


                                       A-3

<PAGE>



                           (A)      disbursements  of the Company for  operating
                                    expenses,  principal payments on debt (other
                                    than Member Loans),  interest (other than on
                                    Member Loans) and other expenses ,

                           (B)      capital expenditures  reasonably  determined
                                    to be necessary or appropriate by the Board,

                           (C)      any  increase in reserves as provided in the
                                    Annual Budget, and

                           (D)      an  additional  amount  necessary  to ensure
                                    that the Company has funds necessary to meet
                                    the cash requirements of the Company for the
                                    period  prior  to  the  date  on  which  the
                                    Company  is  next   anticipated  to  receive
                                    income as set forth in the applicable Annual
                                    Budget or such other date thereafter (to the
                                    extent  no  such  date is  specified  in the
                                    Annual Budget) as determined by the Board.

         "Certificate"  shall  mean the  Certificate  of  Formation  of  Limited
Liability  Company of the  Company  as  provided  for  pursuant  to the Act,  as
originally  filed  with the  office  of the  Secretary  of State of the State of
Delaware, as amended and restated from time to time as herein provided.

         "Code"  shall mean the Internal  Revenue Code of 1986,  as amended from
time to time,  and any  subsequent  Federal law of similar  import,  and, to the
extent applicable, any Treasury Regulations promulgated thereunder.

         "Company" shall mean the limited liability  company hereby  established
in  accordance  with this  Agreement  by the  parties  hereto,  as such  limited
liability company may from time to time be constituted.

         "Company  Interest"  shall  mean,  with  respect  to each  Member,  its
interest  in the  Company as set forth in the Member  Schedule,  subject in each
instance to adjustment  from time to time pursuant to the applicable  provisions
of this Agreement.

         "Control" shall mean,  when used with respect to any Person,  the power
to direct the  management  and policies of such Person,  directly or indirectly,
whether as an officer or manager, through the ownership of voting securities, by
contract or otherwise,  and the terms  "controlling" and "controlled" shall have
meanings correlative to the foregoing.

         "Controlling  Interest"  shall mean,  with  respect to any Person,  the
power to control such Person.

         "CSD" shall have the meaning given such term in the Preamble.

         "Depreciation"  shall mean,  for each fiscal year or other  period,  an
amount equal to the depreciation,  amortization or other cost recovery deduction
allowable  with  respect  to an asset for such year or other  period;  provided,
however,  that if the Book Value of an asset differs from its adjusted basis for
Federal  income tax purposes at the  beginning of any such year or other period,
Depreciation  shall be an amount  that bears the same  relationship  to the Book
Value of such asset as the  depreciation,  amortization,  or other cost recovery
deduction  computed  for  tax  purposes  with  respect  to  such  asset  for the
applicable period bears to the adjusted tax basis of such asset at the beginning
of such period,  or if such asset has a zero  adjusted  tax basis,  Depreciation
shall  be an  amount  determined  under  any  reasonable  method  selected  by a
Determination of the Members.

                                       A-4

<PAGE>



         "Determination  of the  Members"  shall  mean the  affirmative  vote or
approval of Members holding at least fifty and one-tenth  percent (50.1%) of the
Company  Interests (or such greater or lesser percentage of Company Interests as
may otherwise in this Agreement be expressly provided). "Unanimous Determination
of the Members" shall mean the  affirmative  vote or approval of Members holding
one hundred percent (100%) of the Company Interests.

         "Effective Date" shall have the meaning set forth in Section 2.5.

         "Entity"  shall  mean any  general  partnership,  limited  partnership,
corporation,  joint venture,  trust, limited liability company,  business trust,
cooperative or association.

         "Exceptions  Schedule" shall mean the schedule attached hereto and made
a part  hereof  which sets  forth,  as of the date  hereof,  existing  sites and
communication towers owned, leased,  operated or managed by CSD or any Affiliate
thereof  and  which  are  exceptions  to the  provisions  of  Section  7.4.  The
Exceptions  Schedule may be amended,  from time to time,  with the prior written
approval of ATS in its sole and absolute discretion.

         "Fiscal  year"  shall mean the fiscal  year of the Company and shall be
the same as its taxable year,  which shall be the calendar year unless otherwise
required by the Code.  Each fiscal  year shall  commence on the day  immediately
following the last day of the immediately preceding fiscal year.

         "GAAP"  shall  mean  means,  except  to the  extent  that  a  deviation
therefrom is expressly required by this Agreement,  such principles applied on a
consistent  basis,  (i) as set forth in  Opinions of the  Accounting  Principles
Board of the American Institute of Certified Public Accountants ("AICPA") and/or
in statements of the Financial Accounting Standards Board that are applicable in
the  circumstances as of the date in question,  (ii) when not inconsistent  with
such  opinions  and  statements,  as set forth in other AICPA  publications  and
guidelines  and/or  (iii)  that  otherwise  arise by custom  for the  particular
industry, all as the same shall exist on the date of this Agreement.

         "Immediate  Family" shall mean, with respect to any Person, his spouse,
parents,  brothers,  sisters,  children  (natural  or  adopted),   stepchildren,
grandchildren,  grandparents, parents-in-law,  brothers-in-law,  sisters-in-law,
nephews and nieces.

         "Initial Capital Contribution" shall mean any Capital Contribution made
in accordance with Section 3.1.

         "Initial  Investment"  shall mean the aggregate  amount  proposed to be
invested in the project or site,  including for all tower and other improvements
during the initial phase of construction.

         "Initiating Member" shall have the meaning set forth in Section 8.3.

         "Law" shall mean any (a) administrative, judicial, legislative or other
action,  code,  consent  decree,  constitution,  decree,  directive,  enactment,
finding, guideline, law, injunction, interpretation, judgment, order, ordinance,
policy statement,  proclamation,  promulgation,  regulation,  requirement, rule,
rule of law, rule of public policy,  settlement  agreement,  statute, or writ of
any  Authority,  domestic  or  foreign;  (b) the common  law,  or other legal or
quasi-legal  precedent;  or (c)  arbitrator's,  mediator's  or referee's  award,
decision,  finding or recommendation;  including, in each such case or instance,
any interpretation,  directive,  guideline or request, whether or not having the
force of law including, in all cases, without limitation any particular section,
part or provision thereof.

                                       A-5

<PAGE>



         "Liquidating  Transaction"  shall have the meaning set forth in Section
6.2.

         "Management  Agreement" shall mean the agreement,  dated as of the date
hereof, between ATS and the Company, relating to the marketing and management by
ATS on behalf of the Company of all communication towers now or hereafter owned,
leased, operated or managed by the Company.

         "Member" shall mean each of the  undersigned,  together with any Person
who becomes a  substituted  or additional  Member as herein  provided and who is
listed as a member of the  Company in the books and records of the  Company,  in
such Person's capacity as a member of the Company.

         "Member Loan" shall have the meaning set forth in Section 3.2.

         "Member  Schedule"  shall have the meaning set forth in Section 3.1, as
amended from time to time pursuant to the provisions of this Agreement.

         "Objection Notice" shall have the meaning set forth in Section 3.2.

         "Offer" shall have the meaning set forth in Section 8.2.

         "Offeror" shall have the meaning set forth in Section 8.2.

         "Other Member" shall have the meaning set forth in Section 8.3.

         "Parent" shall mean, with respect to any Person,  any Person which owns
directly,  or indirectly through one or more Subsidiaries,  twenty percent (20%)
or more of the voting or  beneficial  interest in, or otherwise has the right or
power  (whether by contract,  through  ownership of  securities or otherwise) to
control, such Person.

         "Permitted Transfer" shall mean any sale, transfer, assignment or other
disposition of a Company Interest by any Member to a Permitted Transferee.

         "Permitted Transferee" shall mean any of the following:

         (a)      any member of the Immediate Family or the estate, executors or
                  legal representatives of any  transferor,

         (b)      the trustees of an inter vivos or testamentary trust for the
                  benefit of any transferor or any member of his Immediate 
                  Family, or

         (c)      any Affiliate of the transferor effecting such transactions.

         "Person" shall mean any individual or Entity, and the heirs, executors,
administrators,  legal  representatives,  successors  and assigns of such Person
where the context so admits.

         "Prime  Rate"  shall  mean  the  annual   floating  rate  of  interest,
determined  daily and expressed as a percentage,  from time to time announced by
Toronto-Dominion  (Texas), Inc. as its "prime" or "base" rate, so-called,  or if
at any time such bank  ceases  to  announce  such a rate,  as  announced  by the
largest  national  or  state-chartered   banking  institution  then  having  its
principal office in the New York City and announcing such a rate. If at any time
neither Toronto-Dominion (Texas), Inc nor any of the five largest other national
or state-chartered  banking  institutions  having their principal offices in the
New York City is announcing such a floating rate, "Prime Rate" shall mean a rate
of interest,  determined  daily,  which is two (2)  percentage  points above the
14-day moving average closing trading price of 90-day Treasury Bills.

         "Profit" and "Loss" shall mean,  for each Fiscal Year or other  period,
an amount equal to the Company's taxable income or loss for such year or period,
determined in accordance with Section 703(a) of the Code (provided that for this
purpose,  all items of income,  gain,  loss, or deduction  required to be stated
separately  pursuant  to  Section  703(a)(1)  of the Code shall be  included  in
taxable income or loss), with the following adjustments:

         (a)      Any income of the Company that is exempt from  Federal  income
                  tax and not otherwise  taken into account in computing  Profit
                  or Loss  pursuant  to this  provision  shall  be added to such
                  taxable income or loss;

         (b)      Any   expenditures   of  the  Company   described  in  Section
                  705(a)(2)(B)   of  the  Code  or  treated   as  Code   Section
                  705(a)(2)(B)      expenditures     pursuant     to     Section
                  1.704-1(b)(2)(iv)(i)  of the  Treasury  Regulations,  and  not
                  otherwise  taken  into  account  in  computing  Profit or Loss
                  pursuant  to this  provision,  shall be  subtracted  from such
                  taxable income or loss;

         (c)      Book Gain or Book Loss shall be taken into  account in lieu of
                  any tax gain or tax loss  recognized  by the Company by reason
                  of any sale or disposition of an asset of the Company; and

         (d)      In lieu  of the  depreciation,  amortization  and  other  cost
                  recovery  deductions  taken  into  account in  computing  such
                  taxable  income or loss,  there  shall be taken  into  account
                  Depreciation  for such  Fiscal  Year,  computed as provided in
                  this Agreement.

         If the  Company's  taxable  income  or loss for such  Fiscal  Year,  as
adjusted in the manner provided above, is a positive  amount,  such amount shall
be the Company's  Profit for such Fiscal Year;  and if a negative  amount,  such
amount shall be the Company's Loss for such Fiscal Year.

         If the Book Value of the  Company  assets is  adjusted  pursuant to the
last  sentence of the  definition of Book Value,  the amount of such  adjustment
shall  be  included  in  computing  Profit  or  Loss.  If any  Company  asset is
distributed in kind (whether in connection  with the  liquidation of the Company
or  otherwise),  the  Company  shall be deemed to have  realized  Profit or Loss
thereon in the same  manner as if the  Company had sold such asset for an amount
equal to its fair market value on the date of  distribution,  as  determined  in
good faith by a Determination of the Members.

         "Regulatory  Allocations"  shall  have the  meaning  given such term in
Section 5.7.

         "Stated Amount" shall have the meaning given such term in Section 8.3.

         "Subsidiary"  shall mean, with respect to any Person, any Entity (i) in
which such Person owns directly, or indirectly through one or more Subsidiaries,
twenty percent (20%) or more of the voting or beneficial  interest or (ii) which
such Person  otherwise  has the right or power to control  (whether by contract,
through ownership of securities or otherwise).

          "Tax Matters Member" shall have the meaning given such term in Section
4.5(b).


                                       A-6

<PAGE>



         "Transfer"  shall mean,  in the  context of a Transfer of a  Membership
Interest,  the  sale,  assignment,  pledge,  hypothecation,  transfer  or  other
voluntary  disposition  (by  gift or  otherwise,  and  whether  as  security  or
otherwise) by a Member of all or a portion of its Interest. For purposes of this
definition,  "Transfer" of a Company Interest includes (i) the sale, assignment,
pledge,  hypothecation,  transfer  or other  voluntary  disposition  (by gift or
otherwise,  and whether as security or otherwise)  of an equity  interest in any
Person substantially all of the assets of which consist, directly or indirectly,
of a Company  Interest,  or (ii) the merger or consolidation of a Member,  or of
any Person referred to in clause (i), with another Person.

         "Treasury  Regulations"  shall mean the Federal income tax regulations,
including any temporary or proposed regulations,  promulgated under the Code, as
such Treasury  Regulations may be amended from time to time (it being understood
that all  references  herein to specific  sections of the  Treasury  Regulations
shall be deemed  also to refer to any  corresponding  provisions  of  succeeding
Treasury Regulations).

         "Unaffiliated  Person" shall mean, with respect to any Person, a Person
who is not an Affiliate as to such Person.


                                       A-7

<PAGE>


                                                                 MEMBER SCHEDULE



                  Initial Capital Contributions of the Members




           Member and Address                                    Contribution

American Tower Systems, Inc.
6400 North Congress Avenue, Suite 1750
Boca Raton, Florida 33487
Attention: Chief Operating Officer and
              Chief Financial Officer
Telecopier No.: (407) 998-2278

Communication Systems Development, Inc.
7488 Shoreline Drive, Suite B-1
Stockton, California 95219
Attention: Michael Wingo, Chief Executive Officer
Telecopier No.: (209) 951-5845




                                       A-8