Document:

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                                                                     EXHIBIT 4.4

                           SPECTRASITE HOLDINGS, INC.

                                    as Issuer

                                       and

                     UNITED STATES TRUST COMPANY OF NEW YORK

                                   as Trustee

                                    INDENTURE

                           Dated as of March 15, 2000

                          10 3/4% Senior Notes due 2010

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                                TABLE OF CONTENTS

                                    ARTICLE I
                   DEFINITIONS AND INCORPORATION BY REFERENCE

SECTION 1.1.  Definitions                                                      2
SECTION 1.2.  Other Definitions                                               20
SECTION 1.3.  Incorporation by Reference of Trust Indenture Act               21
SECTION 1.4.  Rules of Construction                                           21
SECTION 1.5.  One Class of Notes                                              22

                                   ARTICLE II
                                    THE NOTES

SECTION 2.1.  Form and Dating                                                 22
SECTION 2.2.  Execution and Authentication                                    22
SECTION 2.3.  Registrar and Paying Agent                                      23
SECTION 2.4.  Paying Agent to Hold Money in Trust                             23
SECTION 2.5.  Noteholder Lists                                                24
SECTION 2.6.  [Intentionally Omitted]                                         24
SECTION 2.7.  Replacement Notes                                               24
SECTION 2.8.  Outstanding Notes                                               25
SECTION 2.9.  Temporary Notes                                                 25
SECTION 2.10.  Cancellation                                                   25
SECTION 2.11.  Defaulted Interest                                             26
SECTION 2.12.  CUSIP Numbers                                                  26

                                   ARTICLE III
                                   REDEMPTION

SECTION 3.1.  Notices to Trustee                                              26
SECTION 3.2.  Selection of Notes to Be Redeemed                               26
SECTION 3.3.  Notice of Redemption                                            26
SECTION 3.4.  Effect of Notice of Redemption                                  27
SECTION 3.5.  Deposit of Redemption Price                                     27
SECTION 3.6.  Notes Redeemed in Part                                          27

                                   ARTICLE IV
                                    COVENANTS

SECTION 4.1.  Payment of Notes                                                28
SECTION 4.2.  SEC Reports                                                     28
SECTION 4.3.  Limitation on Indebtedness                                      28
SECTION 4.4.  Limitation on Indebtedness and Preferred Stock of Restricted
              Subsidiaries                                                    30
SECTION 4.5.  Limitation on Restricted Payments                               32
SECTION 4.6.  Limitation on Restrictions on Distributions from Restricted
              Subsidiaries                                                    34
SECTION 4.7.  Limitation on Sale of Assets and Subsidiary Stock               35
SECTION 4.8.  Limitation on Transactions with Affiliates                      38
SECTION 4.9.  Change of Control                                               39
SECTION 4.10.  Limitation on Sale or Issuance of Capital Stock of Restricted
               Subsidiaries                                                   40
SECTION 4.11.  Limitation on Liens                                            40
SECTION 4.12.  Limitation on Sale/Leaseback Transactions                      41
SECTION 4.13.  Compliance with Laws                                           41
SECTION 4.14.  Compliance Certificate                                         41
SECTION 4.15.  Further Instruments and Acts                                   41
SECTION 4.16.  Maintenance of Office or Agency                                41
SECTION 4.17.  Corporate Existence                                            42
SECTION 4.18.  Payment of Taxes and Other Claims                              42
SECTION 4.19.  Maintenance of Properties and Insurance                        42

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                                    ARTICLE V
                                SUCCESSOR ISSUER

SECTION 5.1.  When the Issuer May Merge or Transfer Assets                    43

                                   ARTICLE VI
                              DEFAULTS AND REMEDIES

SECTION 6.1.  Events of Default                                               44
SECTION 6.2.  Acceleration                                                    46
SECTION 6.3.  Other Remedies                                                  46
SECTION 6.4.  Waiver of Past Defaults                                         46
SECTION 6.5.  Control by Majority                                             47
SECTION 6.6.  Limitation on Suits                                             47
SECTION 6.7.  Rights of Holders to Receive Payment                            47
SECTION 6.8.  Collection Suit by Trustee                                      47
SECTION 6.9.  Trustee May File Proofs of Claim                                48
SECTION 6.10.  Priorities                                                     48
SECTION 6.11.  Undertaking for Costs                                          48
SECTION 6.12.  Waiver of Stay or Extension Laws                               48

                                   ARTICLE VII
                                     TRUSTEE

SECTION 7.1.  Duties of Trustee                                               49
SECTION 7.2.  Rights of Trustee                                               50
SECTION 7.3.  Individual Rights of Trustee                                    51
SECTION 7.4.  Trustee's Disclaimer                                            51
SECTION 7.5.  Notice of Defaults                                              51
SECTION 7.6.  Reports by Trustee to Holders                                   51
SECTION 7.7.  Compensation and Indemnity                                      51
SECTION 7.8.  Replacement of Trustee                                          52
SECTION 7.9.  Successor Trustee by Merger                                     53
SECTION 7.10.  Eligibility; Disqualification                                  53
SECTION 7.11.  Preferential Collection of Claims Against Issuer               54

                                  ARTICLE VIII
                       DISCHARGE OF INDENTURE; DEFEASANCE

SECTION 8.1.  Discharge of Liability on Notes; Defeasance                     54
SECTION 8.2.  Conditions to Defeasance                                        55
SECTION 8.3.  Application of Trust Money                                      56
SECTION 8.4.  Repayment to Issuer                                             56
SECTION 8.5.  Indemnity for Government Obligations                            56
SECTION 8.6.  Reinstatement                                                   56

                                   ARTICLE IX
                                   AMENDMENTS

SECTION 9.1.  Without Consent of Holders                                      57
SECTION 9.2.  With Consent of Holders                                         58
SECTION 9.3.  Compliance with Trust Indenture Act                             58
SECTION 9.4.  Revocation and Effect of Consents and Waivers                   58
SECTION 9.5.  Notation on or Exchange of Notes                                59
SECTION 9.6.  Trustee to Sign Amendments                                      59
SECTION 9.7.  Payment for Consent                                             59

                                    ARTICLE X
                                  MISCELLANEOUS

SECTION 10.1.  Trust Indenture Act Controls                                   59
SECTION 10.2.  Notices                                                        60
SECTION 10.3.  Communication by Holders with Other Holders                    60
SECTION 10.4.  Certificate and Opinion as to Conditions Precedent             60
SECTION 10.5.  Statements Required in Certificate or Opinion                  61
SECTION 10.6.  When Notes Disregarded                                         61
SECTION 10.7.  Rules by Trustee, Paying Agent and Registrar                   61
SECTION 10.8.  Legal Holidays                                                 61
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SECTION 10.9.  Governing Law                                                  62
SECTION 10.10.  No Recourse Against Others                                    62
SECTION 10.11.  Successors                                                    62
SECTION 10.12.  Multiple Originals                                            62
SECTION 10.13.  Variable Provisions                                           62
SECTION 10.14.  Qualification of Indenture                                    62
SECTION 10.15.  Table of Contents; Headings                                   62
SECTION 10.16.  Severability                                                  62

Rule 144A/Regulation S Appendix
Exhibit 1 to Appendix - Form of Initial Note
Exhibit A - Form of Exchange Note and Private Exchange Note

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                  INDENTURE,  dated as of March 15,  2000,  between  SPECTRASITE
HOLDINGS, INC., a Delaware corporation (as further defined below, the "Issuer"),
and UNITED STATES TRUST COMPANY OF NEW YORK, a bank and trust company  organized
under New York banking law, as trustee (the "Trustee").

                  Each  party  agrees as  follows  for the  benefit of the other
party and for the equal and  ratable  benefit  of the  Holders  of the  Issuer's
$200,000,000  aggregate  principal  amount of 10 3/4% Senior Notes due 2010 (the
"Initial  Notes")  and,  if and when issued in  exchange  for  Initial  Notes as
provided  in the  Registration  Rights  Agreement  (as  defined in the  Appendix
hereto),  the  Issuer's  Series B 10 3/4% Senior  Notes due 2010 (the  "Exchange
Notes")  and, if and when  issued  pursuant  to a private  exchange  for Initial
Notes,  the  Issuer's  Series B 10 3/4%  Senior  Notes  Due 2010  (the  "Private
Exchange  Notes,"  together with the Initial Notes and the Exchange  Notes,  the
"Notes"):
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               ARTICLE IDEFINITIONS AND INCORPORATION BY REFERENCE
                            SECTION 1.1. Definitions

                  "Adjusted  EBITDA" as of any date of  determination  means the
sum of (i) the  EBITDA  of the  Issuer  for the four  most  recent  full  fiscal
quarters  ending  prior to such date,  less the  Issuer's  Tower EBITDA for such
four-quarter  period,  plus (ii) the  product of four times the  Issuer's  Tower
EBITDA for the most recent  quarterly  period,  which Tower  EBITDA for the most
recent  quarterly  period shall be  determined on a pro forma basis after giving
effect to (A) all  acquisitions or dispositions of assets made by the Issuer and
its  Subsidiaries  from the beginning of such quarter through and including such
date of determination  (including any related financing transactions) as if such
acquisitions and dispositions had occurred at the beginning of such quarter, (B)
any new lease or Site  Management  Contract  entered  into by the  Issuer or any
Restricted  Subsidiary in the ordinary  course of business with respect to Tower
Assets from the  beginning of such quarter  through and  including  such date of
determination  as if such new lease or Site Management  Contract had been signed
at the  beginning  of such  quarter  and the rent  required by the terms of such
lease or Site  Management  Contract  for such  quarter and been  received by the
Issuer or a Restricted  Subsidiary  during such  quarter,  (C) the loss from the
beginning of such quarter  through and including such date of  determination  of
any lease or Site Management Contract of the Issuer or a Restricted Subsidiary
with respect to any Tower  Assets  that was in effect on the  first day of such
quarter  as if such lease or Site Management Contract had not been in effect
during such quarter and no rent under such lease had been received  during such
quarter and (D) any rent increases  received by the Issuer or any Restricted
Subsidiary  from during the period  beginning  on the first day of such  quarter
and  ending on the date of determination  related to leases or Site Management
Contracts on Tower Assets as if such  increased  rental  rate had been in effect
at the  beginning  of such quarter and such  increased  amount of rent had been
received by the Issuer or a Restricted   Subsidiary  during  such  quarter. For
purposes  of  making  the computation  referred  to  above,  (1)  acquisitions
that have been made by the Issuer or any of its  Restricted  Subsidiaries,
including  through  mergers  or consolidations  and including  any related
financing  transactions,  during the reference  period or subsequent to such
reference  period and on or prior to the date of  determination  shall be deemed
to have occurred on the first day of the reference  period and  EBITDA  for such
reference  period  shall be  calculated without  giving effect to clause (ii) of
the proviso set forth in the definition of  Consolidated  Net Income,  and (2)
the EBITDA  attributable  to discontinued operations,  as determined in
accordance with GAAP, and operations or businesses disposed of prior to the date
of determination shall be excluded.

                  "Affiliate"  of any  specified  Person means any other Person,
directly or indirectly, controlling or controlled by or under direct or indirect
common control with such specified Person.  For the purposes of this definition,
"control"  when used with  respect to any  Person  means the power to direct the
management and policies of such Person, directly or indirectly,
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whether through the  ownership of voting  securities,  by contract or otherwise;
and the terms "controlling" and "controlled" have meanings correlative to the
foregoing.

                  "Asset  Disposition" means any sale, lease,  transfer or other
disposition (or series of related sales,  leases,  transfers or dispositions) by
the Issuer or any Restricted Subsidiary, including any disposition by means of a
merger,  consolidation or similar transaction (each referred to for the purposes
of this definition as a "disposition"),  of (i) any shares of Capital Stock of a
Restricted  Subsidiary  (other  than  directors'  qualifying  shares  or  shares
required  by  applicable  law to be held by a Person  other than the Issuer or a
Restricted Subsidiary), (ii) all or substantially all the assets of any division
or line of  business  of the Issuer or any  Restricted  Subsidiary  or (iii) any
other assets of the Issuer or any Restricted  Subsidiary outside of the ordinary
course of business of the Issuer or such Restricted  Subsidiary  (other than, in
the  case of (i),  (ii) and  (iii)  above,  (u) a  disposition  by a  Restricted
Subsidiary to the Issuer or by the Issuer or a Restricted  Subsidiary to another
Restricted  Security,  (v) a disposition that  constitutes a Restricted  Payment
permitted by Section 4.5, (w) a  disposition  of assets with a fair market value
of less than $5.0 million,  (x) any transaction not prohibited by Section 4.5 or
that constitutes a Permitted Investment, (y) grants of leases or licenses in the
ordinary course of business, and (z) disposals of cash equivalents).

                  "Attributable  Indebtedness"  in respect  of a  Sale/Leaseback
Transaction  means,  as  at  the  time  of  determination,   the  present  value
(discounted at the interest rate borne by the Notes, compounded annually) of the
total obligations of the lessee for rental payments during the remaining  term
of  the  lease  included  in  such  Sale/Leaseback  Transaction (including any
period for which such lease has been extended).

                  "Average Life" means,  as of the date of  determination,  with
respect to any  Indebtedness  or  Preferred  Stock,  the  quotient  obtained  by
dividing  (i) the sum of the  product  of the  numbers of years from the date of
determination  to the dates of each successive  scheduled  principal  payment of
such  Indebtedness  or  redemption  or  similar  payment  with  respect  to such
Preferred Stock  multiplied by the amount of such payment by (ii) the sum of all
such payments.

                  "Board  of  Directors"  means the  Board of  Directors  of the
Issuer or any committee thereof duly authorized to act on behalf of such Board.

                  "Business  Day" means a day other than a  Saturday,  Sunday or
other day on which  banking  institutions  in New York State are  authorized  or
required by law to close.

                  "Capitalized  Lease  Obligation"  means an obligation  that is
required to be classified and accounted for as a capitalized lease for financial
reporting  purposes  in  accordance  with GAAP,  and the amount of  Indebtedness
represented  by  such  obligation  shall  be  the  capitalized  amount  of  such
obligation determined in accordance with GAAP.

                  "Capital  Stock"  of any  Person  means  any and  all  shares,
interests,  rights  to  purchase,  warrants,  options,  participation  or  other
equivalents  of or  interests  in (however
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designated)  equity of such  Person, including any Preferred  Stock,  but
excluding any debt  securities  convertible into such equity.

                  "Change of Control" means the occurrence of any of the
following events:

(i)               any "person" (as such term is used in Sections 13(d) and 14(d)
         of the Exchange Act), other than one or more Permitted Holders, is or
         becomes the beneficial owner (as such term is used in Sections 13(d)-3
         and 13(d)-5 of the Exchange Act, except that for purposes of this
         clause (i) (a) such Person shall be deemed to have "beneficial
         ownership" of all shares that any such person has the right to acquire,
         whether such right is exercisable immediately or only after the
         passage of time), directly or indirectly, of more than 35% of the total
         voting power of the Voting Stock of the Issuer; provided, however, that
         the Permitted Holders "beneficially own", directly or indirectly, in
         the aggregate a lesser percentage of the total voting power of the
         Voting Stock of the Issuer than such other Person and do not have the
         right or ability by voting power, contract or otherwise to elect or
         designate for election a majority of the Board of Directors of the
         Issuer (for the purposes of this clause (i), such other person shall be
         deemed to beneficially own any Voting Stock of a specified entity held
         by a parent entity, if such other person is the beneficial owner,
         directly or indirectly, of more than 35% of the voting power of the
         Voting Stock of such parent entity and the Permitted Holders
         "beneficially own", directly or indirectly, in the aggregate a lesser
         percentage of the total voting power of the Voting Stock of such parent
         entity than such other Person, and do not have the right or ability by
         voting power,  contract or otherwise to elect or designate for election
         a majority of the board of directors of such parent entity; and (b) the
         Permitted  Holders shall be deemed to beneficially own any Voting Stock
         of an entity held by any other parent entity,  so long as the Permitted
         Holders beneficially own, directly or indirectly,  in the aggregate,  a
         majority of the voting power of the parent entity's Voting Stock);

(i)       during any period of two consecutive years (or, in the case this event
         occurs  within the first two years after the Issue Date,  such  shorter
         period as shall have begun on the Issue Date),  individuals  who at the
         beginning  of such period  constituted  the Board of  Directors  of the
         Issuer (together with any new directors whose election by such Board of
         Directors or whose  nomination for election by the  shareholders of the
         Issuer was  approved  by a vote of a majority of the  directors  of the
         Issuer then still in office who were either  directors at the beginning
         of such  period  or whose  election  or  nomination  for  election  was
         previously  so approved)  cease for any reason to constitute a majority
         of the Board of Directors of the Issuer then in office;

(i)       the merger or consolidation of the Issuer with or into another
         Person or the merger of another Person with or into the Issuer, or the
         sale of all or substantially all the assets of the Issuer to another
         Person (other than a Permitted Holder or a Person that is controlled by
         the Permitted Holders), and, in the case of any such merger or
         consolidation, the securities of the Issuer that are outstanding
         immediately prior to such transaction and which represent 100% of the
         aggregate voting power of the Voting Stock of the Issuer are
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         changed into or exchanged for cash, securities or property, unless
         pursuant to such transaction such securities are changed into or
         exchanged for, in addition to any other consideration, securities of
         the surviving corporation that represent immediately after such
         transaction, at least a majority of the aggregate voting power of the
         Voting Stock of the surviving corporation; and

(i)      the sale of all or substantially  all of the Issuer's assets to another
         person, other than a Permitted Holder or a person that is controlled by
         the Permitted Holders.

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

                  "Completed Broadcast Tower" means a communications tower of at
least  500  feet,  other  than  a  Completed  Tower,  with,  as of the  date  of
determination,  (i) at least one broadcast tenant that has executed a definitive
lease or Site  Management  Contract  with the  Issuer  or any of its  Restricted
Subsidiaries and (ii) capacity for at least one other tenant.

                  "Completed  Tower" means a communications  transmission  tower
with, as of any date of  determination,  (i) at least one anchor tenant that has
executed a definitive  lease or Site Management  Contract with the Issuer or any
of its Restricted Subsidiaries and (ii) capacity for at least three tenants.

                  "Consolidated  Indebtedness"  as of any date of  determination
means (without  duplication)  (i) the total amount of Indebtedness of the Issuer
and its Restricted  Subsidiaries,  (ii) the total amount of  Indebtedness of any
other Person,  to the extent that such  Indebtedness  has been Guaranteed by the
Issuer or one or more of its  Restricted  Subsidiaries,  and (iii) the aggregate
liquidation  value of all  Disqualified  Stock of the Issuer  and all  preferred
stock of  Restricted  Subsidiaries  of the  Issuer  not owned by the Issuer or a
Restricted  Subsidiary,  in each case,  determined  on a  consolidated  basis in
accordance with GAAP.

                  "Consolidated  Interest  Expense" means,  for any period,  the
total  interest   expense  of  the  Issuer  and  its   consolidated   Restricted
Subsidiaries,  plus, to the extent not included in such total interest  expense,
and to the extent incurred by the Issuer or its Restricted Subsidiaries, without
duplication,  (i) interest expense  attributable to capital leases and to leases
constituting  part of a Sale/Leaseback  Transaction,  (ii)  amortization of debt
discount and debt  issuance  cost,  (iii)  capitalized  interest,  (iv) non-cash
interest  expense,  (v)  commissions,  discounts and other fees and charges owed
with respect to letters of credit and bankers'  acceptance  financing,  (vi) net
costs  associated  with Hedging  Obligations  (including  amortization of fees),
(vii)  Preferred  Stock  dividends paid in respect of all Preferred Stock of the
Issuer and its  Subsidiaries  held by Persons  other than the Issuer or a Wholly
Owned  Subsidiary,  (viii) interest  incurred in connection with  Investments in
discontinued operations, (ix) interest accruing on any Indebtedness of any other
Person to the extent  such  Indebtedness  is  Guaranteed  by (or  secured by the
assets  of)  the  Issuer  or  any   Restricted   Subsidiary  and  (x)  the  cash
contributions  to any  employee  stock  ownership  plan or similar  trust to the
extent such contributions are used by such plan or trust to pay interest
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or fees to any Person (other than the Issuer) in connection with  Indebtedness
Incurred by such plan or trust.

                  "Consolidated  Net  Income"  means,  for any  period,  the net
income  (loss)  of the  Issuer  and  its  consolidated  Subsidiaries;  provided,
however, that there shall not be included in such Consolidated Net Income:

(i)      any net income  (loss) of any Person  (other  than the  Issuer) if such
         Person is not a  Restricted  Subsidiary,  except  that,  subject to the
         exclusion  contained  in (iv)  below,  the  Issuer's  equity in the net
         income of any such  Person for such  period  shall be  included in such
         Consolidated  Net Income up to the  aggregate  amount of cash  actually
         distributed  by such  Person  during  such  period  to the  Issuer or a
         Restricted Subsidiary as a dividend or other distribution  (subject, in
         the case of a  dividend  or  other  distribution  paid to a  Restricted
         Subsidiary, to the limitations contained in clause (iii) below);

(i)      any net  income  (loss)  of any  Person  acquired  by the  Issuer  or a
         Subsidiary in a pooling of interests  transaction  for any period prior
         to the date of such acquisition;

(i)      any  net  income  of  any  Restricted  Subsidiary  if  such  Restricted
         Subsidiary  is subject to  restrictions  (other  than any  restrictions
         permitted in Section 4.6),  directly or  indirectly,  on the payment of
         dividends or the making of distributions by such Restricted Subsidiary,
         directly or indirectly,  to the Issuer,  except that (A) subject to the
         exclusion contained in clause (iv) below the Issuer's equity in the net
         income of any such  Restricted  Subsidiary  for such period  shall be
         included in such Consolidated  Net Income up to the aggregate amount of
         cash actually  distributed by such Restricted  Subsidiary during such
         period to the Issuer or another  Restricted  Subsidiary as a dividend
         or other distribution  (subject, in the case of a dividend or other
         distribution
         paid to another Restricted  Subsidiary,  to the limitation contained in
         this   clause)  and  (B)  solely  for  purposes  of   calculating   the
         Indebtedness  to Adjusted  EBITDA Ratio,  the Issuer's  equity in a net
         loss of any  such  Restricted  Subsidiary  for  such  period  shall  be
         included in determining such Consolidated Net Income;

(i)      any gain or loss  realized  upon the sale or other  disposition  of any
         assets of the Issuer, its consolidated Subsidiaries or any other Person
         (including  pursuant to any  Sale/Leaseback  Transaction)  which is not
         sold or otherwise  disposed of in the  ordinary  course of business and
         any gain or loss  realized  upon the sale or other  disposition  of any
         Capital Stock of any Person;

(i)               any net income or loss of any Unrestricted Subsidiary, except
to the extent distributed to the Issuer or one of its Subsidiaries;

(i)               any extraordinary gain or loss; and

(i)               the cumulative effect of a change in accounting principles.
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                                       7

Notwithstanding the foregoing, for the purposes of Section 4.5 only, there shall
be excluded from  Consolidated Net Income any dividends,  repayments of loans or
advances or other  transfers  of assets from  Unrestricted  Subsidiaries  to the
Issuer or a Restricted  Subsidiary to the extent such  dividends,  repayments or
transfers  increase  the  amount of  Restricted  Payments  permitted  under such
covenant pursuant to clause (a)(3)(D) thereof.

                  "Consolidated  Tangible  Assets"  means,  with  respect to the
Issuer, the total consolidated  tangible assets of the Issuer and its Restricted
Subsidiaries, as shown on the most recent internal consolidated balance sheet of
the Issuer and such Restricted  Subsidiaries  calculated on a consolidated basis
in accordance with GAAP.

                  "Credit  Facility"  means  any  debt  or  credit  facility  or
commercial  paper  facility  providing for revolving  credit loans,  term loans,
accounts receivable financing (including through the sale of accounts receivable
to such  lenders  or to  special  purpose  entities  formed to borrow  from such
lenders  against  such  accounts  receivable)  or letters  of  credit,  or other
non-convertible  debt securities or other form of debt financing,  in each case,
as amended,  restated,  supplemented,  extended,  modified,  renewed,  refunded,
replaced or refinanced in whole or in part from time to time, including any such
amendment, restatement, supplement, extension, modification, renewal, refunding,
replacement or refinancing  that increases the amount  borrowable  thereunder or
alters the maturity thereof.

                  "Currency  Agreement" means in respect of a Person any foreign
exchange  contract,  currency swap agreement or other similar agreement designed
to protect such Person against  fluctuations in currency values as to which such
Person is a party or a beneficiary.

                  "Default" means any event which is, or after notice or passage
of time or both would be, an Event of Default.

                  "Disqualified  Stock" means,  with respect to any Person,  any
Capital  Stock which by its terms (or by the terms of any security into which it
is  convertible  or for which it is  exchangeable)  or upon the happening of any
event (i)  matures  or is  mandatorily  redeemable  pursuant  to a sinking  fund
obligation or otherwise,  (ii) is convertible or  exchangeable  at the option of
the holder thereof for Indebtedness or Disqualified Stock or (iii) is redeemable
at the option of the  holder  thereof,  in whole or in part,  in each case on or
prior to the 91st day after the Stated Maturity of the Notes; provided, however,
that any  Capital  Stock that would not  constitute  Disqualified  Stock but for
provisions  thereof giving  holders  thereof the right to require such Person to
repurchase or redeem such Capital  Stock upon the  occurrence of an "asset sale"
or "change of control" occurring prior to the 91st day after the Stated Maturity
of the Notes  shall not  constitute  Disqualified  Stock if the "asset  sale" or
"change  of  control"  provisions  applicable  to  such  Capital  Stock  are not
materially  more favorable taken as a whole to the holders of such Capital Stock
than the provisions described under Section 4.9 and Section 4.7.
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                                       8

                  "EBITDA"  for any  period  means the sum of  Consolidated  Net
Income,   plus  the  following  to  the  extent  deducted  in  calculating  such
Consolidated Net Income: (a) Consolidated  Interest Expense;  (b) all income tax
expense  of  the  Issuer  and  its  consolidated  Restricted  Subsidiaries;  (c)
depreciation expense of the Issuer and its consolidated Restricted Subsidiaries;
(d)  amortization  expense  of  the  Issuer  and  its  consolidated   Restricted
Subsidiaries (excluding amortization expense attributable to a prepaid cash item
that was paid in a prior period);  (e) all other non-cash  charges of the Issuer
and its consolidated Restricted Subsidiaries (excluding any such non-cash charge
to the extent that it represents an accrual of or reserve for cash  expenditures
in any future  period);  and (f) any premium or penalty paid in connection  with
repurchasing, redeeming, retiring, defeasing or acquiring any Indebtedness prior
to maturity to the extent deducted in calculating  Consolidated  Net Income,  in
each case for such period.  Notwithstanding  the  foregoing,  the  provision for
taxes based on the income or profits of, and the  depreciation  and amortization
and  non-cash  charges  of,  a  Restricted  Subsidiary  shall  be  added  to the
Consolidated  Net Income to compute  EBITDA  only to the extent (and in the same
proportion)  that the net income of such  Restricted  Subsidiary was included in
calculating  Consolidated Net Income and only if a corresponding amount would be
permitted at the date of determination to be paid to the Issuer in the form of a
dividend by such Restricted Subsidiary without prior approval (that has not been
obtained), pursuant to the terms of its charter and all agreements, instruments,
judgments,   decrees,  orders,  statutes,  rules  and  governmental  regulations
applicable to such  Restricted  Subsidiary or its  stockholders,  without in any
event giving effect to any restrictions or limitations permitted in Section 4.6.

                  "Equity  Offering"  means a public or private  issuance by the
Issuer of common stock of the Issuer for cash.

                  "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

                  "GAAP" means generally accepted  accounting  principles in the
United States of America as in effect as of the Issue Date,  including those set
forth in (i) the opinions and pronouncements of the Accounting  Principles Board
of the American Institute of Certified Public  Accountants,  (ii) statements and
pronouncements  of the Financial  Accounting  Standards Board,  (iii) such other
statements  by such other  entity as  approved by a  significant  segment of the
accounting  profession  and (iv) the rules and  regulations of the SEC governing
the inclusion of financial statements (including pro forma financial statements)
in periodic  reports required to be filed pursuant to Section 13 of the Exchange
Act,  including  opinions and  pronouncements in staff accounting  bulletins and
similar written statements from the accounting staff of the SEC.

                  "Guarantee" means any obligation,  contingent or otherwise, of
any Person directly or indirectly  guaranteeing  any  Indebtedness of any Person
and any obligation,  direct or indirect, contingent or otherwise, of such Person
(i) to purchase or pay (or advance or supply  funds for the  purchase or payment
of) such  Indebtedness or other  obligation of such Person  (whether  arising by
virtue of partnership  arrangements,  or by agreements to keep-well, to purchase
assets,  goods,  securities or services, to take-or-pay or to maintain financial
statement  conditions  or  otherwise)  or (ii)  entered  into for the purpose of
assuring  in any other  manner the obligee of
<PAGE>   13
                                       9
such  Indebtedness  of the payment thereof or to protect such obligee  against
loss in respect thereof (in whole or in  part);  provided,  however,  that the
term  "Guarantee"  shall  not  include endorsements  for collection or deposit
in the ordinary course of business.  The term "Guarantee" used as a verb has a
corresponding meaning.

                  "Hedging   Obligations"   of  any  Person   means  the  actual
obligations  of such Person  pursuant to any Interest Rate Agreement or Currency
Agreement.

                  "Holder" or "Noteholder" means the Person in whose name a Note
is registered on the Registrar's books.

                  "Incur"  means issue,  assume,  Guarantee,  incur or otherwise
become liable for; provided,  however, that any Indebtedness or Capital Stock of
a Person  existing  at the time such  Person  becomes a  Subsidiary  (whether by
merger, consolidation,  acquisition or otherwise) shall be deemed to be Incurred
by such Subsidiary at the time it becomes a Subsidiary  unless such Indebtedness
or  Capital  Stock is  repaid or  redeemed  on the date  such  Person  becomes a
Subsidiary.  The term  "Incurrence" when used as a noun shall have a correlative
meaning.

                  "Indebtedness" means, with respect to any Person on any date
of determination (without duplication):

(i)      the principal in respect of (A)  indebtedness  of such Person for money
         borrowed and (B) indebtedness evidenced by notes, debentures,  bonds or
         other  similar  instruments  for the  payment of which  such  Person is
         responsible  or liable,  including,  in each case,  any premium on such
         indebtedness to the extent such premium has become due and payable;

(i)      all Capitalized  Lease  Obligations of such Person and all Attributable
         Debt in respect of  Sale/Leaseback  Transactions  entered  into by such
         Person;

(i)      all  obligations  of such  Person  issued or  assumed  as the  deferred
         purchase price of property,  all conditional  sale  obligations of such
         Person and all  obligations  of such Person  under any title  retention
         agreement (but excluding trade accounts payable arising in the ordinary
         course of business);

(i)      all obligations of such Person for the  reimbursement of any obligor on
         any letter of credit, banker's acceptance or similar credit transaction
         (other  than  obligations  with  respect to letters of credit and other
         contingent   liabilities  (but  only  to  the  extent  such  contingent
         liabilities  are  not  reflected  as  liabilities  on the  consolidated
         balance  sheet  of  such  Person)  securing   obligations  (other  than
         obligations  described in clauses (i) through (iii) above) entered into
         in the  ordinary  course of  business of such Person to the extent such
         letters of credit  are not drawn  upon or, if and to the  extent  drawn
         upon,  such drawing is reimbursed no later than the tenth  Business Day
         following payment on the letter of credit);
<PAGE>   14
                                       10

(i)      the  amount of all  obligations  of such  Person  with  respect  to the
         redemption, repayment or other repurchase of any Disqualified Stock or,
         with  respect  to  any  Subsidiary  of  such  Person,  the  liquidation
         preference with respect to, any Preferred Stock (but excluding, in each
         case, any accrued dividends);

(i)      all  obligations  of the type  referred  to in clauses  (i) through (v)
         above,  of other  Persons and all  dividends  of other  Persons for the
         payment of which, in either case, such Person is responsible or liable,
         directly or indirectly, as obligor,  guarantor or otherwise,  including
         by means of any Guarantee;

(i)      all  obligations  of the type  referred to in clauses (i) through  (vi)
         above, of other Persons secured by any Lien on any property or asset of
         such Person (whether or not such obligation is assumed by such Person),
         the  amount of such  obligation  being  deemed to be the  lesser of the
         value of such  property  or assets or the amount of the  obligation  so
         secured; and

(i) to the extent not otherwise included in this definition, Hedging Obligations
of such Person.

The amount of  Indebtedness  of any Person at any date shall be the  outstanding
balance at such date of all unconditional  obligations as described above or the
accreted value thereof,  in the case of Indebtedness  issued with original issue
discount,  and the maximum  liability,  upon the  occurrence of the  contingency
giving rise to the obligation, of any contingent obligations at such date.

                  "Indebtedness  to  Adjusted  EBITDA  Ratio"  as of any date of
determination  means the ratio of (i) Consolidated  Indebtedness as of such date
to (ii) Adjusted EBITDA.

                  "Indenture" means this Indenture, as amended or supplemented
from time to time.

                  "Interest Rate Agreement" means with respect to any Person any
interest rate protection  agreement,  interest rate future  agreement,  interest
rate  option  agreement,   interest  rate  swap  agreement,  interest  rate  cap
agreement,  interest rate collar  agreement,  interest  rate hedge  agreement or
other similar  agreement or arrangement  designed to protect such Person against
fluctuations  in  interest  rates  as to  which  such  Person  is a  party  or a
beneficiary.

                  "Investment"  in any  Person  means  any  direct  or  indirect
advance,  loan (other than  advances to  customers,  lessees or licensees in the
ordinary  course of business  that are  recorded as accounts  receivable  on the
balance sheet of such Person) or other extension of credit  (including by way of
Guarantee or similar  arrangement)  or capital  contribution to (by means of any
transfer of cash or other  property  to others or any  payment  for  property or
services for the account or use of others),  or any purchase or  acquisition  of
Capital Stock,  Indebtedness or other similar instruments issued by such Person.
For purposes of the  definitions of  "Unrestricted  Subsidiary"
<PAGE>   15
                                       11

and "Restricted Payment"  and  Section  4.5,  (i)   "Investment"   shall
include  the  portion (proportionate  to the Issuer's equity interest in such
Subsidiary) of the fair Market value of the net assets of any  Subsidiary of the
Issuer at the time that such Subsidiary is designated an  Unrestricted
Subsidiary;  provided,  however, that upon a  redesignation  of such Subsidiary
as a Restricted  Subsidiary,  the Issuer  shall be deemed  to  continue  to have
a  permanent  "Investment"  in an Unrestricted  Subsidiary  equal  to an  amount
(if  positive)  equal to (x) the Issuer's  "Investment" in such Subsidiary at
the time of such redesignation less (y)  the  portion  (proportionate  to  the
Issuer's  equity  interest  in  such Subsidiary) of the fair market value of the
net assets of such Subsidiary at the time that such Subsidiary is so
re-designated a Restricted Subsidiary;  and (ii) any property  transferred to or
from an Unrestricted  Subsidiary shall be valued at its  fair  market  value  at
the  time of  such  transfer,  in  each  case as determined in good faith by the
Board of Directors and evidenced by a resolution of such Board of Directors.

                  "Issue Date" means the date on which the Notes are originally
issued.

                  "Legal Holiday" has the meaning ascribed in Section 10.8.

                  "Lien"  means  any  mortgage,   pledge,   security   interest,
encumbrance, lien or charge of any kind (including any conditional sale or other
title retention agreement or lease in the nature thereof).

                  "Net  Available  Cash"  from an Asset  Disposition  means cash
payments  received  (including  any cash  payments  received  by way of deferred
payment of principal  pursuant to a note or installment  receivable or otherwise
and proceeds from the sale or other  disposition of any  securities  received as
consideration,   but  only  as  and  when  received,  but  excluding  any  other
consideration  received in the form of  assumption  by the  acquiring  Person of
Indebtedness  or other  obligations  relating  to such  properties  or assets or
received  in any other  non cash  form)  therefrom,  in each case net of (i) all
legal,  title,  accounting,  investment  banking  and  recording  tax  expenses,
commissions  and other  fees and  expenses  incurred,  and all  Federal,  state,
provincial,  foreign  and  local  taxes  required  to be  paid or  accrued  as a
liability  under GAAP,  as a  consequence  of such Asset  Disposition,  (ii) all
payments made on any Indebtedness which is secured by any assets subject to such
Asset  Disposition,  in  accordance  with the  terms  of any Lien  upon or other
security  arrangement of any kind with respect to such assets,  or which must by
its terms, or in order to obtain a necessary consent to such Asset  Disposition,
or by applicable law, be repaid out of the proceeds from such Asset Disposition,
(iii) all  distributions  and other  payments  required  to be made to  minority
interest  holders in Restricted  Subsidiaries  or joint  ventures as a result of
such Asset Disposition, (iv) the deduction of appropriate amounts to be provided
by the seller as a reserve,  in accordance  with GAAP,  against any  liabilities
associated with the assets disposed of in such Asset Disposition and retained by
the Issuer or any Restricted  Subsidiary after such Asset  Disposition,  and (v)
any  reserves  established  in  respect  of the  sales  price of such  asset for
post-closing  adjustments,  indemnification  purposes  or  employee  termination
expenses.
<PAGE>   16
                                       12

                  "Net Cash  Proceeds",  with respect to any issuance or sale of
Capital  Stock,  means  the  cash  proceeds  of such  issuance  or  sale  net of
attorneys' fees,  accountants' fees, printing costs,  underwriters' or placement
agents' fees, discounts or commissions and brokerage,  consultant and other fees
and expenses  actually incurred in connection with such issuance or sale and net
of taxes paid or payable as a result thereof.

                  "Non-Recourse Debt" means Indebtedness (i) as to which neither
the Issuer nor any  Restricted  Subsidiary  (a) provides any Guarantee or credit
support of any kind (including any undertaking,  Guarantee, indemnity, agreement
or  instrument  that  would  constitute  Indebtedness)  or  (b) is  directly  or
indirectly liable (as a guarantor or otherwise) and (ii) no default with respect
to which  (including  any  rights  that  the  holders  thereof  may have to take
enforcement  action  against an  Unrestricted  Subsidiary)  would  permit  (upon
notice,  lapse of time or both)  any  holder of any  other  Indebtedness  of the
Issuer or any  Restricted  Subsidiary  to  declare a default  under  such  other
Indebtedness  or cause the payment thereof to be accelerated or payable prior to
its stated maturity.

                  "Offering  Memorandum"  means the  Offering  Memorandum  dated
March 10, 2000 relating to the Initial  Notes;  provided that after the issuance
of Exchange  Notes,  all  references  herein to "Offering  Memorandum"  shall be
deemed  references to the  prospectus  contained in the  registration  statement
relating to the Exchange Notes.

                  "Officer" means the Chairman of the Board, the President,  the
Chief Executive Officer,  any Vice President,  the Chief Financial Officer,  the
Treasurer or the Secretary of the Issuer, as applicable.

                  "Officer's Certificate" means a certificate signed by any
Officer.

                  "Opinion of Counsel"  means a written  opinion  that meets the
requirements of Section 10.5 hereof from Dow,  Lohnes & Albertson,  PLLC, or any
other legal counsel who is reasonably acceptable to the Trustee. The counsel may
be an employee of or counsel to the Issuer or the Trustee.

                  "Permitted  Acquisition  Indebtedness"  means  Indebtedness or
acquired  debt in an aggregate  principal  amount not to exceed $50.0 million at
any one time outstanding, incurred or assumed in connection with the acquisition
of an  entity  that is  engaged  in a  Permitted  Business  and that  becomes  a
Restricted  Subsidiary or the acquisition of any assets  constituting a business
or line of business as determined by the Board of Directors, that is a Permitted
Business or incurred by such entity or the owner of such assets and  outstanding
on the date of such acquisition.

                  "Permitted  Business"  means  any  business  conducted  by the
Issuer and its Restricted  Subsidiaries on the Issue Date and any other business
related, ancillary or complementary to any such business.
<PAGE>   17
                                       13

                  "Permitted  Holders"  means any or all of  Stephen  H.  Clark,
David P. Tomick,  Joe L. Finley,  Welsh,  Carson,  Anderson & Stowe, VIII, L.P.,
WCAS  Information  Partners,  L.P.,  WCAS  Capital  Partners  III,  L.P.,  their
respective general partners,  employees of Welsh, Carson, Anderson & Stowe, CIBC
WG Argosy Merchant Fund 2, L.L.C., Co-Investment Merchant Fund 3, LLC, Caravelle
Investment Fund, L.L.C., Tower Parent Corp., Whitney Equity Partners, L.P., J.H.
Whitney III, L.P.,  Whitney Strategic Partners III, L.P., J.H. Whitney Mezzanine
Fund,  L.P.,  Waller-Sutton  Media  Partners,  L.P.,  Kitty Hawk Capital Limited
Partnership,  III,  Kitty Hawk  Capital  Limited  Partnership,  IV,  Eagle Creek
Capital, L.L.C., The North Carolina Enterprise Fund, L.P., Finley Family Limited
Partnership, and their respective Affiliates.

                  "Permitted  Investment"  means an  Investment by the Issuer or
any Restricted Subsidiary in (i) the Issuer, a Restricted Subsidiary or a Person
which will, upon the making of such Investment,  become a Restricted Subsidiary;
(ii)  another  Person if as a result of such  Investment  such  other  Person is
merged  or   consolidated   with  or  into,  or  transfers  or  conveys  all  or
substantially  all  its  assets  to,  the  Issuer  or a  Restricted  Subsidiary;
provided,  however, that such Person's primary business is a Permitted Business;
(iii) Temporary Cash  Investments;  (iv) receivables  owing to the Issuer or any
Restricted Subsidiary, if created or acquired in the ordinary course of business
and payable or dischargeable in accordance with customary trade terms; provided,
however, that such trade terms may include such concessionary trade terms as the
Issuer  or  any  such  Restricted   Subsidiary   deems   reasonable   under  the
circumstances;  (v) payroll,  travel and similar  advances to cover matters that
are expected at the time of such advances  ultimately to be treated as expenses
for accounting  purposes and that are made in the ordinary course of business;
(vi) loans or advances to employees made in the ordinary  course of business
consistent  with past  practice of the Issuer or such  Restricted  Subsidiary,
but in any  event  not to  exceed  $2.0 million in the aggregate  outstanding at
any one time; (vii) stock,  obligations or securities  received in settlement of
debts created in the ordinary course of business and owing to the Issuer or any
Restricted Subsidiary or in satisfaction of judgments or pursuant to any plan of
reorganization  or similar  arrangement upon the  bankruptcy or insolvency of a
debtor;  (viii) any Person to the extent such investment  represents the
non-cash portion of the  consideration  received for an Asset  Disposition  as
permitted  pursuant to Section  4.7;  (ix) Capital Stock  of the  Issuer  or any
Restricted  Subsidiary  purchased,  redeemed  or otherwise acquired or retired
for value from members of the Issuer's  management or  employees,  but in any
event not to exceed $2.0  million in aggregate in any twelve-month  period;
(x) other  Investments  in  Permitted  Businesses  not to exceed,  at any one
time outstanding  (each such Investment being measured as of the date made and
without giving effect to subsequent changes in value), the sum of (x) $10.0
million and 10% of the Issuer's  Consolidated Tangible Assets; (xi) any Interest
Rate  Agreement or Currency  Agreement;  (xii) any  acquisition  of assets to
the extent the consideration therefor consists of Capital Stock (other than
Disqualified  Stock) of the Issuer;  (xiii) prepaid  expenses,  negotiable
instruments  held for collection and lease,  utility and workers'  compensation,
performance and other similar deposits;  (xiv) deposits of proceeds or Qualified
Proceeds from Asset  Dispositions  with a "qualified  intermediary,"  "qualified
trustee" or similar person for purposes of  facilitating a "like-kind"  exchange
made in accordance with the applicable  provisions of the Internal  Revenue Code
of 1986,  as  amended;  provided,  however,  that the  making  of any  Permitted
Investment  pursuant to this clause (xiv) will not in any manner violate
<PAGE>   18
14

Section 4.7;  (xv)  Investments  in an amount  not to exceed  the Net Cash
Proceeds  or Qualified  Proceeds of the issuance or sale,  other than to a
Subsidiary  of the Issuer, of Capital Stock of the Issuer,  other than
Disqualified  Stock, to the extent that such Net Cash  Proceeds or Qualified
Proceeds have not been applied to make a Restricted Payment or to effect other
transactions pursuant to Section 4.5 or to the extent such Net Cash Proceeds or
Qualified  Proceeds have not been used to Incur  Indebtedness;  and (xvi) other
Investments not to exceed, at any one time outstanding, $75.0 million.

                  "Permitted  Liens"  means,  with  respect to any  person,  (a)
pledges  or  deposits  by  such  Person  under   worker's   compensation   laws,
unemployment  insurance laws or similar  legislation,  or good faith deposits in
connection  with  bids,  tenders,  contracts  (other  than  for the  payment  of
Indebtedness)  or leases to which such Person is a party,  or deposits to secure
public or  statutory  obligations  of such  Person or deposits or cash or United
States government bonds to secure surety or appeal bonds to which such Person is
a party, or deposits as security for contested taxes or import duties or for the
payment of rent, in each case incurred in the ordinary  course of business;  (b)
Liens  imposed  by  law,  such  as  carriers',  warehousemen's,  landlords'  and
mechanics'  Liens,  in each case for sums not yet due or being contested in good
faith by appropriate proceedings,  or judgment Liens not giving rise to an Event
of Default so long as any appropriate legal proceedings which may have been duly
initiated for the review of such judgment shall not have been finally terminated
or the period  within which such  proceedings  may be  initiated  shall not have
expired; (c) Liens for property taxes not yet subject to penalties for
non-payment  or which  are being  contested  in good  faith by  appropriate
proceedings  (d) Liens in favor of issuers of surety  bonds or letters of credit
issued  pursuant  to the  request of and for the  account of such  Person in the
ordinary course of its business; (e) survey exceptions,  encumbrances, easements
or reservations  of, or rights of others for,  licenses,  rights of way, sewers,
electric  lines,  telegraph and telephone lines and other similar  purposes,  or
zoning  or  other  restrictions  as to  the  use of  real  properties  or  liens
incidental  to the conduct of the business of such Person or to the ownership of
its properties which were not incurred in connection with Indebtedness and which
do not in the aggregate materially adversely affect the value of said properties
or materially  impair their use in the operation of the business of such Person;
(f) Liens securing Hedging  Obligations so long as the related  Indebtedness is,
and is  permitted  to be under  this  Indenture,  secured  by a Lien on the same
property  securing  such Hedging  Obligations;  (g) leases and subleases of real
property which do not interfere with the ordinary conduct of the business of the
Issuer or any of its Restricted Subsidiaries, and Liens securing the obligations
(other than  Indebtedness)  of the Issuer or any of the Restricted  Subsidiaries
under any such leases and subleases of real  property;  (h) Liens existing as of
the date on which the Notes are  originally  issued  and Liens  created  by this
Indenture;  (i) Liens created  solely for the purpose of securing the payment of
all or part of the purchase price of assets or property  acquired or constructed
in the  ordinary  course  of  business  after  the date on which  the  Notes are
originally issued; provided,  however, that (A) the Indebtedness secured by such
Liens shall have  otherwise been permitted to be issued under this Indenture and
(B) such Liens shall not  encumber any other assets or property of the Issuer or
any of its  Restricted  Subsidiaries;  (j) Liens on the assets or  property of a
Restricted  Subsidiary  of the  Issuer  existing  at the  time  such  Restricted
Subsidiary became a Subsidiary of the Issuer and not incurred as a result of (or
in connection with or in
<PAGE>   19
                                       15

anticipation of) such Restricted  Subsidiary becoming a Subsidiary of the
Issuer; provided,  however, that (A) any such Lien does not by its terms cover
any property or assets after the time such Restricted Subsidiary becomes  a
Subsidiary  which  were  not  covered   immediately  prior to  such transaction,
(B) the Incurrence of the Indebtedness  secured by such Lien shall have
otherwise been  permitted to be issued under this  Indenture,  and (C) such
Liens do not  extend to or cover any other  property  or assets of the Issuer or
any of its Restricted Subsidiaries;  (k) Liens securing Indebtedness outstanding
under a Credit  Facility  and any other Liens  securing  Indebtedness  permitted
under this  Indenture  to be  Incurred  by a  Restricted  Subsidiary;  (l) Liens
extending,  renewing or replacing  in whole or in part a Lien  permitted by this
Indenture;  provided,  however,  that (A) such  Liens do not  extend  beyond the
property  subject to the existing Lien and improvements and construction on such
property  and (B) the  Indebtedness  secured  by the  Lien  may not  exceed  the
Indebtedness secured at the time by the existing Lien; (m) Liens Incurred in the
ordinary course of business by the Issuer or any  Restriction  Subsidiary of the
Issuer with respect to  obligations  that do not exceed $25.0 million at any one
time  outstanding and that (i) are not Incurred in connection with the borrowing
of money or the  obtaining of advances of credit (other than trade credit in the
ordinary course of business) and (ii) do not in the aggregate materially detract
from the value of the  property  or  materially  impair  the use  thereof in the
operation of business by the Issuer or such Restricted Subsidiary;  (n) Liens in
favor of the Issuer or a Restricted Subsidiary;  (o) any interest in or title of
a lessor to any property subject to a Capitalized Lease Obligation  permitted to
be Incurred under this Indenture; (p) Liens on the Capital Stock of Unrestricted
Subsidiaries; (q) the Liens granted pursuant to the terms of the Security and
Subordination  Agreement, as amended,  modified or supplemented from time to
time,  entered into pursuant to the terms of the Agreement and Plan of  Merger,
dated as of  February  10,  1999,  among  the  Issuer,  SpectraSite
Communications,  Inc., SHI Merger Sub,  Inc.,  Nextel  Communications,  Inc. and
certain of its subsidiaries;  (r) Liens, rights of set-off or similar rights and
remedies as to deposit  accounts or other funds  maintained with a depository or
other financial institution;  (s) Liens on property subject to Capitalized Lease
Obligations to the extent the related  Capitalized Lease Obligation is permitted
to be incurred under Section 4.3 or Section 4.4 of this Indenture;  (t) Liens on
property  of the  Issuer or a  Restricted  Subsidiary  at the time the Issuer or
Restricted Subsidiary acquired the property,  including any acquisition by means
of a  merger  or  consolidation  with  or  into  the  Issuer  or any  Restricted
Subsidiary;  provided,  however,  that such Liens are not  created,  incurred or
assumed in connection with, or in contemplation of, such  acquisition,  provided
further,  however, that such Liens may not extend to any other property owned by
the Issuer or any Restricted Subsidiary;  and (u) Liens on government securities
that secure  Indebtedness,  to the extent that such  government  securities  are
purchased with the proceeds of such Indebtedness.

                  "Person" means any individual, corporation, partnership, joint
venture,  limited liability company,  association,  joint-stock company,  trust,
unincorporated  organization,  government or any agency or political subdivision
thereof or any other entity.

                  "Preferred  Stock",  as  applied to the  Capital  Stock of any
Person,  means Capital Stock of any class or classes (however  designated) which
is  preferred  as to the payment of  dividends  or  distributions,  or as to the
distribution  of  assets  upon  any  voluntary  or  involuntary
<PAGE>   20
                                       16

liquidation  or
dissolution  of such Person,  over shares of Capital Stock of any other class of
such Person.
                  "Principal" of a Note means the principal of the Note plus the
premium, if any, payable on the Note which is due or overdue or is to become due
at the relevant time.

                  "Qualified  Proceeds" means assets that are used or useful in,
or Capital Stock of any Person engaged in, a Permitted Business.

                  "Refinance"   means,  in  respect  of  any  Indebtedness,   to
refinance,  extend, renew, refund, repay, prepay, redeem,  purchase,  defease or
retire,  or to issue other  Indebtedness  in exchange or  replacement  for, such
indebtedness. "Refinanced" and "Refinancing" shall have correlative meanings.

                  "Refinancing  Indebtedness" means Indebtedness that Refinances
any Indebtedness of the Issuer or any Restricted Subsidiary existing on the date
of this  Indenture  or Incurred in  compliance  with this  Indenture  (including
Indebtedness  of the  Issuer  that  Refinances  Indebtedness  of any  Restricted
Subsidiary  and  Indebtedness  of  any  Restricted  Subsidiary  that  Refinances
Indebtedness  of another  Restricted  Subsidiary)  including  Indebtedness  that
Refinances Refinancing Indebtedness; provided, however, that (i) the Refinancing
Indebtedness has a Stated Maturity no earlier than the earlier of the Stated
Maturity of the Notes and the Stated  Maturity of the  Indebtedness  being
Refinanced,  (ii) the  Refinancing Indebtedness  has an Average Life at the time
such  Refinancing  Indebtedness is Incurred  that is equal to or greater than
the lesser of the Average Life of the Indebtedness  being  Refinanced and the
Average Life of the Notes and (iii) such Refinancing  Indebtedness  is Incurred
in an aggregate  principal  amount (or if issued with original issue discount,
an aggregate issue price) that is equal to or less  than the sum of the
aggregate  principal  amount  (or if  issued  with original  issue  discount,
the aggregate  accreted  value) then  outstanding or committed (plus fees and
expenses,  including any premium and defeasance  costs) under  the  Indebtedness
being  Refinanced;  provided  further,  however,  that Refinancing Indebtedness
shall not include (x) Indebtedness of a Subsidiary that Refinances  Indebtedness
of the Issuer or (y)  Indebtedness  of the Issuer or a Subsidiary that
refinances Indebtedness of an Unrestricted Subsidiary.

                  "Restricted  Payment" with respect to any Person means (i) the
declaration or payment of any dividends or any other  distributions  of any sort
in respect of its  Capital  Stock or similar  payment to the direct or  indirect
holders of its Capital  Stock in respect  thereof  (other than (a)  dividends or
distributions  payable  solely in its Capital  Stock  (other  than  Disqualified
Stock),  (b)  dividends  or  distributions  payable  solely  to the  Issuer or a
Restricted Subsidiary, and (c) pro rata dividends or other distributions made by
a Subsidiary that is not a Wholly Owned Subsidiary to minority  stockholders (or
owners of an equivalent  interest in the case of a Subsidiary  that is an entity
other than a corporation)),  (ii) the purchase,  redemption or other acquisition
or retirement for value of any Capital Stock of the Issuer held by any Person or
of any Capital Stock of a Restricted  Subsidiary  held by any Person (other than
the Issuer or a Restricted Subsidiary), other than the exercise by the Issuer of
any option to convert or exchange any Capital Stock into Indebtedness so long as
such  Indebtedness  is permitted to be Incurred as of the date of such
<PAGE>   21
                                       17

exercise pursuant to this  Indenture,  and other than as  permitted by clause
(ix) of the definition  of  "Permitted   Investments";  (iii)  the  purchase,
repurchase, redemption,  defeasance or other  acquisition or retirement for
value,  prior to scheduled maturity, scheduled repayment or scheduled sinking
fund payment of any Subordinated   Obligations  (other  than  the  purchase,
repurchase  or  other acquisition of Subordinated  Obligations purchased in
anticipation of satisfying a sinking fund obligation, principal installment or
final maturity, in each case due  within  one year of the date of  acquisition);
or (iv) the  making  of any Investment in any Person (other than a Permitted
Investment).

                  "Restricted Subsidiary" means any Subsidiary of the Issuer
other than an Unrestricted Subsidiary.

                  "Sale/Leaseback  Transaction" means an arrangement relating to
property  now owned or  hereafter  acquired  whereby the Issuer or a  Restricted
Subsidiary  transfers  such  property to a Person and the Issuer or a Restricted
Subsidiary leases it from such Person.

                  "SEC" means the U.S. Securities and Exchange Commission.

                  "Secured Indebtedness" means any Indebtedness of the Issuer
secured by a Lien.

                  "Securities Act" means the Securities Act of 1933, as amended.

                  "Senior  Indebtedness"  means (i)  Indebtedness of the Issuer,
whether outstanding on the Issue Date or thereafter  Incurred,  and (ii) accrued
and unpaid interest  (including  interest accruing on or after the filing of any
petition  in  bankruptcy  or for  reorganization  relating  to the Issuer to the
extent  post-filing  interest is allowed in such  proceeding)  in respect of (A)
indebtedness of the Issuer for money borrowed and (B) indebtedness  evidenced by
notes,  debentures,  bonds or other similar instruments for the payment of which
the Issuer is responsible or liable unless,  in the case of (i) and (ii), in the
instrument  creating  or  evidencing  the same or  pursuant to which the same is
outstanding,  it is provided that such  obligations  are subordinate in right of
payment to the Notes;  provided,  however,  that Senior  Indebtedness  shall not
include (1) any  obligation of the Issuer to any  Subsidiary,  (2) any liability
for Federal,  state,  local or other taxes owed or owing by the Issuer,  (3) any
accounts  payable or other liability to trade creditors  arising in the ordinary
course of business (including guarantees thereof or instruments  evidencing such
liabilities),  (4) any  Indebtedness  of the Issuer  (and any accrued and unpaid
interest in respect  thereof)  which is  subordinate or junior in any respect to
any other  Indebtedness or other  obligation of the Issuer,  (5) that portion of
any  Indebtedness  which at the time of  Incurrence  is Incurred in violation of
this Indenture.

                  "Senior   Discount  Notes"  means  the  Issuer's  12%  Senior
Discount Notes due 2010.
<PAGE>   22
                                       18

                  "Significant  Subsidiary" means any Restricted Subsidiary that
would be a  "Significant  Subsidiary"  of the Issuer  within the meaning of Rule
1-02 under Regulation S-X promulgated by the SEC.

                  "Site  Management  Contract"  means any agreement  pursuant to
which  the  Issuer  or any of its  Restricted  Subsidiaries  has  the  right  to
substantially  control Tower Assets and the revenues  derived from the rental or
use thereof.

                  "Stated  Maturity"  means,  with respect to any security,  the
date  specified  in such  security  as the fixed  date on which the  payment  of
principal  of  such  security  is due and  payable,  including  pursuant  to any
mandatory  redemption  provision (but excluding any provision  providing for the
repurchase  of such  security  at the  option  of the  holder  thereof  upon the
happening  of any  contingency  beyond the  control of the  issuer  unless  such
contingency has occurred).

                  "Subordinated Obligation" means any Indebtedness of the Issuer
(whether  outstanding  on the  Issue  Date  or  thereafter  Incurred)  which  is
subordinate  or junior in right of  payment to the Notes  pursuant  to a written
agreement.

                  "Subsidiary" of any Person means any corporation, association,
partnership or other business  entity of which more than 50% of the total voting
power of shares  of  Capital  Stock or other  interests  (including  partnership
interests)  entitled  (without  regard to the occurrence of any  contingency) to
vote in the election of directors, managers or trustees thereof is at the time
owned or controlled,  directly or indirectly, by (i) such Person, (ii) such
Person and one or more  Subsidiaries  of such  Person or (iii) one or more
Subsidiaries of such Person.

                  "Temporary Cash Investments"  means any of the following:  (i)
any  investment  in direct  obligations  of the United  States of America or any
agency thereof or obligations  Guaranteed by the United States of America or any
agency  thereof,  (ii)  investments in time deposit  accounts,  certificates  of
deposit  and  money  market  deposits  maturing  within  one year of the date of
acquisition  thereof issued by a bank or trust company which is organized  under
the laws of the United  States of  America,  any state  thereof  or any  foreign
country  recognized by the United States of America having capital,  surplus and
undivided  profits  aggregating  in  excess of $500.0  million  (or the  foreign
currency  equivalent  thereof)  and whose  long-term  debt is rated "A" (or such
similar  equivalent  rating)  or higher by at least  one  nationally  recognized
statistical  rating  organization  (as defined in Rule 436 under the  Securities
Act) or any money market fund sponsored by a registered  broker dealer or mutual
fund distributor,  (iii) repurchase  obligations with a term of not more than 30
days for  underlying  securities  of the types  described  in  clause  (i) above
entered  into with a bank  meeting the  qualifications  described in clause (ii)
above,  (iv)  investments in commercial  paper,  maturing not more than 270 days
after the date of acquisition,  issued by a corporation (other than an Affiliate
of the Issuer) organized and in existence under the laws of the United States of
America or any foreign country recognized by the United States of America with a
rating  at the time as of which  any  investment  therein  is made of "P-1"  (or
higher)  according  to Moody's  Investors  Service,  Inc.  or " A-1" (or higher)
according to Standard
<PAGE>   23
                                       19

& Poor's Ratings Group,  and (v) investments in securities with maturities of
one year or less from the date of acquisition issued or fully guaranteed  by any
state,  commonwealth  or  territory  of the United  States of America, or by any
political  subdivision or taxing authority thereof, and rated at least "A" by
Standard & Poor's  Ratings  Group or "A" by  Moody's  Investors Service, Inc.

                  "TIA" means the Trust Indenture Act of 1939 (15 U.S.C. ss.ss.
77aaa-77bbbb) as in effect on the date of this Indenture.

                  "Tower  Asset  Exchange"  means any  transaction  in which the
Issuer or a  Restricted  Subsidiary  exchanges  assets for Tower Assets or Tower
Assets and cash or cash equivalents  where the fair market value (evidenced by a
resolution  of the  Board of  Directors)  of the Tower  Assets  and cash or cash
equivalents  received  by the Issuer  and its  Restricted  Subsidiaries  in such
exchange is at least equal to the fair  market  value of the assets  disposed in
such exchange.

                  "Tower  Assets" means  communication  transmission  towers and
related assets that are located on the site of a transmission tower.

                  "Tower EBITDA" means, for any period, the EBITDA of the Issuer
and its Restricted Subsidiaries for such period that is directly attributable to
site  rental  revenue,  license  or  management  fees paid to  manage,  lease or
sublease  space on  communication  sites owned,  leased or managed by the Issuer
(collectively,  "site leasing revenues"), all determined on a consolidated basis
and in accordance with GAAP. Tower EBITDA will not include revenue derived  from
the  sale  of  assets.   In   allocating,   corporate,   general, administrative
and  other  operating  expenses  that are not  allocated  to any particular line
of business in the  financial  statements  of the Issuer, such expenses shall be
allocated to the Issuer's site leasing  business in proportion to the percentage
of the Issuer's total revenues for the applicable  period that were site leasing
revenues.

                  "Trust  Officer"  means  any  trust  officer,  assistant  vice
president,  or  vice  president  of  the  Trustee  assigned  by the  Trustee  to
administer this Indenture.

                  "Trustee"  means  the  party  named as such in this  Indenture
until a successor replaces it and, thereafter, means such successor.

                  "2008 Notes" means the Issuer's 12% Senior Discount Notes Due
2008.

                  "2009 Notes" means the Issuer's 11 1/4% Senior  Discount Notes
Due 2009.

                  "Uniform   Commercial   Code"  means  the  New  York   Uniform
Commercial Code as in effect from time to time.

                  "Unrestricted  Subsidiary"  means  (i) any  Subsidiary  of the
Issuer that at the time of  determination  shall be designated  an  Unrestricted
Subsidiary by the Board of Directors in the
<PAGE>   24
                                       20

manner  provided  below and (ii) any Subsidiary of an Unrestricted  Subsidiary.
The Board of Directors may designate any  Subsidiary  of the Issuer  (including
any newly  acquired or newly  formed Subsidiary  of  the  Issuer)  to  be  an
Unrestricted  Subsidiary  unless  such Subsidiary or any of its Subsidiaries
owns any Capital Stock or Indebtedness of, or owns or holds any Lien on any
property of, the Issuer or any other Restricted Subsidiary  of the Issuer that
is not a Subsidiary  of the  Subsidiary  to be so designated; provided, however,
that  either  (A)  the  Subsidiary  to  be  so designated  has  total
consolidated  assets  of  $1,000  or less or (B) if such Subsidiary has
consolidated  assets greater than $1,000,  then such designation would be
permitted  under  Section 4.5. The Board of Directors may designate any
Unrestricted Subsidiary to be a Restricted Subsidiary;  provided,  however, that
(a)  immediately  after giving effect to such  designation no Default shall have
occurred and be  continuing  and (b) such  designation  shall be deemed to be an
Incurrence  of  Indebtedness  by a  Restricted  Subsidiary  of  any  outstanding
Indebtedness of such Unrestricted  Subsidiary and such designation shall only be
permitted if such  Indebtedness  is  permitted  under this  Indenture.  Any such
designation  by the Board of  Directors  shall be  evidenced  to the  Trustee by
promptly filing with the Trustee a copy of the Board Resolution giving effect to
such designation and an Officer's  Certificate  certifying that such designation
complied with the foregoing provisions.

                  "U.S.  Government  Obligations"  means direct  obligations (or
certificates  representing  an ownership  interest in such  obligations)  of the
United States of America (including any agency or  instrumentality  thereof) for
the  payment of which the full faith and credit of the United  States of America
is pledged and which are not callable or redeemable at the Issuer's option.

                  "Voting  Stock" of a Person means all classes of Capital Stock
or  other  interests  (including  partnership  interests)  of such  Person  then
outstanding  and normally  entitled  (without  regard to the  occurrence  of any
contingency) to vote in the election of directors, managers, or trustee thereof.

                  "Wholly Owned Subsidiary" means a Restricted Subsidiary of the
Issuer all the Capital Stock of which (other than directors'  qualifying shares)
is owned by the Issuer or another Wholly Owned Subsidiary.

                  SECTION 1.2.  Other Definitions .

                                                                      Defined in
         Term                                                           Section

"Affiliate Transaction"...................................................4.8
"Appendix"................................................................2.1
"Authenticating Agent"....................................................2.2
"Bankruptcy Law"..........................................................6.1
<PAGE>   25
                                       21

"covenant defeasance option"..............................................8.1(b)
"Custodian"...............................................................6.1
"Event of Default"........................................................6.1
"legal defeasance option".................................................8.1(b)
"Offer"...................................................................4.7(b)
"Offer Amount"............................................................4.7(b)
"Offer Period"............................................................4.7(b)
"Paying Agent"............................................................2.3
"Purchase Date"...........................................................4.7(b)
"Registrar"...............................................................2.3
"Successor Issuer"........................................................5.1

         .........SECTION 1.3. Incorporation by Reference of Trust Indenture
Act .  The mandatory provisions of the TIA are incorporated by reference in and
made a part of this Indenture.  The following TIA terms have the following
meanings:

         ........."Commission" means the SEC.

         ........."indenture securities" means the Notes.

         ........."indenture security holder" means a Holder.

                  "indenture to be qualified" means this  Indenture.

                  "indenture trustee" or "institutional  trustee" means the
Trustee.

                  "obligor" on the indenture securities means the Issuer and any
 other obligor on the indenture securities.

         .........All other TIA terms used in this Indenture that are defined by
 the TIA, defined by TIA reference to another statute or defined by SEC rule
have the meanings assigned to them by such definitions.

         .........SECTION 1.4.  Rules of Construction .  Unless the context
                                ---------------------
otherwise requires:

         .........(1)      a term has the meaning assigned to it;

                  (2)      an accounting term not otherwise defined has the
                   meaning assigned to it in accordance with GAAP;

         .........(3)      "or" is not exclusive;

                  (4)      "including" means including without limitation;

                  (5) words in the singular  include the plural and words in the
plural include the singular;
<PAGE>   26
                                       22

                  (6)  unsecured   Indebtedness   shall  not  be  deemed  to  be
         subordinate or junior to Secured  Indebtedness  merely by virtue of its
         nature as unsecured Indebtedness;

                  (7) except as  otherwise  expressly  provided,  the  principal
         amount of any  noninterest  bearing or other  discount  security at any
         date shall be the  principal  amount  thereof  that would be shown on a
         balance sheet of the issuer dated such date prepared in accordance with
         GAAP;

                  (8) the principal  amount of any Preferred  Stock shall be (i)
         the maximum liquidation  preference of such Preferred Stock or (ii) the
         maximum mandatory redemption or mandatory repurchase price with respect
         to such Preferred Stock, whichever is greater; and

                  (9) except as otherwise expressly provided,  all references to
         the date the Notes were  originally  issued shall refer to the date the
         Initial Notes were originally issued.

         .........SECTION 1.5.  One Class of Notes .  The Initial Notes, the
Private Exchange Notes and the Exchange Notes shall vote and consent together on
all matters as one class and none of the Initial Notes, the Private Exchange
Notes or the Exchange Notes shall have the right to vote or consent as a
separate class on any matter.

                               ARTICLE II
                               THE NOTES
                               ---------
         .........SECTION 2.1.  Form and Dating .  Certain provisions relating
to the Initial Notes, the Private Exchange Notes and the Exchange Notes are set
forth in the Rule 144A/Regulation S Appendix attached hereto (the "Appendix"),
which is hereby incorporated in and expressly made a part of this Indenture. The
Initial Notes and the Trustee's certificate of authentication thereof shall be
substantially in the form of Exhibit 1 to the Appendix, which is hereby
incorporated in and expressly made a part of this Indenture. The Exchange Notes,
the Private Exchange Notes and the Trustee's certificate of authentication
thereof shall be substantially in the form of Exhibit A, which is hereby
incorporated by reference and expressly made a part of this Indenture.  The
Notes may have notations, legends or endorsements required by law, rule of any
securities exchange or over-the-counter market on which such Notes are then
listed or quoted, or usage, in addition to those set forth on the Appendix and
Exhibit A. The Issuer and the Trustee shall approve the forms of the Notes and
any notation, endorsement or legend on them.  Each Note shall be dated the date
of its authentication.  The terms of the Notes set forth in the Appendix and
Exhibit A are part of the terms of this Indenture and, to the extent applicable,
the Issuer and the Trustee, by their execution and delivery of this Indenture,
expressly agree to be bound by such terms.

         .........SECTION 2.2.  Execution and Authentication .  Two Officers
                                ----------------------------
shall sign the Notes for the Issuer by manual or facsimile signature.
<PAGE>   27
                                       23

         .........If an Officer whose signature is on a Note no longer holds
that office at the time the Trustee authenticates the Note, the Note shall be
valid nevertheless.

         .........A Note shall not be valid until an authorized signatory of the
Trustee manually authenticates the Note.  The signature of the Trustee on a Note
shall be conclusive evidence that such Note has been duly and validly
authenticated and issued under this Indenture.

         .........The Trustee may appoint an agent (the "Authenticating Agent")
reasonably acceptable to the Issuer to authenticate the Notes.  Unless limited
by the terms of such appointment, any such Authenticating Agent may authenticate
Notes whenever the Trustee may do so. Each reference in this Indenture to
authentication by the Trustee includes authentication by such agent.

         .........SECTION 2.3.  Registrar and Paying Agent .  The Issuer shall
(i) appoint an agent (the "Registrar") who shall maintain an office or agency
where Notes may be presented for registration of transfer or for exchange and
(ii) an agent (the "Paying Agent") who shall maintain an office or agency where
Notes may be presented for payment.  The Registrar shall keep a register of the
Notes and of their transfer and exchange.  The Issuer may have one or more
co-registrars and one or more additional paying agents. The term "Paying Agent"
includes any such additional paying agent.

         .........In the event the Issuer shall retain any Person not a party to
this Indenture as an agent hereunder, the Issuer shall enter into an appropriate
agency agreement with any Registrar, Paying Agent or co-registrar not a party to
this Indenture, which shall incorporate the terms of the TIA.  The agreement
shall implement the provisions of this Indenture that relate to such agent.  The
Issuer shall notify the Trustee of the name and address of each such agent.  If
the Issuer fails to maintain a Registrar or Paying Agent, the Trustee shall act
as such and shall be entitled to appropriate compensation therefor pursuant to
Section 7.7. The Issuer or any of its domestically incorporated Wholly Owned
Subsidiaries may act as Paying Agent.

         .........The Issuer initially appoints the Trustee as Registrar and
Paying Agent for the Notes.

         .........SECTION 2.4.  Paying Agent to Hold Money in Trust .  By at
least 11:00 a.m. (New York City time) on the date on which any principal or
interest on any Note is due and payable, the Issuer shall deposit with the
Paying Agent a sum sufficient to pay such principal or interest when due.  The
Issuer shall require each Paying Agent (other than the Trustee) to agree in
writing that such Paying Agent shall hold in trust for the benefit of
Noteholders or the Trustee all money held by such Paying Agent for the payment
of principal or interest on the Notes and shall notify the Trustee of any
default by the Issuer in making any such payment. If the Issuer or a Subsidiary
acts as Paying Agent, it shall segregate the money held by it as Paying Agent
and hold it as a separate trust fund.  The Issuer at any time may require a
Paying Agent (other than the Trustee) to pay all money held by it to the Trustee
and to account for any funds disbursed by
<PAGE>   28
                                       24

such Paying Agent.  Upon complying with this Section, the Paying Agent (if other
than the Issuer or a Subsidiary) shall have no further liability for the money
delivered to the Trustee.  Upon any bankruptcy, reorganization or similar
proceeding with respect to the Issuer, the Trustee shall serve as Paying Agent
for the Notes.

         .........SECTION 2.5.  Noteholder Lists .  The Trustee shall preserve
in as current a form as is reasonably practicable the most recent list available
to it of the names and addresses of Noteholders.  If the Trustee or any Paying
Agent is not the Registrar, the Issuer shall cause the Registrar to furnish to
the Trustee or any such Paying Agent, in writing at least five Business Days
before each interest payment date and at such other times as the Trustee or any
such Paying Agent may request in writing, a list in such form and as of such
date as the Trustee may reasonably require of the names and addresses of
Noteholders.

         .........SECTION 2.6.  [Intentionally Omitted]

         .........SECTION 2.7.  Replacement Notes .  If a mutilated Note is
surrendered to the Trustee or if the Holder of a Note shall provide the Issuer
and the Trustee with evidence to their satisfaction that the Note has been lost,
destroyed or wrongfully taken, the Issuer shall issue and the Trustee shall
authenticate a replacement Note if the requirements of Section 8-405 of the
Uniform Commercial Code are met and the Holder satisfies any other reasonable
requirements of the Trustee.  If required by the Trustee or the Issuer, such
Holder shall furnish an indemnity bond sufficient  in the judgment of the Issuer
and the Trustee to protect the Issuer, the Trustee,  the Paying Agent, the
Registrar and any co-registrar from any loss which any of them may suffer if a
Note is  replaced.  The Issuer and the Trustee may  charge  the  Holder  for
their  expenses  in  replacing  a Note,  including reasonable fees and expenses
of counsel. Every replacement Note is an additional obligation of the Issuer.

         .........SECTION 2.8.  Outstanding Notes .  Notes outstanding at any
time are all Notes authenticated by the Trustee except for those canceled, those
delivered for cancellation and those described in this Section 2.8 as not
outstanding.  A Note does not cease to be outstanding because the Issuer or an
Affiliate of the Issuer holds the Note.

         .........If a Note is replaced pursuant to Section 2.7, it ceases to be
outstanding unless the Trustee and the Issuer receive proof satisfactory to them
that the replaced Note is held by a bona fide purchaser.

         .........If  the  Paying  Agent  segregates  and  holds  in  trust,  in
accordance  with this  Indenture,  on a redemption  date or maturity  date money
sufficient to pay all  principal and interest  payable on that date with respect
to the Notes (or portions  thereof) to be redeemed or maturing,  as the case may
be,  and the  Paying  Agent is not  prohibited  from  paying  such  money to the
Noteholders  on that date pursuant to the terms of this  Indenture,  then on and
after that date such Notes (or portions  thereof)  cease to be  outstanding  and
interest on them ceases to accrue.
<PAGE>   29
                                       25

         .........SECTION 2.9.  Temporary Notes .  Until definitive Notes are
ready for delivery, the Issuer may prepare and the Trustee shall authenticate
temporary Notes.  Temporary Notes shall be substantially in the form of
definitive Notes but may have variations that the Issuer considers appropriate
for temporary Notes.  Without unreasonable delay, the Issuer shall prepare and
the Trustee shall authenticate definitive Notes.  After the preparation of
definitive Notes, the temporary Notes shall be exchangeable for definitive Notes
upon surrender of the temporary Notes at any office or agency maintained by the
Issuer for that purpose and such exchange shall be without charge to the Holder.
Upon surrender for cancellation of any one or more temporary Notes, the Issuer
shall execute, and the Trustee shall authenticate and deliver in exchange
therefor, one or more definitive Notes representing an equal principal amount of
Notes.  Until so exchanged, the Holder of temporary Notes shall in all respects
be entitled to the same benefits under this Indenture as a Holder of definitive
Notes.

         .........SECTION 2.10.  Cancellation .  The Issuer at any time may
deliver Notes to the Trustee for cancellation.  The Registrar and the Paying
Agent shall forward to the Trustee for cancellation any Notes surrendered to
them for registration of transfer or exchange or payment. The Trustee shall
cancel and destroy (subject to the record retention requirements of the Exchange
Act) all Notes surrendered for registration of transfer or exchange, payment or
cancellation and deliver a certificate of such destruction to the Issuer unless
the Issuer directs the Trustee to deliver canceled Notes to the Issuer.  The
Issuer may not issue new Notes to replace Notes it has redeemed, paid or
delivered to the Trustee for cancellation.

         .........SECTION 2.11.  Defaulted Interest .  If the Issuer defaults in
a payment of interest on the Notes, the Issuer shall pay defaulted interest
(plus interest on such defaulted interest to the extent lawful) at the rate
specified therefor in the Notes in any lawful manner.  The Issuer may pay the
defaulted interest to the Persons who are Noteholders on a subsequent special
record date.  The Issuer shall fix or cause to be fixed (or upon the Issuer's
failure to do so the Trustee shall fix) any such special record date and payment
date to the reasonable satisfaction of the Trustee which specified record date
shall not be less than 10 days prior to the payment date for such defaulted
interest and shall promptly mail or cause to be mailed to each Noteholder a
notice that states the special record date, the payment date and the amount of
defaulted interest to be paid.  The Issuer shall notify the Trustee in writing
of the amount of defaulted interest proposed to be paid on each Note and the
date of the proposed payment, and at the same time the Issuer shall deposit with
the Trustee an amount of money equal to the aggregate amount proposed to be paid
in respect of such defaulted interest or shall make arrangements satisfactory to
the Trustee for such deposit prior to the date of the proposed payment, such
money when so deposited to be held in trust for the benefit of the Person
entitled to such defaulted interest as provided in this Section 2.11.

         .........SECTION 2.12.  CUSIP Numbers .  The Issuer in issuing the
Notes may use "CUSIP" numbers (if then generally in use) and, if so, the Trustee
shall use "CUSIP" numbers in notices of redemption as a convenience to Holders;
provided, however, that any such notice may state that no representation is made
as to the correctness of such numbers either as printed on the Notes or as
contained in any notice of a redemption and that reliance may be placed only on
the
<PAGE>   30
                                       26

other identification numbers printed on the Notes, and any such redemption
shall not be affected by any defect in or omission of such numbers.

                              ARTICLE IIIREDEMPTION
         .........SECTION 3.1.  Notices to Trustee .  If the Issuer elects to
redeem Notes pursuant to paragraph 5 of the Notes (Exhibit 1 to the Appendix),
it shall notify the Trustee and the Paying Agent in writing of the redemption
date and the principal amount of Notes to be redeemed and the redemption price.

         .........The  Issuer  shall  give each  notice to the  Trustee  and the
Paying Agent provided for in this Section at least 60 days before the redemption
date unless the Trustee and the Paying Agent consent to a shorter  period.  Such
notice shall be accompanied by an Officer's  Certificate  from the Issuer to the
effect that such redemption will comply with the conditions  herein.  The record
date relating to such  redemption  shall be selected by the Issuer and set forth
in the related  notice given to the Trustee and the Paying  Agent,  which record
date shall be not less than 15 days prior to the date selected for redemption by
the Issuer.

         .........SECTION 3.2.  Selection of Notes to Be Redeemed .  In the case
of any partial redemption, selection of the Notes for redemption will be made by
the Trustee in compliance with the requirements of the principal national
securities exchange, if any, on which the Notes are listed,  or, if the Notes
are not so listed,  on a pro rata basis, by lot or by such other method as the
Trustee in its sole discretion shall deem to be fair and appropriate, although
no Note of $1,000 in original principal amount or less will be redeemed in part.
Provisions  of this  Indenture  that apply to Notes called for  redemption  also
apply to portions of Notes  called for  redemption. Upon request of the Issuer,
the Trustee shall notify the Issuer of the Notes or portions of Notes to be
redeemed.

         .........SECTION 3.3.  Notice of Redemption .  At least 30 days but not
more than 60 days before a date for redemption of Notes, the Trustee at the
expense of the Issuer shall mail a notice of redemption by first-class mail to
each Holder of Notes to be redeemed.

         .........The notice shall identify the Notes to be redeemed and shall
state:

         .........(1)      the redemption date;

                  (2)      the redemption price;

                  (3)      the name and address of the Paying Agent;

                  (4) that Notes called for  redemption  must be  surrendered to
         the Paying  Agent to collect  the  redemption  price plus  accrued  and
         unpaid interest, if any;
<PAGE>   31
                                       27

                  (5)  if  fewer  than  all  the  outstanding  Notes  are  to be
         redeemed,  the  identification  and principal amounts of the particular
         Notes to be redeemed;

                  (6) that, unless the Issuer defaults in making such redemption
         payment or the Paying  Agent is  prohibited  from making  such  payment
         pursuant to the terms of this Indenture,  interest on Notes (or portion
         thereof)  called  for  redemption  ceases  to  accrue  on and after the
         redemption date;

                  (7)      the CUSIP number, if any, printed on the Notes being
redeemed; and

                  (8) that no  representation  is made as to the  correctness or
         accuracy of the CUSIP number,  if any, listed in such notice or printed
         on the Notes.

         .........The Trustee shall give the notice of redemption in the
Issuer's name and at the Issuer's expense.  In such event, the Issuer shall
provide the Trustee with the information required by this Section 3.3.

         .........SECTION 3.4.  Effect of Notice of Redemption .  Once notice of
redemption is mailed, Notes called for redemption shall become due and payable
on the redemption date and at the redemption price stated in the notice.  Upon
surrender to the Paying Agent, such Notes shall be paid at the redemption price
stated in the notice, plus accrued and unpaid interest, if any, to the
redemption date; provided that the Issuer shall have deposited the redemption
price with the Paying Agent or the Trustee on or before 11:00 a.m. (New York
City time) on the date of

redemption;  provided,  further,  that if the redemption date is after a regular
record date and on or prior to the interest payment date, the accrued and unpaid
interest shall be payable to the Noteholder of the redeemed Notes  registered on
the relevant record date.  Failure to give notice or any defect in the notice to
any Holder shall not affect the validity of the notice to any other Holder.

         .........SECTION 3.5.  Deposit of Redemption Price .  By at least 11:00
a.m. (New York City time) on the date on which any principal of or interest on
any Note is due and payable, the Issuer shall deposit with the Paying Agent (or,
if the Issuer or a Subsidiary is the Paying Agent, shall segregate and hold in
trust) money sufficient to pay the redemption price of and accrued and unpaid
interest, if any, on all Notes to be redeemed on that date other than Notes or
portions of Notes called for redemption which are owned by the Issuer or a
Subsidiary and have been delivered by the Issuer or such Subsidiary to the
Trustee for cancellation.

         .........If  the Issuer  complies with the preceding  paragraph,  then,
unless the Issuer defaults in the payment of such redemption price,  interest on
the Notes to be  redeemed  will  cease to  accrue  on and  after the  applicable
redemption date, whether or not such Notes are presented for payment.

         .........SECTION 3.6.  Notes Redeemed in Part .  Upon surrender of a
Note that is redeemed in part, the Issuer shall execute and the Trustee shall
authenticate for the Holder (at the
<PAGE>   32
                                       28
Issuer's expense) a new Note equal in a principal amount to the unredeemed
portion of the Note surrendered.

                                   ARTICLE IV
                                   COVENANTS

         .........SECTION 4.1.  Payment of Notes .  The Issuer shall promptly
pay the principal of and interest on the Notes on the dates and in the manner
provided in the Notes and in this Indenture.  Principal and interest shall be
considered paid on the date due if on or before 11:00 a.m. (New York City time)
on such date the Trustee or the Paying Agent holds (or, if the Issuer or a
Subsidiary is the Paying Agent, the segregated account or separate trust fund
maintained by the Issuer or such Subsidiary pursuant to Section 2.4) in
accordance with this Indenture money sufficient to pay all principal and
interest then due and the Trustee or the Paying Agent (or, if the Issuer or a
Subsidiary is the Paying Agent, the Issuer or such Subsidiary), as the case may
be, is not prohibited from paying such money to the Noteholders on that date
pursuant to the terms of this Indenture.

         .........The Issuer shall pay interest on overdue principal at the rate
specified therefor in the Notes, and it shall pay interest on overdue
installments of interest at the same rate to the extent lawful as provided in
Section 2.11.

         .........Notwithstanding anything to the contrary contained in this
Indenture. the Issuer or the Paying Agent may, to the extent it is required to
do so by law, deduct or withhold income or other similar taxes imposed by the
United States of America or other domestic or foreign taxing authorities from
principal or interest payments hereunder.

         .........SECTION 4.2.  SEC Reports .  Notwithstanding that the Issuer
may not be required to remain subject to the reporting requirements of Section
13 or 15(d) of the Exchange Act, the Issuer will file with the SEC (unless the
SEC does not permit such filing) and provide the Trustee and Noteholders with
the annual reports and such information, documents and other reports which are
specified in Sections 13 and 15(d) of the Exchange Act.  The Issuer also will
comply with the other provisions of TIA ss. 314(a).

         .........SECTION 4.3.  Limitation on Indebtedness .  (a)  The Issuer
will not Incur, directly or indirectly, any Indebtedness unless, on the date of
such Incurrence and after giving effect to such Incurrence and the application
of the proceeds therefrom, the Indebtedness to Adjusted EBITDA Ratio of the
Issuer would be equal to or less than 7.00:1.  Accrual of interest, accretion or
amortization of original issue discount and the payment of interest in the form
of additional Indebtedness will not be deemed to be an Incurrence of
Indebtedness for purposes of this covenant.

         .........(b)      Notwithstanding the foregoing paragraph (a) and
regardless of the amount of outstanding Indebtedness of the Issuer, the Issuer
may Incur any or all of the following Indebtedness: (i) Indebtedness of the
Issuer owing to and held by any Restricted Subsidiary;
<PAGE>   33
                                       29
 provided, however, that any event which results in any such Restricted
Subsidiary ceasing to be a Restricted Subsidiary or any subsequent transfer of
any such Indebtedness (except to another Restricted Subsidiary) will be deemed,
in each case, to constitute the Incurrence of such Indebtedness by the Issuer;
(ii) Indebtedness represented by the Notes and the Exchange Notes; (iii)
Indebtedness of the Issuer outstanding on the Issue Date; (iv) Indebtedness
(including Capitalized Lease Obligations) of the Issuer Incurred to finance the
acquisition, construction or improvement of fixed or capital assets in an
aggregate principal amount (together with the amount of any Indebtedness then
outstanding and Incurred pursuant to clause (b)(vi) of Section 4.4) at any one
time outstanding not to exceed the greater of (x) $25.0 million and (y) an
amount equal to 7.5% of the Issuer's Consolidated Tangible Assets; provided,
that such Indebtedness is Incurred within 180 days after the date of such
acquisition, construction or improvement and does not exceed the fair market
value of such acquired, constructed or improved assets, as determined in good
faith by the Board of Directors of the Issuer; (v) Refinancing Indebtedness
Incurred in respect of any Indebtedness Incurred pursuant to paragraph (a) or
pursuant to clause (ii),(iii) or this clause (v); (vi) Indebtedness (A) in
respect of performance bonds, bankers' acceptances, letters of credit and surety
or appeal bonds provided by the Issuer in the ordinary course of its business
and which do not secure other Indebtedness and (B) under Currency Agreements and
Interest Rate Agreements Incurred which, at the time of Incurrence, is in the
ordinary course of business; provided, however, that, in the case of Currency
Agreements and Interest Rate Agreements, such Currency Agreements and Interest
Rate Agreements are directly related to Indebtedness permitted to be Incurred by
the Issuer pursuant to this Indenture; (vii) Indebtedness represented by
Guarantees by the Issuer of Indebtedness otherwise permitted to be Incurred by a
Restricted Subsidiary pursuant to this Indenture; (viii)  Indebtedness  of any
other Person existing at the time such other Person is merged with or into the
Issuer  outstanding  on or prior to the date on which such Person was merged
with or into the Issuer (other than Indebtedness Incurred in  connection  with,
or to provide  all or any  portion of the funds or credit support   utilized  to
consummate,   the   transaction  or  series  of  related transactions  pursuant
to which such Person was merged with or into the Issuer); provided,  however,
that on the date of such  merger  and after  giving  effect thereto  either (x)
the Issuer  would be  permitted  to incur at least  $1.00 of additional
Indebtedness pursuant to paragraph (a) of this Section 4.3 or (y) the Issuer
would have an  Indebtedness to Adjusted  EBITDA Ratio  immediately  after giving
effect to such merger no greater than the Indebtedness to Adjusted EBITDA Ratio
immediately  prior to such merger;  (ix) the  Incurrence by the Issuer of
Indebtedness  not to  exceed,  at any one time  outstanding  (together  with the
amount of any Indebtedness  then outstanding and Incurred pursuant to clause (b)
(ix) of  Section  4.4),  2.0  times  the sum of 100% of the  aggregate  Net Cash
Proceeds and 50% of the non-cash  proceeds received by the Issuer from the issue
or sale of Capital Stock (other than  Disqualified  Stock) subsequent to July 1,
1999 (other than an  issuance  or sale to a  Subsidiary  of the Issuer and other
than an  issuance  or sale to an  employee  stock  ownership  plan or to a trust
established  by the  Issuer  or any of its  Restricted  Subsidiaries),  less the
aggregate  amount of such Net Cash  Proceeds  used to make  Restricted  Payments
pursuant to clause 3(B) of paragraph  (a) of Section 4.5 or applied  pursuant to
clause  (i)(B) of paragraph  (b) of Section 4.5;  (x) other  Indebtedness  in an
aggregate  principal amount  outstanding at any time not to exceed $25.0 million
(together  with  the  amount  of  any  Indebtedness  and  Preferred  Stock  then
outstanding  and  Incurred  pursuant  to clause  (b)(x) of  Section  4.4);  (xi)
Indebtedness
<PAGE>   34
                                       30

Incurred by the Issuer's  Subsidiaries  in compliance with Section 4.4;  (xii)
Indebtedness  incurred  under  Credit  Facilities,  in an aggregate principal
amount  outstanding  at any  time,  together  with the  amount of any
Indebtedness  then  outstanding  and incurred  under  Section  4.4(b)(i) of this
Indenture, not to exceed the sum of (A) the product of $200,000 times the number
of Completed  Towers on the date of incurrence and (B) the product of $1,000,000
times the number of Completed  Broadcast  Towers on the date of such incurrence;
provided that the amount of such  Indebtedness  incurred pursuant to this clause
(B) does not exceed 25% of the cost of acquiring or constructing  such Completed
Broadcast Towers;  (xiii) Indebtedness  representing the deferred payment of the
purchase  price for any entity that is engaged in a Permitted  Business and that
becomes a Restricted  Subsidiary or the acquisition of any assets constituting a
business  or line of  business,  as  determined  in good  faith by the  Board of
Directors of the Issuer, that is a Permitted Business,  not to exceed at any one
time  outstanding,  together with any Indebtedness then outstanding and incurred
pursuant to Section 4.4(b)(xi) of this Indenture,  50% of the purchase price for
the related entity or business so acquired; provided, however, that after giving
effect  to  such  acquisition  and  all  Indebtedness   incurred  in  connection
therewith, either (A) the Issuer would have been able to incur at least $1.00 of
additional  Indebtedness under this Section 4.3 or (B) the Issuer would have had
an  Indebtedness  to  Adjusted  EBITDA  Ratio  no  greater  than  prior  to such
transaction; and (xiv) Permitted Acquisition Indebtedness.

         .........(c)  Notwithstanding the foregoing, the Issuer shall not Incur
any Indebtedness  pursuant to the foregoing paragraph (b) of this Section 4.3 if
the  proceeds  thereof  are used,  directly  or  indirectly,  to  Refinance  any
Subordinated  Obligations unless such new Indebtedness shall  (i) be
subordinated  to the  Notes to at least  the same  extent as such Subordinated
Obligations  being Refinanced and (ii) have a Stated Maturity that is no earlier
than the  earlier  of the Stated  Maturity  of the  Subordinated Obligations
being Refinanced.

         .........(d)  For purposes of determining  compliance with this Section
4.3,  (i) in the event that an item of  Indebtedness  meets the criteria of more
than one of the types of Indebtedness  described above, the Issuer,  in its sole
discretion,  will classify (and may from time to time  reclassify)  such item of
Indebtedness  and  only be  required  to  include  the  amount  and type of such
Indebtedness in one of the above clauses of this Section 4.3 and (ii) an item of
Indebtedness  may be  divided  and  classified  in more than one of the types of
Indebtedness described in this Section 4.3.

         .........SECTION 4.4.  Limitation on Indebtedness and Preferred Stock
of Restricted Subsidiaries .  (a)  The Issuer shall not permit any Restricted
Subsidiary to Incur, directly or indirectly, any Indebtedness or Preferred Stock
unless, on the date of such Incurrence and after giving effect to such
Incurrence and the application of the net proceeds therefrom, the Indebtedness
to Adjusted EBITDA Ratio of the Issuer would be equal to or less than 7.00:1.
Accrual of interest, accretion or amortization of original issue discount and
the payment of interest in the form of additional Indebtedness will not be
deemed to be an Incurrence of Indebtedness for purposes of this covenant.
<PAGE>   35
                                       31

         .........(b)      Notwithstanding the foregoing paragraph (a) and
regardless of the amount of outstanding Indebtedness of the Restricted
Subsidiaries, any Restricted Subsidiary may Incur any or all of the following
Indebtedness:  (i) Indebtedness Incurred under Credit Facilities in an aggregate
principal amount outstanding at any time (together with the amount of any
Indebtedness then outstanding and incurred under clause (b)(xii) of Section 4.3)
not to exceed the sum of (x) the product of $200,000 times the number of
Completed Towers on the date of such Incurrence; and (y) the product of
$1,000,000 times the number of Completed Broadcast Towers on the date of such
Incurrence, provided that the amount of such Indebtedness incurred pursuant to
this clause (y) does not exceed 25% of the cost of acquiring or constructing
such Completed Broadcast Towers; (ii) Indebtedness or Preferred Stock of a
Restricted Subsidiary issued to and held by the Issuer or a Restricted
Subsidiary; provided, however, that any subsequent issuance or transfer of any
Capital Stock which results in any such Restricted Subsidiary ceasing to be a
Restricted Subsidiary or any subsequent transfer of such Indebtedness or
Preferred Stock (other than to the Issuer or a Restricted Subsidiary) shall be
deemed, in each case, to constitute the Incurrence of such Indebtedness or
Preferred Stock by the issuer thereof; (iii) Indebtedness or Preferred Stock of
a Restricted Subsidiary Incurred and outstanding on or prior to the date on
which such Restricted Subsidiary was acquired by the Issuer and Indebtedness or
Preferred Stock of an entity merged into a Restricted Subsidiary (other than, in
either case, Indebtedness or Preferred Stock Incurred in connection with, or to
provide all or any portion of the funds or credit support utilized to
consummate, the transaction or series of related transactions pursuant to which
such Restricted Subsidiary became a Restricted Subsidiary or was acquired by the
Issuer or such entity was merged into such Restricted Subsidiary); provided,
however, that on the date of such acquisition or merger and after giving effect
thereto, either (x) the Issuer would have been  permitted to incur at least
$1.00 or  additional Indebtedness  pursuant to  paragraph  (a) of Section 4.3 or
(y) the Issuer would have had an  Indebtedness  to Adjusted  EBITDA  Ratio
immediately  after giving effect  to such  merger or  acquisition  no  greater
than the  Indebtedness  to Adjusted EBITDA Ratio immediately  prior to such
transaction;  (iv) Indebtedness or Preferred Stock  outstanding on the Issue
Date; (v) Refinancing  Indebtedness Incurred in respect of  Indebtedness or
Preferred Stock referred to in paragraph (a) above or in clauses  (iii) or (iv)
of this  paragraph  or this  clause  (v); provided,  however, that  Indebtedness
of the  Issuer  may  not be  refinanced pursuant to this clause (v);  (vi)
Indebtedness  (including  Capitalized  Lease Obligations)  Incurred by a
Subsidiary to finance the acquisition,  construction or improvement of fixed or
capital  assets in an aggregate  principal  amount at any one time outstanding
(together with the amount then outstanding and Incurred pursuant  to clause
(b)(iv)  of Section  4.3) not to exceed the  greater of (x)$25.0  million  and
(y) an  amount  equal to 7.5% of the  Issuer's  Consolidated Tangible Assets;
provided,  that such  Indebtedness is Incurred within 180 days after the date of
such  acquisition,  construction  or improvement  and does not exceed the fair
market value of such acquired,  constructed or improved  assets, as  determined
in good faith by the Board of  Directors  of the  Issuer;  (vii) Indebtedness
(A) in respect of performance bonds, bankers' acceptances,  letters of credit
and surety or appeal  bonds  provided  in the  ordinary  course of its business
and which do not  secure  other  Indebtedness  and (B) under  Currency
Agreements  and  Interest  Rate  Agreements  Incurred  which,  at  the  time  of
Incurrence, is in the ordinary course of business;  provided,  however, that, in
the case of Currency  Agreements  and Interest  Rate  Agreements,  such Currency
Agreements  and Interest Rate  Agreements are directly  related to
<PAGE>   36
                                       32
Indebtedness permitted  to be  Incurred  pursuant  to  this  Indenture;
(viii)  Indebtedness represented by Guarantees,  by a Subsidiary, of
Indebtedness otherwise permitted to be  Incurred  by the  Issuer  or a
Subsidiary  pursuant  to this  Indenture; provided that any Subsidiary  which
guarantees the 2008 Notes or the 2009 Notes will  guarantee  the  Notes;  any
Subsidiary  that  guarantees  the Notes  will guarantee the Senior Discount
Notes;  any Subsidiary that guarantees the Senior Discount Notes will guarantee
the Notes; in each case on  substantially  similar terms;  (ix) the  Incurrence
of  Indebtedness  not to  exceed,  at any one time outstanding  (together with
the amount of any Indebtedness  then outstanding and Incurred  pursuant to
clause  (b)(ix) of Section 4.3),  2.0 times (A) the sum of 100%  of the
aggregate  Net  Cash  Proceeds  and 50% of the  non-cash  proceeds received  by
the Issuer  from the issue or sale of  Capital  Stock  (other  than Disqualified
Stock)  subsequent to July 1, 1999, other than an issuance or sale to a
Subsidiary or to an employee stock ownership plan or to a trust established
by the Issuer or any Restricted Subsidiary, less (B) the amount of such Net Cash
Proceeds used to make Restricted  Payments  pursuant to clause 3(B) of paragraph
(a) of Section 4.5 or applied  pursuant  to clause  (i)(B) of  paragraph  (b) of
Section  4.5;  (x)  other  Indebtedness  and  Preferred  Stock  in an  aggregate
principal and/or  liquidation amount outstanding at any time not to exceed $25.0
million  (less the amount of any  Indebtedness  then  outstanding  and  Incurred
pursuant to clause (b)(x) of Section 4.3); (xi)  Indebtedness  representing  the
deferred  payment  of the  purchase  price for any  entity  that is engaged in a
Permitted  Business and that becomes a Restricted  Subsidiary or the acquisition
of any assets constituting a business or line of business, as determined in good
faith by the Board of Directors of the Issuer, that is a Permitted Business, not
to exceed  at any one time  outstanding,  together  with any  Indebtedness  then
outstanding and incurred pursuant to Section 4.3(b)(xiii) of this Indenture, 50%
of the purchase price for the related entity or business so acquired;  provided,
however, that after giving effect  to  such  acquisition  and  all  Indebtedness
incurred  in  connection therewith, either (A) the Issuer would have been able
to incur at least $1.00 of additional  Indebtedness  under  Section 4.3 or (B)
the Issuer would have had an Indebtedness to Adjusted EBITDA Ratio no greater
than prior to such transaction; and (xii) Permitted Acquisition Indebtedness.

         .........(c)  For purposes of determining  compliance with this Section
4.4,  (i) in the event that an item of  Indebtedness  meets the criteria of more
than one of the types of Indebtedness  described above, the Issuer,  in its sole
discretion,  will classify (and may from time to time  reclassify)  such item of
Indebtedness  and  only be  required  to  include  the  amount  and type of such
Indebtedness in one of the above clauses of this Section 4.4 and (ii) an item of
Indebtedness  may be  divided  and  classified  in more than one of the types of
Indebtedness described in this Section 4.4

         .........This Issuer will not permit any Unrestricted Subsidiary to
Incur any Indebtedness other than Non-Recourse Debt.

         .........SECTION 4.5.  Limitation on Restricted Payments .  (a)  The
Issuer will not, and will not permit any Restricted Subsidiary, directly or
indirectly, to make any Restricted Payment if at the time the Issuer or such
Restricted Subsidiary makes such Restricted Payment:  (1) a Default or Event of
Default will have occurred and be continuing (or would result therefrom); (2)
except with respect to making an Investment, the Issuer could not incur at least
$1.00 of
<PAGE>   37
                                       33

additional Indebtedness under paragraph (a) of Section 4.3; or (3) the
aggregate amount of such Restricted Payment and all other Restricted Payments
(the amount so expended, if other than in cash, to be determined in good faith
by the Board of Directors of the Issuer, whose determination will be evidenced
by a resolution of such Board of Directors) declared or made subsequent to the
Issue Date would exceed the sum of:  (A) (x) the aggregate EBITDA (or, in the
event such EBITDA shall be a deficit, minus such deficit) accrued subsequent to
July 1, 1999 to the most recent date for which financial information is
available to the Issuer, taken as one accounting period, (y) less 1.4 times
Consolidated Interest Expense for the same period; (B) (x) 100% of the aggregate
Net Cash Proceeds (less the aggregate amount of such Net Cash Proceeds used to
Incur Indebtedness pursuant to clause (b)(ix) of Section 4.3 and clause (b)(ix)
of Section 4.4) and (y) 70% of the GAAP purchase accounting valuation of
Qualified Proceeds (with each such valuation calculated as of the sale date of
the Capital Stock received as consideration therefor), in each case received by
the Issuer from the issue or sale of Capital Stock (other than Disqualified
Stock) subsequent to July 1, 1999 (other than an issuance or sale to a
Subsidiary of the Issuer and other than an issuance or sale to an employee stock
ownership plan or to a trust established by the Issuer or any of its Restricted
Subsidiaries); (C) the amount by which Indebtedness of the Issuer is reduced on
the Issuer's balance sheet upon the conversion or exchange (other than by a
Restricted Subsidiary) subsequent to the Issue Date of any Indebtedness of the
Issuer convertible or exchangeable for Capital Stock (other than Disqualified
Stock) of the Issuer (less the amount of any cash, or the fair value of any
other property, distributed by the Issuer upon such conversion or exchange); (D)
an amount equal to the sum of (i) the net reduction in Investments in
Unrestricted Subsidiaries resulting from dividends, repayments of loans or
advances or other transfers of assets to the Issuer or any Restricted Subsidiary
from Unrestricted Subsidiaries and (ii)  the  portion  (proportionate  to the
Issuer's  equity  interest  in  such Subsidiary)  of the fair  market  value  of
the net  assets  of an  Unrestricted Subsidiary at the time such  Unrestricted
subsidiary is designated a Restricted Subsidiary;  provided,  that the foregoing
sum shall not exceed,  in the case of any Unrestricted  Subsidiary,  the amount
of Investments  previously made by the Issuer or any  Restricted  Subsidiary  in
such  Unrestricted  Subsidiary,  which amount was included in the calculation of
the amount of Restricted Payments; (E) dividends and distributions  received by
the Issuer subsequent to the Issue Date from Unrestricted  Subsidiaries,  to the
extent such dividends and distributions are not  otherwise  included in
calculating  EBITDA;  and (F) Net Cash Proceeds received by the Issuer
subsequent to the Issue Date from  Investments  that are not Permitted
Investments, to the extent not otherwise included in calculating EBITDA.

         .........(b)      The provisions of the foregoing paragraph (a) of this
Section 4.5 will not prohibit:  (i) any purchase, redemption, defeasance or
other acquisition of Capital Stock of the Issuer or Subordinated Obligations
made by exchange for, or out of the net proceeds of the substantially concurrent
sale of, Capital Stock of the Issuer (other than Disqualified Stock and other
than Capital Stock issued or sold to a Subsidiary of the Issuer or an employee
stock ownership plan or to a trust established by the Issuer or any of its
Subsidiaries); provided, however, that (A) such purchase, redemption, defeasance
or other acquisition will be excluded in the calculation of the amount of
Restricted Payments and (B) to the extent applied toward any such purchase,
redemption, defeasance or other acquisition, the Net Cash Proceeds from such
sale will be excluded from clause (3)(B) of paragraph (a) of this Section 4.5,
clause (b)(ix) of
<PAGE>   38
                                       34

Section 4.3 and clause (b)(ix) of Section 4.4; (ii) any purchase, redemption,
defeasance or other acquisition of Subordinated Obligations made by exchange
for, or out of the net proceeds of the substantially concurrent sale of,
Subordinated Obligations of the Issuer; provided, however, that (A) the
principal amount of such new Indebtedness does not exceed the principal amount
of the Subordinated Obligations being so redeemed, repurchased, acquired or
retired for value (plus the amount of any premium required to be paid under the
terms of the instrument governing the Subordinated Obligations being so
redeemed, repurchased, acquired or retired), (B) such new Indebtedness is
subordinated to the Notes at least to the same extent as such Subordinated
Obligations so purchased, exchanged, redeemed, repurchased, acquired or retired
for value, (C) such new Indebtedness has a final scheduled maturity date later
than the earlier of the final scheduled maturity date of the Subordinated
Obligations being so redeemed, repurchased, acquired or retired and the final
scheduled maturity date of the Notes, (D) such new Indebtedness has an Average
Life equal to or greater than the lesser of the Average Life of the Indebtedness
being so redeemed, repurchased, acquired, or retired, and the Average Life of
the Notes, and (E) any purchase, redemption, defeasance or other acquisition
made pursuant to this clause (b)(ii) will be excluded in the calculation of the
amount of Restricted Payments; (iii) dividends paid within 60 days after the
date of declaration thereof if at such date of declaration such dividend would
have complied with this covenant; provided, however, that the amount of such
dividend will be included in the calculation of the amount of Restricted
Payments; and (iv) purchases of outstanding shares of the Issuer's capital stock
from former employees in an amount not to exceed $5.0 million in the aggregate;
provided, however, that such purchases will be included in the calculation of
the amount of Restricted Payments; provided, however, that, at the time of, and
after giving effect to, any  Restricted  payment  permitted by clauses (i), (ii)
and (iv), no Default or Event of Default shall have occurred and be continuing.

         .........The amount of any Investment shall be measured on the date
made and shall not give effect to subsequent changes in value.

         .........SECTION 4.6.  Limitation on Restrictions on Distributions from
Restricted Subsidiaries .  The Issuer will not, and will not permit any
Restricted Subsidiary to, create or otherwise cause or permit to exist or become
effective any consensual encumbrance or restriction on the ability of any
Restricted Subsidiary to (i) pay dividends or make any other distributions on
its Capital Stock to the Issuer or a Restricted Subsidiary or pay any
Indebtedness or other obligation owed to the Issuer, (ii) make any loans or
advances to the Issuer or (iii) transfer any of its property or assets to the
Issuer or any Restricted Subsidiary, except: (1) any encumbrance or restriction
pursuant to a Credit Facility or any agreement in effect at or entered into on
the Issue Date; (2) any encumbrance or restriction with respect to a Restricted
Subsidiary pursuant to an agreement relating to any Indebtedness or Capital
Stock Incurred or issued by such Restricted Subsidiary on or prior to the date
on which such Restricted Subsidiary was acquired by the Issuer or a Restricted
Subsidiary (other than Indebtedness or Capital Stock Incurred or issued as
consideration for, or to provide any portion of the funds or credit support
utilized to consummate the transaction or series of related transactions
pursuant to which such Restricted Subsidiary became a Subsidiary or was acquired
by the Issuer or a Restricted Subsidiary) and outstanding on such date; (3) any
encumbrance or restriction pursuant to an agreement effecting a
<PAGE>   39
                                       35

Refinancing of Indebtedness Incurred pursuant to an agreement referred to in
clause (1) or (2) of this Section 4.6 or contained in any amendment to an
agreement referred to in clause (1) or (2) of this Section 4.6; provided,
however, that the encumbrances and restrictions with respect to such Restricted
Subsidiary contained in any such refinancing agreement or amendment taken as a
whole are no less favorable to the Noteholders than the encumbrances and
restrictions with respect to such Restricted Subsidiary contained in such
predecessor agreements as determined in good faith by the Board of Directors of
the Issuer; (4) in the case of clause (iii), any encumbrance or restriction that
restricts in a customary manner the subletting, assignment or transfer of any
property or asset that is subject to a lease, license or other contract or such
lease, license or other such contract; (5) in the case of clause (iii),
contained in security agreements or mortgages securing Indebtedness of a
Restricted Subsidiary to the extent such encumbrance or restrictions restrict
the transfer of the property subject to such security agreements or mortgages;
(6) any restriction with respect to a Restricted Subsidiary imposed pursuant to
an agreement entered into for the sale or disposition of all or substantially
all the Capital Stock or assets of such Restricted Subsidiary pending the
closing of such sale or disposition; (7) customary provisions with respect to
the disposition or distribution of assets or property in joint venture and other
similar agreements; and (8) restrictions on cash or other deposits or net worth
imposed by customers under contracts entered into in the ordinary course of
business; provided that the Board of Directors of the Issuer in good faith
determines that such restrictions will not have a material adverse impact on the
Issuer's ability to make payments on the Notes.

         .........SECTION 4.7.  Limitation on Sale of Assets and Subsidiary
Stock .  (a)  The Issuer will not, and will not permit any Restricted Subsidiary
to, directly or indirectly, consummate any Asset Disposition unless (i) the
Issuer or such Restricted Subsidiary receives consideration at the time of such
Asset Disposition at least equal to the fair market value (including as to the
value of all non cash consideration), as determined in good faith by the Board
of Directors of the Issuer of the shares and assets subject to such Asset
Disposition and (ii) except in the case of a Tower Asset Exchange, at least 75%
of the consideration thereof received by the Issuer or such Restricted
Subsidiary is in the form of cash or cash equivalents.

         .........Within  365 days after the receipt of any Net  Available  Cash
from an Asset Disposition,  the Issuer or the applicable  Restricted  Subsidiary
may apply such Net  Available  Cash to: (A)  prepay,  repay,  redeem or purchase
Indebtedness  (other  than  Disqualified  Stock)  of  a  Restricted   Subsidiary
(provided,  that the applicable  Restricted  Subsidiary also may prepay,  repay,
redeem or purchase its own outstanding  Indebtedness) or Senior Indebtedness (in
each case other than  Indebtedness  owed to the  Issuer or an  Affiliate  of the
Issuer);  (B) make an offer with  respect to the 2008 Notes or the 2009 Notes to
the extent  required in the indentures  governing the 2008 Notes and 2009 Notes;
(C) acquire  all or  substantially  all of the assets of an entity  engaged in a
Permitted Business; (D) acquire Voting Stock of an entity engaged in a Permitted
Business  from a Person that is not a Subsidiary of the Issuer;  provided,  that
(x) after giving effect thereto, the Issuer or its Restricted  Subsidiary owns a
majority of such Voting  Stock and (y) such  acquisition  is  otherwise  made in
accordance with this Indenture,  including, without limitation,  Section 4.5; or
(E) make a capital  expenditure or acquire other long-term  assets that are used
or useful in a  Permitted  Business.  To the  extent of the  balance of such Net
Available
<PAGE>   40
                                       36
Cash after  application in accordance  with clauses (A), (B), (C), (D)
or (E), the Issuer shall make an Offer (as defined in Section 4.7(b)) to Holders
of the Notes to purchase  Notes  pursuant to and subject to the  conditions  set
forth in paragraph (b) of this Section 4.7.

         .........Notwithstanding  the foregoing provisions,  the Issuer and its
Restricted Subsidiaries shall not be required to apply any Net Available Cash in
accordance  herewith  except to the extent that the aggregate Net Available Cash
from all  Asset  Dispositions  which are not  applied  in  accordance  with this
covenant  exceeds $10.0  million.  Pending  application  of Net  Available  Cash
pursuant  to this  covenant,  such  Net  Available  Cash  shall be  invested  in
Permitted Investments.

         .........For the purposes of this Section 4.7(a), the following are
deemed to be cash:  (x) the assumption by the transferee of Indebtedness of the
Issuer (other than Disqualified Stock of the Issuer and other than Indebtedness
that is subordinated to the Notes) or Indebtedness of any Restricted Subsidiary
and the release of the Issuer or such Restricted Subsidiary from all liability
on such Indebtedness in connection with such Asset Disposition; (y) securities
received by the Issuer or any Restricted Subsidiary from the transferee that are
converted by the Issuer or such Restricted Subsidiary into cash within 20 days
of the applicable Asset Disposition (to the extent of the cash received); and
(z) any liabilities (as shown on the Issuer's or such Restricted Subsidiary's
most recent balance sheet) of the Issuer or any Restricted Subsidiary (other
than contingent liabilities and liabilities that are by their terms subordinated
to the Notes or any guarantee  thereof)  that are  assumed  by the  transferee
of any  such  assets pursuant to a customary  novation agreement that releases
the Issuer or any such Restricted Subsidiary from further liability.

         .........(b)  In the event of an Asset  Disposition  that  requires the
purchase of Notes pursuant to paragraph (a) of this Section 4.7, the Issuer will
be required to purchase  Notes  tendered  pursuant to an offer by the Issuer for
the Notes (the "Offer") at a purchase price of 100% of their principal amount as
of the date of purchase  (without  premium) plus accrued and unpaid  interest to
the date of purchase in accordance with the procedures  (including  prorating in
the event of  oversubscription)  set forth in this  Indenture.  If the aggregate
purchase  price of Notes  tendered  pursuant  to the  Offer is less than the Net
Available  Cash  allotted to the  purchase of the Notes,  the Issuer may use any
remaining  Net  Available  Cash for general  corporate  purposes  not  otherwise
prohibited by this Indenture.  If the aggregate purchase price of Notes tendered
pursuant to the Offer is greater  than the Net  Available  Cash  allotted to the
purchase of the Notes,  the Trustee will select the Notes to be purchased on the
basis set forth in paragraph  (c) of this Section 4.7.  Upon  completion  of any
required  Offer to the holders of the Notes,  the amount of Net  Available  Cash
will be reset at zero.  The Issuer  shall not be  required  to make an Offer for
Notes pursuant to this Section 4.7 if the Net Available Cash available  therefor
(after  application  of the  proceeds  as provided  in the second  paragraph  of
Section  4.7(a)) are less than $10.0 million for all Asset  Dispositions  (which
lesser amounts shall be carried  forward for purposes of determining  whether an
Offer is required  with respect to the Net  Available  Cash from any  subsequent
Asset Disposition).
<PAGE>   41
                                       37

         .........(c)  (1)  Promptly,  and in any event within 30 days after the
Issuer  becomes  obligated  to make an Offer,  the Issuer  shall be obligated to
deliver to the Trustee and send,  by  first-class  mail to each  Holder,  at the
address  appearing in the security  register,  a written notice stating that the
Holder may elect to have his Notes purchased by the Issuer either in whole or in
part (subject to prorationing as hereinafter described in the event the Offer is
oversubscribed)  in integral  multiples  of $1,000 of principal  amount,  at the
applicable  purchase  price.  The notice shall  specify a purchase date not less
than 30 days nor more than 60 days after the date of such notice (the  "Purchase
Date") and shall  contain all  instructions  and  materials  necessary to tender
Notes pursuant to the Offer.

         .........(2)  Not later than the date upon which  written  notice of an
Offer is delivered to the Trustee as provided below, the Issuer shall deliver to
the  Trustee  an  Officer's  Certificate  as to (i) the amount of the Offer (the
"Offer  Amount"),  (ii) the  allocation of the Net Available Cash from the Asset
Dispositions pursuant to which such Offer is being made and (iii) the compliance
of such allocation with the provisions of Section 4.7(a). Upon the expiration of
the period for which the Offer  remains  open (the "Offer  Period"),  the Issuer
shall  deliver to the Trustee  for  cancellation  the Notes or portions  thereof
which have been properly  tendered to and are to be accepted by the Issuer.  Not
later than 11:00 a.m.  (New York City  time) on the  Purchase  Date,  the Issuer
shall  irrevocably  deposit  with the Trustee or with a paying agent (or, if the
Issuer is acting as Paying Agent, segregate and hold in trust) an amount in cash
sufficient  to pay the Offer  Amount  for all Notes  properly  tendered  to, not
withdrawn from and accepted by the Issuer.  The Trustee shall,  on the Purchase
Date,  mail or deliver payment to each tendering Holder in the amount of the
purchase price.

         .........(3) Holders electing to have a Note purchased will be required
to  surrender  the Note,  together  with all  necessary  endorsements  and other
appropriate materials duly completed,  to the Issuer at the address specified in
the notice at least three Business Days prior to the Purchase Date. Holders will
be entitled to withdraw their election in whole or in part if the Trustee or the
Issuer  receives not later than one  Business Day prior to the Purchase  Date, a
facsimile  transmission  or letter  setting  forth the name of the  Holder,  the
principal  amount of the Note (which shall be $1,000 in  principal  amount or an
integral multiple  thereof) which was delivered for purchase by the Holder,  the
aggregate  principal  amount of such Note (if any) that  remains  subject to the
original notice of the Offer and that has been or will be delivered for purchase
by the Issuer and a statement  that such Holder is  withdrawing  his election to
have such Note purchased. If at the expiration of the Offer Period the aggregate
principal amount of Notes  surrendered by Holders exceeds the Offer Amount,  the
Trustee shall select the Notes to be purchased in accordance with the provisions
of  Section  3.2 (with  such  adjustments  as may be deemed  appropriate  by the
Trustee so that only securities in denominations of $1,000 principal  amount, or
integral  multiples  thereof,  shall be  purchased).  Holders  whose  Notes  are
purchased only in part will be issued new Notes equal in principal amount to the
unpurchased portion of the Notes surrendered.
<PAGE>   42
                                       38

         .........(4)      A Note shall be deemed to have been accepted for
purchase at the time the Trustee, directly or through an agent, mails or
delivers payment therefor to the surrendering Holder.

         .........(d) The Issuer will comply, to the extent applicable, with the
requirements of Section 14(e) of the Exchange Act and any other  securities laws
or  regulations  in connection  with the  repurchase  of Notes  pursuant to this
covenant.  To  the  extent  that  the  provisions  of  any  securities  laws  or
regulations  conflict with  provisions of this covenant,  the Issuer will comply
with the applicable  securities  laws and  regulations and will not be deemed to
have breached its obligations under this covenant by virtue thereof.

         .........(e)      The provisions of this Section 4.7 shall not apply to
any transaction that is permitted under the provisions of Section 5.1.

         .........SECTION 4.8.  Limitation on Transactions with Affiliates .
(a)  The Issuer will not, and will not permit any Restricted Subsidiary to,
directly or indirectly, enter into or conduct any transaction or series of
transactions (including the purchase, sale, lease or exchange of any property,
employee compensation arrangements or the rendering of any service) with any
Affiliate of the Issuer (an "Affiliate Transaction") unless (i) the terms of
such transaction, taken as a whole, are no less favorable to the Issuer or such
Restricted Subsidiary, as the case may be, than those that could be obtained at
the time of such transaction in arm's-length dealings with a Person who is not
such an Affiliate; (ii) in the event such Affiliate Transaction involves an
aggregate amount in excess of $5.0 million, the terms of such transaction are
set forth in writing and shall  have been  approved  by a  majority  of the
members  of the Board of Directors  having no  personal  stake in such
Affiliate  Transaction  (and such majority  determines that such Affiliate
Transaction  satisfies the criteria in clause (i) above) and (iii) in the event
such Affiliate  Transaction involves an aggregate  amount in excess of $10.0
million,  the Issuer has received a written opinion from a nationally
recognized  independent  investment banking firm that such Affiliate Transaction
is fair to the Issuer and its Restricted Subsidiaries from a financial point of
view.

         .........(b)  The provisions of paragraph (a) of this Section 4.8 shall
not prohibit (i) any Restricted Payment permitted to be made pursuant to Section
4.5, (ii) any issuance of  securities,  or other  payments,  awards or grants in
cash,  securities  or  otherwise  pursuant  to, or the  funding  of,  employment
arrangements,  stock options and stock  ownership plans approved by the Board of
Directors of the Issuer, or any arrangements  relating thereto,  (iii) the grant
of stock  options or similar  rights to  employees  and  directors of the Issuer
pursuant to plans  approved by the Board of Directors of the Issuer,  (iv) loans
or advances to employees in the ordinary  course of business in accordance  with
the past practices of the Issuer or its Restricted Subsidiaries, (v) the payment
of reasonable  fees to directors of the Issuer and its  Restricted  Subsidiaries
who are not  employees of the Issuer or its  Restricted  Subsidiaries,  (vi) any
transaction between the Issuer and a Restricted Subsidiary or between Restricted
Subsidiaries,  (vii) the  issuance  or sale of any  Capital  Stock  (other  than
Disqualified Stock) of the Issuer,  (viii) any transaction  consummated pursuant
to the terms of any  agreement  described  in the Form  10-K for the year  ended
December
<PAGE>   43
                                       39

31, 1999,  including the exhibits and  documents  included by reference therein,
giving effect to any subsequent supplements,  amendments, modifications or
alterations  thereof that are approved by the  disinterested  members of the
Issuer's  Board of Directors,  (ix) any  transaction  in the ordinary  course of
business  between the Issuer or any  Restricted  Subsidiary and any Affiliate of
the Issuer relating to the  acquisition,  management,  construction,  leasing or
licensing of Tower Assets, provided,  however, that such transaction is on terms
that are no less  favorable,  taken as a whole,  to the  Issuer or the  relevant
Restricted  Subsidiary  than those that could have been obtained in a comparable
transaction by the Issuer or such Restricted Subsidiary with an unrelated Person
or is otherwise on terms that, taken as a whole, the Issuer has determined to be
fair  to  the  Issuer  or  the  relevant  Restricted  Subsidiary)  and  (x)  any
transaction between the Issuer or any of its Restricted  Subsidiaries and any of
its Affiliates involving ordinary course investment banking,  commercial banking
or related activities.

         .........SECTION 4.9.  Change of Control .  (a)  Upon the occurrence of
a Change of Control, each Holder shall have the right to require that the Issuer
repurchase all or any part of such Holder's Notes at a purchase price in cash
equal to 101% of the principal amount thereof as of the date of repurchase, plus
accrued and unpaid interest, if any, to the date of repurchase, in accordance
with the terms contemplated in Section 4.9(b).

         .........(b)      Within 30 days following any Change of Control, the
Issuer shall mail a notice to each Holder at its registered address with a copy
to the Trustee stating:

                           (1) that a Change of Control  has  occurred  and that
                  such  Holder has the right to require  the Issuer to  purchase
                  such  Holder's  Notes in  denominations  of  $1,000  principal
                  amount or any integral multiple thereof at a purchase price in
                  cash equal to 101% of the principal  amount  thereof as of the
                  date of repurchase,  plus accrued and unpaid interest, if any,
                  to the date of repurchase;

                           (2) the  circumstances  and relevant facts  regarding
                  such Change of Control (including  information with respect to
                  pro forma  historical  income,  cash  flow and  capitalization
                  after giving effect to such Change of Control);

                           (3) the  repurchase  date (which  shall be no earlier
                  than 30 days nor later than 60 days from the date such  notice
                  is mailed); and

                           (4)  the  instructions   determined  by  the  Issuer,
                  consistent with this Section 4.9, that a Holder must follow in
                  order to have its Notes purchased by the Issuer.

         .........(c) Holders electing to have a Note purchased will be required
to  surrender  the Note,  together  with all  necessary  endorsements  and other
appropriate materials duly completed,  to the Issuer at the address specified in
the notice at least three Business Days prior to the purchase date. Holders will
be entitled to withdraw their election if the Trustee or the Issuer receives not
later than one Business Day prior to the purchase date, a facsimile transmission
or
<PAGE>   44
                                       40

letter setting forth the name of the Holder, the principal amount of the Note
which was  delivered  for  purchase  by the  Holder as to which  such  notice of
withdrawal is being  submitted and a statement  that such Holder is  withdrawing
his election to have such Note purchased.

         .........(d)  On the purchase date,  all Notes  purchased by the Issuer
under this Section 4.9 shall be delivered to the Trustee for  cancellation,  and
the Issuer shall pay the purchase price, including premium, if any, plus accrued
and unpaid interest, if any, to the Holders entitled thereto.

         .........(e) The Issuer will comply, to the extent applicable, with the
requirements of Section 14(e) of the Exchange Act and any other  securities laws
or  regulations  in connection  with the  repurchase  of Notes  pursuant to this
Section  4.9.  To the  extent  that the  provisions  of any  securities  laws or
regulations conflict with provisions of this Section 4.9, the Issuer will comply
with the applicable  securities  laws and  regulations and will not be deemed to
have breached its obligations under this Section 4.9 by virtue thereof.

         .........(f)  The Issuer will not be required to make an offer pursuant
to this Section 4.9 upon a Change of Control if a third party, in the manner, at
the times and otherwise in compliance  with the  requirements  set forth in this
Indenture  applicable to a Change of Control made by the Issuer,  makes an offer
to purchase and  purchases all Notes  validly  tendered and not withdrawn  under
such offer.

         .........(g) Notwithstanding the occurrence of a Change of Control, the
Issuer shall not be obligated to repurchase  the Notes or otherwise  comply with
this Section 4.9 if the Issuer has  irrevocably  elected to redeem all the Notes
in accordance with Article III; provided that the Issuer does not default in its
redemption obligations pursuant to such election.

         .........SECTION 4.10.  Limitation on Sale or Issuance of Capital Stock
of Restricted Subsidiaries .  The Issuer (i) will not, and will not permit any
Restricted Subsidiary to, transfer, convey, sell, lease or otherwise dispose of
any Capital Stock of any Restricted Subsidiary to any Person (other than to the
Issuer or a Wholly Owned Subsidiary), and (ii) will not permit any Restricted
Subsidiary to issue any of its Capital Stock (other than, to the extent
necessary or mandated by applicable law, shares of its Capital Stock
constituting directors' qualifying shares or the ownership by foreign nationals
of Capital Stock of any Restricted Subsidiary) to any Person other than to the
Issuer or a Subsidiary unless in either case (a) the Issuer's and Restricted
Subsidiary's minority equity interest in such Person after giving effect to any
such disposition, would be permitted under Section 4.5; and (b) the net cash
proceeds from such transfer, conveyance, sale, lease or other disposition are
applied in accordance with Section 4.7.

         .........SECTION 4.11.  Limitation on Liens .  The Issuer will not, and
will not permit any Restricted Subsidiary to, directly or indirectly, create or
permit to exist any Lien on any of its property or assets (including Capital
Stock), whether owned on the Issue Date or thereafter acquired, securing any
obligation, other than Permitted Liens, unless contemporaneously therewith
effective provision is made to secure the Notes equally and ratably with (or on
a senior
<PAGE>   45
                                       41

basis to, in the case of Subordinated Obligations) such obligation for
so long as such obligation is so secured.

         .........SECTION 4.12.  Limitation on Sale/Leaseback Transactions . The
Issuer will not, and will not permit any Restricted Subsidiary to, enter into
any Sale/Leaseback Transaction with respect to any property unless (i) the
Issuer or such Restricted Subsidiary would be entitled to (A) Incur Indebtedness
in an amount equal to the Attributable Indebtedness with respect to such
Sale/Leaseback Transaction pursuant to Section 4.3 and (B) create a Lien on such
property securing such Attributable Indebtedness without equally and ratably
securing the Notes pursuant to Section 4.11, (ii) the net cash proceeds received
by the Issuer or any Restricted Subsidiary in connection with such Sale/
Leaseback Transaction are at least equal to the fair value (as determined in
good faith by the Board of Directors of the Issuer) of such property and (iii)
the transfer of such property is permitted by, and the Issuer or such Restricted
Subsidiary applies the proceeds of such transaction in compliance with, Section
4.7.

         .........SECTION 4.13.  Compliance with Laws .  The Issuer shall
comply, and shall cause each of its Restricted Subsidiaries to comply, with all
applicable statutes, rules, regulations, orders and restrictions of the United
States of America, all states and municipalities thereof, and of any
governmental department, commission, board, regulatory authority, bureau, agency
and instrumentality of the foregoing, in respect of the conduct of their
respective businesses and the ownership of their respective properties, except
for such noncompliances as are not in the aggregate  reasonably likely to have a
material adverse effect on the  financial  condition  or  results  of
operations  of the  Issuer  and  its Subsidiaries, taken as a whole.

         .........SECTION 4.14.  Compliance Certificate .  The Issuer shall
deliver to the Trustee within 120 days after the end of each fiscal year of the
Issuer an Officer's Certificate signed by the chief executive officer, the chief
financial officer or the chief accounting officer stating that in the course of
the performance by the signer of his duties as an Officer of the Issuer he
would normally have knowledge of any Default or Event of Default and whether or
not the signers know of any Default or Event of Default that occurred during
such period.  If he does, the certificate shall describe the Default or Event of
Default, its status and what action the Issuer is taking or proposes to take
with respect thereto.  The Issuer also shall comply with TIA ss. 314(a)(4).

         .........SECTION 4.15.  Further Instruments and Acts .  Upon reasonable
request of the Trustee, the Issuer will execute and deliver such further
instruments and do such further acts as may be reasonably necessary or proper to
carry out more effectively the purpose of this Indenture.

         .........SECTION 4.16.  Maintenance of Office or Agency .  The Issuer
shall maintain the office or agency required under Section 2.3.  The Issuer
shall give prior written notice to the Trustee of the location, and any change
in the location, of such office or agency.  If at any time the Issuer shall fail
to maintain any such required office or agency or shall fail to furnish the
<PAGE>   46
                                       42

Trustee with the address thereof, such presentations, surrenders, notices and
demands may be made or served at the address of the Trustee set forth in Section
10.2.

         .........SECTION 4.17.  Corporate Existence .  Except as otherwise
permitted by Article V and Section 4.9, the Issuer shall do or cause to be done,
at its own cost and expense, all things necessary to preserve and keep in full
force and effect its corporate existence and the corporate, partnership or
limited liability company existence of each of its Significant Subsidiaries in
accordance with the respective organizational documents of each such Subsidiary
and the material rights (charter and statutory) and franchises of the Issuer and
each such Subsidiary; provided, however, that the Issuer shall not be required
to preserve, with respect to itself, any material right or franchise and, with
respect to any of its Significant Subsidiaries, any such existence, material
right or franchise, if the Board of Directors of the Issuer shall determine in
good faith (such determination to be evidenced by a board resolution), that the
preservation thereof is no longer desirable in the conduct of the business of
the Issuer and the Subsidiaries, taken as a whole.

         .........SECTION 4.18.  Payment of Taxes and Other Claims .  The Issuer
shall pay or discharge or cause to be paid or discharged, before the same shall
become delinquent, (i) all material taxes, assessments and governmental charges
(including withholding taxes and any penalties, interest and additions to taxes)
levied or imposed upon it or any of its Restricted Subsidiaries or properties of
it or any of its Restricted Subsidiaries and (ii) all lawful claims for labor,
materials and supplies that, if unpaid, might by law become a Lien upon the
property of it

or any of its Restricted Subsidiaries;  provided,  however, that the Issue shall
not be required to pay or discharge or cause to be paid or  discharged  any such
tax,  assessment,  charge or claim whose  amount,  applicability  or validity is
being contested in good faith by appropriate proceedings properly instituted and
diligently  conducted for which adequate reserves,  to the extent required under
GAAP, have been taken.

         .........SECTION 4.19.  Maintenance of Properties and Insurance .  (a)
The Issuer shall, and shall cause each of its Significant Subsidiaries to,
maintain its material properties in good working order and condition (subject to
ordinary wear and tear) and make or cause to be made all necessary repairs,
renewals, replacements, additions, betterments and improvements thereto and
actively conduct and carry on its business, all as in the reasonable judgment of
the Issuer is necessary so that the business carried on by Issuer and its
Significant Subsidiaries may be actively conducted; provided, however, that
nothing in this Section 4.19 shall prevent the Issuer or any of its Subsidiaries
from discontinuing the operation and maintenance of any of its properties, if
such discontinuance is, in the good faith judgment of the Issuer or the
Subsidiary, as the case may be, desirable in the conduct of their respective
businesses and is not disadvantageous in any material respect to the Holders.

         .........(b)  The Issuer  shall  provide or cause to be  provided,  for
itself  and  each  of  its  Significant   Subsidiaries,   insurance   (including
appropriate  self-insurance)  against  loss or damage of the kinds that,  in the
good faith judgment of the Issuer,  are adequate and appropriate for the conduct
of the business of the Issuer and such  Subsidiaries in a prudent  manner,  with
reputable
<PAGE>   47
                                       43

insurers or with the government of the United States of America,  any state
thereof or any agency or  instrumentality  of such  governments,  in such
amounts,  with such deductibles,  and by such methods as shall be customary,  in
the good faith judgment of the Issuer,  for companies  similarly situated in the
industry.

                                    ARTICLE V
                                SUCCESSOR ISSUER

         .........SECTION 5.1.  When the Issuer May Merge or Transfer Assets .
The Issuer will not consolidate with or merge with or into, or convey, transfer
or lease, in one transaction or a series of transactions, all or substantially
all its assets to, any Person, unless:

                  (i)  the  resulting,   surviving  or  transferee  Person  (the
         "Successor  Issuer") will be a Person  organized ind existing under the
         laws of the United States of America, any State thereof or the District
         of Columbia and the Successor Issuer (if not the Issuer) will expressly
         assume,  by  supplemental  indenture,  executed  and  delivered  to the
         Trustee,  in form  satisfactory to the Trustee,  all the obligations of
         the Issuer under the Notes and this Indenture;

                  (ii) immediately  after giving effect to such transaction on a
         pro forma  basis  (and  treating  any  Indebtedness  which  becomes  an
         obligation of the Successor  Issuer or any  Restricted  Subsidiary as a
         result of such transaction as having been Incurred by the Successor
         Issuer  or such  Restricted  Subsidiary  at the time of such
         transaction),  no Default or Event of Default will have occurred and be
         continuing;

                  (iii)  except (A) in the case of a merger of the Issuer into a
         Wholly  Owned  Subsidiary,  (B) a merger  entered  into  solely for the
         purpose of reincorporating the Issuer in another  jurisdiction or (C) a
         merger  the Issuer  enters  into  solely  for the  purpose of forming a
         holding  company to hold all of the  outstanding  capital  stock of the
         Issuer,  immediately  after giving effect to such  transaction on a pro
         forma basis as if such transaction had occurred at the beginning of the
         applicable four quarter  period,  the Issuer or the Person formed by or
         surviving any such  consolidation or merger (if other than the Issuer),
         or to which such conveyance, transfer, lease or other disposition shall
         have been made,  either (x) would have been permitted to incur at least
         $1.00 of additional Indebtedness under Section 4.3(a) or (y) would have
         had an Indebtedness to Adjusted EBITDA Ratio  immediately  after giving
         effect to such consolidation,  merger,  conveyance,  transfer, lease or
         other  disposition no greater than the  Indebtedness to Adjusted EBITDA
         Ratio immediately prior to such transaction; and

                  (iv)  the  Issuer  will  have  delivered  to  the  Trustee  an
         Officer's Certificate and an Opinion of Counsel, each stating that such
         consolidation,  merger or transfer and such supplemental  indenture (if
         any) comply with this Indenture, as set forth in this Indenture.

<PAGE>   48
                                       44

          ........The  Successor Issuer will succeed to, and be substituted for,
and may exercise every right and power of, the Issuer under this Indenture,  but
the predecessor Issuer in the case of a conveyance, transfer or lease of all its
assets or  substantially  all its assets will be released  from the  obligations
under this Indenture and the Notes,  including without limitation the obligation
to pay the principal of and interest on the Notes.

                                   ARTICLE VI
                             DEFAULTS AND REMEDIES

             .........SECTION 6.1. Events of Default . An "Event of Default"
                      occurs if:

                  (1) the Issuer defaults in any payment of interest on any Note
         when the same becomes due and payable, and such default continues for a
         period of 30 days;

                  (2) the Issuer defaults in the payment of the principal of any
         Note when the same becomes due and payable at its Stated Maturity, upon
         optional  or  mandatory  redemption,  upon  required  repurchase,  upon
         declaration or otherwise;

                  (3) the  Issuer  fails to comply  with its  obligations  under
         Article V;

                  (4) the Issuer  fails to comply with Section  4.2,  4.3,  4.4,
         4.5, 4.6, 4.7,  4.8, 4.9,  4.10,  4.11 or 4.12 (other than a failure to
         purchase Notes when required pursuant to

         Section 4.7 or 4.9, which failure shall  constitute an Event of Default
         under Section 6.1(2)) and such failure  continues for 30 days after the
         notice specified below;

                  (5) the Issuer fails to comply with any of its  agreements  in
         the Notes or this Indenture  (other than those referred to in (1), (2),
         (3) or (4)  above)  and such  failure  continues  for 60 days after the
         notice specified below;

                  (6) the  Issuer or any  Significant  Subsidiary  of the Issuer
         fails  to pay any  Indebtedness  within  any  applicable  grace  period
         provided in such Indebtedness  after final maturity or the acceleration
         of any such Indebtedness by the holders thereof because of a default if
         the total amount of such  Indebtedness  unpaid or  accelerated  exceeds
         $10.0 million or its foreign currency equivalent at the time;

                  (7) the  Issuer  or a  Significant  Subsidiary  of the  Issuer
         pursuant to or within the meaning of any Bankruptcy Law:

                           (A)      commences a voluntary case;

                           (B)  consents  to the  entry of an order  for  relief
                  against it in an involuntary case in which it is the debtor;

                           (C) consents to the  appointment of a Custodian of it
         or for any substantial part of its property; or
<PAGE>   49

                                     45

                           (D)      makes a general assignment for the benefit
         of its creditors;

         or takes any comparable action under any foreign laws relating to
         insolvency;

                  (8) a court  of  competent  jurisdiction  enters  an  order or
         decree under any Bankruptcy Law that:

                           (A)      is for relief against the Issuer or any
         Significant Subsidiary of the Issuer in an involuntary
                  case;

                           (B)  appoints  a  Custodian  of  the  Issuer  or  any
                  Significant  Subsidiary  or for  any  substantial  part of its
                  property of the Issuer or any Significant Subsidiary; or

                           (C)  orders  the  winding  up or  liquidation  of the
         Issuer or any Significant Subsidiary of the Issuer

         (or any  similar  relief is  granted  under any  foreign  laws) and the
         order, decree or relief remains unstayed and in effect for 90 days; or

                  (9) any final  judgment  or decree for the payment of money in
         excess of $10.0  million  (net of any amounts  with  respect to which a
         creditworthy insurance company has acknowledged full liability (subject
         to any  deductible  amounts of less than $10.0  million  required to be
         paid by the  Issuer  or the  Significant  Subsidiary  of the  Issuer in
         accordance with the applicable  insurance  policy)) is rendered against
         the Issuer or any  Significant  Subsidiary of the Issuer and either (A)
         an enforcement  proceeding has been commenced by any creditor upon such
         judgment or decree or (B) such  judgment or decree  remains  unpaid and
         outstanding  for a period of 60 days following such judgment and is not
         discharged, waived or stayed within 10 days after notice.

         .........The  foregoing will constitute  Events of Default whatever the
reason for any such Event of Default and whether it is voluntary or  involuntary
or is effected by operation of law or pursuant to any judgment,  decree or order
of any  court  or any  order,  rule  or  regulation  of  any  administrative  or
governmental body.

         .........The term "Bankruptcy Law" means Title 11, United States Code,
or any similar Federal or state law for the relief of debtors.  The term
"Custodian" means any receiver, trustee, assignee, liquidator, custodian or
similar official under any Bankruptcy Law.

         .........A Default under clause (4), (5) and (9) of this Section 6.1 is
not an Event of Default until the Trustee by notice to the Issuer or the Holders
of at least 25% in aggregate principal amount of the outstanding Notes by notice
to the Issuer  give  notice of the  Default  and the  Issuer  does not cure such
Default  within the time  specified in said clause (4), (5) or (9) after
<PAGE>   50
                                       46

receipt of such notice. Such notice must specify the Default, demand that it be
remedied and state that such notice is a "Notice of Default".

         .........The Issuer shall deliver to the Trustee,  within 30 days after
it obtains knowledge of the occurrence thereof, written notice in the form of an
Officer's  Certificate  of any Event of Default under clause (6) of this Section
6.1 and any event  which  with the  giving of notice or the lapse of time  would
become an Event of Default  under clause (4), (5) or (9) of this Section 6.1 and
what action the Issuer is taking or proposes to take with respect thereto.

         .........SECTION 6.2.  Acceleration .  If an Event of Default (other
than an Event of Default specified in Section 6.1(7) or (8) with respect to the
Issuer) occurs and is continuing, the Trustee by notice to the Issuer, or the
Holders of at least 25% in aggregate principal amount of the outstanding Notes
by notice to the Issuer, may declare the principal amount of, and accrued but
unpaid interest on all the Notes to be due and payable. Upon such a declaration,
such principal amount and interest shall be due and payable immediately.  If an
Event of Default specified in Section 6.1(7) or (8) with respect to the Issuer
occurs and is continuing, the principal amount of, and accrued interest on all
the Notes shall ipso facto become and be immediately due and payable without any
declaration or other act on the part of the Trustee or any Holders.  The Holders
of a majority in aggregate principal amount of the outstanding Notes by notice
to the Trustee may rescind an acceleration and its consequences if the
rescission would not conflict with any judgment or decree and if all existing
Events of Default have been cured or waived  except  nonpayment  of principal or
interest  that has become due solely because of  acceleration  and the  Trustee
has been paid all  amounts due to it pursuant to Section 7.7. No such rescission
shall affect any subsequent  Default or impair any right consequent thereto.

         .........SECTION 6.3.  Other Remedies .  If an Event of Default occurs
and is continuing, the Trustee may pursue any available remedy to collect the
payment of principal amount of or interest on the Notes or to enforce the
performance of any provision of the Notes or this Indenture.

         .........The Trustee may maintain a proceeding even if it does not
possess any of the Notes or does not produce any of them in the proceeding.  A
delay or omission by the Trustee or any Noteholder in exercising any right or
remedy accruing upon an Event of Default shall not impair the right or remedy or
constitute a waiver of or acquiescence in the Event of Default.  No remedy is
exclusive of any other remedy.  All available remedies are, to the extent
permitted by law, cumulative.

         .........SECTION 6.4.  Waiver of Past Defaults .  The Holders of a
majority in aggregate principal amount of the Notes then outstanding by notice
to the Trustee may waive any past or existing Default and its consequences
except (i) a Default in the payment of the principal of or interest on a Note or
(ii) a Default in respect of a provision that under Section 9.2 cannot be
amended without the consent of each Noteholder affected.  When a Default is
waived, it is deemed cured, and any Event of Default arising therefrom shall be
deemed to have been cured, but no such waiver shall extend to any subsequent or
other Default or impair any consequent right.
<PAGE>   51
                                       47

         .........SECTION 6.5.  Control by Majority .  Upon provision of
reasonable indemnity to the Trustee satisfactory to the Trustee, the Holders of
a majority in aggregate principal amount of the Notes then outstanding may
direct the time, method and place of conducting any proceeding for any remedy
available to the Trustee or of exercising any trust or power conferred on the
Trustee. However, the Trustee, which may rely on opinions of counsel, may refuse
to follow any direction that conflicts with law or this Indenture or, subject to
Section 7.1, that the Trustee determines is unduly prejudicial to the rights of
other Noteholders or would involve the Trustee in personal liability; provided,
however, that the Trustee may take any other action deemed proper by the Trustee
that is not inconsistent with such direction.

         .........SECTION 6.6.  Limitation on Suits .  A Holder may not pursue
any remedy with respect to this Indenture or the Notes
unless:

                  (i)      the Holder gives to the Trustee previous written
         notice stating that an Event of Default is continuing;

                  (ii) the Holders of at least 25% in aggregate principal amount
         of the Notes then  outstanding make a written request to the Trustee to
         pursue the remedy;

                  (iii) such Holder or Holders  offer to the Trustee  reasonable
         security or indemnity against any loss, liability or expense;
                  (iv) the Trustee  does not comply  with the request  within 60
         days  after  receipt  of the  request  and the  offer  of  security  or
         indemnity; and

                  (v) the Holders of a majority in aggregate principal amount of
         the  Notes  then  outstanding  do not  give  the  Trustee  a  direction
         inconsistent with such request within such 60-day period.

         .........A Noteholder may not use this Indenture to prejudice the
rights of another Noteholder or to obtain a preference or priority over another
Noteholder.

         .........SECTION 6.7.  Rights of Holders to Receive Payment .
Notwithstanding any other provision of this Indenture, the right of any Holder
to receive payment of the principal amount of and interest on the Notes held by
such Holder, on or after the respective due dates expressed in the Notes, or to
bring suit for the enforcement of any such payment on or after such respective
dates, shall not be impaired or affected without the consent of such Holder.

         .........SECTION 6.8.  Collection Suit by Trustee .  If an Event of
Default specified in Section 6.1(1) or (2) occurs and is continuing, the Trustee
may recover judgment in its own name and as trustee of an express trust against
the Issuer for the whole amount then due and owing (together with interest on
any unpaid interest to the extent lawful) and the amounts provided for in
Section 7.7.
<PAGE>   52
                                       48

         .........SECTION 6.9.  Trustee May File Proofs of Claim .  The Trustee
may file such proofs of claim and other papers or documents as may be necessary
or advisable in order to have the claims of the Trustee and the Noteholders
allowed in any judicial proceedings relative to the Issuer, its creditors or its
property and shall be entitled and empowered to collect, receive and distribute
any money or other securities or property payable or deliverable on any such
claims and to distribute the same, and, unless prohibited by law or applicable
regulations, may vote on behalf of the Holders in any election of a trustee in
bankruptcy or other Person performing similar functions, and any Custodian in
any such judicial proceeding is hereby authorized by each Holder to make
payments to the Trustee and, in the event that the Trustee shall consent to the
making of such payments directly to the Holders, to pay to the Trustee any
amount due it for the reasonable compensation, expenses, disbursements and
advances of the Trustee, its agents and its counsel, and any other amounts due
the Trustee under Section 7.7.

         .........SECTION 6.10.  Priorities .  If the Trustee collects any money
or property pursuant to this Article VI, it shall pay out the money or property
in the following order:

         .........FIRST:  to the Trustee for amounts due under Section 7.7;

                  SECOND:  to Noteholders for amounts due and unpaid on the
         Notes for principal anmount and interest, ratably, without preference
         or priority of any kind, according to the amounts due and payable on
         the Notes for principal amount and interest, respectively; and

                  THIRD:  to the Issuer or to such party as a court of competent
         jurisdiction shall direct.

         .........The Trustee may fix a record date and payment date for any
payment to Noteholders pursuant to this Section 6.10.  At least 15 days before
such record date, the Issuer shall mail to each Noteholder and the Trustee a
notice that states the record date, the payment date and amount to be paid.

         .........SECTION 6.11.  Undertaking for Costs .  In any suit for the
enforcement of any right or remedy under this Indenture or in any suit against
the Trustee for any action taken or omitted by it as Trustee, a court in its
discretion may require the filing by any party litigant in the suit of an
undertaking to pay the costs of the suit, and the court in its discretion may
assess reasonable costs, including reasonable attorneys' fees and expenses,
against any party litigant in the suit, having due regard to the merits and good
faith of the claims or defenses made by the party litigant.  This Section 6.11
does not apply to a suit by the Trustee, a suit by a Holder pursuant to Section
6.7 or a suit by Holders of more than 10% in aggregate principal amount of the
outstanding Notes.

         .........SECTION 6.12.  Waiver of Stay or Extension Laws .  The Issuer
(to the extent it may lawfully do so) shall not at any time insist upon, or
plead, or in any manner whatsoever claim or take the benefit or advantage of,
any stay or extension law wherever enacted, now or at
<PAGE>   53
                                       49

any time hereafter in force, which may affect the covenants or the performance
of this Indenture; and the Issuer (to the extent that it may lawfully do so)
hereby expressly waives all benefit or advantage of any such law, and shall not
hinder, delay or impede the execution of any power herein granted to the
Trustee, but shall suffer and permit the execution of every such power as though
no such law had been enacted.

                                   ARTICLE VII
                                    TRUSTEE

         .........SECTION 7.1.  Duties of Trustee .  (a)  If an Event of Default
has occurred and is continuing, the Trustee shall exercise the rights and powers
vested in it by this Indenture and use the same degree of care and skill in
their exercise as a prudent Person would exercise or use under the circumstances
in the conduct of such Person's own affairs.

                  (b)      Except during the continuance of an Event of Default:

                  (i) the  Trustee  undertakes  to perform  such duties and only
         such duties as are specifically set forth in this Indenture and the TIA
         and no  implied  covenants  or  obligations  shall  be read  into  this
         Indenture against the Trustee; and

                  (ii) in the absence of bad faith on its part,  the Trustee may
         conclusively   rely,  as  to  the  truth  of  the  statements  and  the
         correctness of the opinions  expressed  therein,  upon  certificates or
         opinions furnished to the Trustee and conforming to the requirements of
         this  Indenture.  However,  in the  case of any  such  certificates  or
         opinions which by any provision hereof are specifically  required to be
         furnished to the Trustee,  the Trustee shall  examine the  certificates
         and  opinions  to  determine   whether  or  not  they  conform  to  the
         requirements of this Indenture.

         .........(c)      The Trustee may not be relieved from liability for
its own negligent action, its own negligent failure to act or its own wilful
misconduct, except that:

                  (i)      this paragraph does not limit the effect of paragraph
(b) of this Section 7.1;

                  (ii) the Trustee shall not be liable for any error of judgment
         made in good  faith by a Trust  Officer  unless it is  proved  that the
         Trustee was negligent in ascertaining the pertinent facts; and

                  (iii) the  Trustee  shall not be liable  with  respect  to any
         action  it takes or omits to take in good  faith in  accordance  with a
         direction received by it pursuant to Section 6.5.

         .........(d)      Whether or not therein expressly so provided, every
provision of this Indenture that in any way relates to the Trustee is subject to
paragraphs (a), (b) and (c) of this Section 7.1.
<PAGE>   54
                                       50

         .........(e)      Money held in trust by the Trustee need not be
segregated from other funds except to the extent required by law.

         .........(f)  No provision of this Indenture  shall require the Trustee
to expend or risk its own funds or otherwise  incur  financial  liability in the
performance  of any of its duties  hereunder  or in the  exercise  of any of its
rights or powers, if it shall have reasonable  grounds to believe that repayment
of such  funds or  adequate  indemnity  against  such risk or  liability  is not
reasonably assured to it.

         .........(g)      Every provision of this Indenture relating to the
conduct or affecting the liability of or affording protection to the Trustee
shall be subject to the provisions of this Section 7.1 and to the provisions of
the TIA.
         .........SECTION 7.2.  Rights of Trustee .  (a)  The Trustee may rely
upon, and shall be fully protected from acting or refraining from acting, on any
document believed by it to be genuine and to have been signed or presented by
the proper person.  The Trustee need not investigate any fact or matter stated
in the document.

         .........(b)      Before the Trustee acts or refrains from acting, it
may request an Officer's Certificate or an Opinion of Counsel or both.  The
Trustee shall not be liable for any action it takes or omits to take in good
faith in reliance on the Officer's Certificate or Opinion of Counsel.

         .........(c)      The Trustee may act through agents and shall not be
responsible for the misconduct or negligence of any agent appointed with due
care.

         .........(d)      The Trustee shall not be liable for any action it
takes or omits to take in good faith which it believes to be authorized or
within its rights or powers; provided, however, that the Trustee's conduct does
not constitute wilful misconduct or negligence.

         .........(e) The Trustee may consult with counsel of its selection, and
the advice or opinion of counsel with respect to legal matters  relating to this
Indenture and the Notes shall be full and complete  authorization and protection
from  liability  in respect  to any action  taken,  omitted  or  suffered  by it
hereunder  in good  faith and in  accordance  with the advice or opinion of such
counsel.

         .........(f)  The Trustee  shall be under no obligation to exercise any
of the  rights  or powers  vested  in it by this  Indenture  at the  request  or
direction of any of the Holders pursuant to this Indenture,  unless such Holders
shall have offered to the Trustee  reasonable  security or indemnity against the
costs, expenses and liabilities which might be incurred by it in compliance with
such request or direction.

         .........(g)  The Trustee  shall not be charged  with  knowledge of any
Default or Event of Default with respect to the Notes unless  either (1) a Trust
Officer  shall have actual  knowledge of such Default or Event of Default or (2)
written  notice of such Default or Event of Default shall have been given to the
Trustee by the Issuer or by any Holder of the Notes.
<PAGE>   55
                                       51

         .........SECTION 7.3.  Individual Rights of Trustee .  The Trustee in
its individual or any other capacity may become the owner or pledgee of Notes
and may otherwise deal with the Issuer or its respective Affiliates with the
same rights it would have if it were not Trustee.  Any Paying Agent, Registrar,
co-registrar or co-paying agent may do the same with like rights.  However, the
Trustee must comply with Sections 7.10 and 7.11.

         .........SECTION 7.4.  Trustee's Disclaimer .  The Trustee shall not be
responsible for and makes no representation as to the validity or adequacy of
this Indenture or the Notes, it shall not be accountable for the Issuer's use of
the proceeds from the Notes, and it shall not be responsible for any statement
of the Issuer in this Indenture or in any document issued in connection with the
sale of the Notes or in the Notes other than the Trustee's certificate of
authentication.

         .........SECTION 7.5.  Notice of Defaults .  If a Default or an Event
of Default occurs and is continuing and if it is known to the Trustee, the
Trustee must mail to each Noteholder notice of the Default within the earlier of
90 days after it occurs or 30 days after it is known to a Trust Officer or
written notice of it is received by the Trustee.  Except in the case of a
Default in payment of principal of,  premium (if any) or interest on any Note,
the Trustee may withhold  notice if and so long as a committee of its Trust
Officers in good faith  determines  that  withholding  notice is not opposed to
the  interests of Noteholders.

         .........SECTION 7.6.  Reports by Trustee to Holders .  As promptly as
practicable after each January 15 beginning with the January 15 following the
date of this Indenture, and in any event prior to March 15 in each year, the
Trustee shall mail to each Noteholder a brief report dated as of such January 15
that complies with TIA ss. 313(a).  The Trustee also shall comply with TIA ss.
313(b).  The Trustee shall promptly deliver to the Issuer a copy of any report
it delivers to Holders pursuant to this Section 7.6.

         .........A copy of each report at the time of its mailing to
Noteholders shall be filed by the Trustee with the SEC and each stock exchange
(if any) on which the Notes are listed.  The Issuer agrees to notify promptly
the Trustee whenever the Notes become listed on any stock exchange and of any
delisting thereof.

         .........SECTION 7.7.  Compensation and Indemnity .  The Issuer shall
pay to the Trustee from time to time such compensation for its services as the
Issuer and the Trustee shall from time to time agree in writing.  The Trustee's
compensation shall not be limited by any law on compensation of a trustee of an
express trust.  The Issuer shall reimburse the Trustee upon request for all
reasonable fees and expenses, including out-of-pocket expenses, incurred or made
by it in connection with the performance of its duties hereunder, including
costs of collection, in addition to such compensation for its services, except
any such expense, disbursement or advance as may arise from its negligence,
wilful misconduct or bad faith, unless the Trustee shall have complied with
the applicable standard of care required by the TIA.  Such expenses shall
include the reasonable compensation and expenses, disbursements and advances of
the Trustee's
<PAGE>   56
                                       52

agents, counsel, accountants and experts.  The Trustee shall provide the Issuer
reasonable notice of any expenditure not in the ordinary course of business;
provided that prior approval by the Issuer of any such expenditure shall not be
a requirement for the making of such expenditure nor for reimbursement by the
Issuer thereof. The Issuer shall indemnify each of the Trustee and any
predecessor Trustees against any and all loss, damage, claim, liability or
expense (including reasonable attorneys' fees and expenses) (other than taxes
applicable to the Trustee's compensation hereunder) incurred by it in connection
with the acceptance or administration of this trust and the performance of its
duties hereunder.  The Trustee shall notify the Issuer promptly of any claim for
which it may seek indemnity.  Failure by the Trustee to so notify the Issuer
shall not relieve the Issuer of its obligations hereunder.  The Issuer shall
defend the claim and the Trustee may have separate counsel, and the Issuer will
pay the reasonable fees and expenses of such counsel.  The Issuer need not
reimburse any expense or indemnify against any loss, liability or expense
incurred by the Trustee through the Trustee's own wilful misconduct, negligence
or bad faith, unless the Trustee shall have complied with the applicable
standard of care required by the TIA.

         .........To  secure the Issuer's  payment  obligations  in this Section
7.7,  the Trustee  shall have a lien prior to the Notes on all money or property
held or collected by the Trustee  other than money or property  held in trust to
pay principal of and interest on particular Notes.

         .........The  Issuer's payment obligations pursuant to this Section 7.7
shall  survive the  resignation  or removal of the Trustee and discharge of this
Indenture.  When the Trustee  incurs  expenses after the occurrence of a Default
specified in Section 6.1(7) or (8) with respect to the Issuer,  the expenses are
intended to constitute  expenses of  administration  under the  Bankruptcy  Law,
provided,  however, that this shall not affect the Trustee's rights as set forth
in the preceding paragraph or Section 6.10.

         .........SECTION 7.8.  Replacement of Trustee .  The Trustee may resign
at any time with 30 days' notice to the Issuer.  The Holders of a majority in
principal amount of the Notes then outstanding, may remove the Trustee with 30
days notice to the Trustee and the Issuer and may appoint a successor Trustee.
The Issuer shall remove the Trustee if:

                  (i)       the Trustee fails to comply with Section 7.10;

                  (ii)     the Trustee is adjudged bankrupt or insolvent;

                  (iii) a receiver or other public  officer  takes charge of the
Trustee or its property; or

                  (iv) the Trustee otherwise becomes incapable of acting.

                  If the  Trustee  resigns,  is  removed by the Issuer or by the
Holders of a majority in  principal  amount of the Notes and such Holders do not
reasonably  promptly appoint a successor Trustee,  or if a vacancy exists in the
office of Trustee  for any reason (the  Trustee in such event
<PAGE>   57
                                       53
being  referred to herein as the retiring  Trustee),  the Issuer shall promptly
appoint a successor Trustee.

                  A successor Trustee shall deliver a written  acceptance of its
appointment to the retiring Trustee and to the Issuer. Thereupon the resignation
or removal of the retiring  Trustee  shall become  effective,  and the successor
Trustee  shall have all the rights,  powers and duties of the Trustee under this
Indenture.  The  successor  Trustee  shall  mail a notice of its  succession  to
Noteholders.  The retiring Trustee shall promptly  transfer all property held by
it as Trustee to the  successor  Trustee,  subject to the lien  provided  for in
Section 7.7.

                  If a successor  Trustee  does not take  office  within 30 days
after the retiring  Trustee resigns or is removed,  the retiring  Trustee or the
Holders  of 10% in  principal  amount  of the Notes  may  petition  any court of
competent jurisdiction for the appointment of a successor Trustee.

                  If  the  Trustee  fails  to  comply  with  Section  7.10,  any
Noteholder may petition any court of competent  jurisdiction  for the removal of
the Trustee and the appointment of a successor Trustee.

                  SECTION  7.9.  Successor  Trustee  by Merger . If the  Trustee
consolidates  with,  merges or converts into, or transfers all or  substantially
all its corporate  trust business or assets to,  another  corporation or banking
association,  the  resulting,  surviving or transferee  corporation  without any
further act shall be the successor Trustee, provided that such corporation shall
be eligible under this Article VII and TIA ss. 3.10(a).

                  In case at the time such  successor or  successors  by merger,
conversion or  consolidation  to the Trustee shall succeed to the trusts created
by this  Indenture  any of the  Notes  shall  have  been  authenticated  but not
delivered,  any such  successor  to the  Trustee  may adopt the  certificate  of
authentication   of  any  predecessor   trustee,   and  deliver  such  Notes  so
authenticated;  and in case at that  time any of the  Notes  shall not have been
authenticated,  any successor to the Trustee may authenticate  such Notes either
in the name of any predecessor  hereunder or in the name of the successor to the
Trustee; and in all such cases such certificates shall have the full force which
it is anywhere in the Notes or in this Indenture  provided that the  certificate
of the Trustee shall have.

                  SECTION  7.10.  Eligibility;  Disqualification  . The  Trustee
shall at all times satisfy the requirements of TIA ss. 310(a). The Trustee shall
have a combined capital and surplus of at least  $50,000,000 as set forth in its
most recent published annual report of condition.  The Trustee shall comply with
TIA ss.  310(b);  provided,  however,  that  there  shall be  excluded  from the
operation of TIA ss.  310(b)(1) any  indenture or  indentures  under which other
securities or certificates of interest or  participation  in other securities of
the Issuer are outstanding if the  requirements  for such exclusion set forth in
TIA ss. 310(b)(1) are met.

<PAGE>   58
                                       54

                  SECTION 7.11. Preferential Collection of Claims Against Issuer
 . The  Trustee  shall  comply  with  TIA  ss.  311(a),  excluding  any  creditor
relationship listed in TIA ss.311(b). A Trustee who has resigned or been removed
shall be subject to TIA ss. 311(a) to the extent indicated.

                                  ARTICLE VIII
                       DISCHARGE OF INDENTURE; DEFEASANCE

                  SECTION 8.1. Discharge of Liability on Notes; Defeasance . (a)
When (i) the Issuer  delivers to the Trustee all  outstanding  Notes (other than
Notes replaced pursuant to Section 2.7) for cancellation or (ii) all outstanding
Notes have  become due and  payable,  whether at  maturity or as a result of the
mailing of a notice of  redemption  pursuant  to Article III hereof or the Notes
will  become due and payable at their  Stated  Maturity  within 91 days,  or the
Notes  are to be  called  for  redemption  within  91  days  under  arrangements
satisfactory  to the  Trustee  for the  giving of notice  of  redemption  by the
Trustee in the name,  and at the  expense,  of the Issuer,  and, in each case of
this clause (ii), the Issuer irrevocably deposits or causes to be deposited with
the  Trustee  funds  sufficient  to pay  at  maturity  or  upon  redemption  all
outstanding  Notes,  including  interest  thereon to maturity or such redemption
date (other than Notes replaced  pursuant to Section 2.7), and if in either case
the Issuer  pays all other  sums  payable  hereunder  by the  Issuer,  then this
Indenture shall,  subject to Section 8.1(c),  cease to be of further effect. The
Trustee shall acknowledge satisfaction and discharge of this Indenture on demand
of the Issuer accompanied by an Officer's  Certificate and an Opinion of Counsel
from the Issuer that all conditions  precedent  provided  herein for relating to
satisfaction  and discharge of this Indenture have been complied with and at the
cost and expense of the Issuer.

                  (b) Subject to Sections 8.1(c) and 8.2, the Issuer at any time
may  terminate  (i) all of its  obligations  under the Notes and this  Indenture
("legal  defeasance  option") or (ii) its  obligations  under Sections 4.2, 4.3,
4.4, 4.5, 4.6, 4.7, 4.8, 4.9,  4.10,  4.11,  4.12,  4.14,  4.18 and 4.19 and the
operation of Sections  6.1(6),  6.1(7) (but only with  respect to a  Significant
Subsidiary),  6.1(8) (but only with respect to a Significant Subsidiary), 6.1(9)
and 5.1(iii) ("covenant  defeasance option").  The Issuer may exercise its legal
defeasance option  notwithstanding its prior exercise of its covenant defeasance
option.

                  If the Issuer exercises its legal defeasance  option,  payment
of the Notes  may not be  accelerated  because  of an Event of  Default.  If the
Issuer exercises its covenant defeasance option, payment of the Notes may not be
accelerated because of an Event of Default specified in Section 6.1(4),  6.1(5),
6.1(6), 6.1(7) (but only with respect to a Significant Subsidiary),  6.1(8) (but
only with respect to a Significant  Subsidiary),  6.1(9),  6.1(10) or because of
the failure of the Issuer to comply with Section 5.1(iii).

                  Upon  satisfaction of the conditions set forth herein and upon
request of the Issuer, the Trustee shall acknowledge in writing the discharge of
those obligations that the Issuer terminates.
<PAGE>   59
                                       55

                  (c)  Notwithstanding  clauses (a) and (b) above,  the Issuer's
obligations in Sections 2.3, 2.4, 2.5, 2.7, 4.1, 4.13,  4.15,  4.16,  4.17, 7.7,
7.8,  8.4,  8.5 and 8.6 shall  survive  until the Notes  have been paid in full.
Thereafter, the Issuer's obligations in Sections 7.7, 8.4 and 8.5 shall survive.

                  SECTION  8.2.  Conditions  to  Defeasance  .  The  Issuer  may
exercise its legal defeasance option or its covenant defeasance option only if:

                  (i) the Issuer irrevocably  deposits or causes to be deposited
         in trust with the Trustee money or U.S.  Government  Obligations  which
         through the  scheduled  payment of  principal  and  interest in respect
         thereof in accordance  with their terms will provide cash at such times
         and in such amounts as will be sufficient to pay principal and interest
         when due on all  outstanding  Notes (except Notes replaced  pursuant to
         Section 2.7) to maturity or redemption, as the case may be;

                  (ii) the Issuer  delivers to the Trustee a certificate  from a
         nationally recognized firm of independent  accountants expressing their
         opinion  that the  payments  of  principal  and  interest  when due and
         without reinvestment on the deposited U.S. Government  Obligations plus
         any deposited money without  investment will provide cash at such times
         and in such amounts as will be sufficient to pay principal and interest
         when due on all  outstanding  Notes (except Notes replaced  pursuant to
         Section 2.7) to maturity or redemption, as the case may be;

                  (iii) 91 days pass  after the  deposit  is made and during the
         91-day  period  no  Default  specified  in  Section  6.1(7) or (8) with
         respect  to the Issuer  occurs  which is  continuing  at the end of the
         period;

                  (iv) the deposit does not constitute a default under any other
         material agreement binding on the Issuer;

                  (v) the Issuer  delivers  to the Trustee an Opinion of Counsel
         to the  effect  that the  trust  resulting  from the  deposit  does not
         constitute,  or is qualified as, a regulated  investment  company under
         the Investment Company Act of 1940;

                  (vi) in the case of the legal  defeasance  option,  the Issuer
         shall have delivered to the Trustee an Opinion of Counsel  stating that
         (i) the Issuer has received  from, or there has been  published by, the
         Internal  Revenue  Service  a  ruling,  or (ii)  since the date of this
         Indenture there has been a change in the applicable  federal income tax
         law, in either case to the effect that,  and based thereon such Opinion
         of Counsel  shall  confirm  that,  the  Noteholders  will not recognize
         income,  gain or loss for  federal  income tax  purposes as a result of
         such deposit and  defeasance  and will be subject to federal income tax
         on the same amounts,  in the same manner and at the same times as would
         have been the case if such deposit and defeasance had not occurred;
<PAGE>   60
                                       56

                  (vii)  in the  case of the  covenant  defeasance  option,  the
         Issuer shall have delivered to the Trustee an Opinion of Counsel to the
         effect that the Noteholders will not recognize income, gain or loss for
         federal income tax purposes as a result of such covenant defeasance and
         will be subject to federal income tax on the same amounts and in the
         same  manner  and at the same times as would have been the case if such
         deposit and covenant defeasance had not occurred; and

                  (viii)  the  Issuer  delivers  to  the  Trustee  an  Officer's
         Certificate and an Opinion of Counsel, each stating that all conditions
         precedent to the defeasance and discharge of the Notes as  contemplated
         by this Article VIII have been complied with.

                  Before or after a deposit,  the  Issuer may make  arrangements
satisfactory  to the  Trustee  for the  redemption  of Notes at a future date in
accordance with Article III.

                  SECTION 8.3.  Application  of Trust Money . The Trustee  shall
hold in trust money or U.S. Government Obligations deposited with it pursuant to
this Article VIII.  It shall apply the  deposited  money and the money from U.S.
Government  Obligations  either  directly  or through  the  Paying  Agent as the
Trustee may determine and in  accordance  with this  Indenture to the payment of
principal of and interest on the Notes.

                  SECTION 8.4.  Repayment to Issuer . The Trustee and the Paying
Agent shall  promptly  turn over to the Issuer upon  request any excess money or
securities held by them at any time.

                  Subject to any applicable  abandoned property law, the Trustee
and the Paying Agent shall pay to the Issuer upon written request any money held
by them for the payment of principal or interest that remains  unclaimed for one
year after such  principal  and  interest  have  become  due and  payable,  and,
thereafter,  Noteholders  entitled  to the  money  must look to the  Issuer  for
payment as general creditors.

                  SECTION 8.5. Indemnity for Government Obligations . The Issuer
shall pay and shall  indemnify the Trustee  against any tax, fee or other charge
imposed on or assessed  against  deposited  U.S.  Government  Obligations or the
principal and interest received on such U.S.  Government  Obligations other than
any such tax, fee or other charge which by law is for the account of the Holders
of the defeased Notes; provided that the Trustee shall be entitled to charge any
such tax, fee or other charge to such Holder's account.

                  SECTION 8.6. Reinstatement . If the Trustee or Paying Agent is
unable to apply any money or U.S. Government Obligations in accordance with this
Article  VIII by  reason of any  legal  proceeding  or by reason of any order or
judgment  of any  court or  governmental  authority  enjoining,  restraining  or
otherwise  prohibiting such  application,  the Issuer's  obligations  under this
Indenture and the Notes shall be revived and reinstated as though no deposit had
occurred  pursuant to this Article VIII until such time as the Trustee or Paying
Agent is permitted  to apply all such money or U.S.  Government  Obligations  in
accordance with
<PAGE>   61
                                       57

this Article VIII;  provided,  however,  that, (a) if the Issuer has made any
payment of  interest on or  principal  of any Notes  following  the
reinstatement of their obligations, the Issuer shall be subrogated to the rights
of the  Holders  of such Notes to receive  such  payment  from the money or U.S.
Government  Obligations  held by the  Trustee  or Paying  Agent  and (b)  unless
otherwise required  by any  legal  proceeding  or any  order or  judgment of any
court or governmental authority,  the Trustee or Paying Agent shall return all
such money and U.S. Government Obligations to the Issuer promptly after
receiving a written request therefor at any time, if such reinstatement of the
Issuer's  obligations has occurred and continues to be in effect.

                                   ARTICLE IX
                                   AMENDMENTS

                   SECTION 9.1. Without Consent of Holders . The Issuer and the
         Trustee may amend this Indenture or the Notes without notice to or
         consent of any Noteholder:

                  (i)      to cure any ambiguity, omission, defect or
         inconsistency;

                  (ii)     to comply with Article V;

                  (iii) to provide for uncertificated Notes in addition to or in
         place of certificated Notes (provided, however, that the uncertificated
         Notes are issued in registered  form for purposes of Section  163(f) of
         the  Code or in a manner  such  that the  uncertificated  Notes  are as
         described in Section 163(f)(2)(B) of the Code);

                  (iv)     to add Guarantees with respect to the Notes;

                  (v)      to secure the Notes;

                  (vi) to add to the  covenants of the Issuer for the benefit of
         the  Noteholders  or to surrender  any right or power herein  conferred
         upon the Issuer;

                  (vii) to make any  change  that  does not,  in the good  faith
         opinion  of the  Board  of  Directors  of the  Issuer,  materially  and
         adversely affect the rights of any Noteholder; and

                  (viii)  to  comply  with  any   requirements  of  the  SEC  in
connection with qualifying this Indenture under the TIA.

                  After an amendment  under this Section 9.1 becomes  effective,
the Issuer shall mail to Noteholders a notice briefly describing such amendment.
The failure to give such notice to all Noteholders, or any defect therein, shall
not impair or affect the validity of an amendment under this Section 9.1.
<PAGE>   62

                                       58

                  SECTION  9.2.  With  Consent  of  Holders . The Issuer and the
Trustee may amend this  Indenture or the Notes without  notice to any Noteholder
but with the written  consent of the Holders of at least a majority in principal
amount of the Notes then outstanding (including  consents  obtained in
connection with a tender offer or exchange for Notes).  However,  without the
consent of each Noteholder of an outstanding Note affected, an amendment may
not:

                  (i)      reduce the amount of Notes whose Holders must consent
         to an amendment;

                  (ii)     reduce the rate of or extend the time for payment of
         interest on any Note;

                  (iii) reduce the principal of or extend the Stated Maturity of
         any Note;

                  (iv) reduce the premium  payable  upon the  redemption  of any
         Note or change the time at which any Note may be redeemed in accordance
         with Article III;

                  (v) make any Note  payable in money  other than that stated in
         the Note;

                  (vi)  impair  the right of any  Holder to  receive  payment of
         principal  of and interest on such  Holder's  Notes on or after the due
         dates therefor or to institute suit for the  enforcement of any payment
         on or with respect to such Holder's Notes; or

                  (vii) make any change in this second sentence of Section 9.2.

                  It shall not be necessary for the consent of the Holders under
this Section 9.2 to approve the particular form of any proposed  amendment,  but
it shall be sufficient if such consent approves the substance thereof.

                  After an amendment  under this Section 9.2 becomes  effective,
the Issuer shall mail to Noteholders a notice briefly describing such amendment.
The failure to give such notice to all Noteholders, or any defect therein, shall
not impair or affect the validity of an amendment under this Section 9.2.

                  SECTION  9.3.  Compliance  with  Trust  Indenture  Act . Every
amendment  to this  Indenture  or the Notes shall comply with the TIA as then in
effect.

                  SECTION 9.4. Revocation and Effect of Consents and Waivers . A
consent to an  amendment or a waiver by a Holder of a Note shall bind the Holder
and every  subsequent  Holder of that Note or portion of the Note that evidences
the same debt as the consenting  Holder's Note,  even if notation of the consent
or  waiver  is not  made on the  Note.  After an  amendment  or  waiver  becomes
effective, it shall bind every Noteholder.

                  The Issuer may,  but shall not be  obligated  to, fix a record
date for the  purpose of  determining  the  Noteholders  entitled  to give their
consent or take any other action  described
<PAGE>   63
                                       59

above or required or permitted to be taken   pursuant  to  this   Indenture.
If  a  record  date  is  fixed,   then notwithstanding  the  immediately
preceding  paragraph,  those Persons who were Noteholders  at such record date
(or their duly  designated  proxies),  and only those Persons, shall be entitled
to give such consent or to revoke any consent  previously given or to take any
such action,  whether or not such  Persons  continue to be Holders  after such
record date.  No such consent  shall be valid or effective for more than 120
days after such record date.

                  SECTION  9.5.  Notation  on  or  Exchange  of  Notes  .  If an
amendment changes the terms of a Note, the Trustee may require the Holder of the
Note to deliver it to the Trustee. The Trustee may place an appropriate notation
on  the  Note  regarding  the  changed  terms  and  return  it  to  the  Holder.
Alternatively, if the Issuer or the Trustee so determine, the Issuer in exchange
for the Note shall  issue and the  Trustee  shall  authenticate  a new Note that
reflects the changed terms. Failure to make the appropriate notation or to issue
a new Note shall not affect the validity of such amendment.

                  SECTION 9.6.  Trustee to Sign  Amendments . The Trustee  shall
sign any amendment  authorized pursuant to this Article IX if the amendment does
not  materially  and  adversely  affect  the  rights,  duties,   liabilities  or
immunities of the Trustee.  If it does, the Trustee may but need not sign it. In
signing  such  amendment  the Trustee  shall be  entitled  to receive  indemnity
reasonably  satisfactory  to it and to  receive,  and  (subject to Section 7. 1)
shall be fully protected in relying upon, in addition to the documents  required
by Section 10.4, an Officer's Certificate and an Opinion of Counsel stating that
such amendment complies with the provisions of this Article IX.

                  SECTION 9.7.  Payment for Consent . Neither the Issuer nor any
affiliate of the Issuer shall,  directly or indirectly,  pay or cause to be paid
any consideration,  whether by way of interest, fee or otherwise,  to any Holder
for, or as an inducement to any consent, waiver or amendment of any of the terms
or  provisions  of this  Indenture  or the Notes  unless such  consideration  is
offered to be paid to all Holders  that so  consent,  waive or agree to amend in
the time frame set forth in  solicitation  documents  relating to such  consent,
waiver or agreement;  provided,  however, that Holders who do not consent, waive
or  agree  to  amend  this  Indenture  in the  time  frame  set  forth  in  such
solicitation  documents shall not be entitled to any  consideration  offered for
timely consent, waiver or amendment, even if the consent, waiver or amendment is
agreed to by sufficient Holders to approve such consent,  waiver or amendment to
this Indenture.

                                    ARTICLE X
                                 MISCELLANEOUS

                  SECTION 10.1.  Trust Indenture Act Controls . If any provision
of this Indenture limits, qualifies or conflicts with another provision which is
required to be included in this Indenture by the TIA, the provision  required by
the TIA shall control.
<PAGE>   64
                                       60

                  SECTION 10.2.  Notices . Any notice or communication  shall be
in writing and delivered in person,  transmitted by facsimile machine, or mailed
by  first-class  mail or overnight  air courier  guaranteeing  next day delivery
addressed as follows:

                  if to the Issuer:

                           SpectraSite Holdings, Inc.
                           100 Regency Forest Drive, Suite 400
                           Cary, North Carolina  27511

                           Attention:  Chief Financial Officer

                  if to the Trustee:

                           United States Trust Company of New York
                           114 West 47th Street, 25th Floor
                           New York, New York  10036-1532

                           Attention:  Corporate Trust Administration

                  The  Issuer  or  the  Trustee  by  notice  to the  others  may
designate   additional  or  different   addresses  for  subsequent   notices  or
communications.

                  Any notice or  communication  mailed to a Noteholder  shall be
mailed to the  Noteholder  at the  Noteholder's  address  as it  appears  on the
registration books of the Registrar and shall be sufficiently given if so mailed
within the time prescribed.

                  Failure to mail a notice or  communication  to a Noteholder or
any  defect  in it shall  not  affect  its  sufficiency  with  respect  to other
Noteholders. Except for a notice to the Trustee, which is deemed given only when
received,  and except as otherwise  provided in this  Indenture,  if a notice or
communication is mailed in the manner provided above, it is duly given,  whether
or not the addressee receives it

                  SECTION  10.3.  Communication  by Holders with Other Holders .
Noteholders  may communicate  pursuant to TIA ss. 312(b) with other  Noteholders
with respect to their rights under this Indenture or the Notes. The Issuer,  the
Trustee, the Registrar and anyone else shall have the protection of TIA ss.
312(c).

                  SECTION  10.4.   Certificate  and  Opinion  as  to  Conditions
Precedent . Upon any request or application by the Issuer to the Trustee to take
or refrain from taking any action under this Indenture, the Issuer shall furnish
to the Trustee:

                  (i) an Officer's  Certificate in form and substance reasonably
         satisfactory to the Trustee stating that, in the opinion of the signer,
         all  conditions  precedent,  if any,
<PAGE>   65
                                       61
provided  for in  this  Indenture relating to the proposed action have been
complied with; and

                  (ii) an Opinion of  Counsel in form and  substance  reasonably
         satisfactory  to the  Trustee  stating  that,  in the  opinion  of such
         counsel, all such conditions precedent have been complied with.

                  SECTION 10.5.  Statements Required in Certificate or Opinion .
Each  certificate  or opinion  with  respect to  compliance  with a covenant  or
condition provided for in this Indenture shall include:

                  (i)      a statement that the individual making such
certificate or opinion has read such covenant or condition;

                  (ii) a brief  statement  as to the  nature  and  scope  of the
         examination  or  investigation  upon which the  statements  or opinions
         contained in such certificate or opinion are based;

                  (iii) a statement that, in the opinion of such individual,  he
         has made such  examination or  investigation  as is necessary to enable
         him to express an informed  opinion as to whether or not such  covenant
         or condition has been complied with; and

                  (iv) a statement  as to whether or not, in the opinion of such
         individual, such covenant or condition has been complied with.

                  SECTION 10.6. When Notes Disregarded . In determining  whether
the Holders of the  required  principal  amount of Notes have  concurred  in any
direction,  waiver  or  consent,  Notes  owned by the  Issuer  or by any  Person
directly or indirectly  controlling or controlled by or under direct or indirect
common  control  with the  Issuer  shall be  disregarded  and  deemed  not to be
outstanding,  except that,  for the purpose of  determining  whether the Trustee
shall be protected  in relying on any such  direction,  waiver or consent,  only
Notes  which a Trust  Officer  of the  Trustee  knows  are so owned  shall be so
disregarded.  Also, subject to the foregoing, only Notes outstanding at the time
shall be considered in any such determination.

                  SECTION 10.7.  Rules by Trustee,  Paying Agent and Registrar .
The  Trustee  may  make  reasonable  rules  for  action  by or at a  meeting  of
Noteholders.  The Registrar and the Paying Agent may make  reasonable  rules for
their functions.

                  SECTION  10.8.  Legal  Holidays  .  A  "Legal  Holiday"  is  a
Saturday, a Sunday or a day on which banking institutions are not required to be
open in the State of New York.  If a payment  date is a Legal  Holiday,  payment
shall be made on the next  succeeding  day that is not a Legal  Holiday,  and no
interest shall accrue on such payment for the intervening  period.  If a regular
date is a Legal Holiday, the record date shall not be affected.
<PAGE>   66
                                       62

                  SECTION  10.9.  Governing  Law . THIS  INDENTURE AND THE NOTES
SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF
NEW YORK BUT WITHOUT GIVING EFFECT TO APPLICABLE  PRINCIPLES OF CONFLICTS OF LAW
TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE
REQUIRED THEREBY.

                  SECTION  10.10.  No  Recourse  Against  Others . No  director,
officer,  employee,  incorporator or stockholder of the Issuer,  as such,  shall
have any  liability  for any  obligations  of the Issuer  under the Notes,  this
Indenture  or for any  claim  based  on,  in  respect  of,  or by reason of such
obligations or their  creation.  Each Holder of Notes by accepting a Note waives
and  releases  all such  liability.  This  waiver  and  release  are part of the
consideration for issuance of the Notes.

                  SECTION  10.11.  Successors . All  agreements of the Issuer in
this  Indenture and the Notes shall bind its  successors.  All agreements of the
Trustee in this Indenture shall bind its successors.

                  SECTION 10.12.  Multiple  Originals . The parties may sign any
number of copies of this Indenture.  Each signed copy shall be an original,  but
all of them together represent the same agreement.  One signed copy is enough to
prove this Indenture.

                  SECTION 10.13.  Variable Provisions .  The Issuer initially
appoints the Trustee as Paying Agent and Registrar and custodian with respect to
any Global Notes.

                  SECTION 10.14.  Qualification  of Indenture . The Issuer shall
qualify this Indenture under the TIA in accordance with the terms and conditions
of the  Registration  Rights  Agreement (as defined in the Appendix  hereto) and
shall pay all reasonable costs and expenses  (including  attorneys' fees for the
Issuer,  the  Trustee  and  the  Holders)  incurred  in  connection   therewith,
including,  but not limited to,  costs and  expenses  of  qualification  of this
Indenture  and the Notes.  The Trustee  shall be  entitled  to receive  from the
Issuer  any  such   Officer's   Certificates,   Opinions  of  Counsel  or  other
documentation  as  it  may  reasonably  request  in  connection  with  any  such
qualification of this Indenture under the TIA.
                  SECTION  10.15.  Table of  Contents;  Headings  . The table of
contents,  cross-  reference  sheet and headings of the Articles and Sections of
this  Indenture have been inserted for  convenience  of reference  only, are not
intended to be  considered a part hereof and shall not modify or restrict any of
the terms or provision hereof.

                  SECTION  10.16.  Severability  . In case any provision in this
Indenture  or in the Notes shall be invalid,  illegal or  unenforceable,  in any
respect for any reason,  the validity,  legality and  enforceability of any such
provision in every other  respect and of the remaining  provisions  shall not in
any way be affected or impaired thereby.
<PAGE>   67

                                       63

                  IN WITNESS WHEREOF,  the parties have caused this Indenture to
be duly executed as of the date first written above.

                           SPECTRASITE HOLDINGS, INC.

                           By: /s/ David P. Tomick
                              --------------------------------
                           Name:      David P. Tomick
                           Title:     Chief Financial Officer

                           UNITED STATES TRUST COMPANY OF
                           NEW YORK, as Trustee

                           By: /s/ Margaret M. Ciesmelewski
                              ---------------------------------
                           Name: Margaret M. Ciesmelewski
                           Title: Assistant Vice President

<PAGE>   68

                                       64

                         RULE 144A/REGULATION S APPENDIX

                              INSTITUTIONAL BUYERS
            PURSUANT TO RULE 144A AND TO CERTAIN PERSONS IN OFFSHORE
                    TRANSACTIONS IN RELIANCE ON REGULATION S.

                      PROVISIONS RELATING TO INITIAL NOTES,
                    PRIVATE EXCHANGE NOTES AND EXCHANGE NOTES

1.       Definitions.

                  1.1.     Definitions.  For the purposes of this Appendix the
following terms shall have the meanings indicated below:

                  "Depositary" means The Depository Trust Company,  its nominees
and their respective successors and assigns.

                  "Exchange Notes" means the 10 3/4% Senior Notes due 2010 to be
issued pursuant to this Indenture in connection with a Registered Exchange Offer
pursuant to the Registration Rights Agreement.

                  "Initial Purchasers" means Credit Suisse First Boston
Corporation, Lehman Brothers Inc. and CIBC Oppenheimer Corp.

                  "Initial  Notes"  means  the 10 3/4%  Senior  Notes  due 2010,
issued under this Indenture on or about the date hereof

                  "Notes" means the Initial  Notes,  the Exchange  Notes and the
Private Exchange Notes, treated as a single class.

                  "Notes Custodian" means the custodian with respect to a Global
Note (as appointed by the Depositary), or any successor person thereto and shall
initially be the Trustee.

                  "Private Exchange" means the offer by the Issuer,  pursuant to
the  Registration  Rights  Agreement,  to the Initial  Purchasers  to issue 'and
deliver to each Initial Purchaser, in exchange for the Initial Notes held by the
Initial  Purchaser  as  part  of its  initial  distribution,  a  like  aggregate
principal amount of Private Exchange Notes.

                  "Private  Exchange  Notes"  means the 10 3/4% Senior Notes due
2010, if any, to be issued pursuant to this Indenture to the Initial  Purchasers
in a Private Exchange.
                  "Purchase  Agreement" means the Purchase Agreement dated March
10, 2000, among the Issuer and the Initial Purchasers.
<PAGE>   69
                                       65

                  "QIB" means a "qualified institutional buyer" as defined in
Rule 144A.

                  "Registered  Exchange  Offer"  means the offer by the  Issuer,
pursuant to the  Registration  Rights  Agreement,  to certain Holders of Initial
Notes, to issue and deliver to such Holders,  in exchange for the Initial Notes,
a like  aggregate  principal  amount  of  Exchange  Notes  registered  under the
Securities Act.

                  "Registration  Rights Agreement" means the Registration Rights
Agreement  dated  as of  March  15,  2000  among  the  Issuer  and  the  Initial
Purchasers.

                  "Regulation S" means Regulation S under the Securities Act.

                  "Rule 144A" means Rule 144A under the Securities Act.

                  "Securities Act" means the Securities Act of 1933, as amended.

                  "Shelf   Registration   Statement"   means  the   registration
statement issued by the Issuer, in connection with the offer and sale of Initial
Notes or Private  Exchange  Notes,  pursuant  to  Section 2 of the  Registration
Rights Agreement.

                  "Transfer  Restricted  Notes"  means  Notes  that  bear or are
required to bear the legend set forth in Section 2.3(b) hereof.

                  1.2.     Other Definitions

                                                                     Defined
                Term                                               in Section
               -------                                           --------------
                "Agent Members"                                      2.1(b)
                "Global Note"                                        2.1(a)

                  2. The Notes.

                  2.1.        Form and  Dating.  The  Initial  Notes  are  being
                              offered  and sold by the  Issuer  pursuant  to the
                              Purchase Agreement.

                          (a) Global Notes. Initial Notes offered and sold to a
QIB in reliance on Rule 144A or in  reliance  on  Regulation  S, in each case as
provided in the Purchase Agreement, shall be issued initially in the form of one
or more permanent  global Notes in  definitive,  fully  registered  form without
interest  coupons with the global  securities  legend and restricted  securities
legend set forth in Exhibit I hereto  (each,  a "Global  Note"),  which shall be
deposited on behalf of the purchasers of the Initial Notes  represented  thereby
with the Trustee as custodian
<PAGE>   70
                                       66

for the Depositary  (or with such other custodian as the Depositary may direct),
and registered in the name of the Depositary or a nominee of the  Depositary,
duly executed by the  Issuer  and  authenticated  by the  Trustee as
hereinafter  provided.  The aggregate  principal  amount  of the  Global  Notes
may  from  time  to time be increased or decreased by adjustments made on the
records of the Trustee and the Depositary or its nominee as hereinafter
provided.

                     (b) Book-Entry Provisions. This Section 2. 1 (b) shall
                         apply only to a Global Note deposited with or on behalf
                         of the Depositary.

                    The  Issuer  shall  execute  and  the  Trustee   shall,   in
accordance with this Section 2.1 (b),  authenticate and deliver initially one or
more Global Notes that (i) shall be registered in the name of the Depositary for
such  Global  Note  or  Global  Notes  or in the  name  of the  nominee  of such
Depositary  and (ii) shall be  delivered  by the Trustee to such  Depositary  or
pursuant to such  Depositary's  instructions or held by the Trustee as custodian
for the Depositary.

                     Members  of, or  participants  in, the  Depositary  ("Agent
Members")  shall have no rights under this  Indenture with respect to any Global
Note held on their behalf by the  Depositary  or by the Trustee as the custodian
of the  Depositary or under such Global Note,  and the Depositary may be treated
by the  Issuer,  the  Trustee  and any agent of the Issuer or the Trustee as the
absolute owner of such Global Note for all purposes whatsoever.  Notwithstanding
the foregoing, nothing herein shall prevent the Issuer, the Trustee or any agent
of the Issuer or the Trustee  from giving  effect to any written  certification,
proxy or other  authorization  furnished by the Depositary or impair, as between
the Depositary and its Agent  Members,  the operation of customary  practices of
such Depositary governing the exercise of the rights of a holder of a beneficial
interest in any Global Note.

                          (c) Certificated  Notes. Except as provided in Section
                  2.1 or Section 2.3 or 2.4,  owners of beneficial  interests in
                  Global Notes will not be entitled to receive physical delivery
                  of certificated Notes.

                       2.2. Authentication. The Trustee shall authenticate and
deliver: (1) Initial Notes for original issue in an
aggregate  principal  amount  of U.S.  $200,000,000  and (2)  Exchange  Notes or
Private  Exchange  Notes  for issue  only in a  Registered  Exchange  Offer or a
Private Exchange,  respectively,  pursuant to the Registration Rights Agreement,
for a like principal  amount of Initial Notes, in each case upon a written order
of the Issuer  signed by two  Officers or by an Officer and either an  Assistant
Treasurer or an Assistant  Secretary of the Issuer. Such order shall specify the
amount of the Notes to be authenticated and the date on which the original issue
of Notes is to be  authenticated  and whether the Notes are to be Initial Notes,
Exchange Notes or Private  Exchange  Notes.  The aggregate  principal  amount of
Notes  outstanding  at any time  may not  exceed  U.S.  $200,000,000  except  as
provided in Section 2.7 of this Indenture.
<PAGE>   71
                                       67

2.3. Transfer and Exchange.

                         (a) Transfer and Exchange of Global Notes. (i) The
transfer and exchange of Global Notes or beneficial  interests  therein shall be
effected  through the Depositary,  in accordance with this Indenture  (including
applicable restrictions on transfer set forth herein, if any) and the procedures
of the Depositary  therefor.  A transferor of a beneficial  interest in a Global
Note shall deliver to the Registrar a written order given in accordance with the
Depositary's procedures containing information regarding the participant account
of the Depositary to be credited with a beneficial  interest in the Global Note.
The  Registrar  shall,  in  accordance  with  such  instructions   instruct  the
Depositary to credit to the account of the Person specified in such instructions
a beneficial  interest in the Global Note and to debit the account of the Person
making  the  transfer  of the  beneficial  interest  in the  Global  Note  being
transferred.

                    (ii)  Notwithstanding  any other provisions of this Appendix
    (other than the  provisions set forth in Section 2.4), a Global Note may not
    be  transferred  as a whole  except by the  Depositary  to a nominee  of the
    Depositary or by a nominee of the  Depositary  to the  Depositary of another
    nominee of the  Depositary  or by the  Depositary  or any such  nominee to a
    successor Depositary or a nominee of such successor Depositary.

                     (iii) In the  event  that a Global  Note is  exchanged  for
    Notes in definitive registered form pursuant to Section 2.4 of this Appendix
    or Section 2.9 of this Indenture  prior to the  consummation of a Registered
    Exchange Offer or the effectiveness of a Shelf  Registration  Statement with
    respect to such Notes,  such Notes may be exchanged only in accordance  with
    such procedures as are substantially  consistent with the provisions of this
    Section  2.3  (including  the  certification  requirements  set forth on the
    reverse of the Initial Notes intended to ensure that such  transfers  comply
    with  Rule  144A or  Regulation  S, as the  case  may  be)  and  such  other
    procedures as may from time to time be adopted by the Issuer.

                       (b)  Legend.  (i) Except as  permitted  by the  following
       paragraphs  (ii),  (iii) and (iv), each Note  certificate  evidencing the
       Global  Notes  (and  all  Notes   issued  in  exchange   therefor  or  in
       substitution thereof) shall bear a legend in
                        substantially the following form:

                    "THIS NOTE HAS NOT BEEN REGISTERED UNDER THE U.S. SECURITIES
ACT OF 1933, AS AMENDED (THE "SECURITIES  ACT"),  AND,  ACCORDINGLY,  MAY NOT BE
OFFERED OR SOLD  WITHIN THE UNITED  STATES OR TO, OR FOR THE  ACCOUNT OR BENEFIT
OF,  U.S.  PERSONS,  EXCEPT  AS SET  FORTH  IN THE  FOLLOWING  SENTENCE.  BY ITS
ACQUISITION  HEREOF,  THE  HOLDER  (1)  REPRESENTS  THAT (A) IT IS A  "QUALIFIED
INSTITUTIONAL  BUYER" (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT), OR (B)
IT IS AN "INSTITUTIONAL ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(A)(1), (2),
(3) OR (7)  OR  REGULATION  D  UNDER  THE  SECURITIES  ACT)  (AN  "INSTITUTIONAL
ACCREDITED  INVESTOR") OR (C) IT IS NOT A U.S. PERSON AND IS ACQUIRING THIS NOTE
<PAGE>   72
                                       68

IN AN OFFSHORE  TRANSACTION IN COMPLIANCE  WITHREGULATION S UNDER THE SECURITIES
ACT, (2) AGREES THAT IT WILL NOT RESELL OR OTHERWISE  TRANSFER  THIS NOTE EXCEPT
(A) TO THE COMPANY OR ANY SUBSIDIARY THEREOF,  (B) TO A QUALIFIED  INSTITUTIONAL
BUYER IN  COMPLIANCE  WITH RULE 144A UNDER THE  SECURITIES  ACT,  (C) INSIDE THE
UNITED  STATES  TO AN  INSTITUTIONAL  ACCREDITED  INVESTOR  THAT,  PRIOR TO SUCH
TRANSFER,   FURNISHES  TO  THE  TRUSTEE  A  SIGNED  LETTER  CONTAINING   CERTAIN
REPRESENTATIONS  AND AGREEMENTS RELATING TO THE RESTRICTIONS ON TRANSFER OF THIS
NOTE (THE FORM OF WHICH LETTER CAN BE OBTAINED  FROM THE  TRUSTEE)  AND, IF SUCH
TRANSFER IS IN RESPECT OF AN AGGREGATE  PRINCIPAL AMOUNT OF NOTES AT THE TIME OF
TRANSFER OF LESS THAN $100,000,  AN OPINION OF COUNSEL ACCEPTABLE TO THE COMPANY
THAT SUCH TRANSFER IS IN  COMPLIANCE  WITH THE  SECURITIES  ACT, (D) OUTSIDE THE
UNITED  STATES  IN AN  OFFSHORE  TRANSACTION  IN  COMPLIANCE  WITH  RULE  904 OF
REGULATION  S  UNDER  THE  SECURITIES  ACT  OR  (E)  PURSUANT  TO  AN  EFFECTIVE
REGISTRATION  STATEMENT  UNDER THE  SECURITIES  ACT AND (3) AGREES  THAT IT WILL
DELIVER TO EACH PERSON TO WHOM THIS NOTE IS  TRANSFERRED A NOTICE  SUBSTANTIALLY
TO THE EFFECT OF THIS LEGEND.  IN CONNECTION WITH ANY TRANSFER OF THIS NOTE, THE
HOLDER MUST CHECK THE  APPROPRIATE  BOX SET FORTH ON THE REVERSE HEREOF RELATING
TO THE MANNER OF SUCH TRANSFER AND SUBMIT THIS  CERTIFICATE  TO THE TRUSTEE.  IF
THE PROPOSED  TRANSFEREE IS AN  INSTITUTIONAL  ACCREDITED  INVESTOR,  THE HOLDER
MUST,  PRIOR TO SUCH  TRANSFER,  FURNISH TO THE  TRUSTEE  AND THE  COMPANY  SUCH
CERTIFICATIONS,  LEGAL  OPINIONS  OR OTHER  INFORMATION  AS  EITHER  OF THEM MAY
REASONABLY  REQUIRE TO CONFIRM THAT SUCH  TRANSFER IS BEING MADE  PURSUANT TO AN
EXEMPTION  FROM,  OR  IN  A  TRANSACTION   NOT  SUBJECT  TO,  THE   REGISTRATION
REQUIREMENTS  OF THE  SECURITIES  ACT.  AS  USED  HEREIN,  THE  TERMS  "OFFSHORE
TRANSACTION,"  "UNITED STATES" AND "U.S. PERSON" HAVE THE MEANINGS GIVEN TO THEM
BY REGULATION S UNDER THE  SECURITIES  ACT. THE  INDENTURE  CONTAINS A PROVISION
REQUIRING  THE  TRUSTEE  TO  REFUSE TO  REGISTER  ANY  TRANSFER  OF THIS NOTE IN
VIOLATION OF THE FOREGOING RESTRICTIONS."

                    (ii) Upon any sale or transfer of a Transfer Restricted Note
(including any Transfer  Restricted Note  represented by a Global Note) pursuant
to Rule 144 under the  Securities  Act, in the case of any  Transfer  Restricted
Note that is represented by a Global Note, the Registrar shall permit the Holder
thereof to exchange such Transfer  Restricted Note for a certificated  Note that
does not bear the legend set forth  above and  rescind  any  restriction  on the
transfer of such Transfer Restricted Note, if the Holder certifies in writing to
the  Registrar  that its request for such  exchange was made in reliance on Rule
144 (such certification to be in the form set forth on the reverse of the Note).
<PAGE>   73
                                       69

                        (iii)  After a transfer  of any  Initial  Securities  or
Private  Exchange  Securities  during  the  period of the  effectiveness  of and
pursuant  to a  Shelf  Registration  Statement  with  respect  to  such  Initial
Securities or Private Exchange Securities,  as the case may be, all requirements
pertaining to legends on such Initial  Securities or such Private Exchange Notes
will cease to apply, but the  requirements  requiring such Initial Notes or such
Private  Exchange Notes issued to certain  Holders be issued in global form will
continue to apply,  and Initial Notes or Private  Exchange  Notes in global form
without  legends  will be  available  to the  transferee  of the  Holder of such
Initial  Notes or Private  Exchange  Notes upon  exchange  of such  transferring
Holder's  Initial Notes or Private Exchange Notes or directions to transfer such
Holder's interest in the Global Note, as applicable.

                      (iv) Upon the consummation of a Registered Exchange Offer
with  respect to the Initial  Notes  pursuant to which  Holders of such  Initial
Notes are  offered  Exchange  Notes in exchange  for their  Initial  Notes,  all
requirements  pertaining  to such  Initial  Notes that  Initial  Notes issued to
certain  Holders be issued in global  form will  continue  to apply and  Initial
Notes in global form with the restricted  securities legend set forth in Exhibit
1 hereto will be available to Holders of such Initial Notes that do not exchange
their Initial Notes,  and Exchange Notes in global form without the  restriction
securities  legend will be available to Holders that exchange such Initial Notes
in such Registered Exchange Offer.

                     (v)  Upon  the  consummation  of a  Private  Exchange  with
respect to the Initial Notes pursuant to which Holders of such Initial Notes are
offered  Private  Exchange  Notes in  exchange  for  their  Initial  Notes,  all
requirements  pertaining  to such  Initial  Notes that  Initial  Notes issued to
certain Holders be issued in global form will still apply,  and Private Exchange
Notes in global form with the restricted  securities legend set forth in Exhibit
1 hereto will be available to Holders that  exchange  such Initial Notes in such
Private Exchange.

                      (c)  Cancellation  or  Adjustment of Global Note. At such
time as all beneficial interests in a Global Note have either been exchanged for
certificated Notes, redeemed, repurchased or canceled, such Global Note shall be
returned to the  Depositary  for  cancellation  or retained  and canceled by the
Trustee. At any time prior to such cancellation, if any beneficial interest in a
Global Note is  exchanged  for  certificated  Notes,  redeemed,  repurchased  or
canceled, the principal amount of Notes represented by such Global Note shall be
reduced and an adjustment  shall be made on the books and records of the Trustee
(if it is then the Notes  Custodian  for such Global  Note) with respect to such
Global Note, by the Trustee or the Notes Custodian, to reflect such reduction.

                       (d)  Obligations  with Respect to Transfers and Exchanges
of Notes. (i) To permit registrations of transfers and exchanges, the Issuer
shall execute and the Trustee shall  authenticate  certificated  Notes and
Global Notes  at  the  Registrar's  or  any  co-registrar's request, subject  to
terms and conditions of this Indenture.
<PAGE>   74
                                       70

                      (ii) No service charge shall be made for any  registration
of  transfer  or  exchange,  but  the  Issuer  may  require  payment  of a sum
sufficient to cover any transfer  tax, assessments,  or similar  governmental
charge payable in connection therewith (other than any such transfer taxes,
assessments or  similar governmental charge payable upon  exchange  or transfer
pursuant to Sections 3.6, 4.7, 4.9 and Section 9.5 of this Indenture).

                    (iii)  The  Registrar  or  any  co-registrar  shall  not  be
required to  register  the  transfer of or exchange of (a) any  certificated
Note selected for  redemption in whole or in part pursuant to Article III of
this Indenture, except the unredeemed portion of any  certificated  Note being
redeemed in part, or (b) any Note for a period  beginning  15 Business  Days
before the mailing of a notice of an offer to  repurchase  or redeem  Notes or
15 Business Days before an interest payment date.

                    (iv)  Prior  to the due  presentation  for  registration  of
transfer of any Note, the Issuer, the Trustee, the Paying Agent, the Registrar
or any co-registrar may deem and treat the person in whose name a Note is
registered as the absolute owner of such Note for the purpose of receiving
payment of principal of and interest on such Note and for all other purposes
whatsoever, whether or not such Note is overdue, and none of the Issuer, the
Trustee, the Paying Agent, the Registrar or any co-registrar shall be affected
by notice to the contrary.

                       (v) All Notes issued on any transfer or exchange pursuant
to the terms of this Indenture shall evidence the same debt and shall be
entitled to the same benefits under this Indenture as the Notes surrendered upon
such transfer or exchange.

                       (e) No Obligation  of the Trustee or the Issuer.  (i) The
Trustee and the Issuer shall have no responsibility or obligation to any
beneficial owner of a Global Note, a member of, or a participant in the
Depositary or other Person with respect to the accuracy of the records of the
Depositary or its nominee or of any participant or member thereof, with respect
to any ownership interest in the Notes or with respect to the delivery to any
participant, member, beneficial owner or other Person (other than the
Depositary) of any notice (including any notice of redemption) or the payment
of any amount, under or with respect to such Notes. All notices and
communications to be given to the Holders and all payments to be made to Holders
under the Notes shall be given or made only to or upon the order of the
registered Holders (which shall be the Depositary or its nominee in the case of
a Global Note). The rights of beneficial owners in any Global Note shall be
exercised only through the Depositary subject to the applicable rules and
procedures of the Depositary. The Trustee and the Issuer may rely and shall be
fully protected in relying upon information furnished by the Depositary with
respect to its members, participants and any beneficial owners.

                         (ii)  The  Trustee   and  the  Issuer   shall  have  no
obligation or duty to monitor, determine or inquire as to compliance with any
restrictions on transfer imposed under this Indenture or under applicable law
with respect to any transfer of any interest in any Note (including any
transfers between or among Depositary participants, members or beneficial owners
in any Global Note) other than to require delivery of such certificates and
other
<PAGE>   75
                                       71
documentation or evidence as are expressly required by, and to do so if
and when expressly required by, the terms of this Indenture, and to examine the
same to determine substantial compliance as to form with the express
requirements hereof.

                      2.4. Certificated Notes. (a) A Global Note deposited with
the Depositary or with the Trustee as custodian for the Depositary pursuant to
Section 2.1 shall be transferred to the beneficial owners thereof in the form of
certificated Notes in an aggregate principal amount equal to the principal
amount of such Global Note, in exchange for such Global Note, only if such
transfer complies with Section 2.3 and (i) the Depositary notifies the Issuer
that it is unwilling or unable to continue as Depositary for such Global Note or
if at any time such Depositary ceases to be a "clearing agency" registered under
the Exchange Act and a successor depositary is not appointed by the Issuer
within 90 days of such notice, or (ii) an Event of Default has occurred and is
continuing or (iii) the Issuer, in its sole discretion, notifies the Trustee in
writing that it elects to cause the issuance of certificated Notes under this
Indenture.

                       (b)  Any  Global  Note  that  is   transferable   to  the
beneficial owners thereof pursuant to this Section shall be surrendered by the
Depositary to the Trustee, to be so transferred, in whole or from time to time
in part, without charge, and the Trustee shall authenticate and deliver, upon
such transfer of each portion of such Global Note, an equal aggregate principal
amount of certificated Initial Notes of authorized denominations. Any portion of
a Global Note transferred pursuant to this Section shall be executed,
authenticated and delivered only in denominations of $1,000 any integral
multiple thereof and registered in such names as the Depositary shall direct.
Any certificated Initial Note delivered in exchange for an interest in the
Global Note shall, except as otherwise provided by Section 2.3(d), bear the
restricted securities legend set forth in Exhibit 1 hereto.

                      (c)  Subject  to the  provisions  of Section  2.4(b),  the
registered Holder of a Global Note may grant proxies and otherwise authorize any
Person, including Agent Members and Persons that may hold interests through
Agent Members, to take any action which a Holder is entitled to take under this
Indenture or the Notes.

                      (d) In the event of the  occurrence  of any of the  events
specified in Section 2.4(a), the Issuer will promptly make  available  to the
Trustee a  reasonable  supply of  certificated  Notes in definitive, fully
registered form without interest coupons.

<PAGE>   76

                                      1
                                                                       EXHIBIT 1
                                                       TO RULE 144A/REGULATION S
                                                                        APPENDIX

                         [FORM OF FACE OF INITIAL NOTE]

                              [Global Notes Legend]

                  UNLESS  THIS   CERTIFICATE   IS  PRESENTED  BY  AN  AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION  ("DTC"),
NEW YORK,  NEW YORK,  TO THE ISSUER OR ITS AGENT FOR  REGISTRATION  OF TRANSFER,
EXCHANGE OR PAYMENT,  AND ANY  CERTIFICATE  ISSUED IS  REGISTERED IN THE NAME OF
CEDE & CO. OR SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF
DTC  (AND ANY  PAYMENT  IS MADE TO CEDE & CO.,  OR TO SUCH  OTHER  ENTITY  AS IS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER
USE HEREOF FOR VALUE OR  OTHERWISE  BY OR TO ANY PERSON IS WRONGFUL  INASMUCH AS
THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

                  TRANSFERS OF THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS IN
WHOLE,  BUT NOT IN PART,  TO NOMINEES  OF DTC OR TO A SUCCESSOR  THEREOF OR SUCH
SUCCESSOR'S  NOMINEES,  AND  TRANSFERS  OF PORTIONS OF THIS GLOBAL NOTE SHALL BE
LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE  RESTRICTIONS  SET FORTH IN THE
INDENTURE REFERRED TO ON THE REVERSE HEREOF.

                         [Restricted Securities Legend]

         THIS  NOTE HAS NOT BEEN  REGISTERED  UNDER THE U.S.  SECURITIES  ACT OF
1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR
SOLD  WITHIN THE UNITED  STATES OR TO, OR FOR THE  ACCOUNT OR BENEFIT  OF,  U.S.
PERSONS,  EXCEPT  AS SET FORTH IN THE  FOLLOWING  SENTENCE.  BY ITS  ACQUISITION
HEREOF,  THE HOLDER (1)  REPRESENTS  THAT (A) IT IS A  "QUALIFIED  INSTITUTIONAL
BUYER"  (AS  DEFINED  IN RULE 144A UNDER THE  SECURITIES  ACT),  OR (B) IT IS AN
"INSTITUTIONAL  ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(A)(1),  (2), (3) OR
(7) OR  REGULATION D UNDER THE  SECURITIES  ACT) (AN  "INSTITUTIONAL  ACCREDITED
INVESTOR")  OR (C) IT IS NOT A U.S.  PERSON  AND IS  ACQUIRING  THIS  NOTE IN AN
OFFSHORE  TRANSACTION IN COMPLIANCE  WITH REGULATION S UNDER THE SECURITIES ACT,
(2) AGREES THAT IT WILL NOT RESELL OR OTHERWISE
<PAGE>   77
                                       2

TRANSFER THIS NOTE EXCEPT (A) TO THE COMPANY OR ANY SUBSIDIARY THEREOF, (B) TO A
QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE WITH RULE 144A UNDER THE SECURITIES
ACT, (C) INSIDE THE UNITED STATES TO AN INSTITUTIONAL ACCREDITED INVESTOR THAT,
PRIOR TO SUCH TRANSFER,  FURNISHES TO THE TRUSTEE A SIGNED LETTER CONTAINING
CERTAIN REPRESENTATIONS AND AGREEMENTS RELATING TO THE  RESTRICTIONS ON TRANSFER
OF THIS NOTE (THE FORM OF WHICH LETTER CAN BE OBTAINED  FROM THE  TRUSTEE)  AND,
IF SUCH  TRANSFER IS IN RESPECT OF AN AGGREGATE  PRINCIPAL  AMOUNT  OF  NOTES
AT THE TIME OF  TRANSFER  OF LESS  THAN $100,000,  AN OPINION OF COUNSEL
ACCEPTABLE TO THE COMPANY THAT SUCH TRANSFER IS IN  COMPLIANCE  WITH THE
SECURITIES  ACT,  (D) OUTSIDE THE UNITED  STATES IN AN OFFSHORE  TRANSACTION  IN
COMPLIANCE  WITH RULE 904 OF  REGULATION  S UNDER THE SECURITIES ACT OR (E)
PURSUANT TO AN EFFECTIVE  REGISTRATION STATEMENT UNDER THE SECURITIES  ACT AND
(3) AGREES THAT IT WILL  DELIVER TO EACH PERSON TO WHOM THIS NOTE IS TRANSFERRED
A NOTICE  SUBSTANTIALLY  TO THE EFFECT OF THIS LEGEND.  IN CONNECTION WITH ANY
TRANSFER OF THIS NOTE, THE HOLDER MUST CHECK THE APPROPRIATE BOX SET FORTH ON
THE REVERSE HEREOF  RELATING TO THE MANNER OF SUCH TRANSFER AND SUBMIT  THIS
CERTIFICATE  TO THE  TRUSTEE.  IF THE  PROPOSED  TRANSFEREE  IS AN INSTITUTIONAL
ACCREDITED  INVESTOR,  THE HOLDER MUST,  PRIOR TO SUCH  TRANSFER, FURNISH TO THE
TRUSTEE AND THE COMPANY SUCH  CERTIFICATIONS,  LEGAL  OPINIONS OR OTHER
INFORMATION AS EITHER OF THEM MAY REASONABLY  REQUIRE TO CONFIRM THAT SUCH
TRANSFER IS BEING MADE PURSUANT TO AN EXEMPTION  FROM,  OR IN A TRANSACTION  NOT
SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT. AS USED HEREIN,
THE TERMS "OFFSHORE  TRANSACTION,"  "UNITED  STATES" AND "U.S.  PERSON" HAVE THE
MEANINGS GIVEN TO THEM BY REGULATION S UNDER THE  SECURITIES  ACT. THE INDENTURE
CONTAINS A PROVISION REQUIRING THE TRUSTEE TO REFUSE TO REGISTER ANY TRANSFER OF
THIS NOTE IN VIOLATION OF THE FOREGOING RESTRICTIONS.
<PAGE>   78
                                       3

                           SPECTRASITE HOLDINGS, INC.

No. __   Principal Amount  $__________

CUSIP NO. ______

                          10 3/4% Senior Note due 2010

                  SpectraSite Holdings,  Inc., a Delaware corporation,  promises
to  pay  to   __________,   or   registered   assigns,   the  principal  sum  of
__________________________ Dollars on March 15, 2010.

                  Interest Payment Dates: March 15 and September 15.

                  Record Dates: March 1 and September 1.

                  Additional  provisions of this Note are set forth on the other
side of this Note.

Dated:                                               SPECTRASITE HOLDINGS, INC.

                                                     By:

                                                     By:

TRUSTEE'S CERTIFICATE OF
AUTHENTICATION

This is one of the Notes referred to in the Indenture.

UNITED STATES TRUST COMPANY OF NEW YORK
   as Trustee

By:
     -------------------------------
       Authorized Signatory

<PAGE>   79
                                       4

                     [FORM OF REVERSE SIDE OF INITIAL NOTE]

                                (Reverse of Note)

                          10 3/4% Senior Note due 2010

1.       Interest

                  SpectraSite  Holdings,  Inc.,  a  Delaware  corporation  (such
corporation,  and its  successors  and assigns under the  Indenture  hereinafter
referred to, being herein called the "Issuer"),  promises to pay interest on the
principal  amount  of this  Note at the rate per annum  shown  above;  provided,
however,  that if a Registration  Default (as defined in the Registration Rights
Agreement)  occurs,  additional cash interest will accrue on this Note at a rate
of 0.50% per annum from and  including  the date on which any such  Registration
Default shall occur to but excluding the date on which all Registration Defaults
have been cured,  calculated on the principal amount of this Note as of the date
on which such interest is payable; provided, however, that in no event shall the
aggregate  amount of such  additional  interest  exceed  0.50% per  annum.  Such
interest is payable in addition to any other interest  payable from time to time
with  respect to this Note.  The Trustee  will not be deemed to have notice of a
Registration  Default  until  it  shall  have  received  actual  notice  of such
Registration Default.

                  The Notes will accrete interest at a rate of 10 3/4% per annum
from the Issue Date,  payable  semi-annually  commencing  September 15, 2000, to
Holders  of record  at the  close of  business  on the  March 1 or  September  1
immediately  preceding the interest payment date of March 15 and September 15 of
each year. The Issuer shall pay interest on overdue principal at 1% per annum in
excess of the rate borne by the Notes to the  extent  lawful.  Interest  will be
computed on the basis of a 360-day year of twelve 30-day months.

2.       Method of Payment

                  By at least  11:00  a.m.  (New York City  time) on the date on
which any  principal of or interest on any Note is due and  payable,  the Issuer
shall irrevocably  deposit with the Trustee or the Paying Agent money sufficient
to pay such  principal  and/or  interest.  The Issuer will pay interest  (except
defaulted  interest) to the Persons who are  registered  Holders of Notes at the
close of business  on the March 1 or  September 1 next  preceding  the  interest
payment  date even if Notes are  cancelled,  repurchased  or redeemed  after the
record date and on or before the interest  payment date.  Holders must surrender
Notes to a Paying  Agent to collect  principal  payments.  The  Issuer  will pay
principal and interest in money of the United States that at the time of payment
is legal tender for payment of public and private debts. However, the Issuer may
pay  principal  and  interest  by check  payable in such  money.  It may mail an
interest check to a Holder's registered address.
<PAGE>   80
                                       5

3. Paying Agent and Registrar

                  Initially, United States Trust Company of New York, a national
banking association (the "Trustee"), will act as Paying Agent and Registrar. The
Issuer  may  appoint  and change any Paying  Agent,  Registrar  or  co-registrar
without  notice  to any  Noteholder.  The  Issuer  or  any  of its  domestically
incorporated Wholly Owned Subsidiaries may act as Paying Agent.

4.       Indenture

                  The Issuer  issued the Notes  under an  Indenture  dated as of
March  15,  2000 (as it may be  amended  or  supplemented  from  time to time in
accordance with the terms thereof, the "Indenture"),  between the Issuer and the
Trustee.  The terms of the Notes include those stated in the Indenture and those
made part of the  Indenture by reference to the Trust  Indenture Act of 1939, as
amended  (15  U.S.C.  ss.ss.  77aaa-77bbbb)  as in  effect  on the  date  of the
Indenture (the "TIA"). Capitalized terms used herein and not defined herein have
the meanings  ascribed  thereto in the  Indenture.  The Notes are subject to all
such terms,  and  Noteholders  are referred to the  Indenture  and the TIA for a
statement of those terms.

                  The Notes  are  unsecured  senior  obligations  of the  Issuer
limited to $200,000,000  aggregate  principal  amount (subject to Section 2.7 of
the Indenture), all of which are being offered on the Issue Date.

                  This  Note  is one of the  Initial  Notes  referred  to in the
Indenture.  The Notes include the Initial Notes and any Private  Exchange  Notes
and  Exchange  Notes issued in exchange  for the Initial  Notes  pursuant to the
Indenture and the Registration Rights Agreement. The Initial Notes., the Private
Exchange  Notes  and the  Exchange  Notes  are  treated  as a  single  class  of
securities under the Indenture. The Indenture imposes certain limitations on the
Incurrence of  Indebtedness by the Issuer and its Restricted  Subsidiaries,  the
payment of dividends and other  distributions on the Capital Stock of the Issuer
and its Restricted Subsidiaries,  the purchase or redemption of Capital Stock of
the Issuer and Capital Stock of such Restricted Subsidiaries,  certain purchases
or redemptions of Subordinated  Obligations,  the sale or transfer of assets and
Capital Stock of Restricted Subsidiaries,  the issuance or sale of Capital Stock
of Restricted  Subsidiaries,  the investments of the Issuer and its Subsidiaries
and transactions with Affiliates.  In addition, the Indenture limits the ability
of the Issuer and its  Restricted  Subsidiaries  to restrict  distributions  and
dividends from Restricted Subsidiaries.
<PAGE>   81
                                       6

5.       Redemption

                  Except as set forth in the following paragraph, the Notes will
not be  redeemable  at the  option  of the  Issuer  prior  to  March  15,  2005.
Thereafter, the Notes will be redeemable, at the Issuer's option, in whole or in
part,  at any time or from time to time,  upon not less than 30 nor more than 60
days'  prior  notice  mailed by  first-class  mail to each  Holder's  registered
address,  at the following  redemption  prices (expressed as a percentage of the
principal amount),  plus accrued and unpaid interest,  if any, on such principal
amount to the redemption  date (subject to the right of Holders of record on the
relevant record date to receive  interest due on the relevant  interest  payment
date),  if redeemed  during the 12-month  period  commencing  on March 15 of the
years set forth below:

                 Period                                         Redemption Price
               ----------                                      -----------------
                 2005                                                   105.375%
                 2006                                                   103.583%
                 2007                                                   101.792%
                 2008 and thereafter                                    100.000%

                  In addition,  at any time and from time to time prior to March
15,  2003,  the Issuer may redeem in the  aggregate  up to 35% of the  aggregate
principal amount of the Notes with the proceeds of one or more Equity Offerings,
at a  redemption  price  (expressed  as a  percentage  of the  principal  amount
thereof) of 110.750% plus accrued and unpaid interest, if any, to the redemption
date  (subject to the right of Holders of record on the relevant  record date to
receive interest due on the relevant interest payment date); provided,  however,
that at least 65% of the  aggregate  principal  amount of the Notes must  remain
outstanding  after each such redemption  (excluding  Notes held by the Issuer or
any of its  Subsidiaries);  provided  further that such  redemption  shall occur
within 90 days of the date of closing of such Equity Offering.

6.       Notice of Redemption

                  Notice of  redemption  will be mailed at least 30 days but not
more than 60 days before the redemption date by first-class  mail to each Holder
of Notes to be redeemed at his registered  address.  Notes in  denominations  of
principal  amount  larger  than $1,000 may be redeemed in part but only in whole
multiples of $1,000.  If money  sufficient  to pay the  redemption  price of and
accrued and unpaid interest on all Notes (or portions thereof) to be redeemed on
the  redemption  date is  deposited  with  the  Paying  Agent on or  before  the
redemption  date and certain other  conditions are satisfied,  on and after such
date interest  ceases to accrue on such Notes (or such portions  thereof) called
for redemption.
<PAGE>   82
                                       7

7.       Put Provisions

                  Upon a Change of  Control,  any  Holder of Notes will have the
right to cause  the  Issuer to  repurchase  all or any part of the Notes of such
Holder at a repurchase price equal to 101% of the principal amount thereof as of
the date of repurchase, plus accrued and unpaid interest, if any, to the date of
repurchase as provided in, and subject to the terms of, the Indenture.

8.       Registration Rights

                  The Issuer is party to a Registration Rights Agreement,  dated
as of March15,  2000, among the Issuer,  and Morgan Stanley & Co.  Incorporated,
CIBC World Markets Corp., Credit Suisse First Boston Corporation,  Deutsche Bank
Securities  Inc.,  Lehman  Brothers  Inc.,  BMO Nesbitt  Burns Corp.  and Scotia
Capital (USA) Inc. pursuant to which it is obligated to pay Additional  Interest
(as defined  therein) upon the occurrence of certain  Registration  Defaults (as
defined therein).

9.       Denominations; Transfer; Exchange

                  The  Notes  are  in   registered   form  without   coupons  in
denominations  of principal  amount of $1,000 and whole  multiples of $1,000.  A
Holder  may  register,  transfer  or  exchange  Notes  in  accordance  with  the
Indenture.  The Registrar may require a Holder,  among other things,  to furnish
appropriate  endorsements  or transfer  documents  and to pay any taxes and fees
required by law or permitted by the  Indenture.  The Registrar need not register
the transfer of or exchange (i) any Notes  selected for redemption  (except,  in
the case of a Note to be  redeemed  in part,  the  portion of the Note not to be
redeemed) for a period beginning 15 business days before a selection of Notes to
be  redeemed  and ending on the date of such  selection  or (ii) any Notes for a
period  beginning 15 business days before an interest payment date and ending on
such interest payment date.

10.      Persons Deemed Owners

                  The registered holder of this Note may be treated as the owner
of it for all purposes.

11.      Unclaimed Money

                  If money for the payment of principal or interest remains
unclaimed for one year after the date of payment of principal and interest, the
Trustee or Paying Agent shall pay the money back to the Issuer at its request
unless an abandoned property law designates another Person.  After any such
payment, Holders entitled to the money must look only to the Issuer and not to
the Trustee for payment.
<PAGE>   83
                                       8
12.      Defeasance

                  Subject to certain conditions set forth in the Indenture,  the
Issuer at any time may terminate some or all of its obligations  under the Notes
and the  Indenture  if the  Issuer  deposits  with  the  Trustee  money  or U.S.
Government Obligations for the payment of principal of and interest on the Notes
to redemption or maturity, as the case may be.

13.      Amendment, Waiver

                  Subject to certain exceptions set forth in the Indenture,  (i)
the  Indenture  or the Notes may be  amended  with the  written  consent  of the
Holders of at least a majority in principal amount of the outstanding  Notes and
(ii) any  default or  noncompliance  with any  provision  may be waived with the
written  consent  of the  Holders  of a  majority  in  principal  amount  of the
outstanding  Notes.  Subject to certain  exceptions  set forth in the Indenture,
without the consent of any Noteholder,  the Issuer and the Trustee may amend the
Indenture or the Notes to cure any ambiguity, omission, defect or inconsistency,
or to comply with Article V of the Indenture,  or to provide for  uncertificated
Notes in addition to or in place of  certificated  Notes,  or to add  guarantees
with respect to the Notes or to secure the Notes, or to add additional covenants
of or surrender rights and powers conferred on the Issuer, or to make any change
that does not materially and adversely  affect the rights of any Noteholder,  or
to  comply  with  any  request  of the SEC in  connection  with  qualifying  the
Indenture under the Act.
<PAGE>   84

                                       9
14.      Defaults and Remedies

                  Under the Indenture,  Events of Default  include (i) a default
in any payment of interest on any Note when due,  continued for 30 days,  (ii) a
default in the payment of principal of any Note when due at its Stated Maturity,
upon  optional  or  mandatory   redemption,   upon  required  repurchase,   upon
declaration  or  otherwise,  (iii) the  failure by the Issuer to comply with its
obligations under Article V of the Indenture,  (iv) the failure by the Issuer to
comply for 30 days after notice with any of its obligations  under the covenants
described  under Section 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9,  4.10,  4.11 or
4.12 of the  Indenture (in each case,  other than a failure to purchase  Notes),
(v) the failure by the Issuer to comply for 60 days after  notice with its other
agreements  contained  in the  Indenture,  (vi) the failure by the Issuer or any
Significant  Subsidiary  of  the  Issuer  to pay  any  Indebtedness  within  any
applicable  grace period after final  maturity or the  acceleration  of any such
Indebtedness  by the holders thereof because of a default if the total amount of
such  Indebtedness  unpaid or  accelerated  exceeds $10.0 million or its foreign
currency  equivalent,   (vii)  certain  events  of  bankruptcy,   insolvency  or
reorganization  of the  Issuer or any  Significant  Subsidiary  of the Issuer or
(viii) any final  judgment or decree for the payment of money in excess of $10.0
million  (net of any  amounts  with  respect to which a  creditworthy  insurance
company has acknowledged  full liability  (subject to any deductible  amounts of
less than $10.0  million  required  to be paid by the Issuer or the  Significant
Subsidiary of the Issuer in accordance with the applicable insurance policy)) is
rendered  against  the Issuer or any  Significant  Subsidiary  of the Issuer and
either (A) an  enforcement  proceeding  has been  commenced by any creditor upon
such  judgment  or decree or (B) such  judgment  or decree  remains  unpaid  and
outstanding  for a  period  of 60  days  following  such  judgment  and  is  not
discharged, waived or stayed within 10 days after notice. If an Event of Default
occurs  and is  continuing,  the  Trustee  or the  Holders  of at  least  25% in
aggregate  principal amount of the Notes may declare all the Notes to be due and
payable  immediately.  Certain  events of bankruptcy or insolvency are Events of
Default  which will result in the Notes being due and payable  immediately  upon
the occurrence of such Events of Default.

                  Noteholders  may not enforce the Indenture or the Notes except
as provided in the Indenture. The Trustee may refuse to enforce the Indenture or
the Notes  unless it  receives  reasonable  indemnity  or  security.  Subject to
certain limitations,  Holders of a majority in principal amount of the Notes may
direct the  Trustee  in its  exercise  of any trust or power.  The  Trustee  may
withhold from Noteholders  notice of any continuing  Default or Event of Default
(except a Default or Event of Default in payment of principal or interest) if it
determines that withholding notice is not opposed to their interest.

<PAGE>   85
                                       10

15.      Trustee Dealings with the Issuer

                  Subject to certain limitations set forth in the Indenture, the
Trustee under the Indenture, in its individual or any other capacity, may become
the  owner  or  pledgee  of  Notes  and may  otherwise  deal  with  and  collect
obligations  owed to it by the Issuer or its  Affiliates  and may otherwise deal
with the Issuer or its Affiliates  with the same rights it would have if it were
not Trustee.

16.      No Recourse Against Others

                  No director, officer, employee, incorporator or stockholder of
the Issuer,  as such, shall have any liability for any obligations of the Issuer
under the Notes,  the  Indenture or for any claim based on, in respect of, or by
reason of such obligations or their creation.  Each Holder of Notes by accepting
a Note waives and releases all such liability.  This waiver and release are part
of the consideration for issuance of the Notes.

17.      Authentication

                  This Note shall not be valid until an authorized  signatory of
the Trustee (or an authenticating agent acting on its behalf) manually signs the
certificate of authentication on the other side of this Note.

18.      Abbreviations

                  Customary   abbreviations  may  be  used  in  the  name  of  a
Noteholder  or an  assignee,  such  as TEN COM  (=tenants  in  common),  TEN ENT
(=tenants by the entirety),  JT TEN (=joint  tenants with rights of survivorship
and not as tenants in common),  CUST  (=custodian) and U/G/M/A (=Uniform Gift to
Minors Act).

19.      CUSIP Numbers

                  Pursuant to a  recommendation  promulgated by the Committee on
Uniform Security Identification  Procedures, the Issuer has caused CUSIP numbers
to be printed on the Notes and has directed the Trustee to use CUSIP  numbers in
notices of redemption as a convenience to Noteholders. No representation is made
as to the  accuracy  of such  numbers  either  as  printed  on the  Notes  or as
contained  in any notice of  redemption  and  reliance may be placed only on the
other identification numbers placed thereon.

<PAGE>   86
                                       11

20.      GOVERNING LAW

                  THIS NOTE SHALL BE GOVERNED BY, AND  CONSTRUED  IN  ACCORDANCE
WITH,  THE LAWS OF THE STATE OF NEW YORK BUT WITHOUT GIVING EFFECT TO APPLICABLE
PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF
ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

                  The Issuer will furnish to any Noteholder upon written request
and without charge to the Noteholder a copy of the Indenture which has in it the
text of this Note in larger type. Requests may be made to: SpectraSite Holdings,
Inc.,  100  Regency  Forest  Drive,  Suite  400,  Cary,  North  Carolina  27511,
Attention: Chief Financial Officer.

<PAGE>   87

                                       12

                                 ASSIGNMENT FORM

                To assign  this  Note,  fill in the form below:

I or we assign and transfer this Note to:

------

------

------
(Print or type assignee's name, address and zip code)

(Insert assignee's soc. sec. or tax I.D. No.)

and irrevocably appoint
agent to transfer this Note on the books of the Issuer. The agent may substitute
another to act for him.

Date:                                       Your Signature:
     ----------------                                      --------------------
                                                           Sign  exactly as
                                                           your name appears on
                                                           the other side of
                                                           this Note.

Signature Guarantee:
                           (Signature  must be guaranteed by a participant  in a
                           recognized  Signature  Guarantee Medallion Program or
                           other   signature    guarantor   program   reasonably
                           acceptable to the Trustee)

In  connection  with any  transfer or exchange of any of the Notes  evidenced by
this  certificate  occurring prior to the date that is two years after the later
of the date of  original  issuance  of such Notes and the last date,  if any, on
which such Notes were owned by the Issuer or any  Affiliate  of the Issuer,  the
undersigned confirms that such Notes are being transferred:

CHECK ONE BOX BELOW:

[ ]      (1)      to the Issuer; or

[ ]      (2)      pursuant to an effective registration statement under the
Securities Act of 1933; or
<PAGE>   88
                                       13

[ ]               (3)  inside the United  States to a  "qualified  institutional
                  buyer" (as  defined in Rule 144A under the  Securities  Act of
                  1933) that purchases for its own account or for the account of
                  a qualified  institutional  buyer to whom notice is given that
                  such  transfer is being made in reliance on Rule 144A, in each
                  case  pursuant to and in  compliance  with Rule 144A under the
                  Securities Act of 1933; or

[ ]      (4)      outside the United States in an offshore transaction within
                  the meaning of Regulation S under the Securities Act in
                  compliance with Rule 904 under the Securities Act of 1933; or

[ ]      (5)      pursuant to another available exemption from registration
                  provided by Rule 144 under the Securities Act of 1933.

Unless one of the boxes is checked,  the Trustee  will refuse to register any of
the Notes evidenced by this certificate in the name of any Person other than the
registered holder thereof; provided, however, that if box (4) or (5) is checked,
the Trustee may require,  prior to  registering  any such transfer of the Notes,
such legal  opinions,  certifications  and other  information  as the Issuer has
reasonably  requested to confirm that such transfer is being made pursuant to an
exemption  from,  or  in  a  transaction   not  subject  to,  the   registration
requirements  of the Securities  Act of 1933, as amended,  such as the exemption
provided by Rule 144 under such Act.

Date:                                       Your Signature:
     --------------------                                  ---------------------
                                                           Sign  exactly as your
                                                           name appears on the
                                                           other side of this
                                                           Note.

Signature Guarantee:
                           (Signature  must be guaranteed by a participant  in a
                           recognized  Signature  Guarantee Medallion Program or
                           other   signature    guarantor   program   reasonably
                           acceptable to the Trustee)

<PAGE>   89
                                       14

              TO BE COMPLETED BY PURCHASER IF (3) ABOVE IS CHECKED.

                  The undersigned  represents and warrants that it is purchasing
this Note for its own account or an account  with  respect to which it exercises
sole  investment  discretion  and that it and any such  account is a  "qualified
institutional buyer" within the meaning of Rule 144A under the Securities Act of
1933, as amended,  and is aware that the sale to it is being made in reliance on
Rule 144A and acknowledges  that it has received such information  regarding the
Issuer as the undersigned has requested  pursuant to Rule 144A or has determined
not to request  such  information  and that it is aware that the  transferor  is
relying upon the undersigned's  foregoing  representations in order to claim the
exemption from registration provided by Rule 144A.

Date:
     --------------------
                                               NOTICE:  To be executed by an
                                                        executive officer

                       OPTION OF HOLDER TO ELECT PURCHASE

                  If you want to elect to have this Note purchased by the Issuer
pursuant to Section 4.7 or 4.9 of the Indenture, check the appropriate box:

                  Section 4.7       [ ]

                  Section 4.9       [ ]

                  If you want to elect to have only part of this Note  purchased
by the Issuer pursuant to Section 4.7 or 4.9 of the Indenture,  state the amount
you elect to have purchased (must be integral multiple of $1,000): $

<PAGE>   90
                                       15

NYDOCS01/682724 4
                        [TO BE ATTACHED TO GLOBAL NOTES]

                SCHEDULE OF INCREASES OR DECREASES IN GLOBAL NOTE

   The  following  increases  or  decreases  in this Global Note have been made:

<TABLE>
<S>                       <C>                      <C>                     <C>                       <C>

Date of Exchange           Amount of decrease in    Amount of increase in   Principal Amount         Signature of
                           -----------------------  ----------------------  -----------------------  authorized
                           Principal Amount of      Principal Amount of     of this Global Note      ----------------------
                           this Global Note         this Global Note        following such           officer of Trustee or
                                                                            decrease or increase     Notes Custodian

</TABLE>

<PAGE>   91

                                      1
                                                                       EXHIBIT A

                         [FORM OF FACE OF EXCHANGE NOTE
                           [OR PRIVATE EXCHANGE NOTE]]

1

2

                           SPECTRASITE HOLDINGS, INC.

No.__    Principal Amount $________________

CUSIP NO.__________

                          10 3/4% Senior Note Due 2010

                  SpectraSite Holdings,  Inc., a Delaware corporation,  promises
to  pay  to  _____________,   or  registered  assigns,   the  principal  sum  of
__________________ Dollars on [___], 2010.

<PAGE>   92
                                       2

                  Interest Payment Dates: March 15 and September 15.

                  Record Dates: March 1 and September 1.

                  Additional  provisions of this Note are set forth on the other
side of this Note.

Dated:                                           SPECTRASITE HOLDINGS, INC.
      --------------------
                                                 By:
                                                    -------------------------

                                                  By:
                                                     ------------------------

TRUSTEE'S CERTIFICATE OF
AUTHENTICATION

This is one of the Notes referred to in the Indenture.

UNITED STATES TRUST COMPANY OF NEW YORK
  as Trustee

By:
            Authorized Signatory

<PAGE>   93
                                       3

                     [FORM OF REVERSE SIDE OF EXCHANGE NOTE
                           [OR PRIVATE EXCHANGE NOTE]]

                          10 3/4% Senior Note due 2010

1.       Interest

                  SpectraSite  Holdings,  Inc.,  a  Delaware  corporation  (such
corporation,  and its  successors  and assigns under the  Indenture  hereinafter
referred to, being herein called the "Issuer"),  promises to pay interest on the
principal  amount  of this Note at the rate per annum  shown  above[;  provided,
however,  that if a Registration  Default (as defined in the Registration Rights
Agreement)  occurs,  additional cash interest will accrue on this Note at a rate
of 0.50% per annum from and  including  the date on which any such  Registration
Default shall occur to but excluding the date on which all Registration Defaults
have been cured,  calculated on the principal amount of this Note as of the date
on which such interest is payable; provided, however, that in no event shall the
aggregate  amount of such  additional  interest  exceed  0.50% per  annum.  Such
interest is payable in addition to any other interest  payable from time to time
with  respect to this Note.  The Trustee  will not be deemed to have notice of a
Registration  Default  until  it  shall  have  received  actual  notice  of such
Registration Default].

                  The Notes will  accrue  interest at a rate of 10 3/4% from the
Issue Date, payable  semi-annually  commencing September 15, 2000, to Holders of
record  at the  close of  business  on the March 1 or  September  1  immediately
preceding  the interest  payment date of March 15 and September 15 of each year.
The Issuer shall pay interest on overdue  principal at 1% per annum in excess of
the rate borne by the Notes to the extent  lawful.  Interest will be computed on
the basis of a 360-day year of twelve 30-day months.

2.       Method of Payment

                  By at least  11:00  a.m.  (New York City  time) on the date on
which any  principal of or interest on any Note is due and  payable,  the Issuer
shall irrevocably  deposit with the Trustee or the Paying Agent money sufficient
to pay such  principal  and/or  interest.  The Issuer will pay interest  (except
defaulted  interest) to the Persons who are  registered  Holders of Notes at the
close of business  on the March 1 or  September 1 next  preceding  the  interest
payment  date even if Notes are  cancelled,  repurchased  or redeemed  after the
record date and on or before the interest  payment date.  Holders must surrender
Notes to a Paying  Agent to collect  principal  payments.  The  Issuer  will pay
principal and interest in money of the United States that at the time of payment
is legal tender for payment of public and private debts. However, the Issuer may
pay  principal  and  interest  by check  payable in such  money.  It may mail an
interest an interest check to a Holder's registered address.

<PAGE>   94
                                       4

3.       Paying Agent and Registrar

                  Initially, United States Trust Company of New York, a national
banking association (the "Trustee"), will act as Paying Agent and Registrar. The
Issuer  may  appoint  and change any Paying  Agent,  Registrar  or  co-registrar
without  notice  to any  Noteholder.  The  Issuer  or  any  of its  domestically
incorporated Wholly Owned Subsidiaries may act as Paying Agent.

4.       Indenture

                  The Issuer  issued the Notes  under an  Indenture  dated as of
March  15,  2000 (as it may be  amended  or  supplemented  from  time to time in
accordance with the terms thereof, the "Indenture"),  between the Issuer and the
Trustee.  The terms of the Notes include those stated in the Indenture and those
made part of the  Indenture by reference to the Trust  Indenture Act of 1939, as
amended  (I5  U.S.C.  ss.ss.  77aaa-77bbbb)  as in  effect  on the  date  of the
Indenture (the "TIA"). Capitalized terms used herein and not defined herein have
the meanings  ascribed  thereto in the  Indenture.  The Notes are subject to all
such terms,  and  Noteholders  are referred to the  Indenture  and the TIA for a
statement of those terms.

                  The Notes  are  unsecured  senior  obligations  of the  Issuer
limited to $200,000,000  aggregate  principal  amount (subject to Section 2.7 of
the Indenture), all of which are being offered on the Issue Date.

                  This  Note is one of the  Exchange  Notes  referred  to in the
Indenture.  The Notes include the Initial Notes and any Private  Exchange  Notes
and  Exchange  Notes issued in exchange  for the Initial  Notes  pursuant to the
Indenture and the Registration Rights Agreement.  The Initial Notes, the Private
Exchange  Notes  and the  Exchange  Notes  are  treated  as a  single  class  of
securities under the Indenture. The Indenture imposes certain limitations on the
Incurrence of  Indebtedness by the Issuer and its Restricted  Subsidiaries,  the
payment of dividends and other  distributions on the Capital Stock of the Issuer
and its Restricted Subsidiaries,  the purchase or redemption of Capital Stock of
the Issuer and Capital Stock of such Restricted Subsidiaries,  certain purchases
or redemptions of Subordinated  Obligations,  the sale or transfer of assets and
Capital Stock of Restricted Subsidiaries,  the issuance or sale of Capital Stock
of Restricted  Subsidiaries,  the investments of the Issuer and its Subsidiaries
and transactions with Affiliates.  In addition, the Indenture limits the ability
of the Issuer and its  Restricted  Subsidiaries  to restrict  distributions  and
dividends from Restricted Subsidiaries.
<PAGE>   95
                                       5

5.       Redemption

                  Except as set forth in the following paragraph, the Notes will
not be  redeemable  at the  option  of the  Issuer  prior  to  March  15,  2005.
Thereafter, the Notes will be redeemable, at the Issuer's option, in whole or in
part,  at any time or from time to time,  upon not less than 30 nor more than 60
days'  prior  notice  mailed by  first-class  mail to each  Holder's  registered
address,  at the following  redemption  prices (expressed as a percentage of the
principal amount),  plus accrued and unpaid interest,  if any, on such principal
amount to the redemption  date (subject to the right of Holders of record on the
relevant record date to receive  interest due on the relevant  interest  payment
date),  if redeemed  during the 12-month  period  commencing  on March 15 of the
years set forth below:

                  Period                                        Redemption Price
                 ---------                                     -----------------
                  2005                                               105.375%
                  2006                                               103.583%
                  2007                                               101.792%
                  2008 and thereafter                                100.000%

                  In addition,  at any time and from time to time prior to March
15,  2003,  the Issuer may redeem in the  aggregate  up to 35% of the  aggregate
principal amount of the Notes with the proceeds of one or more Equity Offerings,
at a  redemption  price  (expressed  as a  percentage  of the  principal  amount
thereof) of 110.750% plus accrued and unpaid interest, if any, to the redemption
date  (subject to the right of Holders of record on the relevant  record date to
receive interest due on the relevant interest payment date); provided,  however,
that at least 65% of the  aggregate  principal  amount of the Notes must  remain
outstanding  after each such redemption  (excluding  Notes held by the Issuer or
any of its  Subsidiaries);  provided  further,  that such redemption shall occur
within 90 days of the date of closing of such Equity Offering.

6.       Notice of Redemption

                  Notice of  redemption  will be mailed at least 30 days but not
more than 60 days before the redemption date by first-class  mail to each Holder
of Notes to be redeemed at his registered  address.  Notes in  denominations  of
principal  amount  larger  than $1,000 may be redeemed in part but only in whole
multiples of $1,000.  If money  sufficient  to pay the  redemption  price of and
accrued and unpaid interest on all Notes (or portions thereof) to be redeemed on
the  redemption  date is  deposited  with  the  Paying  Agent on or  before  the
redemption  date and certain other  conditions are satisfied,  on and after such
date interest  ceases to accrue on such Notes (or such portions  thereof) called
for redemption.
<PAGE>   96
                                       6

7.       Put Provisions

                  Upon a Change of  Control,  any  Holder of Notes will have the
right to cause  the  Issuer to  repurchase  all or any part of the Notes of such
Holder at a repurchase price equal to 101% of the principal amount thereof as of
the date of repurchase, plus accrued and unpaid interest, if any, to the date of
repurchase as provided in, and subject to the terms of, the Indenture.

8.       Denominations, Transfer, Exchange

                  The  Notes  are  in   registered   form  without   coupons  in
denominations  of principal  amount of $1,000 and whole  multiples of $1,000.  A
Holder  may  register,  transfer  or  exchange  Notes  in  accordance  with  the
Indenture.  The Registrar may require a Holder,  among other things,  to furnish
appropriate  endorsements  or transfer  documents  and to pay any taxes and fees
required by law or permitted by the  Indenture.  The Registrar need not register
the transfer of or exchange (i) any Notes  selected for redemption  (except,  in
the case of a Note to be  redeemed  in part,  the  portion of the Note not to be
redeemed) for a period beginning 15 business days before a selection of Notes to
be  redeemed  and ending on the date of such  selection  or (ii) any Notes for a
period  beginning 15 business days before an interest payment date and ending on
such interest payment date.

9.       Persons Deemed Owners

                  The registered holder of this Note may be treated as the owner
of it for all purposes.

10.      Unclaimed Money

                  If money for the  payment of  principal  or  interest  remains
unclaimed for one year after the date of payment of principal and interest,  the
Trustee or Paying  Agent  shall pay the money back to the Issuer at its  request
unless an  abandoned  property law  designates  another  Person.  After any such
payment,  Holders  entitled to the money must look only to the Issuer and not to
the Trustee for payment.

11.      Defeasance

                  Subject to certain conditions set forth in the Indenture,  the
Issuer at any time may terminate some or all of its obligations  under the Notes
and the  Indenture  if the  Issuer  deposits  with  the  Trustee  money  or U.S.
Government Obligations for the payment of principal of and interest on the Notes
to redemption or maturity, as the case may be.
<PAGE>   97
                                       7

12.      Amendment, Waiver

                  Subject to certain exceptions set forth in the Indenture,  (i)
the  Indenture  or the Notes may be  amended  with the  written  consent  of the
Holders of at least a majority in principal amount of the outstanding  Notes and
(ii) any  default or  noncompliance  with any  provision  may be waived with the
written  consent  of the  Holders  of a  majority  in  principal  amount  of the
outstanding  Notes.  Subject to certain  exceptions  set forth in the Indenture,
without the consent of any Noteholder,  the Issuer and the Trustee may amend the
Indenture or the Notes to cure any ambiguity, omission, defect or inconsistency,
or to comply with Article V of the Indenture,  or to provide for  uncertificated
Notes in addition to or in place of  certificated  Notes,  or to add  guarantees
with respect to the Notes or to secure the Notes, or to add additional covenants
of or surrender rights and powers conferred on the Issuer, or to make any change
that does not materially and adversely  affect the rights of any Noteholder,  or
to  comply  with  any  request  of the SEC in  connection  with  qualifying  the
Indenture under the Act.

13.      Defaults and Remedies

                  Under the Indenture,  Events of Default  include (i) a default
in any payment of interest on any Note when due,  continued for 30 days,  (ii) a
default in the payment of principal of any Note when due at its Stated Maturity,
upon  optional  or  mandatory   redemption,   upon  required  repurchase,   upon
declaration  or  otherwise,  (iii) the  failure by the Issuer to comply with its
obligations under Article V of the Indenture,  (iv) the failure by the Issuer to
comply for 30 days after notice with any of its obligations  under the covenants
described  under Section 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9,  4.10,  4.11 or
4.12 of the  Indenture (in each case,  other than a failure to purchase  Notes),
(v) the failure by the Issuer to comply for 60 days after  notice with its other
agreements  contained  in the  Indenture,  (vi) the failure by the Issuer or any
Significant  Subsidiary  of  the  Issuer  to pay  any  Indebtedness  within  any
applicable  grace period after final  maturity or the  acceleration  of any such
Indebtedness  by the holders thereof because of a default if the total amount of
such  Indebtedness  unpaid or  accelerated  exceeds $10.0 million or its foreign
currency  equivalent,   (vii)  certain  events  of  bankruptcy,   insolvency  or
reorganization  of the  Issuer or any  Significant  Subsidiary  of the Issuer or
(viii) any final  judgment or decree for the payment of money in excess of $10.0
million  (net of any  amounts  with  respect to which a  creditworthy  insurance
company has acknowledged  full liability  (subject to any deductible  amounts of
less than $10.0  million  required  to be paid by the Issuer or the  Significant
Subsidiary of the Issuer in accordance with the applicable insurance policy)) is
rendered  against  the Issuer or any  Significant  Subsidiary  of the Issuer and
either (A) an  enforcement  proceeding  has been  commenced by any creditor upon
such  judgment  or decree or (B) such  judgment  or decree  remains  unpaid  and
outstanding  for a  period  of 60  days  following  such  judgment  and  is  not
discharged, waived or stayed within 10 days after notice. If an Event of Default
occurs  and is  continuing,  the  Trustee  or the  Holders  of at  least  25% in
aggregate  principal amount of the Notes may declare all the Notes to be due and
payable  immediately.  Certain  events of bankruptcy or insolvency are Events of
Default  which will result in the Notes being due and payable  immediately  upon
the occurrence of such Events of Default.
<PAGE>   98
                                       8

                  Noteholders  may not enforce the Indenture or the Notes except
as provided in the Indenture. The Trustee may refuse to enforce the Indenture or
the Notes  unless it  receives  reasonable  indemnity  or  security.  Subject to
certain limitations,  Holders of a majority in principal amount of the Notes may
direct the  Trustee  in its  exercise  of any trust or power.  The  Trustee  may
withhold from Noteholders  notice of any continuing  Default or Event of Default
(except a Default or Event of Default in payment of Principal or interest) if it
determines that withholding notice is not opposed to their interest. 14. Trustee
Dealings with the Issuer

                  Subject to certain limitations set forth in the Indenture, the
Trustee under the Indenture, in its individual or any other capacity, may become
the  owner  or  pledgee  of  Notes  and may  otherwise  deal  with  and  collect
obligations  owed to it by the Issuer or its  Affiliates  and may otherwise deal
with the Issuer or its Affiliates  with the same rights it would have if it were
not Trustee.

15.      No Recourse Against Others

                  No director, officer, employee, incorporator or stockholder of
the Issuer,  as such, shall have any liability for any obligations of the Issuer
under the Notes,  the  Indenture or for any claim based on, in respect of, or by
reason of such obligations or their creation.  Each Holder of Notes by accepting
a Note waives and releases all such liability.  This waiver and release are part
of the consideration for issuance of the Notes.

16.      Authentication

                  This Note shall not be valid until an authorized  signatory of
the Trustee (or an authenticating agent acting on its behalf) manually signs the
certificate of authentication on the other side of this Note.

17.      Abbreviations

                  Customary   abbreviations  may  be  used  in  the  name  of  a
Noteholder  or an  assignee,  such  as TEN COM  (=tenants  in  common),  TEN ENT
(=tenants by the entirety),  JT TEN (=joint  tenants with rights of survivorship
and not as tenants in common),  CUST  (=custodian) and U/G/M/A (=Uniform Gift to
Minors Act).

18.      CUSIP Numbers
<PAGE>   99
                                       9

                  Pursuant to a  recommendation  promulgated by the Committee on
Uniform Security  Identification  Procedures the Issuer has caused CUSIP numbers
to be printed on the Notes and has directed the Trustee to use CUSIP  numbers in
notices of redemption as a convenience to Noteholders. No representation is made
as to the  accuracy  of such  numbers  either  as  printed  on the  Notes  or as
contained  in any notice of  redemption  and  reliance may be placed only on the
other identification numbers placed thereon.

19.      GOVERNING LAW

                  THIS NOTE SHALL BE GOVERNED BY, AND  CONSTRUED  IN  ACCORDANCE
WITH,  THE LAWS OF THE STATE OF NEW YORK BUT WITHOUT GIVING EFFECT TO APPLICABLE
PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF
ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

               The Issuer will furnish to any  Noteholder  upon written  request
and without charge to the Noteholder a copy of the Indenture which has in it the
text of this Note in larger type. Requests may be made to: SpectraSite Holdings,
Inc.,  100  Regency  Forest  Drive,  Suite  400,  Cary,  North  Carolina  27511,
Attention: Chief Financial Officer.

<PAGE>   100
                                       10

                                 ASSIGNMENT FORM

            To assign  this  Note,  fill in the form below:

I or we assign and transfer this Note to:

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

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

--------------------------------------------------------------------------------
(Print or type assignee's name, address and zip code)

--------------------------------------------------------------------------------
(Insert assignee's soc. sec. or tax I.D. No.)

and irrevocably appoint
agent to transfer this Note on the books of the Issuer.  The agent may
substitute another to act for him.

Date:                                    Your Signature:
     -------------------                                -----------------------
                                                        Sign   exactly  as your
                                                        name appears on the
                                                        other side of this Note.

Signature Guarantee:
                           (Signature  must be guaranteed by a participant  in a
                           recognized  Signature  Guarantee Medallion Program or
                           other   signature    guarantor   program   reasonably
                           acceptable to the Trustee)

                       OPTION-OF-HOLDER TO ELECT PURCHASE

                  If you want to elect to have this Note purchased by the Issuer
pursuant to Section 4.7 or 4.9 of the Indenture, check the appropriate box:

                  Section 4.7      [ ]

                  Section 4.9      [ ]

                  If you want to elect to have only part of this Note  purchased
by the Issuer pursuant to Section 4.7 or 4.9 of the Indenture,  state the amount
you elect to have purchased (must be integral multiple of $1,000): $
                                                                    ------------<PAGE>   1
                                                                     EXHIBIT 4.5

                           SPECTRASITE HOLDINGS, INC.

                                    as Issuer

                                       and

                     UNITED STATES TRUST COMPANY OF NEW YORK

                                   as Trustee

                                    INDENTURE

                           Dated as of March 15, 2000

                       12 7/8% Senior Discount Notes due 2010

<PAGE>   2

                                       i

                                TABLE OF CONTENTS

                                      Page

                                    ARTICLE I
                   DEFINITIONS AND INCORPORATION BY REFERENCE

SECTION 1.1.  Definitions                                                      1
SECTION 1.2.  Other Definitions                                               20
SECTION 1.3.  Incorporation by Reference of Trust Indenture Act               20
SECTION 1.4.  Rules of Construction                                           21
SECTION 1.5.  One Class of Notes                                              21

                                   ARTICLE II
                                    THE NOTES

SECTION 2.1.  Form and Dating                                                 22
SECTION 2.2.  Execution and Authentication                                    22
SECTION 2.3.  Registrar and Paying Agent                                      22
SECTION 2.4.  Paying Agent to Hold Money in Trust                             23
SECTION 2.5.  Noteholder Lists                                                23
SECTION 2.6.  [Intentionally Omitted]                                         23
SECTION 2.7.  Replacement Notes                                               23
SECTION 2.8.  Outstanding Notes                                               24
SECTION 2.9.  Temporary Notes                                                 24
SECTION 2.10.  Cancellation                                                   24
SECTION 2.11.  Defaulted Interest                                             25
SECTION 2.12.  CUSIP Numbers                                                  25

                                   ARTICLE III
                                   REDEMPTION

SECTION 3.1.  Notices to Trustee                                              25
SECTION 3.2.  Selection of Notes to Be Redeemed                               25
SECTION 3.3.  Notice of Redemption                                            26
SECTION 3.4.  Effect of Notice of Redemption                                  26
SECTION 3.5.  Deposit of Redemption Price                                     27
SECTION 3.6.  Notes Redeemed in Part                                          27

                                   ARTICLE IV
                                    COVENANTS

SECTION 4.1.  Payment of Notes                                                27
SECTION 4.2.  SEC Reports                                                     28
SECTION 4.3.  Limitation on Indebtedness                                      28
SECTION 4.4.  Limitation on Indebtedness and Preferred Stock of Restricted
              Subsidiaries                                                    30
SECTION 4.5.  Limitation on Restricted Payments                               32
SECTION 4.6.  Limitation on Restrictions on Distributions from Restricted
              Subsidiaries                                                    34
SECTION 4.7.  Limitation on Sale of Assets and Subsidiary Stock               35
SECTION 4.8.  Limitation on Transactions with Affiliates                      37
SECTION 4.9.  Change of Control                                               38
SECTION 4.10.  Limitation on Sale or Issuance of Capital Stock of Restricted
               Subsidiaries                                                   40
SECTION 4.11.  Limitation on Liens                                            40
SECTION 4.12.  Limitation on Sale/Leaseback Transactions                      40
SECTION 4.13.  Compliance with Laws                                           40
SECTION 4.14.  Compliance Certificate                                         41
SECTION 4.15.  Further Instruments and Acts                                   41
SECTION 4.16.  Maintenance of Office or Agency                                41
SECTION 4.17.  Corporate Existence                                            41
SECTION 4.18.  Payment of Taxes and Other Claims                              41
SECTION 4.19.  Maintenance of Properties and Insurance                        42
<PAGE>   3
                                       ii

                                    ARTICLE V
                                SUCCESSOR ISSUER

SECTION 5.1.  When the Issuer May Merge or Transfer Assets                    42

                                   ARTICLE VI
                              DEFAULTS AND REMEDIES

SECTION 6.1.  Events of Default                                               43
SECTION 6.2.  Acceleration                                                    43
SECTION 6.3.  Other Remedies                                                  45
SECTION 6.4.  Waiver of Past Defaults                                         46
SECTION 6.5.  Control by Majority                                             46
SECTION 6.6.  Limitation on Suits                                             46
SECTION 6.7.  Rights of Holders to Receive Payment                            46
SECTION 6.8.  Collection Suit by Trustee                                      47
SECTION 6.9.  Trustee May File Proofs of Claim                                47
SECTION 6.10.  Priorities                                                     47
SECTION 6.11.  Undertaking for Costs                                          47
SECTION 6.12.  Waiver of Stay or Extension Laws                               48

                                   ARTICLE VII
                                     TRUSTEE

SECTION 7.1.  Duties of Trustee                                               48
SECTION 7.2.  Rights of Trustee                                               48
SECTION 7.3.  Individual Rights of Trustee                                    49
SECTION 7.4.  Trustee's Disclaimer                                            50
SECTION 7.5.  Notice of Defaults                                              50
SECTION 7.6.  Reports by Trustee to Holders                                   50
SECTION 7.7.  Compensation and Indemnity                                      51
SECTION 7.8.  Replacement of Trustee                                          51
SECTION 7.9.  Successor Trustee by Merger                                     52
SECTION 7.10.  Eligibility; Disqualification                                  53
SECTION 7.11.  Preferential Collection of Claims Against Issuer               53

                                  ARTICLE VIII
                       DISCHARGE OF INDENTURE; DEFEASANCE

SECTION 8.1.  Discharge of Liability on Notes; Defeasance                     54
SECTION 8.2.  Conditions to Defeasance                                        55
SECTION 8.3.  Application of Trust Money                                      56
SECTION 8.4.  Repayment to Issuer                                             56
SECTION 8.5.  Indemnity for Government Obligations                            56
SECTION 8.6.  Reinstatement                                                   56

                                   ARTICLE IX
                                   AMENDMENTS

SECTION 9.1.  Without Consent of Holders                                      57
SECTION 9.2.  With Consent of Holders                                         57
SECTION 9.3.  Compliance with Trust Indenture Act                             58
SECTION 9.4.  Revocation and Effect of Consents and Waivers                   58
SECTION 9.5.  Notation on or Exchange of Notes                                59
SECTION 9.6.  Trustee to Sign Amendments                                      59
SECTION 9.7.  Payment for Consent                                             59

                                    ARTICLE X
                                  MISCELLANEOUS

SECTION 10.1.  Trust Indenture Act Controls                                   59
SECTION 10.2.  Notices                                                        59
SECTION 10.3.  Communication by Holders with Other Holders                    60
SECTION 10.4.  Certificate and Opinion as to Conditions Precedent             60
SECTION 10.5.  Statements Required in Certificate or Opinion                  61
SECTION 10.6.  When Notes Disregarded                                         61
SECTION 10.7.  Rules by Trustee, Paying Agent and Registrar                   61
SECTION 10.8.  Legal Holidays                                                 61
<PAGE>   4
                                      iii

SECTION 10.9.  Governing Law                                                  61
SECTION 10.10.  No Recourse Against Others                                    62
SECTION 10.11.  Successors                                                    62
SECTION 10.12.  Multiple Originals                                            62
SECTION 10.13.  Variable Provisions                                           62
SECTION 10.14.  Qualification of Indenture                                    62
SECTION 10.15.  Table of Contents; Headings                                   62
SECTION 10.16.  Severability                                                  62

Rule 144A/Regulation S Appendix
Exhibit 1 to Appendix - Form of Initial Note
Exhibit A - Form of Exchange Note and Private Exchange Note

--------

<PAGE>   5

                  INDENTURE,  dated as of March 15,  2000,  between  SPECTRASITE
HOLDINGS, INC., a Delaware corporation (as further defined below, the "Issuer"),
and UNITED STATES TRUST COMPANY OF NEW YORK, a bank and trust company  organized
under New York banking law, as trustee (the "Trustee").

                  Each party  agrees as  follows for  the  benefit  of the other
party and  for  the equal  and ratable benefit  of the  Holders  of the Issuer's
$559,800,000 aggregate  principal  amount at maturity  12 7/8%  Senior  Discount
Notes  due 2010  (the "Initial Notes")  and, if and when  issued in exchange for
Initial  Notes as  provided in the  Registration  Rights  Agreement  (as defined
in  the Appendix  hereto), the  Issuer's Series B  12 7/8% Senior Discount Notes
due  2010 (the  "Exchange  Notes")  and,  if  and  when  issued  pursuant  to  a
private  exchange  for  Initial  Notes,  the  Issuer's  Series  B 12 7/8% Senior
Discount  Notes  Due  2010  (the "Private  Exchange  Notes,"  together  with the
Initial  Notes and the  Exchange Notes, the "Notes"):

               ARTICLE IDEFINITIONS AND INCORPORATION BY REFERENCE
                            SECTION 1.1. Definitions

                  "Accreted  Value" means an amount per $1,000  principal amount
at  maturity of the Notes that is equal to (a) as of any date prior to March 15,
2005, the sum of (x) the initial offering price of each Note and (y) the portion
of the excess of the principal amount at maturity of each Note over such initial
offering price which shall have been amortized through such date, such amount to
be so amortized on a daily basis and compounded  semi-annually  on each March 15
and  September 15 at the rate of 12[]% per annum from the Issue Date through the
date of  determination  computed on the basis of a 360-day year of twelve 30-day
months, and (b) as of any date after March 15, 2005, $1,000.

                  "Adjusted  EBITDA" as of any date of  determination  means the
sum of (i) the  EBITDA  of the  Issuer  for the four  most  recent  full  fiscal
quarters  ending  prior to such date,  less the  Issuer's  Tower EBITDA for such
four-quarter  period,  plus (ii) the  product of four times the  Issuer's  Tower
EBITDA for the most recent  quarterly  period,  which Tower  EBITDA for the most
recent  quarterly  period shall be  determined on a pro forma basis after giving
effect to (A) all  acquisitions or dispositions of assets made by the Issuer and
its  Subsidiaries  from the beginning of such quarter through and including such
date of determination  (including any related financing transactions) as if such
acquisitions and dispositions had occurred at the beginning of such quarter, (B)
any new lease or Site  Management  Contract  entered  into by the  Issuer or any
Restricted  Subsidiary in the ordinary  course of business with respect to Tower
Assets from the  beginning of such quarter  through and  including  such date of
determination  as if such new lease or Site Management  Contract had been signed
at the  beginning  of such  quarter  and the rent  required by the terms of such
lease or Site  Management  Contract  for such  quarter and been  received by the
Issuer or a Restricted  Subsidiary  during such  quarter,  (C) the loss from the
beginning of such quarter  through and including such date of  determination  of
any lease or Site
<PAGE>   6
                                       2

Management  Contract of the Issuer or a Restricted  Subsidiary with  respect  to
any Tower  Assets  that was in effect on the first day of such quarter  as if
such  lease or Site  Management  Contract  had not been in effect during such
quarter and no rent under such lease had been  received  during such quarter and
D) any rent  increases  received  by the Issuer or any  Restricted Subsidiary
during the period  beginning  on the first day of such  quarter  and ending  on
the  date of  determination  related  to  leases  or Site  Management Contracts
on Tower Assets as if such increased rental rate had been in effect at the
beginning  of such  quarter  and  such  increased  amount  of rent had been
received  by the Issuer or a  Restricted  Subsidiary  during such  quarter.  For
purposes of making the computation referred to above, (1) acquisitions that have
been made by the Issuer or any of its Restricted Subsidiaries, including through
mergers or  consolidations  and  including any related  financing  transactions,
during the reference  period or subsequent  to such  reference  period and on or
prior to the date of determination shall be deemed to have occurred on the first
day of the  reference  period  and  EBITDA for such  reference  period  shall be
calculated  without giving effect to clause (ii) of the proviso set forth in the
definition  of  Consolidated  Net  Income,  and (2) the EBITDA  attributable  to
discontinued  operations,  as determined in accordance with GAAP, and operations
or businesses disposed of prior to the date of determination shall be excluded.

                  "Affiliate"  of any  specified  Person means any other Person,
directly or indirectly, controlling or controlled by or under direct or indirect
common control with such specified Person.  For the purposes of this definition,
"control"  when used with  respect to any  Person  means the power to direct the
management and policies of such Person, directly or indirectly,  whether through
the  ownership of voting  securities,  by contract or  otherwise;  and the terms
"controlling" and "controlled" have meanings correlative to the foregoing.

                  "Asset  Disposition" means any sale, lease,  transfer or other
disposition (or series of related sales,  leases,  transfers or dispositions) by
the Issuer or any Restricted Subsidiary, including any disposition by means of a
merger,  consolidation or similar transaction (each referred to for the purposes
of this definition as a "disposition"),  of (i) any shares of Capital Stock of a
Restricted  Subsidiary  (other  than  directors'  qualifying  shares  or  shares
required  by  applicable  law to be held by a Person  other than the Issuer or a
Restricted Subsidiary), (ii) all or substantially all the assets of any division
or line of  business  of the Issuer or any  Restricted  Subsidiary  or (iii) any
other assets of the Issuer or any Restricted  Subsidiary outside of the ordinary
course of business of the Issuer or such Restricted  Subsidiary  (other than, in
the  case of (i),  (ii) and  (iii)  above,  (u) a  disposition  by a  Restricted
Subsidiary to the Issuer or by the Issuer or a Restricted  Subsidiary to another
Restricted  Security,  (v) a disposition that  constitutes a Restricted  Payment
permitted by Section 4.5, (w) a  disposition  of assets with a fair market value
of less than $5.0 million,  (x) any transaction not prohibited by Section 4.5 or
that constitutes a Permitted Investment, (y) grants of leases or licenses in the
ordinary course of business, and (z) disposals of cash equivalents).

                  "Attributable  Indebtedness"  in respect  of a  Sale/Leaseback
Transaction  means,  as  at  the  time  of  determination,   the  present  value
(discounted at the interest rate borne by the Notes, compounded annually) of the
total obligations of the lessee for rental payments during the
<PAGE>   7
                                       3

remaining term of the lease included in such Sale/Leaseback  Transaction
(including any period for which such lease has been extended).

                  "Average Life" means,  as of the date of  determination,  with
respect to any  Indebtedness  or  Preferred  Stock,  the  quotient  obtained  by
dividing  (i) the sum of the  product  of the  numbers of years from the date of
determination  to the dates of each successive  scheduled  principal  payment of
such  Indebtedness  or  redemption  or  similar  payment  with  respect  to such
Preferred Stock  multiplied by the amount of such payment by (ii) the sum of all
such payments.

                  "Board  of  Directors"  means the  Board of  Directors  of the
Issuer or any committee thereof duly authorized to act on behalf of such Board.

                  "Business  Day" means a day other than a  Saturday,  Sunday or
other day on which  banking  institutions  in New York State are  authorized  or
required by law to close.

                  "Capitalized  Lease  Obligation"  means an obligation  that is
required to be classified and accounted for as a capitalized lease for financial
reporting  purposes  in  accordance  with GAAP,  and the amount of  Indebtedness
represented  by  such  obligation  shall  be  the  capitalized  amount  of  such
obligation determined in accordance with GAAP.

                  "Capital  Stock"  of any  Person  means  any and  all  shares,
interests,  rights  to  purchase,  warrants,  options,  participation  or  other
equivalents  of or  interests  in (however  designated)  equity of such  Person,
including any Preferred  Stock,  but excluding any debt  securities  convertible
into such equity.

                  "Change of Control" means the occurrence of any of the
following events:

(i)               any "person" (as such term is used in Sections 13(d) and 14(d)
         of the Exchange Act), other than one or more Permitted Holders, is or
         becomes the beneficial owner (as such term is used in Sections 13(d)-3
         and 13(d)-5 of the Exchange Act, except that for purposes of this
         clause (i) such Person shall be deemed to have "beneficial ownership"
         of all shares that any such person has the right to acquire, whether
         such right is exercisable immediately or only after the passage of
         time), directly or indirectly, of more than 35% of the total voting
         power of the Voting Stock of the Issuer; provided, however, that the
         Permitted Holders "beneficially own", directly or indirectly, in the
         aggregate a lesser percentage of the total voting power of the Voting
         Stock of the Issuer than such other Person and do not have the right or
         ability by voting power, contract or otherwise to elect or designate
         for election a majority of the Board of Directors of the Issuer (for
         the purposes of this clause (i), (a) such other person shall be deemed
         to beneficially own any Voting Stock of a specified entity held by a
         parent entity, if such other person is the beneficial owner, directly
         or indirectly, of more than 35% of  the voting power of the Voting
         Stock of such parent entity and the Permitted Holders "beneficially
         own", directly or indirectly, in the aggregate a lesser percentage of
         the total voting power of the Voting Stock of such parent entity than
         such other Person, and do not have the right or ability by
<PAGE>   8
                                       4

         voting power, contract or otherwise to elect or designate for election
         a majority of the board of directors of  such parent entity, and (b)
         the Permitted Holders shall be deemed to beneficially own any Voting
         Stock of an entity held by any other parent entity, so long as the
         Permitted Holders beneficially own, directly or indirectly, in the
         aggregate, a majority of the voting power of the parent entity's Voting
         Stock);

(i)               during any period of two consecutive years (or, in the case
         this event occurs within the first two years after the Issue Date, such
         shorter period as shall have begun on the Issue Date), individuals
         who at the beginning of such period constituted the Board of Directors
         of the Issuer (together with any new directors whose election by such
         Board of Directors or whose nomination for election by the shareholders
         of the Issuer was approved by a vote of a majority of the directors of
         the Issuer then still in office who were either directors at the
         beginning of such period or whose election or nomination for election
         was previously so approved) cease for any reason to constitute a
         majority of the Board of Directors of the Issuer then in office;

(i)               the merger or consolidation of the Issuer with or into another
         Person or the merger of another Person with or into the Issuer, or the
         sale of all or substantially all the assets of the Issuer to another
         Person (other than a Permitted Holder or a Person that is controlled by
         the Permitted Holders),and, in the case of any such merger or
         consolidation, the securities of the Issuer that are outstanding
         immediately prior to such transaction and which represent 100% of the
         aggregate voting power of the Voting Stock of the Issuer are changed
         into or exchanged for cash, securities or property, unless pursuant to
         such transaction such securities are changed into or exchanged for, in
         addition to any other consideration, securities of the surviving
         corporation that represent immediately after such transaction, at least
         a majority of the aggregate voting power of the Voting Stock of the
         surviving corporation; and

(i)      the sale of all or substantially  all of the Issuer's assets to another
         person, other than a Permitted Holder or a person that is controlled by
         the Permitted Holders.

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

                  "Completed Broadcast Tower" means a communications tower of at
least  500  feet,  other  than  a  Completed  Tower,  with,  as of the  date  of
determination,  (i) at least one broadcast tenant that has executed a definitive
lease or Site  Management  Contract  with the  Issuer  or any of its  Restricted
Subsidiaries and (ii) capacity for at least one other tenant.

                  "Completed  Tower" means a communications  transmission  tower
with, as of any date of  determination,  (i) at least one anchor tenant that has
executed a definitive  lease or Site Management  Contract with the Issuer or any
of its Restricted Subsidiaries and (ii) capacity for at least three tenants.
<PAGE>   9
                                       5

                  "Consolidated  Indebtedness"  as of any date of  determination
means (without  duplication)  (i) the total amount of Indebtedness of the Issuer
and its Restricted  Subsidiaries,  (ii) the total amount of  Indebtedness of any
other Person,  to the extent that such  Indebtedness  has been Guaranteed by the
Issuer or one or more of its  Restricted  Subsidiaries,  and (iii) the aggregate
liquidation  value of all  Disqualified  Stock of the Issuer  and all  preferred
stock of  Restricted  Subsidiaries  of the  Issuer  not owned by the Issuer or a
Restricted  Subsidiary,  in each case,  determined  on a  consolidated  basis in
accordance with GAAP.

                  "Consolidated  Interest  Expense" means,  for any period,  the
total  interest   expense  of  the  Issuer  and  its   consolidated   Restricted
Subsidiaries,  plus, to the extent not included in such total interest  expense,
and to the extent incurred by the Issuer or its Restricted Subsidiaries, without
duplication,  (i) interest expense  attributable to capital leases and to leases
constituting  part of a Sale/Leaseback  Transaction,  (ii)  amortization of debt
discount and debt  issuance  cost,  (iii)  capitalized  interest,  (iv) non-cash
interest  expense,  (v)  commissions,  discounts and other fees and charges owed
with respect to letters of credit and bankers'  acceptance  financing,  (vi) net
costs  associated  with Hedging  Obligations  (including  amortization of fees),
(vii)  Preferred  Stock  dividends paid in respect of all Preferred Stock of the
Issuer and its  Subsidiaries  held by Persons  other than the Issuer or a Wholly
Owned  Subsidiary,  (viii) interest  incurred in connection with  Investments in
discontinued operations, (ix) interest accruing on any Indebtedness of any other
Person to the extent  such  Indebtedness  is  Guaranteed  by (or  secured by the
assets  of)  the  Issuer  or  any   Restricted   Subsidiary  and  (x)  the  cash
contributions  to any  employee  stock  ownership  plan or similar  trust to the
extent such contributions are used by such plan or trust to pay interest or fees
to any Person (other than the Issuer) in connection with  Indebtedness  Incurred
by such plan or trust.

                  "Consolidated  Net  Income"  means,  for any  period,  the net
income  (loss)  of the  Issuer  and  its  consolidated  Subsidiaries;  provided,
however, that there shall not be included in such Consolidated Net Income:

(i)      any net income  (loss) of any Person  (other  than the  Issuer) if such
         Person is not a  Restricted  Subsidiary,  except  that,  subject to the
         exclusion  contained  in (iv)  below,  the  Issuer's  equity in the net
         income of any such  Person for such  period  shall be  included in such
         Consolidated  Net Income up to the  aggregate  amount of cash  actually
         distributed  by such  Person  during  such  period  to the  Issuer or a
         Restricted Subsidiary as a dividend or other distribution  (subject, in
         the case of a  dividend  or  other  distribution  paid to a  Restricted
         Subsidiary, to the limitations contained in clause (iii) below);

(i)      any net  income  (loss)  of any  Person  acquired  by the  Issuer  or a
         Subsidiary in a pooling of interests  transaction  for any period prior
         to the date of such acquisition;

(i)               any net income of any Restricted Subsidiary if such Restricted
         Subsidiary is subject to restrictions (other than any restrictions
         permitted in Section 4.6), directly or indirectly, on the payment of
         dividends or the making of distributions by such Restricted Subsidiary,
         directly or indirectly, to the Issuer, except that (A) subject to the
         exclusion
<PAGE>   10
                                       6

         contained in clause (iv) below the Issuer's equity in the net income of
         any such Restricted Subsidiary for such period shall be included in
         such Consolidated Net Income up to the aggregate amount of cash
         actually distributed by such Restricted  Subsidiary during such period
         to the Issuer or another Restricted Subsidiary as a dividend or other
         distribution (subject, in the case of a dividend or other distribution
         paid to another Restricted Subsidiary, to the limitation contained in
         this clause) and (B) solely for purposes of calculating the
         Indebtedness to Adjusted EBITDA Ratio, the Issuer's equity in a net
         loss of any such Restricted Subsidiary for such period shall be
         included in determining such Consolidated Net Income;

(i)      any gain or loss  realized  upon the sale or other  disposition  of any
         assets of the Issuer, its consolidated Subsidiaries or any other Person
         (including  pursuant to any  Sale/Leaseback  Transaction)  which is not
         sold or otherwise  disposed of in the  ordinary  course of business and
         any gain or loss  realized  upon the sale or other  disposition  of any
         Capital Stock of any Person;

(i)               any net income or loss of any Unrestricted Subsidiary, except
to the extent distributed to the Issuer or one of its Subsidiaries;

(i)               any extraordinary gain or loss; and

(i)               the cumulative effect of a change in accounting principles.

Notwithstanding the foregoing, for the purposes of Section 4.5 only, there shall
be excluded from  Consolidated Net Income any dividends,  repayments of loans or
advances or other  transfers  of assets from  Unrestricted  Subsidiaries  to the
Issuer or a Restricted  Subsidiary to the extent such  dividends,  repayments or
transfers  increase  the  amount of  Restricted  Payments  permitted  under such
covenant pursuant to clause (a)(3)(D) thereof.

                  "Consolidated  Tangible  Assets"  means,  with  respect to the
Issuer, the total consolidated  tangible assets of the Issuer and its Restricted
Subsidiaries, as shown on the most recent internal consolidated balance sheet of
the Issuer and such Restricted  Subsidiaries  calculated on a consolidated basis
in accordance with GAAP.

                  "Credit  Facility"  means  any  debt  or  credit  facility  or
commercial  paper  facility  providing for revolving  credit loans,  term loans,
accounts receivable financing (including through the sale of accounts receivable
to such  lenders  or to  special  purpose  entities  formed to borrow  from such
lenders  against  such  accounts  receivable)  or letters  of  credit,  or other
non-convertible  debt securities or other form of debt financing,  in each case,
as amended,  restated,  supplemented,  extended,  modified,  renewed,  refunded,
replaced or refinanced in whole or in part from time to time, including any such
amendment, restatement, supplement, extension, modification, renewal, refunding,
replacement or refinancing  that increases the amount  borrowable  thereunder or
alters the maturity thereof.
<PAGE>   11
                                       7

                  "Currency  Agreement" means in respect of a Person any foreign
exchange  contract,  currency swap agreement or other similar agreement designed
to protect such Person against  fluctuations in currency values as to which such
Person is a party or a beneficiary.

                  "Default" means any event which is, or after notice or passage
of time or both would be, an Event of Default.

                  "Disqualified  Stock" means,  with respect to any Person,  any
Capital  Stock which by its terms (or by the terms of any security into which it
is  convertible  or for which it is  exchangeable)  or upon the happening of any
event (i)  matures  or is  mandatorily  redeemable  pursuant  to a sinking  fund
obligation or otherwise,  (ii) is convertible or  exchangeable  at the option of
the holder thereof for Indebtedness or Disqualified Stock or (iii) is redeemable
at the option of the  holder  thereof,  in whole or in part,  in each case on or
prior to the 91st day after the Stated Maturity of the Notes; provided, however,
that any  Capital  Stock that would not  constitute  Disqualified  Stock but for
provisions  thereof giving  holders  thereof the right to require such Person to
repurchase or redeem such Capital  Stock upon the  occurrence of an "asset sale"
or "change of control" occurring prior to the 91st day after the Stated Maturity
of the Notes  shall not  constitute  Disqualified  Stock if the "asset  sale" or
"change  of  control"  provisions  applicable  to  such  Capital  Stock  are not
materially  more favorable taken as a whole to the holders of such Capital Stock
than the provisions described under Section 4.9 and Section 4.7.

                  "EBITDA"  for any  period  means the sum of  Consolidated  Net
Income,   plus  the  following  to  the  extent  deducted  in  calculating  such
Consolidated Net Income: (a) Consolidated  Interest Expense;  (b) all income tax
expense  of  the  Issuer  and  its  consolidated  Restricted  Subsidiaries;  (c)
depreciation expense of the Issuer and its consolidated Restricted Subsidiaries;
(d)  amortization  expense  of  the  Issuer  and  its  consolidated   Restricted
Subsidiaries (excluding amortization expense attributable to a prepaid cash item
that was paid in a prior period);  (e) all other non-cash  charges of the Issuer
and its consolidated Restricted Subsidiaries (excluding any such non-cash charge
to the extent that it represents an accrual of or reserve for cash  expenditures
in any future  period);  and (f) any premium or penalty paid in connection  with
repurchasing, redeeming, retiring, defeasing or acquiring any Indebtedness prior
to maturity to the extent deducted in calculating  Consolidated  Net Income,  in
each case for such period.  Notwithstanding  the  foregoing,  the  provision for
taxes based on the income or profits of, and the  depreciation  and amortization
and  non-cash  charges  of,  a  Restricted  Subsidiary  shall  be  added  to the
Consolidated  Net Income to compute  EBITDA  only to the extent (and in the same
proportion)  that the net income of such  Restricted  Subsidiary was included in
calculating  Consolidated Net Income and only if a corresponding amount would be
permitted at the date of determination to be paid to the Issuer in the form of a
dividend by such Restricted Subsidiary without prior approval (that has not been
obtained), pursuant to the terms of its charter and all agreements, instruments,
judgments,   decrees,  orders,  statutes,  rules  and  governmental  regulations
applicable to such  Restricted  Subsidiary or its  stockholders,  without in any
event giving effect to any restrictions or limitations permitted in Section 4.6.

<PAGE>   12
                                       8
                  "Equity  Offering"  means a public or private  issuance by the
Issuer of common stock of the Issuer for cash.

                  "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

                  "GAAP" means generally accepted  accounting  principles in the
United States of America as in effect as of the Issue Date,  including those set
forth in (i) the opinions and pronouncements of the Accounting  Principles Board
of the American Institute of Certified Public  Accountants,  (ii) statements and
pronouncements  of the Financial  Accounting  Standards Board,  (iii) such other
statements  by such other  entity as  approved by a  significant  segment of the
accounting  profession  and (iv) the rules and  regulations of the SEC governing
the inclusion of financial statements (including pro forma financial statements)
in periodic  reports required to be filed pursuant to Section 13 of the Exchange
Act,  including  opinions and  pronouncements in staff accounting  bulletins and
similar written statements from the accounting staff of the SEC.

                  "Guarantee" means any obligation,  contingent or otherwise, of
any Person directly or indirectly  guaranteeing  any  Indebtedness of any Person
and any obligation,  direct or indirect, contingent or otherwise, of such Person
(i) to purchase or pay (or advance or supply  funds for the  purchase or payment
of) such  Indebtedness or other  obligation of such Person  (whether  arising by
virtue of partnership  arrangements,  or by agreements to keep-well, to purchase
assets,  goods,  securities or services, to take-or-pay or to maintain financial
statement  conditions  or  otherwise)  or (ii)  entered  into for the purpose of
assuring  in any other  manner the obligee of such  Indebtedness  of the payment
thereof or to protect such obligee  against loss in respect thereof (in whole or
in  part);  provided,  however,  that the term  "Guarantee"  shall  not  include
endorsements  for collection or deposit in the ordinary course of business.  The
term "Guarantee" used as a verb has a corresponding meaning.

                  "Hedging   Obligations"   of  any  Person   means  the  actual
obligations  of such Person  pursuant to any Interest Rate Agreement or Currency
Agreement.

                  "Holder" or "Noteholder" means the Person in whose name a Note
is registered on the Registrar's books.

                  "Incur"  means issue,  assume,  Guarantee,  incur or otherwise
become liable for; provided,  however, that any Indebtedness or Capital Stock of
a Person  existing  at the time such  Person  becomes a  Subsidiary  (whether by
merger, consolidation,  acquisition or otherwise) shall be deemed to be Incurred
by such Subsidiary at the time it becomes a Subsidiary  unless such Indebtedness
or  Capital  Stock is  repaid or  redeemed  on the date  such  Person  becomes a
Subsidiary.  The term  "Incurrence" when used as a noun shall have a correlative
meaning.

                  "Indebtedness" means, with respect to any Person on any date
of determination (without duplication):

<PAGE>   13
                                       9

(i)      the principal in respect of (A)  indebtedness  of such Person for money
         borrowed and (B) indebtedness evidenced by notes, debentures,  bonds or
         other  similar  instruments  for the  payment of which  such  Person is
         responsible  or liable,  including,  in each case,  any premium on such
         indebtedness to the extent such premium has become due and payable;

(i)      all Capitalized  Lease  Obligations of such Person and all Attributable
         Debt in respect of  Sale/Leaseback  Transactions  entered  into by such
         Person;

(i)      all  obligations  of such  Person  issued or  assumed  as the  deferred
         purchase price of property,  all conditional  sale  obligations of such
         Person and all  obligations  of such Person  under any title  retention
         agreement (but excluding trade accounts payable arising in the ordinary
         course of business);

(i)               all obligations of such Person for the reimbursement of any
         obligor on any letter of credit, banker's acceptance or similar credit
         transaction (other than obligations with respect to letters of credit
         and other contingent liabilities (but only to the extent such
         contingent liabilities are not reflected as liabilities on the
         consolidated balance sheet of such Person) securing obligations (other
         than obligations described in clauses (i) through (iii) above) entered
         into in the ordinary course of business of such Person to the extent
         such letters of credit are not drawn upon or, if and to the extent
         drawn upon, such drawing is reimbursed no later than the tenth Business
         Day following payment on the letter of credit);

(i)      the  amount of all  obligations  of such  Person  with  respect  to the
         redemption, repayment or other repurchase of any Disqualified Stock or,
         with  respect  to  any  Subsidiary  of  such  Person,  the  liquidation
         preference with respect to, any Preferred Stock (but excluding, in each
         case, any accrued dividends);

(i)      all  obligations  of the type  referred  to in clauses  (i) through (v)
         above,  of other  Persons and all  dividends  of other  Persons for the
         payment of which, in either case, such Person is responsible or liable,
         directly or indirectly, as obligor,  guarantor or otherwise,  including
         by means of any Guarantee;

(i)      all  obligations  of the type  referred to in clauses (i) through  (vi)
         above, of other Persons secured by any Lien on any property or asset of
         such Person (whether or not such obligation is assumed by such Person),
         the  amount of such  obligation  being  deemed to be the  lesser of the
         value of such  property  or assets or the amount of the  obligation  so
         secured; and

(i)               to the extent not otherwise included in this definition,
Hedging Obligations of such Person.

<PAGE>   14
                                       10

The amount of  Indebtedness  of any Person at any date shall be the  outstanding
balance at such date of all unconditional  obligations as described above or the
accreted value thereof,  in the case of Indebtedness  issued with original issue
discount,  and the maximum  liability,  upon the  occurrence of the  contingency
giving rise to the obligation, of any contingent obligations at such date.

                  "Indebtedness  to  Adjusted  EBITDA  Ratio"  as of any date of
determination  means the ratio of (i) Consolidated  Indebtedness as of such date
to (ii) Adjusted EBITDA.

                  "Indenture" means this Indenture, as amended or supplemented
from time to time.

                  "Interest Rate Agreement" means with respect to any Person any
interest rate protection  agreement,  interest rate future  agreement,  interest
rate  option  agreement,   interest  rate  swap  agreement,  interest  rate  cap
agreement,  interest rate collar  agreement,  interest  rate hedge  agreement or
other similar  agreement or arrangement  designed to protect such Person against
fluctuations  in  interest  rates  as to  which  such  Person  is a  party  or a
beneficiary.

                  "Investment"  in any  Person  means  any  direct  or  indirect
advance,  loan (other than  advances to  customers,  lessees or licensees in the
ordinary  course of business  that are  recorded as accounts  receivable  on the
balance sheet of such Person) or other extension of credit  (including by way of
Guarantee or similar  arrangement)  or capital  contribution to (by means of any
transfer of cash or other  property  to others or any  payment  for  property or
services for the account or use of others),  or any purchase or  acquisition  of
Capital Stock,  Indebtedness or other similar instruments issued by such Person.
For purposes of the  definitions of  "Unrestricted  Subsidiary"  and "Restricted
Payment"  and  Section  4.5,  (i)   "Investment"   shall   include  the  portion
(proportionate  to the Issuer's equity interest in such  Subsidiary) of the fair
Market value of the net assets of any  Subsidiary of the Issuer at the time that
such Subsidiary is designated an  Unrestricted  Subsidiary;  provided,  however,
that upon a  redesignation  of such Subsidiary as a Restricted  Subsidiary,  the
Issuer  shall be deemed  to  continue  to have a  permanent  "Investment"  in an
Unrestricted  Subsidiary  equal  to an  amount  (if  positive)  equal to (x) the
Issuer's  "Investment" in such Subsidiary at the time of such redesignation less
(y)  the  portion  (proportionate  to  the  Issuer's  equity  interest  in  such
Subsidiary) of the fair market value of the net assets of such Subsidiary at the
time that such Subsidiary is so re-designated a Restricted Subsidiary;  and (ii)
any property  transferred to or from an Unrestricted  Subsidiary shall be valued
at its  fair  market  value  at the  time of  such  transfer,  in  each  case as
determined in good faith by the Board of Directors and evidenced by a resolution
of such Board of Directors.

                  "Issue Date" means the date on which the Notes are originally
issued.

                  "Legal Holiday" has the meaning ascribed in Section 10.8.

                  "Lien"  means  any  mortgage,   pledge,   security   interest,
encumbrance, lien or charge of any kind (including any conditional sale or other
title retention agreement or lease in the nature thereof).
<PAGE>   15
                                       11

                  "Net  Available  Cash"  from an Asset  Disposition  means cash
payments  received  (including  any cash  payments  received  by way of deferred
payment of principal  pursuant to a note or installment  receivable or otherwise
and proceeds from the sale or other  disposition of any  securities  received as
consideration,   but  only  as  and  when  received,  but  excluding  any  other
consideration  received in the form of  assumption  by the  acquiring  Person of
Indebtedness  or other  obligations  relating  to such  properties  or assets or
received  in any other  non-cash  form)  therefrom,  in each case net of (i) all
legal,  title,  accounting,  investment  banking  and  recording  tax  expenses,
commissions  and other  fees and  expenses  incurred,  and all  Federal,  state,
provincial,  foreign  and  local  taxes  required  to be  paid or  accrued  as a
liability  under GAAP,  as a  consequence  of such Asset  Disposition,  (ii) all
payments made on any Indebtedness which is secured by any assets subject to such
Asset  Disposition,  in  accordance  with the  terms  of any Lien  upon or other
security  arrangement of any kind with respect to such assets,  or which must by
its terms, or in order to obtain a necessary consent to such Asset  Disposition,
or by applicable law, be repaid out of the proceeds from such Asset Disposition,
(iii) all  distributions  and other  payments  required  to be made to  minority
interest  holders in Restricted  Subsidiaries  or joint  ventures as a result of
such Asset Disposition, (iv) the deduction of appropriate amounts to be provided
by the seller as a reserve,  in accordance  with GAAP,  against any  liabilities
associated with the assets disposed of in such Asset Disposition and retained by
the Issuer or any Restricted  Subsidiary after such Asset  Disposition,  and (v)
any  reserves  established  in  respect  of the  sales  price of such  asset for
post-closing  adjustments,  indemnification  purposes  or  employee  termination
expenses.

                  "Net Cash  Proceeds",  with respect to any issuance or sale of
Capital  Stock,  means  the  cash  proceeds  of such  issuance  or  sale  net of
attorneys' fees,  accountants' fees, printing costs,  underwriters' or placement
agents' fees, discounts or commissions and brokerage,  consultant and other fees
and expenses  actually incurred in connection with such issuance or sale and net
of taxes paid or payable as a result thereof.

                  "Non-Recourse Debt" means Indebtedness (i) as to which neither
the Issuer nor any  Restricted  Subsidiary  (a) provides any Guarantee or credit
support of any kind (including any undertaking,  Guarantee, indemnity, agreement
or  instrument  that  would  constitute  Indebtedness)  or  (b) is  directly  or
indirectly liable (as a guarantor or otherwise) and (ii) no default with respect
to which  (including  any  rights  that  the  holders  thereof  may have to take
enforcement  action  against an  Unrestricted  Subsidiary)  would  permit  (upon
notice,  lapse of time or both)  any  holder of any  other  Indebtedness  of the
Issuer or any  Restricted  Subsidiary  to  declare a default  under  such  other
Indebtedness  or cause the payment thereof to be accelerated or payable prior to
its stated maturity.
<PAGE>   16
                                       12

                  "Offering  Memorandum"  means the  Offering  Memorandum  dated
March 10, 2000 relating to the Initial  Notes;  provided that after the issuance
of Exchange  Notes,  all  references  herein to "Offering  Memorandum"  shall be
deemed  references to the  prospectus  contained in the  registration  statement
relating to the Exchange Notes.

                  "Officer" means the Chairman of the Board, the President,  the
Chief Executive Officer,  any Vice President,  the Chief Financial Officer,  the
Treasurer or the Secretary of the Issuer, as applicable.

                  "Officer's Certificate" means a certificate signed by any
Officer.

                  "Opinion of Counsel" means a written opinion that meets the
requirements of Section 10.5 hereof from Dow, Lohnes & Albertson, PLLC, or any
other legal counsel who is reasonably acceptable to the Trustee.  The counsel
may be an employee of or counsel to the Issuer or the Trustee.

                  "Permitted  Acquisition  Indebtedness"  means  Indebtedness or
acquired  debt in an aggregate  principal  amount not to exceed $50.0 million at
any one time outstanding, incurred or assumed in connection with the acquisition
of an  entity  that is  engaged  in a  Permitted  Business  and that  becomes  a
Restricted  Subsidiary or the acquisition of any assets  constituting a business
or  line of  business,  as  determined  by the  Board  of  Directors,  that is a
Permitted  Business  or  incurred by such entity or the owner of such assets and
outstanding on the date of such acquisition.

                  "Permitted  Business"  means  any  business  conducted  by the
Issuer and its Restricted  Subsidiaries on the Issue Date and any other business
related, ancillary or complementary to any such business.

                  "Permitted  Holders"  means any or all of  Stephen  H.  Clark,
David P. Tomick,  Joe L. Finley,  Welsh,  Carson,  Anderson & Stowe, VIII, L.P.,
WCAS  Information  Partners,  L.P.,  WCAS  Capital  Partners  III,  L.P.,  their
respective general partners,  employees of Welsh, Carson, Anderson & Stowe, CIBC
WG Argosy Merchant Fund 2, L.L.C., Co-Investment Merchant Fund 3, LLC, Caravelle
Investment Fund, L.L.C., Tower Parent Corp., Whitney Equity Partners, L.P., J.H.
Whitney III, L.P.,  Whitney Strategic Partners III, L.P., J.H. Whitney Mezzanine
Fund,  L.P.,  Waller-Sutton  Media  Partners,  L.P.,  Kitty Hawk Capital Limited
Partnership,  III,  Kitty Hawk  Capital  Limited  Partnership,  IV,  Eagle Creek
Capital, L.L.C., The North Carolina Enterprise Fund, L.P., Finley Family Limited
Partnership, and their respective Affiliates.

                  "Permitted  Investment"  means an  Investment by the Issuer or
any Restricted Subsidiary in (i) the Issuer, a Restricted Subsidiary or a Person
which will, upon the making of such Investment,  become a Restricted Subsidiary;
(ii)  another  Person if as a result of such  Investment  such  other  Person is
merged  or   consolidated   with  or  into,  or  transfers  or  conveys  all  or
substantially  all  its  assets  to,  the  Issuer  or a  Restricted  Subsidiary;
provided,  however, that such Person's primary business is a Permitted Business;
(iii) Temporary Cash  Investments;  (iv) receivables  owing to the Issuer or any
Restricted Subsidiary, if created or acquired in the ordinary course of business
and payable or dischargeable in accordance with customary trade terms; provided,
however, that such trade terms may include such concessionary trade terms as the
Issuer  or  any  such  Restricted   Subsidiary   deems   reasonable   under  the
circumstances;  (v) payroll,  travel and similar  advances to cover matters that
are expected at the time of such
<PAGE>   17
                                       13

advances  ultimately to be treated as expenses for  accounting  purposes and
that are made in the ordinary  course of business; (vi) loans or  advances to
employees  made in the  ordinary  course of business consistent with past
practice of the Issuer or such Restricted  Subsidiary,  but in any event not to
exceed $2.0 million in the aggregate  outstanding at any one time;  (vii) stock,
obligations  or securities  received in settlement of debts created  in the
ordinary  course of  business  and  owing to the  Issuer or any Restricted
Subsidiary or in satisfaction of judgments or pursuant to any plan of
reorganization  or similar  arrangement  upon the  bankruptcy or insolvency of a
debtor;  (viii) any Person to the extent such investment represents the non-cash
portion of the  consideration  received  for an Asset  Disposition  as permitted
pursuant to Section  4.7;  (ix)  Capital  Stock of the Issuer or any  Restricted
Subsidiary  purchased,  redeemed or otherwise acquired or retired for value from
members of the Issuer's management or employees,  but in any event not to exceed
$2.0 million in aggregate in any twelve-month  period;  (x) other Investments in
Permitted  Businesses  not to  exceed,  at any one time  outstanding  (each such
Investment  being  measured  as of the date made and  without  giving  effect to
subsequent  changes  in  value),  the sum of (x)  $10.0  million  and 10% of the
Issuer's  Consolidated  Tangible  Assets;  (xi) any Interest  Rate  Agreement or
Currency  Agreement;   (xii)  any  acquisition  of  assets  to  the  extent  the
consideration therefor consists of Capital Stock (other than Disqualified Stock)
of  the  Issuer;  (xiii)  prepaid  expenses,  negotiable  instruments  held  for
collection and lease, utility and workers'  compensation,  performance and other
similar  deposits;  (xiv) deposits of proceeds or Qualified  Proceeds from Asset
Dispositions  with a "qualified  intermediary,"  "qualified  trustee" or similar
person for purposes of  facilitating  a "like-kind"  exchange made in accordance
with the applicable provisions of the Internal Revenue Code of 1986, as amended;
provided,  however, that the making of any Permitted Investment pursuant to this
clause (xiv) will not in any manner violate Section 4.7; (xv)  Investments in an
amount not to exceed the Net Cash Proceeds or Qualified Proceeds of the issuance
or sale,  other than to a  Subsidiary  of the  Issuer,  of Capital  Stock of the
Issuer, other than Disqualified Stock, to the extent that such Net Cash Proceeds
or Qualified  Proceeds have not been applied to make a Restricted  Payment or to
effect other transactions pursuant to Section 4.5 or to the extent such Net Cash
Proceeds or Qualified  Proceeds  have not been used to Incur  Indebtedness;  and
(xvi)  other  Investments  not to  exceed,  at any one time  outstanding,  $75.0
million.

                  "Permitted  Liens"  means,  with  respect to any  person,  (a)
pledges  or  deposits  by  such  Person  under   worker's   compensation   laws,
unemployment  insurance laws or similar  legislation,  or good faith deposits in
connection  with  bids,  tenders,  contracts  (other  than  for the  payment  of
Indebtedness)  or leases to which such Person is a party,  or deposits to secure
public or  statutory  obligations  of such  Person or deposits or cash or United
States government bonds to secure surety or appeal bonds to which such Person is
a party, or deposits as security for contested taxes or import duties or for the
payment of rent, in each case incurred in the ordinary  course of business;  (b)
Liens  imposed  by  law,  such  as  carriers',  warehousemen's,  landlords'  and
mechanics'  Liens,  in each case for sums not yet due or being contested in good
faith by appropriate proceedings,  or judgment Liens not giving rise to an Event
of Default so long as any appropriate legal proceedings which may have been duly
initiated for the review of such judgment shall not have been finally terminated
or the period  within which such  proceedings  may be  initiated  shall not have
expired;  (c)  Liens  for  property  taxes  not yet  subject  to  penalties
<PAGE>   18
                                       14
 for
non-payment  or  which  are  being   contested  in  good  faith  by  appropriate
proceedings  (d) Liens in favor of issuers of surety  bonds or letters of credit
issued  pursuant  to the  request of and for the  account of such  Person in the
ordinary course of its business; (e) survey exceptions,  encumbrances, easements
or reservations  of, or rights of others for,  licenses,  rights of way, sewers,
electric  lines,  telegraph and telephone lines and other similar  purposes,  or
zoning  or  other  restrictions  as to  the  use of  real  properties  or  liens
incidental  to the conduct of the business of such Person or to the ownership of
its properties which were not incurred in connection with Indebtedness and which
do not in the aggregate materially adversely affect the value of said properties
or materially  impair their use in the operation of the business of such Person;
(f) Liens securing Hedging  Obligations so long as the related  Indebtedness is,
and is  permitted  to be under  this  Indenture,  secured  by a Lien on the same
property  securing  such Hedging  Obligations;  (g) leases and subleases of real
property which do not interfere with the ordinary conduct of the business of the
Issuer or any of its Restricted Subsidiaries, and Liens securing the obligations
(other than  Indebtedness)  of the Issuer or any of the Restricted  Subsidiaries
under any such leases and subleases of real  property;  (h) Liens existing as of
the date on which the Notes are  originally  issued  and Liens  created  by this
Indenture;  (i) Liens created  solely for the purpose of securing the payment of
all or part of the purchase price of assets or property  acquired or constructed
in the  ordinary  course  of  business  after  the date on which  the  Notes are
originally issued; provided,  however, that (A) the Indebtedness secured by such
Liens shall have  otherwise been permitted to be issued under this Indenture and
(B) such Liens shall not  encumber any other assets or property of the Issuer or
any of its  Restricted  Subsidiaries;  (j) Liens on the assets or  property of a
Restricted  Subsidiary  of the  Issuer  existing  at the  time  such  Restricted
Subsidiary became a Subsidiary of the Issuer and not incurred as a result of (or
in connection with or in anticipation of) such Restricted  Subsidiary becoming a
Subsidiary of the Issuer; provided,  however, that (A) any such Lien does not by
its terms cover any property or assets after the time such Restricted Subsidiary
becomes  a  Subsidiary  which  were  not  covered   immediately  prior  to  such
transaction,  (B) the Incurrence of the Indebtedness  secured by such Lien shall
have otherwise been  permitted to be issued under this  Indenture,  and (C) such
Liens do not  extend to or cover any other  property  or assets of the Issuer or
any of its Restricted Subsidiaries;  (k) Liens securing Indebtedness outstanding
under a Credit  Facility  and any other Liens  securing  Indebtedness  permitted
under this  Indenture  to be  Incurred  by a  Restricted  Subsidiary;  (l) Liens
extending,  renewing or replacing  in whole or in part a Lien  permitted by this
Indenture;  provided,  however,  that (A) such  Liens do not  extend  beyond the
property  subject to the existing Lien and improvements and construction on such
property  and (B) the  Indebtedness  secured  by the  Lien  may not  exceed  the
Indebtedness secured at the time by the existing Lien; (m) Liens Incurred in the
ordinary course of business by the Issuer or any  Restriction  Subsidiary of the
Issuer with respect to  obligations  that do not exceed $25.0 million at any one
time  outstanding and that (i) are not Incurred in connection with the borrowing
of money or the  obtaining of advances of credit (other than trade credit in the
ordinary course of business) and (ii) do not in the aggregate materially detract
from the value of the  property  or  materially  impair  the use  thereof in the
operation of business by the Issuer or such Restricted Subsidiary;  (n) Liens in
favor of the Issuer or a Restricted Subsidiary;  (o) any interest in or title of
a lessor to any property subject to a Capitalized Lease Obligation  permitted to
be Incurred under this Indenture; (p) Liens on the Capital Stock of Unrestricted
Subsidiaries;  (q) the Liens  granted  pursuant to the terms of
<PAGE>   19
                                       15

the Security and Subordination Agreement, as amended, modified or supplemented
from time to time, entered into pursuant to the terms of the Agreement and Plan
of Merger, dated as of February 10, 1999, among the Issuer,  SpectraSite
Communications,  Inc., SHI Merger Sub, Inc., Nextel  Communications,  Inc. and
certain of its subsidiaries; (r)  Liens,  rights of set-off or  similar  rights
and  remedies  as to deposit accounts  or  other  funds  maintained  with a
depository  or  other  financial institution;  (s) Liens on property subject to
Capitalized  Lease Obligations to the extent the related  Capitalized Lease
Obligation is permitted to be incurred under Section 4.3 or Section 4.4 of this
Indenture; (t) Liens on property of the Issuer  or a  Restricted  Subsidiary  at
the  time  the  Issuer  or  Restricted Subsidiary acquired the property,
including any acquisition by means of a merger or consolidation with or into the
Issuer or any Restricted Subsidiary; provided, however,  that such Liens are not
created,  incurred  or assumed in  connection with, or in contemplation of, such
acquisition,  provided further, however, that such  Liens  may not  extend to
any other  property  owned by the  Issuer or any Restricted  Subsidiary;  and
(u)  Liens on  government  securities  that  secure Indebtedness,  to the extent
that such government  securities are purchased with the proceeds of such
Indebtedness.

                  "Person" means any individual, corporation, partnership, joint
venture,  limited liability company,  association,  joint-stock company,  trust,
unincorporated  organization,  government or any agency or political subdivision
thereof or any other entity.

                  "Preferred  Stock",  as  applied to the  Capital  Stock of any
Person,  means Capital Stock of any class or classes (however  designated) which
is  preferred  as to the payment of  dividends  or  distributions,  or as to the
distribution  of  assets  upon  any  voluntary  or  involuntary  liquidation  or
dissolution  of such Person,  over shares of Capital Stock of any other class of
such Person.

                  "Principal" of a Note means the principal of the Note plus the
premium, if any, payable on the Note which is due or overdue or is to become due
at the relevant time.

                  "Qualified  Proceeds" means assets that are used or useful in,
or Capital Stock of any Person engaged in, a Permitted Business.

                  "Refinance"   means,  in  respect  of  any  Indebtedness,   to
refinance,  extend, renew, refund, repay, prepay, redeem,  purchase,  defease or
retire,  or to issue other  Indebtedness  in exchange or  replacement  for, such
indebtedness. "Refinanced" and "Refinancing" shall have correlative meanings.

                  "Refinancing  Indebtedness" means Indebtedness that Refinances
any Indebtedness of the Issuer or any Restricted Subsidiary existing on the date
of this  Indenture  or Incurred in  compliance  with this  Indenture  (including
Indebtedness  of the  Issuer  that  Refinances  Indebtedness  of any  Restricted
Subsidiary  and  Indebtedness  of  any  Restricted  Subsidiary  that  Refinances
Indebtedness  of another  Restricted  Subsidiary)  including  Indebtedness  that
Refinances Refinancing Indebtedness; provided, however, that (i) the Refinancing
Indebtedness  has a Stated  Maturity  no earlier  than the earlier of the Stated
Maturity  of the  Notes  and  the  Stated
<PAGE>   20
                                       16

Maturity  of the  Indebtedness  being Refinanced,  (ii) the Refinancing
Indebtedness  has an Average Life at the time such  Refinancing  Indebtedness is
Incurred that is equal to or greater than the lesser of the Average Life of the
Indebtedness  being Refinanced and the Average Life of the Notes and (iii) such
Refinancing  Indebtedness  is  Incurred  in an aggregate  principal  amount
(or if issued  with  original  issue  discount,  an aggregate  issue  price)
that is equal to or less than the sum of the  aggregate principal  amount
(or if issued with  original  issue  discount,  the  aggregate accreted value)
then outstanding or committed (plus fees and expenses, including any premium and
defeasance  costs)  under the  Indebtedness  being  Refinanced; provided
further,  however, that Refinancing  Indebtedness shall not include (x)
Indebtedness of a Subsidiary  that Refinances  Indebtedness of the Issuer or (y)
Indebtedness of the Issuer or a Subsidiary  that  refinances  Indebtedness of an
Unrestricted Subsidiary.

                  "Restricted  Payment" with respect to any Person means (i) the
declaration or payment of any dividends or any other  distributions  of any sort
in respect of its  Capital  Stock or similar  payment to the direct or  indirect
holders of its Capital  Stock in respect  thereof  (other than (a)  dividends or
distributions  payable  solely in its Capital  Stock  (other  than  Disqualified
Stock),  (b)  dividends  or  distributions  payable  solely  to the  Issuer or a
Restricted Subsidiary, and (c) pro rata dividends or other distributions made by
a Subsidiary that is not a Wholly Owned Subsidiary to minority  stockholders (or
owners of an equivalent  interest in the case of a Subsidiary  that is an entity
other than a corporation)),  (ii) the purchase,  redemption or other acquisition
or retirement for value of any Capital Stock of the Issuer held by any Person or
of any Capital Stock of a Restricted  Subsidiary  held by any Person (other than
the Issuer or a Restricted Subsidiary), other than the exercise by the Issuer of
any option to convert or exchange any Capital Stock into Indebtedness so long as
such  Indebtedness  is permitted to be Incurred as of the date of such  exercise
pursuant to this  Indenture,  and other than as  permitted by clause (ix) of the
definition  of  "Permitted   Investments";   (iii)  the  purchase,   repurchase,
redemption,  defeasance or other  acquisition or retirement for value,  prior to
scheduled maturity, scheduled repayment or scheduled sinking fund payment of any
Subordinated   Obligations  (other  than  the  purchase,   repurchase  or  other
acquisition of Subordinated  Obligations purchased in anticipation of satisfying
a sinking fund obligation, principal installment or final maturity, in each case
due  within  one year of the date of  acquisition);  or (iv) the  making  of any
Investment in any Person (other than a Permitted Investment).

                  "Restricted Subsidiary" means any Subsidiary of the Issuer
other than an Unrestricted Subsidiary.

                  "Sale/Leaseback  Transaction" means an arrangement relating to
property  now owned or  hereafter  acquired  whereby the Issuer or a  Restricted
Subsidiary  transfers  such  property to a Person and the Issuer or a Restricted
Subsidiary leases it from such Person.

                  "SEC" means the U.S. Securities and Exchange Commission.

                  "Secured Indebtedness" means any Indebtedness of the Issuer
secured by a Lien.

<PAGE>   21
                                       17

                  "Securities Act" means the Securities Act of 1933, as amended.

                  "Senior  Indebtedness"  means (i)  Indebtedness of the Issuer,
whether outstanding on the Issue Date or thereafter  Incurred,  and (ii) accrued
and unpaid interest  (including  interest accruing on or after the filing of any
petition  in  bankruptcy  or for  reorganization  relating  to the Issuer to the
extent  post-filing  interest is allowed in such  proceeding)  in respect of (A)
indebtedness of the Issuer for money borrowed and (B) indebtedness  evidenced by
notes,  debentures,  bonds or other similar instruments for the payment of which
the Issuer is responsible or liable unless,  in the case of (i) and (ii), in the
instrument  creating  or  evidencing  the same or  pursuant to which the same is
outstanding,  it is provided that such  obligations  are subordinate in right of
payment to the Notes;  provided,  however,  that Senior  Indebtedness  shall not
include (1) any  obligation of the Issuer to any  Subsidiary,  (2) any liability
for Federal,  state,  local or other taxes owed or owing by the Issuer,  (3) any
accounts  payable or other liability to trade creditors  arising in the ordinary
course of business (including guarantees thereof or instruments  evidencing such
liabilities),  (4) any  Indebtedness  of the Issuer  (and any accrued and unpaid
interest in respect  thereof)  which is  subordinate or junior in any respect to
any other  Indebtedness or other  obligation of the Issuer,  (5) that portion of
any  Indebtedness  which at the time of  Incurrence  is Incurred in violation of
this Indenture.

                  "Senior Notes" means the Issuer's 10 3/4% Senior Notes due
2010.

                  "Significant  Subsidiary" means any Restricted Subsidiary that
would be a  "Significant  Subsidiary"  of the Issuer  within the meaning of Rule
1-02 under Regulation S-X promulgated by the SEC.

                  "Site  Management  Contract"  means any agreement  pursuant to
which  the  Issuer  or any of its  Restricted  Subsidiaries  has  the  right  to
substantially  control Tower Assets and the revenues  derived from the rental or
use thereof.

                  "Stated  Maturity"  means,  with respect to any security,  the
date  specified  in such  security  as the fixed  date on which the  payment  of
principal  of  such  security  is due and  payable,  including  pursuant  to any
mandatory  redemption  provision (but excluding any provision  providing for the
repurchase  of such  security  at the  option  of the  holder  thereof  upon the
happening  of any  contingency  beyond the  control of the  issuer  unless  such
contingency has occurred).

                  "Subordinated Obligation" means any Indebtedness of the Issuer
(whether  outstanding  on the  Issue  Date  or  thereafter  Incurred)  which  is
subordinate  or junior in right of  payment to the Notes  pursuant  to a written
agreement.

                  "Subsidiary" of any Person means any corporation, association,
partnership or other business  entity of which more than 50% of the total voting
power of shares  of  Capital  Stock or other  interests  (including  partnership
interests)  entitled  (without  regard to the occurrence of any  contingency) to
vote in the election of directors,  managers or trustees  thereof
<PAGE>   22
                                       18

is at the time owned or  controlled,  directly or  indirectly,  by (i) such
Person,  (ii) such Person  and one or  more  Subsidiaries  of  such  Person  or
(iii)  one or more Subsidiaries of such Person.

                  "Temporary Cash Investments"  means any of the following:  (i)
any  investment  in direct  obligations  of the United  States of America or any
agency thereof or obligations  Guaranteed by the United States of America or any
agency  thereof,  (ii)  investments in time deposit  accounts,  certificates  of
deposit  and  money  market  deposits  maturing  within  one year of the date of
acquisition  thereof issued by a bank or trust company which is organized  under
the laws of the United  States of  America,  any state  thereof  or any  foreign
country  recognized by the United States of America having capital,  surplus and
undivided  profits  aggregating  in  excess of $500.0  million  (or the  foreign
currency  equivalent  thereof)  and whose  long-term  debt is rated "A" (or such
similar  equivalent  rating)  or higher by at least  one  nationally  recognized
statistical  rating  organization  (as defined in Rule 436 under the  Securities
Act) or any money market fund sponsored by a registered  broker dealer or mutual
fund distributor,  (iii) repurchase  obligations with a term of not more than 30
days for  underlying  securities  of the types  described  in  clause  (i) above
entered  into with a bank  meeting the  qualifications  described in clause (ii)
above,  (iv)  investments in commercial  paper,  maturing not more than 270 days
after the date of acquisition,  issued by a corporation (other than an Affiliate
of the Issuer) organized and in existence under the laws of the United States of
America or any foreign country recognized by the United States of America with a
rating  at the time as of which  any  investment  therein  is made of "P-1"  (or
higher)  according  to Moody's  Investors  Service,  Inc.  or " A-1" (or higher)
according to Standard & Poor's Ratings Group,  and (v) investments in securities
with maturities of one year or less from the date of acquisition issued or fully
guaranteed  by any state,  commonwealth  or  territory  of the United  States of
America, or by any political  subdivision or taxing authority thereof, and rated
at least "A" by  Standard & Poor's  Ratings  Group or "A" by  Moody's  Investors
Service, Inc.

                  "TIA" means the Trust Indenture Act of 1939 (15 U.S.C. ss.ss.
77aaa-77bbbb) as in effect on the date of this Indenture.

                  "Tower  Asset  Exchange"  means any  transaction  in which the
Issuer or a  Restricted  Subsidiary  exchanges  assets for Tower Assets or Tower
Assets and cash or cash equivalents  where the fair market value (evidenced by a
resolution  of the  Board of  Directors)  of the Tower  Assets  and cash or cash
equivalents  received  by the Issuer  and its  Restricted  Subsidiaries  in such
exchange is at least equal to the fair  market  value of the assets  disposed in
such exchange.

                  "Tower  Assets" means  communication  transmission  towers and
related assets that are located on the site of a transmission tower.

                  "Tower EBITDA" means, for any period, the EBITDA of the Issuer
and its Restricted Subsidiaries for such period that is directly attributable to
site  rental  revenue,  license  or  management  fees paid to  manage,  lease or
sublease  space on  communication  sites owned,  leased or managed by the Issuer
(collectively,  "site leasing revenues"), all determined on a consolidated basis
and in accordance with GAAP.  Tower EBITDA will not include revenue
<PAGE>   23
                                       19

derived from the sale of assets. In allocating,  corporate, general,
administrative and other operating  expenses that are not allocated to any
particular line of business in the financial  statements of the Issuer, such
expenses shall be allocated to the Issuer's site leasing  business in proportion
to the  percentage of the Issuer's total revenues for the applicable period that
were site leasing revenues.

                  "Trust  Officer"  means  any  trust  officer,  assistant  vice
president,  or  vice  president  of  the  Trustee  assigned  by the  Trustee  to
administer this Indenture.
                  "Trustee"  means  the  party  named as such in this  Indenture
until a successor replaces it and, thereafter, means such successor.

                  "2008 Notes" means the Issuer's 12% Senior Discount Notes Due
2008.

                  "2009 Notes" means the Issuer's 11 1/4% Senior  Discount Notes
Due 2009.

                  "Uniform Commercial Code" means the New York Uniform
Commercial Code as in effect from time to time.

                  "Unrestricted  Subsidiary"  means  (i) any  Subsidiary  of the
Issuer that at the time of  determination  shall be designated  an  Unrestricted
Subsidiary by the Board of Directors in the manner  provided  below and (ii) any
Subsidiary of an Unrestricted  Subsidiary.  The Board of Directors may designate
any  Subsidiary  of the Issuer  (including  any newly  acquired or newly  formed
Subsidiary  of  the  Issuer)  to  be  an  Unrestricted  Subsidiary  unless  such
Subsidiary or any of its Subsidiaries owns any Capital Stock or Indebtedness of,
or owns or holds any Lien on any property of, the Issuer or any other Restricted
Subsidiary  of the Issuer that is not a Subsidiary  of the  Subsidiary  to be so
designated;  provided,  however,  that  either  (A)  the  Subsidiary  to  be  so
designated  has  total  consolidated  assets  of  $1,000  or less or (B) if such
Subsidiary has  consolidated  assets greater than $1,000,  then such designation
would be permitted  under  Section 4.5. The Board of Directors may designate any
Unrestricted Subsidiary to be a Restricted Subsidiary;  provided,  however, that
(a)  immediately  after giving effect to such  designation no Default shall have
occurred and be  continuing  and (b) such  designation  shall be deemed to be an
Incurrence  of  Indebtedness  by a  Restricted  Subsidiary  of  any  outstanding
Indebtedness of such Unrestricted  Subsidiary and such designation shall only be
permitted if such  Indebtedness  is  permitted  under this  Indenture.  Any such
designation  by the Board of  Directors  shall be  evidenced  to the  Trustee by
promptly filing with the Trustee a copy of the Board Resolution giving effect to
such designation and an Officer's  Certificate  certifying that such designation
complied with the foregoing provisions.

                  "U.S.  Government  Obligations"  means direct  obligations (or
certificates  representing  an ownership  interest in such  obligations)  of the
United States of America (including any agency or  instrumentality  thereof) for
the  payment of which the full faith and credit of the United  States of America
is pledged and which are not callable or redeemable at the Issuer's option.
<PAGE>   24
                                       20

                  "Voting  Stock" of a Person means all classes of Capital Stock
or  other  interests  (including  partnership  interests)  of such  Person  then
outstanding  and normally  entitled  (without  regard to the  occurrence  of any
contingency) to vote in the election of directors, managers, or trustee thereof.

                  "Wholly Owned Subsidiary" means a Restricted Subsidiary of the
Issuer all the Capital Stock of which (other than directors'  qualifying shares)
is owned by the Issuer or another Wholly Owned Subsidiary.

                  SECTION 1.2.  Other Definitions .

                                                                    Defined in
         Term                                                          Section

"Affiliate Transaction".............................................      4.8
"Appendix"..........................................................      2.1
"Authenticating Agent"..............................................      2.2
"Bankruptcy Law"....................................................      6.1
"covenant defeasance option"........................................      8.1(b)
"Custodian".........................................................      6.1
"Event of Default"..................................................      6.1
"legal defeasance option"...........................................      8.1(b)
"Offer".............................................................      4.7(b)
"Offer Amount"......................................................      4.7(b)
"Offer Period"......................................................      4.7(b)
"Paying Agent"......................................................      2.3
"Purchase Date".....................................................      4.7(b)
"Registrar".........................................................      2.3
"Successor Issuer"..................................................      5.1

         .........SECTION 1.3.  Incorporation by Reference of Trust Indenture
Act .  The mandatory provisions of the TIA are incorporated by reference in and
made a part of this Indenture.  The following TIA terms have the following
meanings:

         ........."Commission" means the SEC.

         ........."indenture securities" means the Notes.

         ........."indenture security holder" means a Holder.

                  "indenture to be qualified" means this  Indenture.

                  "indenture trustee" or "institutional  trustee" means the
Trustee.

<PAGE>   25
                                       21

                  "obligor" on the indenture securities means the Issuer and any
other obligor on the indenture securities.

         .........All other TIA terms used in this Indenture that are defined by
the TIA, defined by TIA reference to another statute or defined by SEC rule have
the meanings assigned to them by such definitions.

         .........SECTION 1.4.  Rules of Construction .  Unless the context
otherwise requires:

         .........(1)      a term has the meaning assigned to it;

                  (2)      an accounting term not otherwise defined has the
meaning assigned to it in accordance with GAAP;

         .........(3)      "or" is not exclusive;

                  (4)      "including" means including without limitation;

                  (5) words in the singular  include the plural and words in the
plural include the singular;

                  (6)  unsecured   Indebtedness   shall  not  be  deemed  to  be
         subordinate or junior to Secured  Indebtedness  merely by virtue of its
         nature as unsecured Indebtedness;

                  (7) except as  otherwise  expressly  provided,  the  principal
         amount of any  noninterest  bearing or other  discount  security at any
         date shall be the  principal  amount  thereof  that would be shown on a
         balance sheet of the issuer dated such date prepared in accordance with
         GAAP;

                  (8) the principal  amount of any Preferred  Stock shall be (i)
         the maximum liquidation  preference of such Preferred Stock or (ii) the
         maximum mandatory redemption or mandatory repurchase price with respect
         to such Preferred Stock, whichever is greater; and

                  (9) except as otherwise expressly provided,  all references to
         the date the Notes were  originally  issued shall refer to the date the
         Initial Notes were originally issued.

         .........SECTION 1.5.  One Class of Notes .  The Initial Notes, the
Private Exchange Notes and the Exchange Notes shall vote and consent together on
all matters as one class and none of the Initial Notes, the Private Exchange
Notes or the Exchange Notes shall have the right to vote or consent as a
separate class on any matter.

<PAGE>   26
                                       22

                                   ARTICLE II
                                   THE NOTES

         .........SECTION 2.1.  Form and Dating .  Certain provisions relating
to the Initial Notes, the Private Exchange Notes and the Exchange Notes are set
forth in the Rule 144A/Regulation S Appendix attached hereto (the "Appendix"),
which is hereby incorporated in and expressly made a part of this Indenture.
The Initial Notes and the Trustee's certificate of authentication thereof shall
be substantially in the form of Exhibit 1 to the Appendix, which is hereby
incorporated in and expressly made a part of this Indenture. The Exchange Notes,
the Private Exchange Notes and the Trustee's certificate of authentication
thereof shall be substantially in the form of Exhibit A, which is hereby
incorporated by reference and expressly made a part of this Indenture. The Notes
may have notations, legends or endorsements required by law, rule of any
securities exchange or over-the-counter market on which such Notes are then
listed or quoted, or usage, in addition to those set forth on the Appendix
and Exhibit A. The Issuer and the Trustee shall approve the forms of the Notes
and any notation, endorsement or legend on them.  Each Note shall be dated the
date of its authentication.  The terms of the Notes set forth in the Appendix
and Exhibit A are part of the terms of this Indenture and, to the extent
applicable, the Issuer and the Trustee, by their execution and delivery of this
Indenture, expressly agree to be bound by such terms.

         .........SECTION 2.2.  Execution and Authentication .  Two Officers
shall sign the Notes for the Issuer by manual or facsimile signature.

         .........If an Officer whose signature is on a Note no longer holds
that office at the time the Trustee authenticates the Note, the Note shall be
valid nevertheless.

         .........A Note shall not be valid until an authorized signatory of the
Trustee manually authenticates the Note.  The signature of the Trustee on a Note
shall be conclusive evidence that such Note has been duly and validly
authenticated and issued under this Indenture.

         .........The Trustee may appoint an agent (the "Authenticating Agent")
reasonably acceptable to the Issuer to authenticate the Notes.  Unless limited
by the terms of such appointment, any such Authenticating Agent may authenticate
Notes whenever the Trustee may do so. Each reference in this Indenture to
authentication by the Trustee includes authentication by such agent.

         .........SECTION 2.3.  Registrar and Paying Agent .  The Issuer shall
(i) appoint an agent (the "Registrar") who shall maintain an office or agency
where Notes may be presented for registration of transfer or for exchange and
(ii) an agent (the "Paying Agent") who shall maintain an office or agency where
Notes may be presented for payment.  The Registrar shall keep a register of the
Notes and of their transfer and exchange.  The Issuer may have one or more
co-registrars and one or more additional paying agents.  The term "Paying Agent"
includes any such additional paying agent.
<PAGE>   27
                                       23

         .........In the event the Issuer shall retain any Person not a party to
this Indenture as an agent hereunder, the Issuer shall enter into an appropriate
agency agreement with any Registrar, Paying Agent or co-registrar not a party to
this Indenture, which shall incorporate the terms of the TIA.  The agreement
shall implement the provisions of this Indenture that relate to such agent.  The
Issuer shall notify the Trustee of the name and address of each such agent.  If
the Issuer fails to maintain a Registrar or Paying Agent, the Trustee shall act
as such and shall be entitled to appropriate compensation therefor pursuant to
Section 7.7.  The Issuer or any of its domestically incorporated Wholly Owned
Subsidiaries may act as Paying Agent.

         .........The Issuer initially appoints the Trustee as Registrar and
Paying Agent for the Notes.

         .........SECTION 2.4.  Paying Agent to Hold Money in Trust .  By at
least 11:00 a.m. (New York City time) on the date on which any principal or
interest on any Note is due and payable, the Issuer shall deposit with the
Paying Agent a sum sufficient to pay such principal or interest when due.  The
Issuer shall require each Paying Agent (other than the Trustee) to agree in
writing that such Paying Agent shall hold in trust for the benefit of
Noteholders or the Trustee all money held by such Paying Agent for the payment
of principal or interest on the Notes and shall notify the Trustee of any
default by the Issuer in making any such payment.  If the Issuer or a Subsidiary
acts as Paying Agent, it shall segregate the money held by it as Paying Agent
and hold it as a separate trust fund.  The Issuer at any time may require a
Paying Agent (other than the Trustee) to pay all money held by it to the Trustee
and to account for any funds disbursed by such Paying Agent.  Upon complying
with this Section, the Paying Agent (if other than the Issuer or a Subsidiary)
shall have no further liability for the money delivered to the Trustee.  Upon
any bankruptcy, reorganization or similar proceeding with respect to the Issuer,
the Trustee shall serve as Paying Agent for the Notes.

         .........SECTION 2.5.  Noteholder Lists .  The Trustee shall preserve
in as current a form as is reasonably practicable the most recent list available
to it of the names and addresses of Noteholders.  If the Trustee or any Paying
Agent is not the Registrar, the Issuer shall cause the Registrar to furnish to
the Trustee or any such Paying Agent, in writing at least five Business Days
before each interest payment date and at such other times as the Trustee or any
such Paying Agent may request in writing, a list in such form and as of such
date as the Trustee may reasonably require of the names and addresses of
Noteholders.

         .........SECTION 2.6.  [Intentionally Omitted]

         .........SECTION 2.7.  Replacement Notes .  If a mutilated Note is
surrendered to the Trustee or if the Holder of a Note shall provide the Issuer
and the Trustee with evidence to their satisfaction that the Note has been lost,
destroyed or wrongfully taken, the Issuer shall issue and the Trustee shall
authenticate a replacement Note if the requirements of Section 8-405 of the
Uniform Commercial Code are met and the Holder satisfies any other reasonable
requirements of the Trustee.  If required by the Trustee or the Issuer, such
Holder shall furnish an indemnity bond
<PAGE>   28
                                       24

sufficient in the judgment of the Issuer and the Trustee to protect the Issuer,
the Trustee, the Paying Agent, the Registrar and any co-registrar from any loss
which any of them may suffer if a Note is replaced.  The Issuer and the Trustee
may charge the Holder for their expenses in replacing a Note, including
reasonable fees and expenses of counsel.  Every replacement Note is an
additional obligation of the Issuer.

         .........SECTION 2.8.  Outstanding Notes .  Notes outstanding at any
time are all Notes authenticated by the Trustee except for those canceled, those
delivered for cancellation and those described in this Section 2.8 as not
outstanding.  A Note does not cease to be outstanding because the Issuer or an
Affiliate of the Issuer holds the Note.

         .........If a Note is replaced pursuant to Section 2.7, it ceases to be
outstanding unless the Trustee and the Issuer receive proof satisfactory to them
that the replaced Note is held by a bona fide purchaser.

         .........If  the  Paying  Agent  segregates  and  holds  in  trust,  in
accordance  with this  Indenture,  on a redemption  date or maturity  date money
sufficient to pay all  principal and interest  payable on that date with respect
to the Notes (or portions  thereof) to be redeemed or maturing,  as the case may
be,  and the  Paying  Agent is not  prohibited  from  paying  such  money to the
Noteholders  on that date pursuant to the terms of this  Indenture,  then on and
after that date such Notes (or portions  thereof)  cease to be  outstanding  and
interest on them ceases to accrue.

         .........SECTION 2.9.  Temporary Notes .  Until definitive Notes are
ready for delivery, the Issuer may prepare and the Trustee shall authenticate
temporary Notes.  Temporary Notes shall be substantially in the form of
definitive Notes but may have variations that the Issuer considers appropriate
for temporary Notes.  Without unreasonable delay, the Issuer shall prepare and
the Trustee shall authenticate definitive Notes.  After the preparation of
definitive Notes, the temporary Notes shall be exchangeable for definitive Notes
upon surrender of the temporary Notes at any office or agency maintained by the
Issuer for that purpose and such exchange shall be without charge to the Holder.
Upon surrender for cancellation of any one or more temporary Notes, the Issuer
shall execute, and the Trustee shall authenticate and deliver in exchange
therefor, one or more definitive Notes representing an equal principal amount of
Notes.  Until so exchanged, the Holder of temporary Notes shall in all respects
be entitled to the same benefits under this Indenture as a Holder of definitive
Notes.

         .........SECTION 2.10.  Cancellation .  The Issuer at any time may
deliver Notes to the Trustee for cancellation.  The Registrar and the Paying
Agent shall forward to the Trustee for cancellation any Notes surrendered to
them for registration of transfer or exchange or payment. The Trustee shall
cancel and destroy (subject to the record retention requirements of the
Exchange Act) all Notes surrendered for registration of transfer or exchange,
payment or cancellation and deliver a certificate of such destruction to the
Issuer unless the Issuer directs the Trustee to deliver canceled Notes to the
Issuer.  The Issuer may not issue new Notes to replace Notes it has redeemed,
paid or delivered to the Trustee for cancellation.

<PAGE>   29
                                       25

         .........SECTION 2.11.  Defaulted Interest .  If the Issuer defaults in
a payment of interest on the Notes, the Issuer shall pay defaulted interest
(plus interest on such defaulted interest to the extent lawful) at the rate
specified therefor in the Notes in any lawful manner.  The Issuer may pay the
defaulted interest to the Persons who are Noteholders on a subsequent special
record date.  The Issuer shall fix or cause to be fixed (or upon the Issuer's
failure to do so the Trustee shall fix) any such special record date and payment
date to the reasonable satisfaction of the Trustee which specified record date
shall not be less than 10 days prior to the payment date for such defaulted
interest and shall promptly mail or cause to be mailed to each Noteholder a
notice that states the special record date, the payment date and the amount of
defaulted interest to be paid. The Issuer shall notify the Trustee in writing of
the amount of defaulted interest proposed to be paid on each Note and the date
of the proposed payment, and at the same time the Issuer shall deposit with the
Trustee an amount of money equal to the aggregate amount proposed to be paid
in respect of such defaulted interest or shall make arrangements satisfactory to
the Trustee for such deposit prior to the date of the proposed payment, such
money when so deposited to be held in trust for the benefit of the Person
entitled to such defaulted interest as provided in this Section 2.11.

         .........SECTION 2.12.  CUSIP Numbers .  The Issuer in issuing the
Notes may use "CUSIP" numbers (if then generally in use) and, if so, the Trustee
shall use "CUSIP" numbers in notices of redemption as a convenience to Holders;
provided, however, that any such notice may state that no representation is made
as to the correctness of such numbers either as printed on the Notes or as
contained in any notice of a redemption and that reliance may be placed only on
the other identification numbers printed on the Notes, and any such redemption
shall not be affected by any defect in or omission of such numbers.

                                   ARTICLE III
                                   REDEMPTION

         .........SECTION 3.1.  Notices to Trustee .  If the Issuer elects to
redeem Notes pursuant to paragraph 5 of the Notes (Exhibit 1 to the Appendix),
it shall notify the Trustee and the Paying Agent in writing of the redemption
date and the principal amount at maturity of Notes to be redeemed and the
redemption price.

         .........The  Issuer  shall  give each  notice to the  Trustee  and the
Paying Agent provided for in this Section at least 60 days before the redemption
date unless the Trustee and the Paying Agent consent to a shorter  period.  Such
notice shall be accompanied by an Officer's  Certificate  from the Issuer to the
effect that such redemption will comply with the conditions  herein.  The record
date relating to such  redemption  shall be selected by the Issuer and set forth
in the related  notice given to the Trustee and the Paying  Agent,  which record
date shall be not less than 15 days prior to the date selected for redemption by
the Issuer.

         .........SECTION 3.2.  Selection of Notes to Be Redeemed .  In the case
of any partial redemption, selection of the Notes for redemption will be made by
the Trustee in compliance with the requirements of the principal national
securities exchange, if any, on which the Notes
<PAGE>   30
                                       26

are listed, or, if the Notes are not so listed, on a pro rata basis, by lot or
by such other method as the Trustee in its sole discretion shall deem to be fair
and appropriate, although no Note of $1,000 in original principal amount or less
will be redeemed in part.  Provisions of this Indenture that apply to Notes
called for redemption also apply to portions of Notes called for redemption.
Upon request of the Issuer, the Trustee shall notify the Issuer of the Notes or
portions of Notes to be redeemed.

         .........SECTION 3.3.  Notice of Redemption .  At least 30 days but not
more than 60 days before a date for redemption of Notes, the Trustee at the
expense of the Issuer shall mail a notice of redemption by first-class mail to
each Holder of Notes to be redeemed.

         .........The notice shall identify the Notes to be redeemed and shall
state:

         .........(1)      the redemption date;

                  (2)      the redemption price;

                  (3)      the name and address of the Paying Agent;

                  (4) that Notes called for  redemption  must be  surrendered to
         the Paying  Agent to collect  the  redemption  price plus  accrued  and
         unpaid interest, if any;

                  (5)  if  fewer  than  all  the  outstanding  Notes  are  to be
         redeemed,  the  identification  and principal amounts of the particular
         Notes to be redeemed;

                  (6) that, unless the Issuer defaults in making such redemption
         payment or the Paying  Agent is  prohibited  from making  such  payment
         pursuant to the terms of this Indenture,  interest on Notes (or portion
         thereof)  called  for  redemption  ceases  to  accrue  on and after the
         redemption date;

                  (7)      the CUSIP number, if any, printed on the Notes being
redeemed; and

                  (8)      that no representation is made as to the correctness
or accuracy of the CUSIP number, if any, listed in such notice or printed on the
Notes.
         .........The Trustee shall give the notice of redemption in the
Issuer's name and at the Issuer's expense.  In  such  event,  the  Issuer  shall
provide  the  Trustee  with  the information required by this Section 3.3.

         .........SECTION 3.4.  Effect of Notice of Redemption .  Once notice of
redemption is mailed, Notes called for redemption shall become due and payable
on the redemption date and at the redemption price stated in the notice.  Upon
surrender to the Paying Agent, such Notes shall be paid at the redemption price
stated in the notice, plus accrued and unpaid interest, if any, to the
redemption date; provided that the Issuer shall have deposited the redemption
price with the Paying Agent or the Trustee on or before 11:00 a.m. (New York
City time) on the date of
<PAGE>   31
                                       27

redemption; provided, further, that if the redemption date is after a regular
record date and on or prior to the interest payment date, the accrued and unpaid
interest shall be payable to the Noteholder of the redeemed Notes registered on
the relevant record date.  Failure to give notice or any defect in the notice to
any Holder shall not affect the validity of the notice to any other Holder.

         .........SECTION 3.5.  Deposit of Redemption Price .  By at least 11:00
a.m. (New York City time) on the date on which any principal of or interest on
any Note is due and payable, the Issuer shall deposit with the Paying Agent (or,
if the Issuer or a Subsidiary is the Paying Agent, shall segregate and hold in
trust) money sufficient to pay the redemption price of and accrued and unpaid
interest, if any, on all Notes to be redeemed on that date other than Notes or
portions of Notes called for redemption which are owned by the Issuer or a
Subsidiary and have been delivered by the Issuer or such Subsidiary to the
Trustee for cancellation.

         .........If  the Issuer  complies with the preceding  paragraph,  then,
unless the Issuer  defaults in the payment of such redemption  price,  the Notes
shall  cease to accrete and  interest on the Notes to be redeemed  will cease to
accrue on and after the applicable  redemption  date,  whether or not such Notes
are presented for payment.

         .........SECTION 3.6.  Notes Redeemed in Part .  Upon surrender of a
Note that is redeemed in part, the Issuer shall execute and the Trustee shall
authenticate for the Holder (at the Issuer's expense) a new Note equal in a
principal amount at maturity to the unredeemed portion of the Note surrendered.

                                   ARTICLE IV
                                   COVENANTS

         .........SECTION 4.1.  Payment of Notes .  The Issuer shall promptly
pay the principal of and interest on the Notes on the dates and in the manner
provided in the Notes and in this Indenture.  Principal and interest shall be
considered paid on the date due if on or before 11:00 a.m. (New York City time)
on such date the Trustee or the Paying Agent holds (or, if the Issuer or a
Subsidiary is the Paying Agent, the segregated account or separate trust fund
maintained by the Issuer or such Subsidiary pursuant to Section 2.4) in
accordance with this Indenture money sufficient to pay all principal and
interest then due and the Trustee or the Paying Agent (or, if the Issuer or a
Subsidiary is the Paying Agent, the Issuer or such Subsidiary), as the case may
be, is not prohibited from paying such money to the Noteholders on that date
pursuant to the terms of this Indenture.

         .........The Issuer shall pay interest on overdue principal at the rate
specified therefor in the Notes, and it shall pay interest on overdue
installments of interest at the same rate to the extent lawful as provided in
Section 2.11.

         .........Notwithstanding anything to the contrary contained in this
Indenture. the Issuer or the Paying Agent may, to the extent it is required to
do so by law, deduct or withhold income or
<PAGE>   32
                                       28

other similar taxes imposed
by the United States of America or other domestic or foreign taxing authorities
from principal or interest payments hereunder.

         .........SECTION 4.2.  SEC Reports .  Notwithstanding that the Issuer
may not be required to remain subject to the reporting requirements of Section
13 or 15(d) of the Exchange Act, the Issuer will file with the SEC (unless the
SEC does not permit such filing) and provide the Trustee and Noteholders with
the annual reports and such information, documents and other reports which are
specified in Sections 13 and 15(d) of the Exchange Act.  The Issuer also will
comply with the other provisions of TIA ss. 314(a).

         .........SECTION 4.3.  Limitation on Indebtedness .  (a)  The Issuer
will not Incur, directly or indirectly, any Indebtedness unless, on the date of
such Incurrence and after giving effect to such Incurrence and the application
of the proceeds therefrom, the Indebtedness to Adjusted EBITDA Ratio of the
Issuer would be equal to or less than 7.00:1.  Accrual of interest, accretion or
amortization of original issue discount and the payment of interest in the form
of additional Indebtedness will not be deemed to be an Incurrence of
Indebtedness for purposes of this covenant.

         .........(b)      Notwithstanding the foregoing paragraph (a) and
regardless of the amount of outstanding Indebtedness of the Issuer, the Issuer
may Incur any or all of the following Indebtedness: (i) Indebtedness of the
Issuer owing to and held by any Restricted Subsidiary; provided, however, that
any event which results in any such Restricted Subsidiary ceasing to be a
Restricted Subsidiary or any subsequent transfer of any such Indebtedness
(except to another Restricted Subsidiary) will be deemed, in each case, to
constitute the Incurrence of such Indebtedness by the Issuer; (ii) Indebtedness
represented by the Notes and the Exchange Notes; (iii) Indebtedness of the
Issuer outstanding on the Issue Date; (iv) Indebtedness (including Capitalized
Lease Obligations) of the Issuer Incurred to finance the acquisition,
construction or improvement of fixed or capital assets in an aggregate principal
amount (together with the amount of any Indebtedness then outstanding and
Incurred pursuant to clause (b)(vi) of Section 4.4) at any one time outstanding
not to exceed the greater of (x) $25.0 million and (y) an amount equal to 7.5%
of the Issuer's Consolidated Tangible Assets; provided, that such Indebtedness
is Incurred within 180 days after the date of such acquisition, construction or
improvement and does not exceed the fair market value of such acquired,
constructed or improved assets, as determined in good faith by the Board of
Directors of the Issuer; (v) Refinancing Indebtedness Incurred in respect of any
Indebtedness Incurred pursuant to paragraph (a) or pursuant to clause (ii),
(iii) or this clause (v); (vi) Indebtedness (A) in respect of performance bonds,
bankers' acceptances, letters of credit and surety or appeal bonds provided by
the Issuer in the ordinary course of its business and which do not secure other
Indebtedness and (B) under Currency Agreements and Interest Rate Agreements
Incurred which, at the time of Incurrence, is in the ordinary course of
business; provided, however, that, in the case of Currency Agreements and
Interest Rate Agreements, such Currency Agreements and Interest Rate Agreements
are directly related to Indebtedness permitted to be Incurred by the Issuer
pursuant to this Indenture; (vii) Indebtedness represented by Guarantees by the
Issuer of Indebtedness otherwise permitted to be Incurred by a Restricted
Subsidiary pursuant to this Indenture;
<PAGE>   33
                                       29

(viii) Indebtedness of any other Person existing at the time such other Person
is merged with or into the Issuer outstanding on or prior to the date on which
such Person was merged with or into the Issuer (other than Indebtedness Incurred
in connection with, or to provide all or any portion of the funds or credit
support utilized to consummate, the transaction or series of related
transactions pursuant to which such Person was merged with or into the Issuer);
 provided, however, that on the date of such merger and after giving effect
thereto either (x) the Issuer would be permitted to incur at least $1.00 of
additional Indebtedness pursuant to paragraph (a) of this Section 4.3 or (y) the
Issuer would have an Indebtedness to Adjusted EBITDA Ratio immediately after
giving effect to such merger no greater than the Indebtedness to Adjusted EBITDA
Ratio immediately prior to such merger; (ix) the Incurrence by the Issuer of
Indebtedness not to exceed, at any one time outstanding (together with the
amount of any Indebtedness then outstanding and Incurred pursuant to clause (b)
(ix) of Section 4.4), 2.0 times the sum of 100% of the aggregate Net Cash
Proceeds and 50% of the non-cash proceeds received by the Issuer from the issue
or sale of Capital Stock (other than Disqualified Stock) subsequent to July 1,
1999 (other than an issuance or sale to a Subsidiary of the Issuer and other
than an issuance or sale to an employee stock ownership plan or to a trust
established by the Issuer or any of its Restricted Subsidiaries), less the
aggregate amount of such Net Cash Proceeds used to make Restricted Payments
pursuant to clause 3(B) of paragraph (a) of Section 4.5 or applied pursuant to
clause (i)(B) of paragraph (b) of Section 4.5; (x) other Indebtedness in an
aggregate principal amount outstanding at any time not to exceed $25.0 million
(together with the amount of any Indebtedness and Preferred Stock then
outstanding and Incurred pursuant to clause (b)(x) of Section 4.4); (xi)
Indebtedness Incurred by the Issuer's Subsidiaries in compliance with Section
4.4; (xii) Indebtedness incurred under Credit Facilities, in an aggregate
principal amount outstanding at any time, together with the amount of any
Indebtedness then outstanding and incurred under Section 4.4(b)(i) of this
Indenture, not to exceed the sum of (A) the product of $200,000 times the number
of Completed Towers on the date of incurrence and (B) the product of $1,000,000
times the number of Completed Broadcast Towers on the date of such incurrence;
provided that the amount of such Indebtedness incurred pursuant to this clause
(B) does not exceed 25% of the cost of acquiring or constructing such Completed
Broadcast Towers; (xiii) Indebtedness representing the deferred payment of the
purchase price for any entity that is engaged in a Permitted Business and that
becomes a Restricted Subsidiary or the acquisition of any assets constituting a
business or line of business, as determined in good faith by the Board of
Directors of the Issuer, that is a Permitted Business, not to exceed at any one
time outstanding, together with any Indebtedness then outstanding and incurred
pursuant to Section 4.4(b)(xi) of this Indenture, 50% of the purchase price for
the related entity or business so acquired; provided, however, that after giving
effect to such acquisition and all Indebtedness incurred in connection
therewith, either (A) the Issuer would have been able to incur at least $1.00 of
additional Indebtedness under this Section 4.3 or (B) the Issuer would have had
an Indebtedness to Adjusted EBITDA Ratio no greater than prior to such
transaction; and (xiv) Permitted Acquisition Indebtedness.

         .........(c)  Notwithstanding the foregoing, the Issuer shall not Incur
any Indebtedness  pursuant to the foregoing paragraph (b) of this Section 4.3 if
the  proceeds  thereof  are used,  directly  or  indirectly,  to  Refinance  any
Subordinated  Obligations unless such new Indebtedness
<PAGE>   34

                                     30
shall (i) be subordinated to the Notes to at least the same extent as such
Subordinated  Obligations being Refinanced  and (ii) have a Stated  Maturity
that is no earlier than the earlier of the Stated Maturity of the Subordinated
Obligations being Refinanced.

         .........(d)  For purposes of determining  compliance with this Section
4.3,  (i) in the event that an item of  Indebtedness  meets the criteria of more
than one of the types of Indebtedness  described above, the Issuer,  in its sole
discretion,  will classify (and may from time to time  reclassify)  such item of
Indebtedness  and  only be  required  to  include  the  amount  and type of such
Indebtedness in one of the above clauses of this Section 4.3 and (ii) an item of
Indebtedness  may be  divided  and  classified  in more than one of the types of
Indebtedness described in this Section 4.3.

         .........SECTION 4.4.  Limitation on Indebtedness and Preferred Stock
of Restricted Subsidiaries . (a)  The Issuer shall not permit any Restricted
Subsidiary to Incur, directly or indirectly, any Indebtedness or Preferred Stock
unless, on the date of such Incurrence and after giving effect to such
Incurrence and the application of the net proceeds therefrom, the Indebtedness
to Adjusted EBITDA Ratio of the Issuer would be equal to or less than 7.00:1.
Accrual of interest, accretion or amortization of original issue discount and
the payment of interest in the form of additional Indebtedness will not be
deemed to be an Incurrence of Indebtedness for purposes of this covenant.

         .........(b)      Notwithstanding the foregoing paragraph (a) and
regardless of the amount of outstanding Indebtedness of the Restricted
Subsidiaries, any Restricted Subsidiary may Incur any or all of the following
Indebtedness:  (i) Indebtedness Incurred under Credit Facilities in an aggregate
principal amount outstanding at any time (together with the amount of any
Indebtedness then outstanding and incurred under clause (b)(xii) of Section 4.3)
not to exceed the sum of (x) the product of $200,000 times the number of
Completed Towers on the date of such Incurrence; and (y) the product of
$1,000,000 times the number of Completed Broadcast Towers on the date of such
Incurrence, provided that the amount of such Indebtedness incurred pursuant to
this clause (y) does not exceed 25% of the cost of acquiring or constructing
such Completed Broadcast Towers; (ii) Indebtedness or Preferred Stock of a
Restricted Subsidiary issued to and held by the Issuer or a Restricted
Subsidiary; provided, however, that any subsequent issuance or transfer of any
Capital Stock which results in any such Restricted Subsidiary ceasing to be a
Restricted Subsidiary or any subsequent transfer of such Indebtedness or
Preferred Stock (other than to the Issuer or a Restricted Subsidiary) shall be
deemed, in each case, to constitute the Incurrence of such Indebtedness or
Preferred Stock by the issuer thereof; (iii) Indebtedness or Preferred Stock of
a Restricted Subsidiary Incurred and outstanding on or prior to the date on
which such Restricted Subsidiary was acquired by the Issuer and Indebtedness or
Preferred Stock of an entity merged into a Restricted Subsidiary (other than, in
either case, Indebtedness or Preferred Stock Incurred in connection with, or to
provide all or any portion of the funds or credit support utilized to
consummate, the transaction or series of related transactions pursuant to which
such Restricted Subsidiary became a Restricted Subsidiary or was acquired by the
Issuer or such entity was merged into such Restricted Subsidiary); provided,
however, that on the date of such acquisition or merger and after giving effect
thereto, either
<PAGE>   35
                                       31

(x) the Issuer would have been permitted to incur at least $1.00 or additional
Indebtedness pursuant to paragraph (a) of Section 4.3 or (y) the Issuer would
have had an Indebtedness to Adjusted EBITDA Ratio immediately after giving
effect to such merger or acquisition no greater than the Indebtedness to
Adjusted EBITDA Ratio immediately prior to such transaction; (iv) Indebtedness
or Preferred Stock outstanding on the Issue Date; (v) Refinancing Indebtedness
Incurred in respect of Indebtedness or Preferred Stock referred to in paragraph
(a) above or in clauses (iii) or (iv) of this paragraph or this clause (v);
provided, however, that Indebtedness of the Issuer may not be refinanced
pursuant to this clause (v); (vi) Indebtedness (including Capitalized Lease
Obligations) Incurred by a Subsidiary to finance the acquisition, construction
or improvement of fixed or capital assets in an aggregate principal amount at
any one time outstanding (together with the amount then outstanding and Incurred
pursuant to clause (b)(iv) of Section 4.3) not to exceed the greater of (x)
$25.0 million and (y) an amount equal to 7.5% of the Issuer's Consolidated
Tangible Assets; provided, that such Indebtedness is Incurred within 180 days
after the date of such acquisition, construction or improvement and does not
exceed the fair market value of such acquired, constructed or improved assets,
as determined in good faith by the Board of Directors of the Issuer; (vii)
Indebtedness (A) in respect of performance bonds, bankers' acceptances, letters
of credit and surety or appeal bonds provided in the ordinary course of its
business and which do not secure other Indebtedness and (B) under Currency
Agreements and Interest Rate Agreements Incurred which, at the time of
Incurrence, is in the ordinary course of business; provided, however, that, in
the case of Currency Agreements and Interest Rate Agreements, such Currency
Agreements and Interest Rate Agreements are directly related to Indebtedness
permitted to be Incurred pursuant to this Indenture; (viii) Indebtedness
represented by Guarantees, by a Subsidiary, of Indebtedness otherwise permitted
to be Incurred by the Issuer or a Subsidiary pursuant to this Indenture;
provided that any Subsidiary which guarantees the 2008 Notes or the 2009 Notes
will guarantee the Notes; any Subsidiary that guarantees the Notes will
guarantee the Senior Notes; any Subsidiary that guarantees the Senior Notes will
guarantee the Notes; in each case on substantially similar terms; (ix) the
Incurrence of Indebtedness not to exceed, at any one time outstanding (together
with the amount of any Indebtedness then outstanding and Incurred pursuant to
clause (b)(ix) of Section 4.3), 2.0 times (A) the sum of 100% of the aggregate
Net Cash Proceeds and 50% of the non-cash proceeds received by the Issuer from
the issue or sale of Capital Stock (other than Disqualified Stock) subsequent to
July 1, 1999, other than an issuance or sale to a Subsidiary or to an employee
stock ownership plan or to a trust established by the Issuer or any Restricted
Subsidiary, less (B) the amount of such Net Cash Proceeds used to make
Restricted Payments pursuant to clause 3(B) of paragraph (a) of Section 4.5 or
applied pursuant to clause (i)(B) of paragraph (b) of Section 4.5; (x) other
Indebtedness and Preferred Stock in an aggregate principal and/or liquidation
amount outstanding at any time not to exceed $25.0 million (less the amount of
any Indebtedness then outstanding and Incurred pursuant to clause (b)(x) of
Section 4.3); (xi) Indebtedness representing the deferred payment of the
purchase price for any entity that is engaged in a Permitted Business and that
becomes a Restricted Subsidiary or the acquisition of any assets constituting a
business or line of business, as determined in good faith by the Board of
Directors of the Issuer, that is a Permitted Business, not to exceed at any one
time outstanding, together with any Indebtedness then outstanding and incurred
pursuant to Section 4.3(b)(xiii) of this Indenture, 50% of the purchase price
for the related entity or business so acquired; provided, however, that after
giving
<PAGE>   36
                                       32
effect to such acquisition and all Indebtedness incurred in connection
therewith, either (A) the Issuer would have been able to incur at least $1.00 of
additional Indebtedness under Section 4.3 or (B) the Issuer would have had an
Indebtedness to Adjusted EBITDA Ratio no greater than prior to such transaction;
and (xii) Permitted Acquisition Indebtedness.

         .........(c)  For purposes of determining  compliance with this Section
4.4,  (i) in the event that an item of  Indebtedness  meets the criteria of more
than one of the types of Indebtedness  described above, the Issuer,  in its sole
discretion,  will classify (and may from time to time  reclassify)  such item of
Indebtedness  and  only be  required  to  include  the  amount  and type of such
Indebtedness in one of the above clauses of this Section 4.4 and (ii) an item of
Indebtedness  may be  divided  and  classified  in more than one of the types of
Indebtedness described in this Section 4.4

         .........This Issuer will not permit any Unrestricted Subsidiary to
Incur any Indebtedness other than Non-Recourse Debt.

         .........SECTION 4.5.  Limitation on Restricted Payments .  (a)  The
Issuer will not, and will not permit any Restricted Subsidiary, directly or
indirectly, to make any Restricted Payment if at the time the Issuer or such
Restricted Subsidiary makes such Restricted Payment:  (1) a Default or Event of
Default will have occurred and be continuing (or would result therefrom); (2)
except with respect to making an Investment, the Issuer could not incur at least
$1.00 of additional Indebtedness under paragraph (a) of Section 4.3; or (3) the
aggregate amount of such Restricted Payment and all other Restricted Payments
(the amount so expended, if other than in cash, to be determined in good faith
by the Board of Directors of the Issuer, whose determination will be evidenced
by a resolution of such Board of Directors) declared or made subsequent to the
Issue Date would exceed the sum of:  (A) (x) the aggregate EBITDA (or, in the
event such EBITDA shall be a deficit, minus such deficit) accrued subsequent to
July 1, 1999 to the most recent date for which financial information is
available to the Issuer, taken as one accounting period, (y) less 1.4 times
Consolidated Interest Expense for the same period; (B) (x) 100% of the aggregate
Net Cash Proceeds (less the aggregate amount of such Net Cash Proceeds used to
Incur Indebtedness pursuant to clause (b)(ix) of Section 4.3 and clause (b)(ix)
of Section 4.4) and (y) 70% of the GAAP purchase accounting valuation of
Qualified Proceeds (with each such valuation calculated as of the sale date of
the Capital Stock received as consideration therefor), in each case received by
the Issuer from the issue or sale of Capital Stock (other than Disqualified
Stock) subsequent to July 1, 1999 (other than an issuance or sale to a
Subsidiary of the Issuer and other than an issuance or sale to an employee stock
ownership plan or to a trust established by the Issuer or any of its Restricted
Subsidiaries); (C) the amount by which Indebtedness of the Issuer is reduced on
the Issuer's balance sheet upon the conversion or exchange (other than by a
Restricted Subsidiary) subsequent to the Issue Date of any Indebtedness of the
Issuer convertible or exchangeable for Capital Stock (other than Disqualified
Stock) of the Issuer (less the amount of any cash, or the fair value of any
other property, distributed by the Issuer upon such conversion or exchange); (D)
an amount equal to the sum of (i) the net reduction in Investments in
Unrestricted Subsidiaries resulting from dividends, repayments of loans or
advances or other transfers of assets to the Issuer or any Restricted Subsidiary
from Unrestricted Subsidiaries and
<PAGE>   37
                                       33

(ii) the portion (proportionate to the Issuer's equity interest in such
Subsidiary) of the fair market value of the net assets of an Unrestricted
Subsidiary at the time such Unrestricted subsidiary is designated a Restricted
Subsidiary; provided, that the foregoing sum shall not exceed, in the case of
any Unrestricted Subsidiary, the amount of Investments previously made by the
Issuer or any Restricted Subsidiary in such Unrestricted Subsidiary, which
amount was included in the calculation of the amount of Restricted Payments;
(E) dividends and distributions received by the Issuer subsequent to the Issue
Date from Unrestricted Subsidiaries, to the extent such dividends and
distributions are not otherwise included in calculating EBITDA; and (F) Net Cash
Proceeds received by the Issuer subsequent to the Issue Date from Investments
that are not Permitted Investments, to the extent not otherwise included in
calculating EBITDA.

         .........(b)      The provisions of the foregoing paragraph (a) of this
Section 4.5 will not prohibit: (i) any purchase, redemption, defeasance or other
acquisition of Capital Stock of the Issuer or Subordinated Obligations made by
exchange for, or out of the net proceeds of the substantially concurrent sale
of, Capital Stock of the Issuer (other than Disqualified Stock and other than
Capital Stock issued or sold to a Subsidiary of the Issuer or an employee stock
ownership plan or to a trust established by the Issuer or any of its
Subsidiaries); provided, however, that (A) such purchase, redemption, defeasance
or other acquisition will be excluded in the calculation of the amount of
Restricted Payments and (B) to the extent applied toward any such purchase,
redemption, defeasance or other acquisition, the Net Cash Proceeds from such
sale will be excluded from clause (3)(B) of paragraph (a) of this Section 4.5,
clause (b)(ix) of Section 4.3 and clause (b)(ix) of Section 4.4; (ii) any
purchase, redemption, defeasance or other acquisition of Subordinated
Obligations made by exchange for, or out of the net proceeds of the
substantially concurrent sale of, Subordinated Obligations of the Issuer;
provided, however, that (A) the principal amount of such new Indebtedness does
not exceed the principal amount of the Subordinated Obligations being so
redeemed, repurchased, acquired or retired for value (plus the amount of any
premium required to be paid under the terms of the instrument governing the
Subordinated Obligations being so redeemed, repurchased, acquired or retired),
(B) such new Indebtedness is subordinated to the Notes at least to the same
extent as such Subordinated Obligations so purchased, exchanged, redeemed,
repurchased, acquired or retired for value, (C) such new Indebtedness has a
final scheduled maturity date later than the earlier of the final scheduled
maturity date of the Subordinated Obligations being so redeemed, repurchased,
acquired or retired and the final scheduled maturity date of the Notes, (D) such
new Indebtedness has an Average Life equal to or greater than the lesser of the
Average Life of the Indebtedness being so redeemed, repurchased, acquired, or
retired, and the Average Life of the Notes, and (E) any purchase, redemption,
defeasance or other acquisition made pursuant to this clause (b)(ii) will be
excluded in the calculation of the amount of Restricted Payments; (iii)
dividends paid within 60 days after the date of declaration thereof if at
such date of declaration such dividend would have complied with this covenant;
provided, however, that the amount of such dividend will be included in the
calculation of the amount of Restricted Payments; and (iv) purchases of
outstanding shares of the Issuer's capital stock from former employees in an
amount not to exceed $5.0 million in the aggregate; provided, however, that such
purchases will be included in the calculation of the amount of Restricted
Payments; provided, however, that, at the time of, and
<PAGE>   38
                                       34

after giving effect to, any Restricted payment permitted by clauses (i), (ii)
and (iv), no Default or Event of Default shall have occurred and be continuing.

         .........The amount of any Investment shall be measured on the date
made and shall not give effect to subsequent changes in value.

         .........SECTION 4.6.  Limitation on Restrictions on Distributions from
Restricted Subsidiaries .  The Issuer will not, and will not permit any
Restricted Subsidiary to, create or otherwise cause or permit to exist or become
effective any consensual encumbrance or restriction on the ability of any
Restricted Subsidiary to (i) pay dividends or make any other distributions on
its Capital Stock to the Issuer or a Restricted Subsidiary or pay any
Indebtedness or other obligation owed to the Issuer, (ii) make any loans or
advances to the Issuer or (iii) transfer any of its property or assets to the
Issuer or any Restricted Subsidiary, except:  (1) any encumbrance or restriction
pursuant to a Credit Facility or any agreement in effect on the Issue Date; (2)
any encumbrance or restriction with respect to a Restricted Subsidiary pursuant
to an agreement relating to any Indebtedness or Capital Stock Incurred or issued
by such Restricted Subsidiary on or prior to the date on which such Restricted
Subsidiary was acquired by the Issuer or a Restricted Subsidiary (other than
Indebtedness or Capital Stock Incurred or issued as consideration for, or to
provide any portion of the funds or credit support utilized to consummate the
transaction or series of related transactions pursuant to which such Restricted
Subsidiary became a Subsidiary or was acquired by the Issuer or a Restricted
Subsidiary) and outstanding on such date; (3) any encumbrance or restriction
pursuant to an agreement effecting a Refinancing of Indebtedness Incurred
pursuant to an agreement referred to in clause (1) or (2) of this Section 4.6 or
contained in any amendment to an agreement referred to in clause (1) or (2) of
this Section 4.6; provided, however, that the encumbrances and restrictions with
respect to such Restricted Subsidiary contained in any such refinancing
agreement or amendment taken as a whole are no less favorable to the Noteholders
than the encumbrances and restrictions with respect to such Restricted
Subsidiary contained in such predecessor agreements as determined in good faith
by the Board of Directors of the Issuer; (4) in the case of clause (iii), any
encumbrance or restriction that restricts in a customary manner the subletting,
assignment or transfer of any property or asset that is subject to a lease,
license or other contract or such lease, license or other such contract; (5) in
the case of clause (iii), contained in security agreements or mortgages securing
Indebtedness of a Restricted Subsidiary to the extent such encumbrance or
restrictions restrict the transfer of the property subject to such security
agreements or mortgages; (6) any restriction with respect to a Restricted
Subsidiary imposed pursuant to an agreement entered into for the sale or
disposition of all or substantially all the Capital Stock or assets of
such Restricted Subsidiary pending the closing of such sale or disposition; (7)
customary provisions with respect to the disposition or distribution of assets
or property in joint venture and other similar agreements; and (8) restrictions
on cash or other deposits or net worth imposed by customers under contracts
entered into in the ordinary course of business; provided that the Board of
Directors of the Issuer in good faith determines that such restrictions will not
have a material adverse impact on the Issuer's ability to make payments on the
Notes.
<PAGE>   39
                                       35

         .........SECTION 4.7.  Limitation on Sale of Assets and Subsidiary
Stock .  (a)  The Issuer will not, and will not permit any Restricted Subsidiary
to, directly or indirectly, consummate any Asset Disposition unless (i) the
Issuer or such Restricted Subsidiary receives consideration at the time of such
Asset Disposition at least equal to the fair market value (including as to the
value of all non-cash consideration), as determined in good faith by the Board
of Directors of the Issuer of the shares and assets subject to such Asset
Disposition and (ii) except in the case of a Tower Asset Exchange, at least 75%
of the consideration thereof received by the Issuer or such Restricted
Subsidiary is in the form of cash or cash equivalents.

         .........Within  365 days after the receipt of any Net  Available  Cash
from an Asset Disposition,  the Issuer or the applicable  Restricted  Subsidiary
may apply such Net  Available  Cash to: (A)  prepay,  repay,  redeem or purchase
Indebtedness  (other  than  Disqualified  Stock)  of  a  Restricted   Subsidiary
(provided,  that the applicable  Restricted  Subsidiary also may prepay,  repay,
redeem or purchase its own outstanding  Indebtedness) or Senior Indebtedness (in
each case other than  Indebtedness  owed to the  Issuer or an  Affiliate  of the
Issuer);  (B) make an offer with  respect to the 2008 Notes or the 2009 Notes to
the extent  required in the indentures  governing the 2008 Notes and 2009 Notes;
(C) acquire  all or  substantially  all of the assets of an entity  engaged in a
Permitted Business; (D) acquire Voting Stock of an entity engaged in a Permitted
Business  from a Person that is not a Subsidiary of the Issuer;  provided,  that
(x) after giving effect thereto, the Issuer or its Restricted  Subsidiary owns a
majority of such Voting  Stock and (y) such  acquisition  is  otherwise  made in
accordance with this Indenture,  including, without limitation,  Section 4.5; or
(E) make a capital  expenditure or acquire other long-term  assets that are used
or useful in a  Permitted  Business.  To the  extent of the  balance of such Net
Available Cash after  application in accordance  with clauses (A), (B), (C), (D)
or (E), the Issuer shall make an Offer (as defined in Section 4.7(b)) to Holders
of the Notes to purchase  Notes  pursuant to and subject to the  conditions  set
forth in paragraph (b) of this Section 4.7.

         .........Notwithstanding  the foregoing provisions,  the Issuer and its
Restricted Subsidiaries shall not be required to apply any Net Available Cash in
accordance  herewith  except to the extent that the aggregate Net Available Cash
from all  Asset  Dispositions  which are not  applied  in  accordance  with this
covenant  exceeds $10.0  million.  Pending  application  of Net  Available  Cash
pursuant  to this  covenant,  such  Net  Available  Cash  shall be  invested  in
Permitted Investments.

         .........For the purposes of this Section 4.7(a), the following are
deemed to be cash:  (x) the assumption by the transferee of Indebtedness of the
Issuer (other than Disqualified Stock of the Issuer and other than Indebtedness
that is subordinated to the Notes) or Indebtedness of any Restricted Subsidiary
and the release of the Issuer or such Restricted Subsidiary from all liability
on such Indebtedness in connection with such Asset Disposition; (y) securities
received by the Issuer or any Restricted Subsidiary from the transferee that are
converted by the Issuer or such Restricted Subsidiary into cash within 20 days
of the applicable Asset Disposition (to the extent of the cash received); and
(z) any liabilities (as shown on the Issuer's or such Restricted Subsidiary's
most recent balance sheet) of the Issuer or any Restricted Subsidiary (other
than contingent liabilities and liabilities that are by their terms subordinated
to the Notes or any
<PAGE>   40
                                       36

guarantee thereof) that are assumed by the transferee of any such assets
pursuant to a customary novation agreement that releases the Issuer or any such
Restricted Subsidiary from further liability.

         .........(b)  In the event of an Asset  Disposition  that  requires the
purchase of Notes pursuant to paragraph (a) of this Section 4.7, the Issuer will
be required to purchase  Notes  tendered  pursuant to an offer by the Issuer for
the Notes (the "Offer") at a purchase  price of 100% of their  Accreted Value as
of the date of purchase  (without  premium) plus accrued and unpaid  interest to
the date of purchase in accordance with the procedures  (including  prorating in
the event of  oversubscription)  set forth in this  Indenture.  If the aggregate
purchase  price of Notes  tendered  pursuant  to the  Offer is less than the Net
Available  Cash  allotted to the  purchase of the Notes,  the Issuer may use any
remaining  Net  Available  Cash for general  corporate  purposes  not  otherwise
prohibited by this Indenture.  If the aggregate purchase price of Notes tendered
pursuant to the Offer is greater  than the Net  Available  Cash  allotted to the
purchase of the Notes,  the Trustee will select the Notes to be purchased on the
basis set forth in paragraph  (c) of this Section 4.7.  Upon  completion  of any
required  Offer to the holders of the Notes,  the amount of Net  Available  Cash
will be reset at zero.  The Issuer  shall not be  required  to make an Offer for
Notes pursuant to this Section 4.7 if the Net Available Cash available  therefor
(after  application  of the  proceeds  as provided  in the second  paragraph  of
Section  4.7(a)) are less than $10.0 million for all Asset  Dispositions  (which
lesser amounts shall be carried  forward for purposes of determining  whether an
Offer is required  with respect to the Net  Available  Cash from any  subsequent
Asset Disposition).

         .........(c)  (1)  Promptly,  and in any event within 30 days after the
Issuer  becomes  obligated  to make an Offer,  the Issuer  shall be obligated to
deliver to the Trustee and send,  by  first-class  mail to each  Holder,  at the
address  appearing in the security  register,  a written notice stating that the
Holder may elect to have his Notes purchased by the Issuer either in whole or in
part (subject to prorationing as hereinafter described in the event the Offer is
oversubscribed) in integral multiples of $1,000 of principal amount at maturity,
at the applicable  purchase price.  The notice shall specify a purchase date not
less  than 30 days nor more  than 60 days  after  the date of such  notice  (the
"Purchase Date") and shall contain all  instructions and materials  necessary to
tender Notes pursuant to the Offer.

         .........(2)  Not later than the date upon which  written  notice of an
Offer is delivered to the Trustee as provided below, the Issuer shall deliver to
the  Trustee  an  Officer's  Certificate  as to (i) the amount of the Offer (the
"Offer  Amount"),  (ii) the  allocation of the Net Available Cash from the Asset
Dispositions pursuant to which such Offer is being made and (iii) the compliance
of such allocation with the provisions of Section 4.7(a). Upon the expiration of
the period for which the Offer  remains  open (the "Offer  Period"),  the Issuer
shall  deliver to the Trustee  for  cancellation  the Notes or portions  thereof
which have been properly  tendered to and are to be accepted by the Issuer.  Not
later than 11:00 a.m.  (New York City  time) on the  Purchase  Date,  the Issuer
shall  irrevocably  deposit  with the Trustee or with a paying agent (or, if the
Issuer is acting as Paying Agent, segregate and hold in trust) an amount in cash
sufficient  to pay the Offer  Amount  for all Notes  properly  tendered  to, not
withdrawn from and accepted by the Issuer.  The
<PAGE>   41
                                       37

Trustee  shall,  on the Purchase Date,  mail or  deliver  payment to each
tendering  Holder in the amount of the purchase price.

         .........(3) Holders electing to have a Note purchased will be required
to  surrender  the Note,  together  with all  necessary  endorsements  and other
appropriate materials duly completed,  to the Issuer at the address specified in
the notice at least three Business Days prior to the Purchase Date. Holders will
be entitled to withdraw their election in whole or in part if the Trustee or the
Issuer  receives not later than one  Business Day prior to the Purchase  Date, a
facsimile  transmission  or letter  setting  forth the name of the  Holder,  the
principal  amount of the Note  (which  shall be $1,000  in  principal  amount at
maturity or an integral  multiple  thereof)  which was delivered for purchase by
the Holder,  the  aggregate  principal  amount at maturity of such Note (if any)
that remains  subject to the  original  notice of the Offer and that has been or
will be delivered for purchase by the Issuer and a statement that such Holder is
withdrawing  his election to have such Note  purchased.  If at the expiration of
the Offer Period the aggregate principal amount at maturity of Notes surrendered
by Holders  exceeds the Offer  Amount,  the Trustee shall select the Notes to be
purchased  in  accordance   with  the  provisions  of  Section  3.2  (with  such
adjustments as may be deemed  appropriate by the Trustee so that only securities
in denominations of $1,000 principal amount at maturity,  or integral  multiples
thereof,  shall be  purchased).  Holders whose Notes are purchased  only in part
will  be  issued  new  Notes  equal  in  principal  amount  at  maturity  to the
unpurchased portion of the Notes surrendered.

         .........(4)      A Note shall be deemed to have been accepted for
purchase at the time the Trustee, directly or through an agent, mails or
delivers payment therefor to the surrendering Holder.

         .........(d) The Issuer will comply, to the extent applicable, with the
requirements of Section 14(e) of the Exchange Act and any other  securities laws
or  regulations  in connection  with the  repurchase  of Notes  pursuant to this
covenant.  To  the  extent  that  the  provisions  of  any  securities  laws  or
regulations  conflict with  provisions of this covenant,  the Issuer will comply
with the applicable  securities  laws and  regulations and will not be deemed to
have breached its obligations under this covenant by virtue thereof.

         .........(e)      The provisions of this Section 4.7 shall not apply to
any transaction that is permitted under the provisions of Section 5.1.

         .........SECTION 4.8.  Limitation on Transactions with Affiliates .
(a)  The Issuer will not, and will not permit any Restricted Subsidiary to,
directly or indirectly, enter into or conduct any transaction or series
of transactions (including the purchase, sale, lease or exchange of any
property, employee compensation arrangements or the rendering of any service)
with any Affiliate of the Issuer (an "Affiliate Transaction") unless (i) the
terms of such transaction, taken as a whole, are no less favorable to the Issuer
or such Restricted Subsidiary, as the case may be, than those that could be
obtained at the time of such transaction in arm's-length dealings with a Person
who is not such an Affiliate; (ii) in the event such Affiliate Transaction
involves an aggregate amount in excess of $5.0 million, the terms of such
transaction are set forth in writing
<PAGE>   42
                                       38

and shall have been approved by a majority of the members of the Board of
Directors having no personal stake in such Affiliate Transaction (and such
majority determines that such Affiliate Transaction satisfies the criteria
in clause (i) above) and (iii) in the event such Affiliate Transaction involves
an aggregate amount in excess of $10.0 million, the Issuer has received a
written opinion from a nationally recognized independent investment banking firm
that such Affiliate Transaction is fair to the Issuer and its Restricted
Subsidiaries from a financial point of view.

         .........(b)  The provisions of paragraph (a) of this Section 4.8 shall
not prohibit (i) any Restricted Payment permitted to be made pursuant to Section
4.5, (ii) any issuance of  securities,  or other  payments,  awards or grants in
cash,  securities  or  otherwise  pursuant  to, or the  funding  of,  employment
arrangements,  stock options and stock  ownership plans approved by the Board of
Directors of the Issuer, or any arrangements  relating thereto,  (iii) the grant
of stock  options or similar  rights to  employees  and  directors of the Issuer
pursuant to plans  approved by the Board of Directors of the Issuer,  (iv) loans
or advances to employees in the ordinary  course of business in accordance  with
the past practices of the Issuer or its Restricted Subsidiaries, (v) the payment
of reasonable  fees to directors of the Issuer and its  Restricted  Subsidiaries
who are not  employees of the Issuer or its  Restricted  Subsidiaries,  (vi) any
transaction between the Issuer and a Restricted Subsidiary or between Restricted
Subsidiaries,  (vii) the  issuance  or sale of any  Capital  Stock  (other  than
Disqualified Stock) of the Issuer,  (viii) any transaction  consummated pursuant
to the terms of any  agreement  described  in the Form  10-K for the year  ended
December 31, 1999,  including the exhibits and  documents  included by reference
therein, giving effect to any subsequent supplements,  amendments, modifications
or  alterations  thereof that are approved by the  disinterested  members of the
Issuer's  Board of Directors,  (ix) any  transaction  in the ordinary  course of
business  between the Issuer or any  Restricted  Subsidiary and any Affiliate of
the Issuer relating to the  acquisition,  management,  construction,  leasing or
licensing of Tower Assets, provided,  however, that such transaction is on terms
that are no less  favorable,  taken as a whole,  to the  Issuer or the  relevant
Restricted  Subsidiary  than those that could have been obtained in a comparable
transaction by the Issuer or such Restricted Subsidiary with an unrelated Person
or is otherwise on terms that, taken as a whole, the Issuer has determined to be
fair  to  the  Issuer  or  the  relevant  Restricted  Subsidiary)  and  (x)  any
transaction between the Issuer or any of its Restricted  Subsidiaries and any of
its Affiliates involving ordinary course investment banking,  commercial banking
or related activities.

         .........SECTION 4.9.  Change of Control .  (a)  Upon the occurrence of
a Change of Control, each Holder shall have the right to require that the Issuer
repurchase all or any part of such Holder's Notes at a purchase price in cash
equal to 101% of the Accreted Value thereof as of the date of repurchase, plus
accrued and unpaid interest, if any, to the date of repurchase, in accordance
with the terms contemplated in Section 4.9(b).

         .........(b)      Within 30 days following any Change of Control, the
Issuer shall mail a notice to each Holder at its registered address with a copy
to the Trustee stating:
<PAGE>   43
                                       39

                           (1) that a Change of Control  has  occurred  and that
                  such  Holder has the right to require  the Issuer to  purchase
                  such  Holder's  Notes in  denominations  of  $1,000  principal
                  amount at  maturity  or any  integral  multiple  thereof  at a
                  purchase  price in cash  equal to 101% of the  Accreted  Value
                  thereof as of the date of repurchase,  plus accrued and unpaid
                  interest, if any, to the date of repurchase;

                           (2) the  circumstances  and relevant facts  regarding
                  such Change of Control (including  information with respect to
                  pro forma  historical  income,  cash  flow and  capitalization
                  after giving effect to such Change of Control);

                           (3) the  repurchase  date (which  shall be no earlier
                  than 30 days nor later than 60 days from the date such  notice
                  is mailed); and

                           (4)  the  instructions   determined  by  the  Issuer,
                  consistent with this Section 4.9, that a Holder must follow in
                  order to have its Notes purchased by the Issuer.

         .........(c) Holders electing to have a Note purchased will be required
to  surrender  the Note,  together  with all  necessary  endorsements  and other
appropriate materials duly completed,  to the Issuer at the address specified in
the notice at least three Business Days prior to the purchase date. Holders will
be entitled to withdraw their election if the Trustee or the Issuer receives not
later than one Business Day prior to the purchase date, a facsimile transmission
or letter setting forth the name of the Holder, the principal amount at maturity
of the Note  which was  delivered  for  purchase  by the Holder as to which such
notice of  withdrawal  is being  submitted  and a statement  that such Holder is
withdrawing his election to have such Note purchased.

         .........(d)  On the purchase date,  all Notes  purchased by the Issuer
under this Section 4.9 shall be delivered to the Trustee for  cancellation,  and
the Issuer shall pay the purchase price, including premium, if any, plus accrued
and unpaid interest, if any, to the Holders entitled thereto.

         .........(e) The Issuer will comply, to the extent applicable, with the
requirements of Section 14(e) of the Exchange Act and any other  securities laws
or  regulations  in connection  with the  repurchase  of Notes  pursuant to this
Section  4.9.  To the  extent  that the  provisions  of any  securities  laws or
regulations conflict with provisions of this Section 4.9, the Issuer will comply
with the applicable  securities  laws and  regulations and will not be deemed to
have breached its obligations under this Section 4.9 by virtue thereof.

         .........(f)  The Issuer will not be required to make an offer pursuant
to this Section 4.9 upon a Change of Control if a third party, in the manner, at
the times and otherwise in compliance  with the  requirements  set forth in this
Indenture  applicable to a Change of Control made by the Issuer,  makes an offer
to purchase and  purchases all Notes  validly  tendered and not withdrawn  under
such offer.
<PAGE>   44
                                       40

         .........(g) Notwithstanding the occurrence of a Change of Control, the
Issuer shall not be obligated to repurchase  the Notes or otherwise  comply with
this Section 4.9 if the Issuer has  irrevocably  elected to redeem all the Notes
in accordance with Article III; provided that the Issuer does not default in its
redemption obligations pursuant to such election.

         .........SECTION 4.10.  Limitation on Sale or Issuance of Capital Stock
of Restricted Subsidiaries . The Issuer (i) will not, and will not permit any
Restricted Subsidiary to, transfer, convey, sell, lease or otherwise dispose of
any Capital Stock of any Restricted Subsidiary to any Person (other than to the
Issuer or a Wholly Owned Subsidiary), and (ii) will not permit any Restricted
Subsidiary to issue any of its Capital Stock (other than, to the extent
necessary or mandated by applicable law, shares of its Capital Stock
constituting directors' qualifying shares or the ownership by foreign nationals
of Capital Stock of any Restricted Subsidiary) to any Person other than to the
Issuer or a Subsidiary unless in either case (a) the Issuer's and Restricted
Subsidiary's minority equity interest in such Person, after giving effect to any
such disposition, would be permitted under Section 4.5; and (b) the net cash
proceeds from such transfer, conveyance, sale, lease or other disposition are
applied in accordance with Section 4.7.

         .........SECTION 4.11.  Limitation on Liens .  The Issuer will not, and
will not permit any Restricted Subsidiary to, directly or indirectly, create or
permit to exist any Lien on any of its property or assets (including Capital
Stock), whether owned on the Issue Date or thereafter acquired, securing any
obligation, other than Permitted Liens, unless contemporaneously therewith
effective provision is made to secure the Notes equally and ratably with (or on
a senior basis to, in the case of Subordinated Obligations) such obligation for
so long as such obligation is so secured.

         .........SECTION 4.12.  Limitation on Sale/Leaseback Transactions .
The Issuer will not, and will not permit any Restricted Subsidiary to, enter
into any Sale/Leaseback Transaction with respect to any property unless (i) the
Issuer or such Restricted Subsidiary would be entitled to (A) Incur Indebtedness
in an amount equal to the Attributable Indebtedness with respect to such
Sale/Leaseback Transaction pursuant to Section 4.3 and (B) create a Lien on such
property securing such Attributable Indebtedness without equally and ratably
securing the Notes pursuant to Section 4.11, (ii) the net cash proceeds received
by the Issuer or any Restricted Subsidiary in connection with such
Sale/Leaseback Transaction are at least equal to the fair value (as determined
in good faith by the Board of Directors of the Issuer) of such property and
(iii) the transfer of such property is permitted by, and the Issuer or such
Restricted Subsidiary applies the proceeds of such transaction in compliance
with, Section 4.7.

         .........SECTION 4.13.  Compliance with Laws .  The Issuer shall
comply, and shall cause each of its Restricted Subsidiaries to comply, with all
applicable statutes, rules, regulations, orders and restrictions of the United
States of America, all states and municipalities thereof, and of any
governmental department, commission, board, regulatory authority, bureau, agency
and instrumentality of the foregoing, in respect of the conduct of their
respective businesses and the ownership of their respective properties, except
for such noncompliances as
<PAGE>   45
                                       41

are not in the aggregate reasonably likely to have a material adverse effect on
the financial condition or results of operations of the Issuer and its
Subsidiaries, taken as a whole.

         .........SECTION 4.14.  Compliance Certificate .  The Issuer shall
deliver to the Trustee within 120 days after the end of each fiscal year of the
Issuer an Officer's Certificate signed by the chief executive officer, the chief
financial officer or the chief accounting officer stating that in the course of
the performance by the signer of his duties as an Officer of the Issuer he would
normally have knowledge of any Default or Event of Default and whether or not
the signers know of any Default or Event of Default that occurred during such
period.  If he does, the certificate shall describe the Default or Event of
Default, its status and what action the Issuer is taking or proposes to take
with respect thereto.  The Issuer also shall comply with TIA ss. 314(a)(4).

         .........SECTION 4.15.  Further Instruments and Acts .  Upon reasonable
request of the Trustee, the Issuer will execute and deliver such further
instruments and do such further acts as may be reasonably necessary or proper to
carry out more effectively the purpose of this Indenture.

         .........SECTION 4.16.  Maintenance of Office or Agency .  The Issuer
shall maintain the office or agency required under Section 2.3.  The Issuer
shall give prior written notice to the Trustee of the location, and any change
in the location, of such office or agency.  If at any time the Issuer shall fail
to maintain any such required office or agency or shall fail to furnish the
Trustee with the address thereof, such presentations, surrenders, notices and
demands may be made or served at the address of the Trustee set forth in Section
10.2.

         .........SECTION 4.17.  Corporate Existence .  Except as otherwise
permitted by Article V and Section 4.9, the Issuer shall do or cause to be done,
at its own cost and expense, all things necessary to preserve and keep in full
force and effect its corporate existence and the corporate, partnership or
limited liability company existence of each of its Significant Subsidiaries in
accordance with the respective organizational documents of each such Subsidiary
and the material rights (charter and statutory) and franchises of the Issuer and
each such Subsidiary; provided, however, that the Issuer shall not be required
to preserve, with respect to itself, any material right or franchise and, with
respect to any of its Significant Subsidiaries, any such existence, material
right or franchise, if the Board of Directors of the Issuer shall determine in
good faith (such determination to be evidenced by a board resolution), that the
preservation thereof is no longer desirable in the conduct of the business of
the Issuer and the Subsidiaries, taken as a whole.

         .........SECTION 4.18.  Payment of Taxes and Other Claims .  The Issuer
shall pay or discharge or cause to be paid or discharged, before the same shall
 become delinquent, (i) all material taxes, assessments and governmental charges
(including withholding taxes and any penalties, interest and additions to taxes)
 levied or imposed upon it or any of its Restricted Subsidiaries or properties
of it or any of its Restricted Subsidiaries and (ii) all lawful claims for
labor, materials and supplies that, if unpaid, might by law become a Lien upon
the property of it
<PAGE>   46
                                       42

or any of its Restricted Subsidiaries; provided, however, that the Issue shall
not be required to pay or discharge or cause to be paid or discharged any such
tax, assessment, charge or claim whose amount, applicability or validity is
being contested in good faith by appropriate proceedings properly instituted and
diligently conducted for which adequate reserves, to the extent required under
GAAP, have been taken.

 .........SECTION 4.19.  Maintenance of Properties and Insurance .  (a)  The
Issuer shall, and shall cause each of its Significant Subsidiaries to, maintain
its material properties in good working order and condition (subject to ordinary
wear and tear) and make or cause to be made all necessary repairs, renewals,
replacements, additions, betterments and improvements thereto and actively
conduct and carry on its business, all as in the reasonable judgment of the
Issuer is necessary so that the business carried on by Issuer and its
Significant Subsidiaries may be actively conducted; provided, however, that
nothing in this Section 4.19 shall prevent the Issuer or any of its Subsidiaries
from discontinuing the operation and maintenance of any of its properties, if
such discontinuance is, in the good faith judgment of the Issuer or the
Subsidiary, as the case may be, desirable in the conduct of their respective
businesses and is not disadvantageous in any material respect to the Holders.

         .........(b)  The Issuer  shall  provide or cause to be  provided,  for
itself  and  each  of  its  Significant   Subsidiaries,   insurance   (including
appropriate  self-insurance)  against  loss or damage of the kinds that,  in the
good faith judgment of the Issuer,  are adequate and appropriate for the conduct
of the business of the Issuer and such  Subsidiaries in a prudent  manner,  with
reputable  insurers or with the government of the United States of America,  any
state  thereof or any agency or  instrumentality  of such  governments,  in such
amounts,  with such deductibles,  and by such methods as shall be customary,  in
the good faith judgment of the Issuer,  for companies  similarly situated in the
industry.

                                    ARTICLE V
                                SUCCESSOR ISSUER

         .........SECTION 5.1.  When the Issuer May Merge or Transfer Assets .
The Issuer will not consolidate with or merge with or into, or convey, transfer
or lease, in one transaction or a series of transactions, all or substantially
all its assets to, any Person, unless:

                  (i)  the  resulting,   surviving  or  transferee  Person  (the
         "Successor  Issuer") will be a Person  organized ind existing under the
         laws of the United States of America, any State thereof or the District
         of Columbia and the Successor Issuer (if not the Issuer) will expressly
         assume,  by  supplemental  indenture,  executed  and  delivered  to the
         Trustee,  in form  satisfactory to the Trustee,  all the obligations of
         the Issuer under the Notes and this Indenture;

                  (ii) immediately  after giving effect to such transaction on a
         pro forma  basis  (and  treating  any  Indebtedness  which  becomes  an
         obligation of the Successor  Issuer or any  Restricted  Subsidiary as a
         result of such  transaction  as having been  Incurred by the
<PAGE>   47
                                       43
         Successor Issuer or such Restricted  Subsidiary at the time of such
         transaction), no Default or Event of Default will have occurred and be
         continuing;

                  (iii)  except (A) in the case of a merger of the Issuer into a
         Wholly  Owned  Subsidiary,  (B) a merger  entered  into  solely for the
         purpose of reincorporating the Issuer in another  jurisdiction or (C) a
         merger  the Issuer  enters  into  solely  for the  purpose of forming a
         holding  company to hold all of the  outstanding  capital  stock of the
         Issuer,  immediately after giving effect to such transaction,  on a pro
         forma basis as if such transaction had occurred at the beginning of the
         applicable four quarter  period,  the Issuer or the Person formed by or
         surviving any such  consolidation or merger (if other than the Issuer),
         or to which such conveyance, transfer, lease or other disposition shall
         have been made,  either (x) would have been permitted to incur at least
         $1.00 of additional Indebtedness under Section 4.3(a) or (y) would have
         had an Indebtedness to Adjusted EBITDA Ratio  immediately  after giving
         effect to such consolidation,  merger,  conveyance,  transfer, lease or
         other  disposition no greater than the  Indebtedness to Adjusted EBITDA
         Ratio immediately prior to such transaction; and

                  (iv)  the  Issuer  will  have  delivered  to  the  Trustee  an
         Officer's Certificate and an Opinion of Counsel, each stating that such
         consolidation,  merger or transfer and such supplemental  indenture (if
         any) comply with this Indenture, as set forth in this Indenture.

          ........The  Successor Issuer will succeed to, and be substituted for,
and may exercise every right and power of, the Issuer under this Indenture,  but
the predecessor Issuer in the case of a conveyance, transfer or lease of all its
assets or  substantially  all its assets will be released  from the  obligations
under this Indenture and the Notes,  including without limitation the obligation
to pay the principal of and interest on the Notes.

                                   ARTICLE VI
                             DEFAULTS AND REMEDIES

                         .........SECTION 6.1. Events of Default . An "Event of
Default" occurs if:

                  (1) the Issuer defaults in any payment of interest on any Note
         when the same becomes due and payable, and such default continues for a
         period of 30 days;

                  (2) the Issuer defaults in the payment of the principal of any
         Note when the same becomes due and payable at its Stated Maturity, upon
         optional  or  mandatory  redemption,  upon  required  repurchase,  upon
         declaration or otherwise;

                  (3) the  Issuer  fails to comply  with its  obligations  under
Article V;

                  (4) the Issuer  fails to comply with Section  4.2,  4.3,  4.4,
         4.5, 4.6, 4.7,  4.8, 4.9,  4.10,  4.11 or 4.12 (other than a failure to
         purchase  Notes when  required  pursuant to
<PAGE>   48
                                       44

         Section  4.7 or 4.9,  which failure shall  constitute an Event of
         Default under Section 6.1(2)) and such failure continues for 30 days
         after the notice specified below;

                  (5) the Issuer fails to comply with any of its  agreements  in
         the Notes or this Indenture  (other than those referred to in (1), (2),
         (3) or (4)  above)  and such  failure  continues  for 60 days after the
         notice specified below;

                  (6) the  Issuer or any  Significant  Subsidiary  of the Issuer
         fails  to pay any  Indebtedness  within  any  applicable  grace  period
         provided in such Indebtedness  after final maturity or the acceleration
         of any such Indebtedness by the holders thereof because of a default if
         the total amount of such  Indebtedness  unpaid or  accelerated  exceeds
         $10.0 million or its foreign currency equivalent at the time;

                  (7) the  Issuer  or a  Significant  Subsidiary  of the  Issuer
         pursuant to or within the meaning of any Bankruptcy Law:

                           (A)      commences a voluntary case;

                           (B)  consents  to the  entry of an order  for  relief
                  against it in an involuntary case in which it is the debtor;

                           (C) consents to the  appointment of a Custodian of it
                  or for any substantial part of its property; or

                           (D)      makes a general assignment for the benefit
of its creditors;

         or takes any comparable action under any foreign laws relating to
insolvency;

                  (8)      a court of competent jurisdiction enters an order or
decree under any Bankruptcy Law that:

                           (A)      is for relief against the Issuer or any
Significant Subsidiary of the Issuer in an involuntary case;

                           (B)  appoints  a  Custodian  of  the  Issuer  or  any
                  Significant  Subsidiary  or for  any  substantial  part of its
                  property of the Issuer or any Significant Subsidiary; or

                           (C)  orders  the  winding  up or  liquidation  of the
                  Issuer or any Significant Subsidiary of the Issuer

         (or any  similar  relief is  granted  under any  foreign  laws) and the
         order, decree or relief remains unstayed and in effect for 90 days; or

<PAGE>   49
                                       45

               (9) any final  judgment  or decree for the payment of money in
         excess of $10.0  million  (net of any amounts  with  respect to which a
         creditworthy insurance company has acknowledged full liability (subject
         to any  deductible  amounts of less than $10.0  million  required to be
         paid by the  Issuer  or the  Significant  Subsidiary  of the  Issuer in
         accordance with the applicable  insurance  policy)) is rendered against
         the Issuer or any  Significant  Subsidiary of the Issuer and either (A)
         an enforcement  proceeding has been commenced by any creditor upon such
         judgment or decree or (B) such  judgment or decree  remains  unpaid and
         outstanding  for a period of 60 days following such judgment and is not
         discharged, waived or stayed within 10 days after notice.

         .........The  foregoing will constitute  Events of Default whatever the
reason for any such Event of Default and whether it is voluntary or  involuntary
or is effected by operation of law or pursuant to any judgment,  decree or order
of any  court  or any  order,  rule  or  regulation  of  any  administrative  or
governmental body.

         .........The term "Bankruptcy Law" means Title 11, United States Code,
or any similar Federal or state law for the relief of debtors.  The term
"Custodian" means any receiver, trustee, assignee, liquidator, custodian or
similar official under any Bankruptcy Law.

         .........A Default under clause (4), (5) and (9) of this Section 6.1 is
not an Event of Default until the Trustee by notice to the Issuer or the Holders
of at least 25% in aggregate principal amount of the outstanding Notes by notice
to the Issuer  give  notice of the  Default  and the  Issuer  does not cure such
Default  within the time  specified in said clause (4), (5) or (9) after receipt
of such notice. Such notice must specify the Default, demand that it be remedied
and state that such notice is a "Notice of Default".

         .........The Issuer shall deliver to the Trustee,  within 30 days after
it obtains knowledge of the occurrence thereof, written notice in the form of an
Officer's  Certificate  of any Event of Default under clause (6) of this Section
6.1 and any event  which  with the  giving of notice or the lapse of time  would
become an Event of Default  under clause (4), (5) or (9) of this Section 6.1 and
what action the Issuer is taking or proposes to take with respect thereto.

         .........SECTION 6.2.  Acceleration .  If an Event of Default (other
than an Event of Default specified in Section 6.1(7) or (8) with respect to the
Issuer) occurs and is continuing, the Trustee by notice to the Issuer, or the
Holders of at least 25% in aggregate principal amount at maturity of the
outstanding Notes by notice to the Issuer, may declare the Accreted Value of,
and accrued but unpaid interest on all the Notes to be due and payable.  Upon
such a declaration, such Accreted Value and interest shall be due and payable
immediately.  If an Event of Default specified in Section 6.1(7) or (8) with
respect to the Issuer occurs and is continuing, the Accreted Value of, and
accrued interest on all the Notes shall ipso facto become and be immediately due
and payable without any declaration or other act on the part of the Trustee or
any Holders.  The Holders of a majority in aggregate principal amount at
maturity of the outstanding Notes by notice to the Trustee may rescind an
acceleration and its consequences if the rescission would not conflict with any
judgment or decree and if all existing Events of Default have been cured or
<PAGE>   50
                                       46

waived except nonpayment of principal or interest that has become due solely
because of acceleration and the Trustee has been paid all amounts due to it
pursuant to Section 7.7.  No such rescission shall affect any subsequent Default
or impair any right consequent thereto.

         .........SECTION 6.3.  Other Remedies .  If an Event of Default occurs
and is continuing, the Trustee may pursue any available remedy to collect the
payment of Accreted Value of or interest on the Notes or to enforce the
performance of any provision of the Notes or this Indenture.

         .........The Trustee may maintain a proceeding even if it does not
possess any of the Notes or does not produce any of them in the proceeding.  A
delay or omission by the Trustee or any Noteholder in exercising any right or
remedy accruing upon an Event of Default shall not impair the right or remedy or
constitute a waiver of or acquiescence in the Event of Default.  No remedy is
exclusive of any other remedy.  All available remedies are, to the extent
permitted by law, cumulative.

         .........SECTION 6.4.  Waiver of Past Defaults .  The Holders of a
majority in aggregate principal amount at maturity of the Notes then outstanding
by notice to the Trustee may waive any past or existing Default and its
consequences except (i) a Default in the payment of the principal of or interest
on a Note or (ii) a Default in respect of a provision that under Section 9.2
cannot be amended without the consent of each Noteholder affected.  When a
Default is waived, it is deemed cured, and any Event of Default arising
therefrom shall be deemed to have been cured, but no such waiver shall extend to
any subsequent or other Default or impair any consequent right.

         .........SECTION 6.5.  Control by Majority .  Upon provision of
reasonable indemnity to the Trustee satisfactory to the Trustee, the Holders of
a majority in aggregate principal amount of the Notes then outstanding may
direct the time, method and place of conducting any proceeding for any remedy
available to the Trustee or of exercising any trust or power conferred on the
Trustee.  However, the Trustee, which may rely on opinions of counsel, may
refuse to follow any direction that conflicts with law or this Indenture or,
subject to Section 7.1, that the Trustee determines is unduly prejudicial to the
rights of other Noteholders or would involve the Trustee in personal liability;
provided, however, that the Trustee may take any other action deemed proper by
the Trustee that is not inconsistent with such direction.

         .........SECTION 6.6.  Limitation on Suits .  A Holder may not pursue
any remedy with respect to this Indenture or the Notes unless:

                  (i)      the Holder gives to the Trustee previous written
notice stating that an Event of Default is continuing;
                  (ii) the Holders of at least 25% in aggregate principal amount
         at maturity of the Notes then outstanding make a written request to the
         Trustee to pursue the remedy;

<PAGE>   51
                                       47

                  (iii) such Holder or Holders  offer to the Trustee  reasonable
         security or indemnity against any loss, liability or expense;

                  (iv) the Trustee  does not comply  with the request  within 60
         days  after  receipt  of the  request  and the  offer  of  security  or
         indemnity; and

                  (v) the Holders of a majority in aggregate principal amount at
         maturity  of the  Notes  then  outstanding  do not give the  Trustee  a
         direction inconsistent with such request within such 60-day period.

         .........A Noteholder may not use this Indenture to prejudice the
rights of another Noteholder or to obtain a preference or priority over another
Noteholder.

         .........SECTION 6.7.  Rights of Holders to Receive Payment .
Notwithstanding any other provision of this Indenture, the right of any Holder
to receive payment of the Accreted Value of and interest on the Notes held by
such Holder, on or after the respective due dates expressed in the Notes, or to
bring suit for the enforcement of any such payment on or after such respective
dates, shall not be impaired or affected without the consent of such Holder.

         .........SECTION 6.8.  Collection Suit by Trustee .  If an Event of
Default specified in Section 6.1(1) or (2) occurs and is continuing, the Trustee
may recover judgment in its own name and as trustee of an express trust against
the Issuer for the whole amount then due and owing (together with interest on
any unpaid interest to the extent lawful) and the amounts provided for in
Section 7.7.

         .........SECTION 6.9.  Trustee May File Proofs of Claim .  The Trustee
may file such proofs of claim and other papers or documents as may be necessary
or advisable in order to have the claims of the Trustee and the Noteholders
allowed in any judicial proceedings relative to the Issuer, its creditors or its
property and shall be entitled and empowered to collect, receive and distribute
any money or other securities or property payable or deliverable on any such
claims and to distribute the same, and, unless prohibited by law or applicable
regulations, may vote on behalf of the Holders in any election of a trustee in
bankruptcy or other Person performing similar functions, and any Custodian in
any such judicial proceeding is hereby authorized by each Holder to make
payments to the Trustee and, in the event that the Trustee shall consent to the
making of such payments directly to the Holders, to pay to the Trustee any
amount due it for the reasonable compensation, expenses, disbursements and
advances of the Trustee, its agents and its counsel, and any other amounts due
the Trustee under Section 7.7.

         .........SECTION 6.10.  Priorities .  If the Trustee collects any money
or property pursuant to this Article VI, it shall pay out the money or property
in the following order:

         .........FIRST:  to the Trustee for amounts due under Section 7.7;
<PAGE>   52
                                       48

                  SECOND:  to Noteholders for amounts due and unpaid on the
         Notes for Accreted Value and interest, ratably, without preference or
         priority of any kind, according to the amounts due and payable on the
         Notes for Accreted Value and interest, respectively; and

                  THIRD:  to the Issuer or to such party as a court of competent
jurisdiction shall direct.

         .........The Trustee may fix a record date and payment date for any
payment to Noteholders pursuant to this Section 6.10.  At least 15 days before
such record date, the Issuer shall mail to each Noteholder and the Trustee a
notice that states the record date, the payment date and amount to be paid.

         .........SECTION 6.11.  Undertaking for Costs .  In any suit for the
enforcement of any right or remedy under this Indenture or in any suit against
the Trustee for any action taken or omitted by it as Trustee, a court in its
discretion may require the filing by any party litigant in the suit of an
undertaking to pay the costs of the suit, and the court in its discretion may
assess reasonable costs, including reasonable attorneys' fees and expenses,
against any party litigant in the suit, having due regard to the merits and good
faith of the claims or defenses made by the party litigant.  This Section 6.11
does not apply to a suit by the Trustee, a suit by a Holder pursuant to Section
6.7 or a suit by Holders of more than 10% in aggregate principal amount of the
outstanding Notes.

         .........SECTION 6.12.  Waiver of Stay or Extension Laws .  The Issuer
(to the extent it may lawfully do so) shall not at any time insist upon, or
plead, or in any manner whatsoever claim or take the benefit or advantage of,
any stay or extension law wherever enacted, now or at any time hereafter in
force, which may affect the covenants or the performance of this Indenture; and
the Issuer (to the extent that it may lawfully do so) hereby expressly waives
all benefit or advantage of any such law, and shall not hinder, delay or impede
the execution of any power herein granted to the Trustee, but shall suffer and
permit the execution of every such power as though no such law had been enacted.

                                   ARTICLE VII
                                    TRUSTEE

         .........SECTION 7.1.  Duties of Trustee .  (a)  If an Event of Default
has occurred and is continuing, the Trustee shall exercise the rights and powers
vested in it by this Indenture and use the same degree of care and skill in
their exercise as a prudent Person would exercise or use under the circumstances
in the conduct of such Person's own affairs.

                  (b)      Except during the continuance of an Event of Default:

                  (i) the  Trustee  undertakes  to perform  such duties and only
         such duties as are specifically set forth in this Indenture and the TIA
         and no  implied  covenants  or  obligations  shall  be read  into  this
         Indenture against the Trustee; and
<PAGE>   53
                                       49

                  (ii) in the absence of bad faith on its part,  the Trustee may
         conclusively   rely,  as  to  the  truth  of  the  statements  and  the
         correctness of the opinions  expressed  therein,  upon  certificates or
         opinions furnished to the Trustee and conforming to the requirements of
         this  Indenture.  However,  in the  case of any  such  certificates  or
         opinions which by any provision hereof are specifically  required to be
         furnished to the Trustee,  the Trustee shall  examine the  certificates
         and  opinions  to  determine   whether  or  not  they  conform  to  the
         requirements of this Indenture.

         .........(c)      The Trustee may not be relieved from liability for
its own negligent action, its own negligent failure to act or its own wilful
misconduct, except that:

                  (i)      this paragraph does not limit the effect of paragraph
(b) of this Section 7.1;

                  (ii) the Trustee shall not be liable for any error of judgment
         made in good  faith by a Trust  Officer  unless it is  proved  that the
         Trustee was negligent in ascertaining the pertinent facts; and

                  (iii) the  Trustee  shall not be liable  with  respect  to any
         action  it takes or omits to take in good  faith in  accordance  with a
         direction received by it pursuant to Section 6.5.

         .........(d)      Whether or not therein expressly so provided, every
provision of this Indenture that in any way relates to the Trustee is subject to
paragraphs (a), (b) and (c) of this Section 7.1.

         .........(e)      Money held in trust by the Trustee need not be
segregated from other funds except to the extent required by law.

         .........(f)  No provision of this Indenture  shall require the Trustee
to expend or risk its own funds or otherwise  incur  financial  liability in the
performance  of any of its duties  hereunder  or in the  exercise  of any of its
rights or powers, if it shall have reasonable  grounds to believe that repayment
of such  funds or  adequate  indemnity  against  such risk or  liability  is not
reasonably assured to it.

         .........(g)      Every provision of this Indenture relating to the
conduct or affecting the liability of or affording protection to the Trustee
shall be subject to the provisions of this Section 7.1 and to the provisions of
the TIA.

         .........SECTION 7.2.  Rights of Trustee .  (a)  The Trustee may rely
upon, and shall be fully protected from acting or refraining from acting, on any
document believed by it to be genuine and to have been signed or presented by
the proper person.  The Trustee need not investigate any fact or matter stated
in the document.

<PAGE>   54
                                       50

         .........(b)      Before the Trustee acts or refrains from acting, it
may request an Officer's Certificate or an Opinion of Counsel or both.  The
Trustee shall not be liable for any action it takes or omits to take in good
faith in reliance on the Officer's Certificate or Opinion of Counsel.

         .........(c)      The Trustee may act through agents and shall not be
responsible for the misconduct or negligence of any agent appointed with due
care.

         .........(d)      The Trustee shall not be liable for any action it
takes or omits to take in good faith which it believes to be authorized or
within its rights or powers; provided, however, that the Trustee's conduct
does not constitute wilful misconduct or negligence.

         .........(e) The Trustee may consult with counsel of its selection, and
the advice or opinion of counsel with respect to legal matters  relating to this
Indenture and the Notes shall be full and complete  authorization and protection
from  liability  in respect  to any action  taken,  omitted  or  suffered  by it
hereunder  in good  faith and in  accordance  with the advice or opinion of such
counsel.

         .........(f)  The Trustee  shall be under no obligation to exercise any
of the  rights  or powers  vested  in it by this  Indenture  at the  request  or
direction of any of the Holders pursuant to this Indenture,  unless such Holders
shall have offered to the Trustee  reasonable  security or indemnity against the
costs, expenses and liabilities which might be incurred by it in compliance with
such request or direction.

         .........(g)  The Trustee  shall not be charged  with  knowledge of any
Default or Event of Default with respect to the Notes unless  either (1) a Trust
Officer  shall have actual  knowledge of such Default or Event of Default or (2)
written  notice of such Default or Event of Default shall have been given to the
Trustee by the Issuer or by any Holder of the Notes.

         .........SECTION 7.3.  Individual Rights of Trustee .  The Trustee in
its individual or any other capacity may become the owner or pledgee of Notes
and may otherwise deal with the Issuer or its respective Affiliates with the
same rights it would have if it were not Trustee.  Any Paying Agent, Registrar,
co-registrar or co-paying agent may do the same with like rights.  However, the
Trustee must comply with Sections 7.10 and
7.11.

         .........SECTION 7.4.  Trustee's Disclaimer .  The Trustee shall not be
responsible for and makes no representation as to the validity or adequacy of
this Indenture or the Notes, it shall not be accountable for the Issuer's use of
the proceeds from the Notes, and it shall not be responsible for any statement
of the Issuer in this Indenture or in any document issued in connection with the
sale of the Notes or in the Notes other than the Trustee's certificate of
authentication.

         .........SECTION 7.5.  Notice of Defaults .  If a Default or an Event
of Default occurs and is continuing and if it is known to the Trustee, the
Trustee must mail to each Noteholder notice of the Default within the earlier of
90 days after it occurs or 30 days after it is known to a Trust Officer or
written notice of it is received by the Trustee.  Except in the case of a
Default in
<PAGE>   55
                                       51

payment of principal of, premium (if any) or interest on any Note, the Trustee
may withhold notice if and so long as a committee of its Trust Officers in
good faith determines that withholding notice is not opposed to the interests of
Noteholders.

         .........SECTION 7.6.  Reports by Trustee to Holders .  As promptly as
practicable after each January 15 beginning with the January 15 following the
date of this Indenture, and in any event prior to March 15 in each year, the
Trustee shall mail to each Noteholder a brief report dated as of such January 15
that complies with TIA ss. 313(a).  The Trustee also shall comply with TIA ss.
313(b).  The Trustee shall promptly deliver to the Issuer a copy of any report
it delivers to Holders pursuant to this Section 7.6.

         .........A copy of each report at the time of its mailing to
Noteholders shall be filed by the Trustee with the SEC and each stock exchange
(if any) on which the Notes are listed.  The Issuer agrees to notify promptly
the Trustee whenever the Notes become listed on any stock exchange and of any
delisting thereof.

         .........SECTION 7.7.  Compensation and Indemnity .  The Issuer shall
pay to the Trustee from time to time such compensation for its services as the
Issuer and the Trustee shall from time to time agree in writing. The Trustee's
compensation shall not be limited by any law on compensation of a trustee of an
express trust.  The Issuer shall reimburse the Trustee upon request for all
reasonable fees and expenses, including out-of-pocket expenses, incurred or made
by it in connection with the performance of its duties hereunder, including
costs of collection, in addition to such compensation for its services, except
any such expense, disbursement or advance as may arise from its negligence,
wilful misconduct or bad faith, unless the Trustee shall have complied with the
applicable standard of care required by the TIA.  Such expenses shall include
the reasonable compensation and expenses, disbursements and advances of the
Trustee's agents, counsel, accountants and experts.  The Trustee shall provide
the Issuer reasonable notice of any expenditure not in the ordinary course of
business; provided that prior approval by the Issuer of any such expenditure
shall not be a requirement for the making of such expenditure nor for
reimbursement by the Issuer thereof.  The Issuer shall indemnify each of the
Trustee and any predecessor Trustees against any and all loss, damage, claim,
liability or expense (including reasonable attorneys' fees and expenses)
(other than taxes applicable to the Trustee's compensation hereunder) incurred
by it in connection with the acceptance or administration of this trust and the
performance of its duties hereunder.  The Trustee shall notify the Issuer
promptly of any claim for which it may seek indemnity.  Failure by the Trustee
to so notify the Issuer shall not relieve the Issuer of its obligations
hereunder.  The Issuer shall defend the claim and the Trustee may have separate
counsel, and the Issuer will pay the reasonable fees and expenses of such
counsel.  The Issuer need not reimburse any expense or indemnify against any
loss, liability or expense incurred by the Trustee through the Trustee's own
wilful misconduct, negligence or bad faith, unless the Trustee shall have
complied with the applicable standard of care required by the TIA.
<PAGE>   56
                                       52

         .........To  secure the Issuer's  payment  obligations  in this Section
7.7,  the Trustee  shall have a lien prior to the Notes on all money or property
held or collected by the Trustee  other than money or property  held in trust to
pay principal of and interest on particular Notes.

         .........The  Issuer's payment obligations pursuant to this Section 7.7
shall  survive the  resignation  or removal of the Trustee and discharge of this
Indenture.  When the Trustee  incurs  expenses after the occurrence of a Default
specified in Section 6.1(7) or (8) with respect to the Issuer,  the expenses are
intended to constitute  expenses of  administration  under the  Bankruptcy  Law,
provided,  however, that this shall not affect the Trustee's rights as set forth
in the preceding paragraph or Section 6.10.

         .........SECTION 7.8.  Replacement of Trustee .  The Trustee may resign
at any time with 30 days' notice to the Issuer.  The Holders of a majority in
principal amount of the Notes then outstanding, may remove the Trustee with 30
days notice to the Trustee and the Issuer and may appoint a successor Trustee.
The Issuer shall remove the Trustee if:

                  (i)       the Trustee fails to comply with Section 7.10;

                  (ii)     the Trustee is adjudged bankrupt or insolvent;

                  (iii) a receiver or other public  officer  takes charge of the
Trustee or its property; or

                  (iv) the Trustee otherwise becomes incapable of acting.

                  If the  Trustee  resigns,  is  removed by the Issuer or by the
Holders of a majority in  principal  amount of the Notes and such Holders do not
reasonably  promptly appoint a successor Trustee,  or if a vacancy exists in the
office of Trustee  for any reason (the  Trustee in such event being  referred to
herein as the retiring  Trustee),  the Issuer shall promptly appoint a successor
Trustee.

                  A successor Trustee shall deliver a written  acceptance of its
appointment to the retiring Trustee and to the Issuer. Thereupon the resignation
or removal of the retiring  Trustee  shall become  effective,  and the successor
Trustee  shall have all the rights,  powers and duties of the Trustee under this
Indenture.  The  successor  Trustee  shall  mail a notice of its  succession  to
Noteholders.  The retiring Trustee shall promptly  transfer all property held by
it as Trustee to the  successor  Trustee,  subject to the lien  provided  for in
Section 7.7.

                  If a successor  Trustee  does not take  office  within 30 days
after the retiring  Trustee resigns or is removed,  the retiring  Trustee or the
Holders  of 10% in  principal  amount  of the Notes  may  petition  any court of
competent jurisdiction for the appointment of a successor Trustee.
<PAGE>   57
                                       53

                  If  the  Trustee  fails  to  comply  with  Section  7.10,  any
Noteholder may petition any court of competent  jurisdiction  for the removal of
the Trustee and the appointment of a successor Trustee.

                  SECTION  7.9.  Successor  Trustee  by Merger . If the  Trustee
consolidates  with,  merges or converts into, or transfers all or  substantially
all its corporate  trust business or assets to,  another  corporation or banking
association,  the  resulting,  surviving or transferee  corporation  without any
further act shall be the successor Trustee, provided that such corporation shall
be eligible under this Article VII and TIA ss. 3.10(a).

                  In case at the time such  successor or  successors  by merger,
conversion or  consolidation  to the Trustee shall succeed to the trusts created
by this  Indenture  any of the  Notes  shall  have  been  authenticated  but not
delivered,  any such  successor  to the  Trustee  may adopt the  certificate  of
authentication   of  any  predecessor   trustee,   and  deliver  such  Notes  so
authenticated;  and in case at that  time any of the  Notes  shall not have been
authenticated,  any successor to the Trustee may authenticate  such Notes either
in the name of any predecessor  hereunder or in the name of the successor to the
Trustee; and in all such cases such certificates shall have the full force which
it is anywhere in the Notes or in this Indenture  provided that the  certificate
of the Trustee shall have.

                  SECTION  7.10.  Eligibility;  Disqualification  . The  Trustee
shall at all times satisfy the requirements of TIA ss. 310(a). The Trustee shall
have a combined capital and surplus of at least  $50,000,000 as set forth in its
most recent published annual report of condition.  The Trustee shall comply with
TIA ss.  310(b);  provided,  however,  that  there  shall be  excluded  from the
operation of TIA ss.  310(b)(1) any  indenture or  indentures  under which other
securities or certificates of interest or  participation  in other securities of
the Issuer are outstanding if the  requirements  for such exclusion set forth in
TIA ss. 310(b)(1) are met.

                  SECTION 7.11. Preferential Collection of Claims Against Issuer
 . The  Trustee  shall  comply  with  TIA  ss.  311(a),  excluding  any  creditor
relationship listed in TIA ss.311(b). A Trustee who has resigned or been removed
shall be subject to TIA ss. 311(a) to the extent indicated.
<PAGE>   58
                                       54

                                  ARTICLE VIII
                       DISCHARGE OF INDENTURE; DEFEASANCE

                  SECTION 8.1. Discharge of Liability on Notes; Defeasance . (a)
When (i) the Issuer  delivers to the Trustee all  outstanding  Notes (other than
Notes replaced pursuant to Section 2.7) for cancellation or (ii) all outstanding
Notes have  become due and  payable,  whether at  maturity or as a result of the
mailing of a notice of  redemption  pursuant  to Article III hereof or the Notes
will  become due and payable at their  Stated  Maturity  within 91 days,  or the
Notes  are to be  called  for  redemption  within  91  days  under  arrangements
satisfactory  to the  Trustee  for the  giving of notice  of  redemption  by the
Trustee in the name,  and at the  expense,  of the Issuer,  and, in each case of
this clause (ii), the Issuer irrevocably deposits or causes to be deposited with
the  Trustee  funds  sufficient  to pay  at  maturity  or  upon  redemption  all
outstanding  Notes,  including  interest  thereon to maturity or such redemption
date (other than Notes replaced  pursuant to Section 2.7), and if in either case
the Issuer  pays all other  sums  payable  hereunder  by the  Issuer,  then this
Indenture shall,  subject to Section 8.1(c),  cease to be of further effect. The
Trustee shall acknowledge satisfaction and discharge of this Indenture on demand
of the Issuer accompanied by an Officer's  Certificate and an Opinion of Counsel
from the Issuer that all conditions  precedent  provided  herein for relating to
satisfaction  and discharge of this Indenture have been complied with and at the
cost and expense of the Issuer.

                  (b) Subject to Sections 8.1(c) and 8.2, the Issuer at any time
may  terminate  (i) all of its  obligations  under the Notes and this  Indenture
("legal  defeasance  option") or (ii) its  obligations  under Sections 4.2, 4.3,
4.4, 4.5, 4.6, 4.7, 4.8, 4.9,  4.10,  4.11,  4.12,  4.14,  4.18 and 4.19 and the
operation of Sections  6.1(6),  6.1(7) (but only with  respect to a  Significant
Subsidiary),  6.1(8) (but only with respect to a Significant Subsidiary), 6.1(9)
and 5.1(iii) ("covenant  defeasance option").  The Issuer may exercise its legal
defeasance option  notwithstanding its prior exercise of its covenant defeasance
option.

                  If the Issuer exercises its legal defeasance  option,  payment
of the Notes  may not be  accelerated  because  of an Event of  Default.  If the
Issuer exercises its covenant defeasance option, payment of the Notes may not be
accelerated because of an Event of Default specified in Section 6.1(4),  6.1(5),
6.1(6), 6.1(7) (but only with respect to a Significant Subsidiary),  6.1(8) (but
only with respect to a Significant  Subsidiary),  6.1(9),  6.1(10) or because of
the failure of the Issuer to comply with Section 5.1(iii).

                  Upon  satisfaction of the conditions set forth herein and upon
request of the Issuer, the Trustee shall acknowledge in writing the discharge of
those obligations that the Issuer terminates.

                  (c)  Notwithstanding  clauses (a) and (b) above,  the Issuer's
obligations in Sections 2.3, 2.4, 2.5, 2.7, 4.1, 4.13,  4.15,  4.16,  4.17, 7.7,
7.8,  8.4,  8.5 and 8.6 shall  survive  until the Notes  have been paid in full.
Thereafter, the Issuer's obligations in Sections 7.7, 8.4 and 8.5 shall survive.
<PAGE>   59
                                       55

                  SECTION  8.2.  Conditions  to  Defeasance  .  The  Issuer  may
exercise its legal defeasance option or its covenant defeasance option only if:

                  (i) the Issuer irrevocably  deposits or causes to be deposited
         in trust with the Trustee money or U.S.  Government  Obligations  which
         through the  scheduled  payment of  principal  and  interest in respect
         thereof in accordance  with their terms will provide cash at such times
         and in such amounts as will be sufficient to pay principal and interest
         when due on all  outstanding  Notes (except Notes replaced  pursuant to
         Section 2.7) to maturity or redemption, as the case may be;

                  (ii) the Issuer  delivers to the Trustee a certificate  from a
         nationally recognized firm of independent  accountants expressing their
         opinion  that the  payments  of  principal  and  interest  when due and
         without reinvestment on the deposited U.S. Government  Obligations plus
         any deposited money without  investment will provide cash at such times
         and in such amounts as will be sufficient to pay principal and interest
         when due on all  outstanding  Notes (except Notes replaced  pursuant to
         Section 2.7) to maturity or redemption, as the case may be;

                  (iii) 91 days pass  after the  deposit  is made and during the
         91-day  period  no  Default  specified  in  Section  6.1(7) or (8) with
         respect  to the Issuer  occurs  which is  continuing  at the end of the
         period;

                  (iv) the deposit does not constitute a default under any other
         material agreement binding on the Issuer;

                  (v) the Issuer  delivers  to the Trustee an Opinion of Counsel
         to the  effect  that the  trust  resulting  from the  deposit  does not
         constitute,  or is qualified as, a regulated  investment  company under
         the Investment Company Act of 1940;

                  (vi) in the case of the legal  defeasance  option,  the Issuer
         shall have delivered to the Trustee an Opinion of Counsel  stating that
         (i) the Issuer has received  from, or there has been  published by, the
         Internal  Revenue  Service  a  ruling,  or (ii)  since the date of this
         Indenture there has been a change in the applicable  federal income tax
         law, in either case to the effect that,  and based thereon such Opinion
         of Counsel  shall  confirm  that,  the  Noteholders  will not recognize
         income,  gain or loss for  federal  income tax  purposes as a result of
         such deposit and  defeasance  and will be subject to federal income tax
         on the same amounts,  in the same manner and at the same times as would
         have been the case if such deposit and defeasance had not occurred;

                  (vii)  in the  case of the  covenant  defeasance  option,  the
         Issuer shall have delivered to the Trustee an Opinion of Counsel to the
         effect that the Noteholders will not recognize income, gain or loss for
         federal income tax purposes as a result of such covenant defeasance and
         will be subject to federal  income tax on the same  amounts  and
<PAGE>   60
                                       56

         in the
         same  manner  and at the same times as would have been the case if such
         deposit and covenant defeasance had not occurred; and

                  (viii)  the  Issuer  delivers  to  the  Trustee  an  Officer's
         Certificate and an Opinion of Counsel, each stating that all conditions
         precedent to the defeasance and discharge of the Notes as  contemplated
         by this Article VIII have been complied with.

                  Before or after a deposit,  the  Issuer may make  arrangements
satisfactory  to the  Trustee  for the  redemption  of Notes at a future date in
accordance with Article III.

                  SECTION 8.3.  Application  of Trust Money . The Trustee  shall
hold in trust money or U.S. Government Obligations deposited with it pursuant to
this Article VIII.  It shall apply the  deposited  money and the money from U.S.
Government  Obligations  either  directly  or through  the  Paying  Agent as the
Trustee may determine and in  accordance  with this  Indenture to the payment of
principal of and interest on the Notes.

                  SECTION 8.4.  Repayment to Issuer . The Trustee and the Paying
Agent shall  promptly  turn over to the Issuer upon  request any excess money or
securities held by them at any time.

                  Subject to any applicable  abandoned property law, the Trustee
and the Paying Agent shall pay to the Issuer upon written request any money held
by them for the payment of principal or interest that remains  unclaimed for one
year after such  principal  and  interest  have  become  due and  payable,  and,
thereafter,  Noteholders  entitled  to the  money  must look to the  Issuer  for
payment as general creditors.

                  SECTION 8.5. Indemnity for Government Obligations . The Issuer
shall pay and shall  indemnify the Trustee  against any tax, fee or other charge
imposed on or assessed  against  deposited  U.S.  Government  Obligations or the
principal and interest received on such U.S.  Government  Obligations other than
any such tax, fee or other charge which by law is for the account of the Holders
of the defeased Notes; provided that the Trustee shall be entitled to charge any
such tax, fee or other charge to such Holder's account.

                  SECTION 8.6. Reinstatement . If the Trustee or Paying Agent is
unable to apply any money or U.S. Government Obligations in accordance with this
Article  VIII by  reason of any  legal  proceeding  or by reason of any order or
judgment  of any  court or  governmental  authority  enjoining,  restraining  or
otherwise  prohibiting such  application,  the Issuer's  obligations  under this
Indenture and the Notes shall be revived and reinstated as though no deposit had
occurred  pursuant to this Article VIII until such time as the Trustee or Paying
Agent is permitted  to apply all such money or U.S.  Government  Obligations  in
accordance with this Article VIII;  provided,  however,  that, (a) if the Issuer
has made any payment of  interest on or  principal  of any Notes  following  the
reinstatement of their obligations, the Issuer shall be subrogated to the rights
of the  Holders  of such Notes to receive  such  payment  from the money or U.S.
Government  Obligations  held by the  Trustee  or Paying  Agent  and (b)  unless
otherwise
<PAGE>   61
                                       57

required by any legal proceeding or any order or judgment of any court
or  governmental  authority,  the Trustee or Paying  Agent shall return all such
money and U.S.  Government  Obligations to the Issuer promptly after receiving a
written  request  therefor at any time,  if such  reinstatement  of the Issuer's
obligations has occurred and continues to be in effect.

                                   ARTICLE IX
                                   AMENDMENTS

                    SECTION 9.1. Without Consent of Holders . The Issuer and the
Trustee may amend this Indenture or the Notes without notice to or consent of
any Noteholder:

                  (i)      to cure any ambiguity, omission, defect or
inconsistency;

                  (ii)     to comply with Article V;

                  (iii) to provide for uncertificated Notes in addition to or in
         place of certificated Notes (provided, however, that the uncertificated
         Notes are issued in registered  form for purposes of Section  163(f) of
         the  Code or in a manner  such  that the  uncertificated  Notes  are as
         described in Section 163(f)(2)(B) of the Code);

                  (iv)     to add Guarantees with respect to the Notes;

                  (v)      to secure the Notes;

                  (vi) to add to the  covenants of the Issuer for the benefit of
         the  Noteholders  or to surrender  any right or power herein  conferred
         upon the Issuer;

                  (vii) to make any  change  that  does not,  in the good  faith
         opinion  of the  Board  of  Directors  of the  Issuer,  materially  and
         adversely affect the rights of any Noteholder; and

                  (viii)  to  comply  with  any   requirements  of  the  SEC  in
         connection with qualifying this Indenture under the TIA.

                  After an amendment  under this Section 9.1 becomes  effective,
the Issuer shall mail to Noteholders a notice briefly describing such amendment.
The failure to give such notice to all Noteholders, or any defect therein, shall
not impair or affect the validity of an amendment under this Section 9.1.

                  SECTION  9.2.  With  Consent  of  Holders . The Issuer and the
Trustee may amend this  Indenture or the Notes without  notice to any Noteholder
but with the written  consent of the Holders of at least a majority in principal
amount at maturity of the Notes then outstanding
<PAGE>   62
                                       58

(including consents obtained in
connection  with a tender  offer or exchange  for Notes).  However,  without the
consent of each  Noteholder of an outstanding  Note  affected,  an amendment may
not:

                  (i)      reduce the amount of Notes whose Holders must consent
to an amendment;

                  (ii)     reduce the rate of or extend the time for payment of
interest on any Note;

                  (iii) reduce the principal of or extend the Stated Maturity of
any Note;

                  (iv) reduce the premium  payable  upon the  redemption  of any
         Note or change the time at which any Note may be redeemed in accordance
         with Article III;

                  (v) make any Note  payable in money  other than that stated in
the Note;

                  (vi)  impair  the right of any  Holder to  receive  payment of
         principal  of and interest on such  Holder's  Notes on or after the due
         dates therefor or to institute suit for the  enforcement of any payment
         on or with respect to such Holder's Notes; or

                  (vii) make any change in this second sentence of Section 9.2.

                  It shall not be necessary for the consent of the Holders under
this Section 9.2 to approve the particular form of any proposed  amendment,  but
it shall be sufficient if such consent approves the substance thereof.

                  After an amendment  under this Section 9.2 becomes  effective,
the Issuer shall mail to Noteholders a notice briefly describing such amendment.
The failure to give such notice to all Noteholders, or any defect therein, shall
not impair or affect the validity of an amendment under this Section 9.2.

                  SECTION  9.3.  Compliance  with  Trust  Indenture  Act . Every
amendment  to this  Indenture  or the Notes shall comply with the TIA as then in
effect.

                  SECTION 9.4. Revocation and Effect of Consents and Waivers . A
consent to an  amendment or a waiver by a Holder of a Note shall bind the Holder
and every  subsequent  Holder of that Note or portion of the Note that evidences
the same debt as the consenting  Holder's Note,  even if notation of the consent
or  waiver  is not  made on the  Note.  After an  amendment  or  waiver  becomes
effective, it shall bind every Noteholder.

                  The Issuer may,  but shall not be  obligated  to, fix a record
date for the  purpose of  determining  the  Noteholders  entitled  to give their
consent or take any other action  described above or required or permitted to be
taken   pursuant  to  this   Indenture.   If  a  record  date  is  fixed,   then
notwithstanding  the  immediately  preceding  paragraph,  those Persons who were
Noteholders  at such record date (or their duly  designated  proxies),  and only
those  Persons,  shall be entitled to
<PAGE>   63
                                       59
give such consent or to revoke any consent previously  given or to take  any
such  action,  whether  or not  such  Persons continue to be Holders after such
record date. No such consent shall be valid or effective for more than 120 days
after such record date.

                  SECTION  9.5.  Notation  on  or  Exchange  of  Notes  .  If an
amendment changes the terms of a Note, the Trustee may require the Holder of the
Note to deliver it to the Trustee. The Trustee may place an appropriate notation
on  the  Note  regarding  the  changed  terms  and  return  it  to  the  Holder.
Alternatively, if the Issuer or the Trustee so determine, the Issuer in exchange
for the Note shall  issue and the  Trustee  shall  authenticate  a new Note that
reflects the changed terms. Failure to make the appropriate notation or to issue
a new Note shall not affect the validity of such amendment.

                  SECTION 9.6.  Trustee to Sign  Amendments . The Trustee  shall
sign any amendment  authorized pursuant to this Article IX if the amendment does
not  materially  and  adversely  affect  the  rights,  duties,   liabilities  or
immunities of the Trustee.  If it does, the Trustee may but need not sign it. In
signing  such  amendment  the Trustee  shall be  entitled  to receive  indemnity
reasonably  satisfactory  to it and to  receive,  and  (subject to Section 7. 1)
shall be fully protected in relying upon, in addition to the documents  required
by Section 10.4, an Officer's Certificate and an Opinion of Counsel stating that
such amendment complies with the provisions of this Article IX.

                  SECTION 9.7.  Payment for Consent . Neither the Issuer nor any
affiliate of the Issuer shall,  directly or indirectly,  pay or cause to be paid
any consideration,  whether by way of interest, fee or otherwise,  to any Holder
for, or as an inducement to any consent, waiver or amendment of any of the terms
or  provisions  of this  Indenture  or the Notes  unless such  consideration  is
offered to be paid to all Holders  that so  consent,  waive or agree to amend in
the time frame set forth in  solicitation  documents  relating to such  consent,
waiver or agreement;  provided,  however, that Holders who do not consent, waive
or  agree  to  amend  this  Indenture  in the  time  frame  set  forth  in  such
solicitation  documents shall not be entitled to any  consideration  offered for
timely consent, waiver or amendment, even if the consent, waiver or amendment is
agreed to by sufficient Holders to approve such consent,  waiver or amendment to
this Indenture.

                                    ARTICLE X
                                 MISCELLANEOUS

                  SECTION 10.1.  Trust Indenture Act Controls . If any provision
of this Indenture limits, qualifies or conflicts with another provision which is
required to be included in this Indenture by the TIA, the provision  required by
the TIA shall control.

                  SECTION 10.2.  Notices . Any notice or communication  shall be
in writing and delivered in person,  transmitted by facsimile machine, or mailed
by  first-class  mail or overnight  air courier  guaranteeing  next day delivery
addressed as follows:

<PAGE>   64
                                       60

                  if to the Issuer:

                           SpectraSite Holdings, Inc.
                           100 Regency Forest Drive, Suite 400
                           Cary, North Carolina  27511

                           Attention:  Chief Financial Officer

                  if to the Trustee:

                           United States Trust Company of New York
                           114 West 47th Street, 25th Floor
                           New York, New York  10036-1532

                           Attention:  Corporate Trust Administration

                  The  Issuer  or  the  Trustee  by  notice  to the  others  may
designate   additional  or  different   addresses  for  subsequent   notices  or
communications.

                  Any notice or  communication  mailed to a Noteholder  shall be
mailed to the  Noteholder  at the  Noteholder's  address  as it  appears  on the
registration books of the Registrar and shall be sufficiently given if so mailed
within the time prescribed.
                  Failure to mail a notice or  communication  to a Noteholder or
any  defect  in it shall  not  affect  its  sufficiency  with  respect  to other
Noteholders. Except for a notice to the Trustee, which is deemed given only when
received,  and except as otherwise  provided in this  Indenture,  if a notice or
communication is mailed in the manner provided above, it is duly given,  whether
or not the addressee receives it

                  SECTION  10.3.  Communication  by Holders with Other Holders .
Noteholders  may communicate  pursuant to TIA ss. 312(b) with other  Noteholders
with respect to their rights under this Indenture or the Notes. The Issuer,  the
Trustee, the Registrar and anyone else shall have the protection of TIA ss.
312(c).

                  SECTION  10.4.   Certificate  and  Opinion  as  to  Conditions
Precedent . Upon any request or application by the Issuer to the Trustee to take
or refrain from taking any action under this Indenture, the Issuer shall furnish
to the Trustee:

                  (i) an Officer's  Certificate in form and substance reasonably
         satisfactory to the Trustee stating that, in the opinion of the signer,
         all  conditions  precedent,  if any,  provided  for in  this  Indenture
         relating to the proposed action have been complied with; and
<PAGE>   65
                                       61

                  (ii) an Opinion of  Counsel in form and  substance  reasonably
         satisfactory  to the  Trustee  stating  that,  in the  opinion  of such
         counsel, all such conditions precedent have been complied with.

                  SECTION 10.5.  Statements Required in Certificate or Opinion .
Each  certificate  or opinion  with  respect to  compliance  with a covenant  or
condition provided for in this Indenture shall include:

                  (i)      a statement that the individual making such
certificate or opinion has read such covenant or condition;

                  (ii) a brief  statement  as to the  nature  and  scope  of the
         examination  or  investigation  upon which the  statements  or opinions
         contained in such certificate or opinion are based;

                  (iii) a statement that, in the opinion of such individual,  he
         has made such  examination or  investigation  as is necessary to enable
         him to express an informed  opinion as to whether or not such  covenant
         or condition has been complied with; and

                  (iv) a statement  as to whether or not, in the opinion of such
         individual, such covenant or condition has been complied with.

                  SECTION 10.6. When Notes Disregarded . In determining  whether
the Holders of the  required  principal  amount of Notes have  concurred  in any
direction,  waiver  or  consent,  Notes  owned by the  Issuer  or by any  Person
directly or indirectly  controlling or controlled by or under direct or indirect
common  control  with the  Issuer  shall be  disregarded  and  deemed  not to be
outstanding,  except that,  for the purpose of  determining  whether the Trustee
shall be protected  in relying on any such  direction,  waiver or consent,  only
Notes  which a Trust  Officer  of the  Trustee  knows  are so owned  shall be so
disregarded.  Also, subject to the foregoing, only Notes outstanding at the time
shall be considered in any such determination.

                  SECTION 10.7.  Rules by Trustee,  Paying Agent and Registrar .
The  Trustee  may  make  reasonable  rules  for  action  by or at a  meeting  of
Noteholders.  The Registrar and the Paying Agent may make  reasonable  rules for
their functions.

                  SECTION  10.8.  Legal  Holidays  .  A  "Legal  Holiday"  is  a
Saturday, a Sunday or a day on which banking institutions are not required to be
open in the State of New York.  If a payment  date is a Legal  Holiday,  payment
shall be made on the next  succeeding  day that is not a Legal  Holiday,  and no
interest shall accrue on such payment for the intervening  period.  If a regular
date is a Legal Holiday, the record date shall not be affected.

                  SECTION  10.9.  Governing  Law . THIS  INDENTURE AND THE NOTES
SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF
NEW YORK BUT WITHOUT GIVING EFFECT TO
<PAGE>   66
                                       62

APPLICABLE  PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF
THE LAWS OF ANOTHER  JURISDICTION WOULD BE REQUIRED THEREBY.

                  SECTION  10.10.  No  Recourse  Against  Others . No  director,
officer,  employee,  incorporator or stockholder of the Issuer,  as such,  shall
have any  liability  for any  obligations  of the Issuer  under the Notes,  this
Indenture  or for any  claim  based  on,  in  respect  of,  or by reason of such
obligations or their  creation.  Each Holder of Notes by accepting a Note waives
and  releases  all such  liability.  This  waiver  and  release  are part of the
consideration for issuance of the Notes.

                  SECTION  10.11.  Successors . All  agreements of the Issuer in
this  Indenture and the Notes shall bind its  successors.  All agreements of the
Trustee in this Indenture shall bind its successors.

                  SECTION 10.12.  Multiple Originals .  The parties may sign any
number of copies of this Indenture.  Each signed copy shall be an original, but
all of them together represent the same agreement.  One signed copy is enough to
prove this Indenture.

                  SECTION 10.13.  Variable Provisions .  The Issuer initially
appoints the Trustee as Paying Agent and Registrar and custodian with respect to
any Global Notes.

                  SECTION 10.14.  Qualification  of Indenture . The Issuer shall
qualify this Indenture under the TIA in accordance with the terms and conditions
of the  Registration  Rights  Agreement (as defined in the Appendix  hereto) and
shall pay all reasonable costs and expenses  (including  attorneys' fees for the
Issuer,  the  Trustee  and  the  Holders)  incurred  in  connection   therewith,
including,  but not limited to,  costs and  expenses  of  qualification  of this
Indenture  and the Notes.  The Trustee  shall be  entitled  to receive  from the
Issuer  any  such   Officer's   Certificates,   Opinions  of  Counsel  or  other
documentation  as  it  may  reasonably  request  in  connection  with  any  such
qualification of this Indenture under the TIA.

                  SECTION  10.15.  Table of  Contents;  Headings  . The table of
contents,  cross-  reference  sheet and headings of the Articles and Sections of
this  Indenture have been inserted for  convenience  of reference  only, are not
intended to be  considered a part hereof and shall not modify or restrict any of
the terms or provision hereof.

                  SECTION  10.16.  Severability  . In case any provision in this
Indenture  or in the Notes shall be invalid,  illegal or  unenforceable,  in any
respect for any reason,  the validity,  legality and  enforceability of any such
provision in every other  respect and of the remaining  provisions  shall not in
any way be affected or impaired thereby.

<PAGE>   67
                                       63

                  IN WITNESS WHEREOF,  the parties have caused this Indenture to
be duly executed as of the date first written above.

                           SPECTRASITE HOLDINGS, INC.

                                              By:  /s/ David P. Tomick
                                                  ------------------------------
                                              Name:      David P. Tomick
                                              Title:     Chief Financial Officer

                         UNITED STATES TRUST COMPANY OF
                              NEW YORK, as Trustee

                                              By:  /s/ Margaret M. Ciesmelewski
                                                  ------------------------------
                                              Name: Margaret M. Ciesmelewski
                                              Title: Assistant Vice President

<PAGE>   68
                                       64

                         RULE 144A/REGULATION S APPENDIX

                              INSTITUTIONAL BUYERS
            PURSUANT TO RULE 144A AND TO CERTAIN PERSONS IN OFFSHORE
                    TRANSACTIONS IN RELIANCE ON REGULATION S.

                      PROVISIONS RELATING TO INITIAL NOTES,
                    PRIVATE EXCHANGE NOTES AND EXCHANGE NOTES

1.       Definitions.

                  1.1.     Definitions.  For the purposes of this Appendix the
following terms shall have the meanings indicated below:

                  "Depositary" means The Depository Trust Company,  its nominees
and their respective successors and assigns.

                  "Exchange Notes" means the 12?% Senior Discount Notes due 2010
to be issued pursuant to this Indenture in connection with a Registered Exchange
Offer pursuant to the Registration Rights Agreement.

                  "Initial Purchasers" means Credit Suisse First Boston
Corporation, Lehman Brothers Inc. and CIBC Oppenheimer Corp.

                  "Initial Notes" means the 12?% Senior Discount Notes due 2010,
issued under this Indenture on or about the date hereof

                  "Notes" means the Initial  Notes,  the Exchange  Notes and the
Private Exchange Notes, treated as a single class.

                  "Notes Custodian" means the custodian with respect to a Global
Note (as appointed by the Depositary), or any successor person thereto and shall
initially be the Trustee.

                  "Private Exchange" means the offer by the Issuer,  pursuant to
the  Registration  Rights  Agreement,  to the Initial  Purchasers  to issue 'and
deliver to each Initial Purchaser, in exchange for the Initial Notes held by the
Initial  Purchaser  as  part  of its  initial  distribution,  a  like  aggregate
principal amount at maturity of Private Exchange Notes.

                  "Private  Exchange Notes" means the 12?% Senior Discount Notes
due 2010,  if any,  to be  issued  pursuant  to this  Indenture  to the  Initial
Purchasers in a Private Exchange.

                  "Purchase  Agreement" means the Purchase Agreement dated March
10, 2000, among the Issuer and the Initial Purchasers.
<PAGE>   69
                                       65

                  "QIB" means a "qualified institutional buyer" as defined in
Rule 144A.

                  "Registered  Exchange  Offer"  means the offer by the  Issuer,
pursuant to the  Registration  Rights  Agreement,  to certain Holders of Initial
Notes, to issue and deliver to such Holders,  in exchange for the Initial Notes,
a like  aggregate  principal  amount  of  Exchange  Notes  registered  under the
Securities Act.

                  "Registration  Rights Agreement" means the Registration Rights
Agreement  dated  as of  March  15,  2000  among  the  Issuer  and  the  Initial
Purchasers.

                  "Regulation S" means Regulation S under the Securities Act.

                  "Rule 144A" means Rule 144A under the Securities Act.

                  "Securities Act" means the Securities Act of 1933, as amended.

                  "Shelf   Registration   Statement"   means  the   registration
statement issued by the Issuer, in connection with the offer and sale of Initial
Notes or Private  Exchange  Notes,  pursuant  to  Section 2 of the  Registration
Rights Agreement.

                  "Transfer  Restricted  Notes"  means  Notes  that  bear or are
required to bear the legend set forth in Section 2.3(b) hereof.

                  1.2.     Other Definitions

                                                                 Defined
                Term                                           in Section
               ---------                                    -----------------
                "Agent Members"                                  2.1(b)
                "Global Note"                                    2.1(a)

                  2. The Notes.

                  2.1. Form and Dating. The Initial  Notes are  being  offered
                       and sold by the Issuer pursuant to the Purchase
                       Agreement.

                      (a) Global Notes.  Initial Notes offered and sold to a QIB
in reliance on Rule 144A or in reliance on Regulation S, in each case as
provided in the Purchase Agreement, shall be issued initially in the form of one
or more permanent global Notes in definitive, fully registered form without
interest coupons with the global securities legend and restricted securities
legend set forth in Exhibit I hereto (each, a "Global Note"), which shall be
deposited on behalf of the purchasers of the Initial Notes represented thereby
with the Trustee as custodian for the Depositary (or with such other custodian
as the Depositary may direct), and registered in
<PAGE>   70
                                       66

the name of the Depositary or a nominee of the Depositary, duly executed by the
Issuer and authenticated by the Trustee as hereinafter provided. The aggregate
principal amount of the Global Notes may from time to time be increased or
decreased by adjustments made on the records of the Trustee and the Depositary
or its nominee as hereinafter provided.

                      (b) Book-Entry Provisions. This Section 2. 1 (b) shall
apply only to a Global Note deposited with or on behalf of the Depositary.

The Issuer shall execute and the Trustee shall, in accordance with this Section
2.1 (b), authenticate and deliver initially one or more Global Notes that (i)
shall be registered in the name of the Depositary for such Global Note or
Global Notes or in the name of the nominee of such Depositary and (ii) shall be
delivered by the Trustee to such Depositary or pursuant to such Depositary's
instructions or held by the Trustee as custodian for the Depositary.

Members of, or participants in, the Depositary ("Agent Members") shall have no
rights under this Indenture with respect to any Global Note held on their behalf
by the Depositary or by the Trustee as the custodian of the Depositary or under
such Global Note, and the Depositary may be treated by the Issuer, the Trustee
and any agent of the Issuer or the Trustee as the absolute owner of such Global
Note for all purposes whatsoever. Notwithstanding the foregoing, nothing herein
shall prevent the Issuer, the Trustee or any agent of the Issuer or the Trustee
from giving effect to any written certification, proxy or other authorization
furnished by the Depositary or impair, as between the Depositary and its Agent
Members, the operation of customary practices of such Depositary governing the
exercise of the rights of a holder of a beneficial interest in any Global Note.

                       (c) Certificated Notes. Except as provided in Section 2.1
or Section 2.3 or 2.4, owners  of  beneficial  interests  in Global  Notes
will not be  entitled  to  receive physical delivery of certificated Notes.

                       2.2. Authentication. The Trustee shall authenticate and
deliver: (1) Initial Notes for original issue in an aggregate principal amount
at maturity of U.S. $559,800,000 and (2) Exchange Notes or Private Exchange
Notes for issue only in a Registered Exchange Offer or a Private Exchange,
respectively, pursuant to the Registration Rights Agreement, for a like
principal amount at maturity of Initial Notes, in each case upon a written order
of the Issuer signed by two Officers or by an Officer and either an Assistant
Treasurer or an Assistant Secretary of the Issuer. Such order shall specify the
amount of the Notes to be authenticated and the date on which the original issue
of Notes is to be authenticated and whether the Notes are to be Initial Notes,
Exchange Notes or Private Exchange Notes. The aggregate principal amount at
maturity of Notes outstanding at any time may not exceed U.S. $559,800,000
except as provided in Section 2.7 of this Indenture.

<PAGE>   71
                                       67

 2.3. Transfer and Exchange.

                      (a) Transfer and Exchange of Global Notes. (i) The transfe
and exchange of Global Notes or beneficial interests therein shall be effected
through the Depositary, in accordance with this Indenture (including applicable
restrictions on transfer set forth herein, if any) and the procedures of the
Depositary therefor. A transferor of a beneficial interest in a Global Note
shall deliver to the Registrar a written order given in accordance with the
Depositary's procedures containing information regarding the participant account
of the Depositary to be credited with a beneficial interest in the Global Note.
The Registrar shall, in accordance with such instructions instruct the
Depositary to credit to the account of the Person specified in such instructions
a beneficial interest in the Global Note and to debit the account of the Person
making the transfer of the beneficial interest in the Global Note being
transferred.

                      (ii) Notwithstanding any other provisions of this Appendix
(other than the provisions set forth in Section 2.4), a Global Note may not be
transferred as a whole except by the Depositary to a nominee of the Depositary
or by a nominee of the Depositary to the Depositary of another nominee of the
Depositary or by the Depositary or any such nominee to a successor Depositary or
a nominee of such successor Depositary.

                     (iii) In the  event  that a Global  Note is  exchanged  for
Notes in definitive registered form pursuant to Section 2.4 of this Appendix or
Section 2.9 of this Indenture prior to the consummation of a Registered Exchange
Offer or the effectiveness of a Shelf Registration Statement with respect to
such Notes, such Notes may be exchanged only in accordance with such procedures
as are substantially consistent with the provisions of this Section 2.3
(including the certification requirements set forth on the reverse of the
Initial Notes intended to ensure that such transfers comply with Rule 144A or
Regulation S, as the case may be) and such other procedures as may from time to
time be adopted by the Issuer.

                        (b) Legend.  (i) Except as  permitted  by the  following
paragraphs (ii), (iii) and (iv), each Note  certificate  evidencing the Global
Notes (and all Notes  issued in exchange  therefor or in  substitution thereof)
shall  bear a  legend  in  substantially  the following form:

"THIS NOTE HAS NOT BEEN REGISTERED UNDER THE U.S. SECURITIES ACT OF 1933, AS
AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD
WITHIN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR BENEFIT OF, U.S. PERSONS,
EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE. BY ITS ACQUISITION HEREOF, THE
HOLDER (1) REPRESENTS THAT (A) IT IS A "QUALIFIED INSTITUTIONAL BUYER" (AS
DEFINED IN RULE 144A UNDER THE SECURITIES ACT), OR (B) IT IS AN "INSTITUTIONAL
ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(A)(1), (2), (3) OR (7) OR
REGULATION D UNDER THE SECURITIES ACT) (AN "INSTITUTIONAL ACCREDITED INVESTOR")
OR (C) IT IS NOT A U.S. PERSON AND IS ACQUIRING THIS NOTE
<PAGE>   72
                                       68

IN AN OFFSHORE TRANSACTION IN COMPLIANCE WITH REGULATION S UNDER THE SECURITIES
ACT, (2) AGREES THAT IT WILL NOT RESELL OR OTHERWISE TRANSFER THIS NOTE EXCEPT
(A) TO THE COMPANY OR ANY SUBSIDIARY THEREOF, (B) TO A QUALIFIED INSTITUTIONAL
BUYER IN COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, (C) INSIDE THE
UNITED STATES TO AN INSTITUTIONAL ACCREDITED INVESTOR THAT, PRIOR TO SUCH
TRANSFER, FURNISHES TO THE TRUSTEE A SIGNED LETTER CONTAINING CERTAIN
REPRESENTATIONS AND AGREEMENTS RELATING TO THE RESTRICTIONS ON TRANSFER OF THIS
NOTE (THE FORM OF WHICH LETTER CAN BE OBTAINED FROM THE TRUSTEE) AND, IF SUCH
TRANSFER IS IN RESPECT OF AN AGGREGATE PRINCIPAL AMOUNT OF NOTES AT THE TIME OF
TRANSFER OF LESS THAN $100,000, AN OPINION OF COUNSEL ACCEPTABLE TO THE COMPANY
THAT SUCH TRANSFER IS IN COMPLIANCE WITH THE SECURITIES ACT, (D) OUTSIDE THE
UNITED STATES IN AN OFFSHORE TRANSACTION IN COMPLIANCE WITH RULE 904 OF
REGULATION S UNDER THE SECURITIES ACT OR (E) PURSUANT TO AN EFFECTIVE
REGISTRATION STATEMENT UNDER THE SECURITIES ACT AND (3) AGREES THAT IT WILL
DELIVER TO EACH PERSON TO WHOM THIS NOTE IS TRANSFERRED A NOTICE SUBSTANTIALLY
TO THE EFFECT OF THIS LEGEND. IN CONNECTION WITH ANY TRANSFER OF THIS NOTE, THE
HOLDER MUST CHECK THE APPROPRIATE BOX SET FORTH ON THE REVERSE HEREOF RELATING
TO THE MANNER OF SUCH TRANSFER AND SUBMIT THIS CERTIFICATE TO THE TRUSTEE. IF
THE PROPOSED TRANSFEREE IS AN INSTITUTIONAL ACCREDITED INVESTOR, THE HOLDER
MUST, PRIOR TO SUCH TRANSFER, FURNISH TO THE TRUSTEE AND THE COMPANY SUCH
CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION AS EITHER OF THEM MAY
REASONABLY REQUIRE TO CONFIRM THAT SUCH TRANSFER IS BEING MADE PURSUANT TO AN
EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION
REQUIREMENTS OF THE SECURITIES ACT. AS USED HEREIN, THE TERMS "OFFSHORE
TRANSACTION," "UNITED STATES" AND "U.S. PERSON" HAVE THE MEANINGS GIVEN TO THEM
BY REGULATION S UNDER THE SECURITIES ACT. THE INDENTURE CONTAINS A PROVISION
REQUIRING THE TRUSTEE TO REFUSE TO REGISTER ANY TRANSFER OF THIS NOTE IN
VIOLATION OF THE FOREGOING RESTRICTIONS."
                        (ii) Upon any sale or transfer of a Transfer Restricted
 Note (including any Transfer   Restricted  Note  represented by a Global Note)
pursuant to Rule 144 under the Securities Act, in the case of any Transfer
Restricted Note that is represented by a Global Note, the Registrar shall permit
the Holder thereof to exchange such Transfer Restricted Note for a certificated
Note that does not bear the legend set forth above and rescind any restriction
on the transfer of such Transfer Restricted Note, if the Holder certifies in
writing to the Registrar that its request for such exchange was made in reliance
on Rule 144 (such certification to be in the form set forth on the reverse of
the Note).
<PAGE>   73
                                       69

                     (iii) After a transfer of any Initial Securities or Private
Exchange Securities during the period of the effectiveness of and pursuant to a
Shelf Registration Statement with respect to such Initial Securities or Private
Exchange Securities, as the case may be, all requirements pertaining to legends
on such Initial Securities or such Private Exchange Notes will cease to apply,
but the requirements requiring such Initial Notes or such Private Exchange Notes
issued to certain Holders be issued in global form will continue to apply, and
Initial Notes or Private Exchange Notes in global form without legends will be
available to the transferee of the Holder of such Initial Notes or Private
Exchange Notes upon exchange of such transferring Holder's Initial Notes or
Private Exchange Notes or directions to transfer such Holder's interest in the
Global Note, as applicable.

                     (iv) Upon the  consummation of a Registered  Exchange Offer
with respect to the Initial Notes pursuant to which Holders of such Initial
Notes are offered Exchange Notes in exchange for their Initial Notes, all
requirements pertaining to such Initial Notes that Initial Notes issued to
certain Holders be issued in global form will continue to apply and Initial
Notes in global form with the restricted securities legend set forth in Exhibit
1 hereto will be available to Holders of such Initial Notes that do not exchange
their Initial Notes, and Exchange Notes in global form without the restriction
securities legend will be available to Holders that exchange such Initial Notes
in such Registered Exchange Offer.

                     (v)  Upon  the  consummation  of a  Private  Exchange  with
respect to the Initial Notes pursuant to which Holders of such Initial Notes
are offered Private Exchange Notes in exchange for their Initial Notes, all
requirements pertaining to such Initial Notes that Initial Notes issued
to certain Holders be issued in global form will still apply, and Private
Exchange Notes in global form with the restricted securities legend set forth
in Exhibit 1 hereto will be available to Holders that exchange such Initial
Notes in such Private Exchange.

                       (c)  Cancellation  or  Adjustment of Global Note. At such
time as all beneficial interests in a Global Note have either been exchanged
for certificated Notes, redeemed, repurchased or canceled, such Global Note
shall be returned to the Depositary for cancellation or retained and canceled by
the Trustee. At any time prior to such cancellation, if any beneficial interest
in a Global Note is exchanged for certificated Notes, redeemed, repurchased or
canceled, the principal amount of Notes represented by such Global Note shall be
reduced and an adjustment shall be made on the books and records of the Trustee
(if it is then the Notes Custodian for such Global Note) with respect to such
Global Note, by the Trustee or the Notes Custodian, to reflect such
reduction.

                           (d)   Obligations   with  Respect  to  Transfers  and
Exchanges of Notes. (i) To permit registrations of transfers and exchanges, the
Issuer shall execute and the Trustee shall authenticate certificated Notes and
Global Notes at the Registrar's or any co-registrar's request, subject to terms
and conditions of this Indenture.

                     (ii) No service  charge shall be made for any  registration
of transfer or exchange, but the Issuer may require payment of a sum sufficient
to cover any transfer tax,
<PAGE>   74
                                       70

assessments, or similar governmental charge payable in connection therewith
(other than any such transfer taxes, assessments or similar governmental charge
payable upon exchange or transfer pursuant to Sections 3.6, 4.7, 4.9 and Section
9.5 of this Indenture).

                    (iii)  The  Registrar  or  any  co-registrar  shall  not  be
required to register the transfer of or exchange of (a) any certificated Note
selected for redemption in whole or in part pursuant to Article III of this
Indenture, except the unredeemed portion of any certificated Note being
redeemed in part, or (b) any Note for a period beginning 15 Business Days
before the mailing of a notice of an offer to repurchase or redeem Notes or 15
Business Days before an interest payment date.

                      (iv) Prior to the due  presentation  for  registration  of
transfer of any Note, the Issuer, the Trustee, the Paying Agent, the Registrar
or any co-registrar may deem and treat the person in whose name a Note is
registered as the absolute owner of such Note for the purpose of receiving
payment of principal of and interest on such Note and for all other purposes
whatsoever, whether or not such Note is overdue, and none of the Issuer, the
Trustee, the Paying Agent, the Registrar or any co-registrar shall be affected
by notice to the contrary.

                      (v) All Notes issued on any transfer or exchange  pursuant
to the terms of this Indenture shall evidence the same debt and shall be
entitled to the same benefits under this Indenture as the Notes surrendered upon
such transfer or exchange.

                        (e) No Obligation of the Trustee or the Issuer.  (i) The
Trustee and the Issuer shall
have no responsibility or obligation to any beneficial owner of a Global Note,
a member of, or a participant in the Depositary or other Person with respect to
the accuracy of the records of the Depositary or its nominee or of
any participant or member thereof, with respect to any ownership interest in
the Notes or with respect to the delivery to any participant, member,
beneficial owner or other Person (other than the Depositary) of any notice
(including any notice of redemption) or the payment of any amount, under or with
respect to such Notes. All notices and communications to be given to the Holders
and all payments to be made to Holders under the Notes shall be given or made
only to or upon the order of the registered Holders (which shall be the
Depositary or its nominee in the case of a Global Note). The rights of
beneficial owners in any Global Note shall be exercised only through the
Depositary subject to the applicable rules and procedures of the Depositary. The
Trustee and the Issuer may rely and shall be fully protected in relying upon
information furnished by the Depositary with respect to its members,
participants and any beneficial owners.

                      (ii) The Trustee and the Issuer  shall have no  obligation
or duty to monitor, determine or inquire as to compliance with any restrictions
on transfer imposed under this Indenture or under applicable law withrespect to
any transfer of any interest in any Note (including any transfers between or
among Depositary participants, members or beneficial owners in any Global Note)
other than to require delivery of such certificates and other documentation or
evidence as are expressly required by, and to do so if and when expressly
<PAGE>   75
                                       71

required by, the terms of this Indenture, and to examine the same to determine
substantial compliance as to form with the express requirements hereof.

                        2.4. Certificated Notes. (a) A Global Note deposited
with the Depositary or with the Trustee as custodian for the Depositary pursuant
to Section 2.1 shall be transferred to the beneficial owners thereof in the form
of certificated Notes in an aggregate principal amount at maturity equal to the
principal amount at maturity of such Global Note, in exchange for such Global
Note, only if such transfer complies with Section 2.3 and (i) the Depositary
notifies the Issuer that it is unwilling or unable to continue as Depositary for
such Global Note or if at any time such Depositary ceases to be a "clearing
agency" registered under the Exchange Act and a successor depositary is not
appointed by the Issuer within 90 days of such notice, or (ii) an Event of
Default has occurred and is continuing or (iii) the Issuer, in its sole
discretion, notifies the Trustee in writing that it elects to cause the issuance
of certificated Notes under this Indenture.

                     (b) Any Global Note that is  transferable to the beneficial
owners thereof pursuant to this Section shall be surrendered by the Depositary
to the Trustee, to be so transferred, in whole or from time to time in part,
without charge, and the Trustee shall authenticate and deliver, upon such
transfer of each portion of such Global Note, an equal aggregate principal
amount at maturity of certificated Initial Notes of authorized denominations.
Any portion of a Global Note transferred pursuant to this Section shall be
executed, authenticated and delivered only in denominations of $1,000 any
integral multiple thereof and registered in such names as the Depositary shall
direct. Any certificated Initial Note delivered in exchange for an interest in
the Global Note shall, except as otherwise provided by Section 2.3(d), bear the
restricted securities legend set forth in Exhibit 1 hereto.

                       (c)  Subject to the  provisions  of Section  2.4(b),  the
registered Holder of a Global Note may grant proxies and otherwise authorize any
Person, including Agent Members and Persons that may hold interests through
Agent Members, to take any action which a Holder is entitled to take under this
Indenture or the Notes.

                      (d) In the event of the  occurrence  of any of the  events
specified in Section 2.4(a), the Issuer will promptly make available to the
Trustee a reasonable supply of certificated Notes in definitive, fully
registered form without interest coupons.

<PAGE>   76
                                       1

                                    EXHIBIT 1
                            TO RULE 144A/REGULATION S
                                    APPENDIX

                         [FORM OF FACE OF INITIAL NOTE]

                              [Global Notes Legend]

                  UNLESS  THIS   CERTIFICATE   IS  PRESENTED  BY  AN  AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION  ("DTC"),
NEW YORK,  NEW YORK,  TO THE ISSUER OR ITS AGENT FOR  REGISTRATION  OF TRANSFER,
EXCHANGE OR PAYMENT,  AND ANY  CERTIFICATE  ISSUED IS  REGISTERED IN THE NAME OF
CEDE & CO. OR SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF
DTC  (AND ANY  PAYMENT  IS MADE TO CEDE & CO.,  OR TO SUCH  OTHER  ENTITY  AS IS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER
USE HEREOF FOR VALUE OR  OTHERWISE  BY OR TO ANY PERSON IS WRONGFUL  INASMUCH AS
THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

                  TRANSFERS OF THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS IN
WHOLE,  BUT NOT IN PART,  TO NOMINEES  OF DTC OR TO A SUCCESSOR  THEREOF OR SUCH
SUCCESSOR'S  NOMINEES,  AND  TRANSFERS  OF PORTIONS OF THIS GLOBAL NOTE SHALL BE
LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE  RESTRICTIONS  SET FORTH IN THE
INDENTURE REFERRED TO ON THE REVERSE HEREOF.

                                          [Restricted Securities Legend]

                  THIS NOTE HAS NOT BEEN  REGISTERED  UNDER THE U.S.  SECURITIES
ACT OF 1933, AS AMENDED (THE "SECURITIES  ACT"),  AND,  ACCORDINGLY,  MAY NOT BE
OFFERED OR SOLD  WITHIN THE UNITED  STATES OR TO, OR FOR THE  ACCOUNT OR BENEFIT
OF,  U.S.  PERSONS,  EXCEPT  AS SET  FORTH  IN THE  FOLLOWING  SENTENCE.  BY ITS
ACQUISITION  HEREOF,  THE  HOLDER  (1)  REPRESENTS  THAT (A) IT IS A  "QUALIFIED
INSTITUTIONAL  BUYER" (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT), OR (B)
IT IS AN "INSTITUTIONAL ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(A)(1), (2),
(3) OR (7)  OR  REGULATION  D  UNDER  THE  SECURITIES  ACT)  (AN  "INSTITUTIONAL
ACCREDITED  INVESTOR") OR (C) IT IS NOT A U.S. PERSON AND IS ACQUIRING THIS NOTE
IN AN OFFSHORE  TRANSACTION IN COMPLIANCE WITH REGULATION S UNDER THE SECURITIES
ACT, (2) AGREES THAT IT WILL NOT RESELL OR OTHERWISE
<PAGE>   77
                                       2

TRANSFER  THIS NOTE EXCEPT (A) TO THE COMPANY OR ANY SUBSIDIARY THEREOF,  (B)
TO A QUALIFIED  INSTITUTIONAL BUYER IN  COMPLIANCE  WITH RULE 144A UNDER THE
SECURITIES  ACT,  (C) INSIDE THE UNITED  STATES  TO AN  INSTITUTIONAL
ACCREDITED  INVESTOR  THAT,  PRIOR TO SUCH TRANSFER,   FURNISHES  TO  THE
TRUSTEE  A  SIGNED  LETTER  CONTAINING   CERTAIN REPRESENTATIONS  AND AGREEMENTS
RELATING TO THE RESTRICTIONS ON TRANSFER OF THIS NOTE (THE FORM OF WHICH LETTER
CAN BE OBTAINED  FROM THE  TRUSTEE)  AND, IF SUCH TRANSFER IS IN RESPECT OF AN
AGGREGATE  PRINCIPAL AMOUNT OF NOTES AT THE TIME OF TRANSFER OF LESS THAN
$100,000,  AN OPINION OF COUNSEL ACCEPTABLE TO THE COMPANY THAT SUCH TRANSFER IS
IN  COMPLIANCE  WITH THE  SECURITIES  ACT, (D) OUTSIDE THE UNITED  STATES  IN AN
OFFSHORE  TRANSACTION  IN  COMPLIANCE  WITH  RULE  904 OF REGULATION  S  UNDER
THE  SECURITIES  ACT  OR  (E)  PURSUANT  TO  AN  EFFECTIVE REGISTRATION
STATEMENT  UNDER THE  SECURITIES  ACT AND (3) AGREES  THAT IT WILL DELIVER TO
EACH PERSON TO WHOM THIS NOTE IS  TRANSFERRED A NOTICE  SUBSTANTIALLY TO THE
EFFECT OF THIS LEGEND.  IN CONNECTION WITH ANY TRANSFER OF THIS NOTE, THE
HOLDER MUST CHECK THE  APPROPRIATE  BOX SET FORTH ON THE REVERSE HEREOF RELATING
TO THE MANNER OF SUCH TRANSFER AND SUBMIT THIS  CERTIFICATE  TO THE TRUSTEE.  IF
THE PROPOSED  TRANSFEREE IS AN  INSTITUTIONAL  ACCREDITED  INVESTOR,  THE HOLDER
MUST,  PRIOR TO SUCH  TRANSFER,  FURNISH TO THE  TRUSTEE  AND THE  COMPANY  SUCH
CERTIFICATIONS,  LEGAL  OPINIONS  OR OTHER  INFORMATION  AS  EITHER  OF THEM MAY
REASONABLY  REQUIRE TO CONFIRM THAT SUCH  TRANSFER IS BEING MADE  PURSUANT TO AN
EXEMPTION  FROM,  OR  IN  A  TRANSACTION   NOT  SUBJECT  TO,  THE   REGISTRATION
REQUIREMENTS  OF THE  SECURITIES  ACT.  AS  USED  HEREIN,  THE  TERMS  "OFFSHORE
TRANSACTION,"  "UNITED STATES" AND "U.S. PERSON" HAVE THE MEANINGS GIVEN TO THEM
BY REGULATION S UNDER THE  SECURITIES  ACT. THE  INDENTURE  CONTAINS A PROVISION
REQUIRING  THE  TRUSTEE  TO  REFUSE TO  REGISTER  ANY  TRANSFER  OF THIS NOTE IN
VIOLATION OF THE FOREGOING RESTRICTIONS.

                        [Original Issue Discount Legend]

                  THIS  NOTE  WAS  ISSUED  WITH  ORIGINAL  ISSUE  DISCOUNT,  FOR
PURPOSES OF SECTIONS 1272, 1273 AND 1275 OF THE UNITED STATES  INTERNAL  REVENUE
CODE OF 1986,  AS  AMENDED,  THE  ISSUE  PRICE OF THIS  NOTE IS  $535.86  OF ITS
PRINCIPAL  AMOUNT AT MATURITY,  THE AMOUNT OF ORIGINAL ISSUE DISCOUNT IS $464.14
PER $1,000 OF PRINCIPAL AMOUNT AT MATURITY, THE ISSUE DATE IS MARCH 15, 2000 AND
THE YIELD TO MATURITY IS 12.875%.

<PAGE>   78
                                       3

                                            SPECTRASITE HOLDINGS, INC.

No. __   Principal Amount at Maturity $__________

CUSIP NO. ______

                                        12[ ]% Senior Discount Note due 2010

                  SpectraSite Holdings,  Inc., a Delaware corporation,  promises
to  pay  to   __________,   or   registered   assigns,   the  principal  sum  of
__________________________ Dollars on March 15, 2010.

                  Interest Payment Dates: March 15 and September 15.

                  Record Dates: March 1 and September 1.

                  Additional  provisions of this Note are set forth on the other
side of this Note.

Dated:                                               SPECTRASITE HOLDINGS, INC.

                                                     By:
                                                       ------------------------

                                                     By:
                                                       ------------------------

TRUSTEE'S CERTIFICATE OF
AUTHENTICATION

This is one of the Notes referred to in the Indenture.

UNITED STATES TRUST COMPANY OF NEW YORK
   as Trustee

By:
   --------------------------------
       Authorized Signatory

<PAGE>   79
                                       4

                     [FORM OF REVERSE SIDE OF INITIAL NOTE]

                                (Reverse of Note)

                       12[ ]% Senior Discount Note due 2010

1.       Interest

                  SpectraSite  Holdings,  Inc.,  a  Delaware  corporation  (such
corporation,  and its  successors  and assigns under the  Indenture  hereinafter
referred to, being herein called the "Issuer"),  promises to pay interest on the
principal  amount  of this  Note at the rate per annum  shown  above;  provided,
however,  that if a Registration  Default (as defined in the Registration Rights
Agreement)  occurs,  additional cash interest will accrue on this Note at a rate
of 0.50% per annum from and  including  the date on which any such  Registration
Default shall occur to but excluding the date on which all Registration Defaults
have been cured, calculated on the Accreted Value of this Note as of the date on
which such interest is payable;  provided,  however,  that in no event shall the
aggregate  amount of such  additional  interest  exceed  0.50% per  annum.  Such
interest is payable in addition to any other interest  payable from time to time
with  respect to this Note.  The Trustee  will not be deemed to have notice of a
Registration  Default  until  it  shall  have  received  actual  notice  of such
Registration Default.

                  Until March 15,2005, the Notes will accrete at a rate of 12[]%
per annum and be compounded semi-annually on each March 15 and September 15 with
respect to the Notes,  but, except as described  herein,  will not be payable in
cash.  Interest  on the  Accreted  Value of each Note as of March 15,  2005 will
accrue at the same rate but will be paid semi-annually  commencing September 15,
2005,  to Holders of record at the close of business on the March 1 or September
1 immediately  preceding the interest  payment date of March 15 and September 15
of each year. The Issuer shall pay interest on overdue principal at 1% per annum
in excess of the rate borne by the Notes to the extent lawful.  Interest will be
computed on the basis of a 360-day year of twelve 30-day months.

<PAGE>   80
                                       5

2.       Method of Payment

                  By at least  11:00  a.m.  (New York City  time) on the date on
which any  principal of or interest on any Note is due and  payable,  the Issuer
shall irrevocably  deposit with the Trustee or the Paying Agent money sufficient
to pay such  principal  and/or  interest.  The Issuer will pay interest  (except
defaulted  interest) to the Persons who are  registered  Holders of Notes at the
close of business  on the March 1 or  September 1 next  preceding  the  interest
payment  date even if Notes are  cancelled,  repurchased  or redeemed  after the
record date and on or before the interest  payment date.  Holders must surrender
Notes to a Paying  Agent to collect  principal  payments.  The  Issuer  will pay
principal and interest in money of the United States that at the time of payment
is legal tender for payment of public and private debts. However, the Issuer may
pay  principal  and  interest  by check  payable in such  money.  It may mail an
interest check to a Holder's registered address.

3.       Paying Agent and Registrar

                  Initially, United States Trust Company of New York, a national
banking association (the "Trustee"), will act as Paying Agent and Registrar. The
Issuer  may  appoint  and change any Paying  Agent,  Registrar  or  co-registrar
without  notice  to any  Noteholder.  The  Issuer  or  any  of its  domestically
incorporated Wholly Owned Subsidiaries may act as Paying Agent.

4.       Indenture

                  The Issuer  issued the Notes  under an  Indenture  dated as of
March  15,  2000 (as it may be  amended  or  supplemented  from  time to time in
accordance with the terms thereof, the "Indenture"),  between the Issuer and the
Trustee.  The terms of the Notes include those stated in the Indenture and those
made part of the  Indenture by reference to the Trust  Indenture Act of 1939, as
amended  (15  U.S.C.  ss.ss.  77aaa-77bbbb)  as in  effect  on the  date  of the
Indenture (the "TIA"). Capitalized terms used herein and not defined herein have
the meanings  ascribed  thereto in the  Indenture.  The Notes are subject to all
such terms,  and  Noteholders  are referred to the  Indenture  and the TIA for a
statement of those terms.

                  The Notes  are  unsecured  senior  obligations  of the  Issuer
limited to  $559,800,000  aggregate  principal  amount at  maturity  (subject to
Section 2.7 of the Indenture), all of which are being offered on the Issue Date.

                  This  Note  is one of the  Initial  Notes  referred  to in the
Indenture.  The Notes include the Initial Notes and any Private  Exchange  Notes
and  Exchange  Notes issued in exchange  for the Initial  Notes  pursuant to the
Indenture and the Registration Rights Agreement. The Initial Notes., the Private
Exchange  Notes  and the  Exchange  Notes  are  treated  as a  single  class  of
securities under the Indenture. The Indenture imposes certain limitations on the
Incurrence of  Indebtedness by the Issuer and its Restricted  Subsidiaries,  the
payment of dividends and other  distributions on the Capital Stock of the Issuer
and its Restricted
<PAGE>   81
                                       6

 Subsidiaries,  the purchase or redemption of Capital Stock of
the Issuer and Capital Stock of such Restricted Subsidiaries,  certain purchases
or redemptions of Subordinated  Obligations,  the sale or transfer of assets and
Capital Stock of Restricted Subsidiaries,  the issuance or sale of Capital Stock
of Restricted  Subsidiaries,  the investments of the Issuer and its Subsidiaries
and transactions with Affiliates.  In addition, the Indenture limits the ability
of the Issuer and its  Restricted  Subsidiaries  to restrict  distributions  and
dividends from Restricted Subsidiaries.

5.       Redemption

                  Except as set forth in the following paragraph, the Notes will
not be  redeemable  at the  option  of the  Issuer  prior  to  March  15,  2005.
Thereafter, the Notes will be redeemable, at the Issuer's option, in whole or in
part,  at any time or from time to time,  upon not less than 30 nor more than 60
days'  prior  notice  mailed by  first-class  mail to each  Holder's  registered
address,  at the following  redemption  prices (expressed as a percentage of the
Accreted  Value),  plus accrued and unpaid  interest,  if any, on such  Accreted
Value to the  redemption  date (subject to the right of Holders of record on the
relevant record date to receive  interest due on the relevant  interest  payment
date),  if redeemed  during the 12-month  period  commencing  on March 15 of the
years set forth below:

                 Period                                   Redemption Price
               ----------                              -------------------------
                 2005                                             106.438%
                 2006                                             104.292%
                 2007                                             102.146%
                 2008 and thereafter                              100.000%

                  In addition,  at any time and from time to time prior to March
15,  2003,  the Issuer may redeem in the  aggregate  up to 35% of the  aggregate
principal  amount at  maturity  of the Notes  with the  proceeds  of one or more
Equity  Offerings,  at a redemption  price  (expressed  as a  percentage  of the
Accreted Value thereof) of 112.875% plus accrued and unpaid interest, if any, to
the  redemption  date (subject to the right of Holders of record on the relevant
record date to receive  interest due on the  relevant  interest  payment  date);
provided,  however,  that at least  65% of the  aggregate  principal  amount  at
maturity  of the Notes  must  remain  outstanding  after  each  such  redemption
(excluding  Notes  held  by the  Issuer  or any of its  Subsidiaries);  provided
further that such  redemption  shall occur within 90 days of the date of closing
of such Equity Offering.

<PAGE>   82
                                       7

6.       Notice of Redemption

                  Notice of  redemption  will be mailed at least 30 days but not
more than 60 days before the redemption date by first-class  mail to each Holder
of Notes to be redeemed at his registered  address.  Notes in  denominations  of
principal  amount  larger  than $1,000 may be redeemed in part but only in whole
multiples of $1,000.  If money  sufficient  to pay the  redemption  price of and
accrued and unpaid interest on all Notes (or portions thereof) to be redeemed on
the  redemption  date is  deposited  with  the  Paying  Agent on or  before  the
redemption  date and certain other  conditions are satisfied,  on and after such
date interest  ceases to accrue on such Notes (or such portions  thereof) called
for redemption.

7.       Put Provisions

                  Upon a Change of  Control,  any  Holder of Notes will have the
right to cause  the  Issuer to  repurchase  all or any part of the Notes of such
Holder at a repurchase  price equal to 101% of the Accreted  Value thereof as of
the date of repurchase, plus accrued and unpaid interest, if any, to the date of
repurchase as provided in, and subject to the terms of, the Indenture.

8.       Registration Rights

                  The Issuer is party to a Registration Rights Agreement,  dated
as of March15,  2000, among the Issuer,  and Morgan Stanley & Co.  Incorporated,
CIBC World Markets Corp., Credit Suisse First Boston Corporation,  Deutsche Bank
Securities  Inc.,  Lehman  Brothers  Inc.,  BMO Nesbitt  Burns Corp.  and Scotia
Capital (USA) Inc. pursuant to which it is obligated to pay Additional  Interest
(as defined  therein) upon the occurrence of certain  Registration  Defaults (as
defined therein).

9.       Denominations; Transfer; Exchange

                  The  Notes  are  in   registered   form  without   coupons  in
denominations  of principal  amount of $1,000 and whole  multiples of $1,000.  A
Holder  may  register,  transfer  or  exchange  Notes  in  accordance  with  the
Indenture.  The Registrar may require a Holder,  among other things,  to furnish
appropriate  endorsements  or transfer  documents  and to pay any taxes and fees
required by law or permitted by the  Indenture.  The Registrar need not register
the transfer of or exchange (i) any Notes  selected for redemption  (except,  in
the case of a Note to be  redeemed  in part,  the  portion of the Note not to be
redeemed) for a period beginning 15 business days before a selection of Notes to
be  redeemed  and ending on the date of such  selection  or (ii) any Notes for a
period  beginning 15 business days before an interest payment date and ending on
such interest payment date.
<PAGE>   83
                                       8

10.      Persons Deemed Owners

                  The registered holder of this Note may be treated as the owner
of it for all purposes.

11.      Unclaimed Money

                  If money for the payment of principal or interest remains
unclaimed for one year after the date of payment of principal and interest, the
Trustee or Paying Agent shall pay the money back to the Issuer at its request
unless an abandoned property law designates another Person.  After any such
payment, Holders entitled to the money must look only to the Issuer and not to
the Trustee for payment.

12.      Defeasance

                  Subject to certain conditions set forth in the Indenture,  the
Issuer at any time may terminate some or all of its obligations  under the Notes
and the  Indenture  if the  Issuer  deposits  with  the  Trustee  money  or U.S.
Government Obligations for the payment of principal of and interest on the Notes
to redemption or maturity, as the case may be.

13.      Amendment, Waiver

                  Subject to certain exceptions set forth in the Indenture,  (i)
the  Indenture  or the Notes may be  amended  with the  written  consent  of the
Holders  of at  least  a  majority  in  principal  amount  at  maturity  of  the
outstanding  Notes and (ii) any default or noncompliance  with any provision may
be waived  with the written  consent of the  Holders of a majority in  principal
amount at maturity of the outstanding  Notes.  Subject to certain exceptions set
forth in the Indenture,  without the consent of any  Noteholder,  the Issuer and
the  Trustee  may  amend  the  Indenture  or the  Notes to cure  any  ambiguity,
omission, defect or inconsistency, or to comply with Article V of the Indenture,
or  to  provide  for  uncertificated  Notes  in  addition  to  or  in  place  of
certificated  Notes, or to add guarantees with respect to the Notes or to secure
the Notes,  or to add  additional  covenants of or  surrender  rights and powers
conferred  on the  Issuer,  or to make any change that does not  materially  and
adversely affect the rights of any Noteholder,  or to comply with any request of
the SEC in connection with qualifying the Indenture under the Act.
<PAGE>   84
                                       9

14.      Defaults and Remedies

                  Under the Indenture,  Events of Default  include (i) a default
in any payment of interest on any Note when due,  continued for 30 days,  (ii) a
default in the payment of principal of any Note when due at its Stated Maturity,
upon  optional  or  mandatory   redemption,   upon  required  repurchase,   upon
declaration  or  otherwise,  (iii) the  failure by the Issuer to comply with its
obligations under Article V of the Indenture,  (iv) the failure by the Issuer to
comply for 30 days after notice with any of its obligations  under the covenants
described  under Section 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9,  4.10,  4.11 or
4.12 of the  Indenture (in each case,  other than a failure to purchase  Notes),
(v) the failure by the Issuer to comply for 60 days after  notice with its other
agreements  contained  in the  Indenture,  (vi) the failure by the Issuer or any
Significant  Subsidiary  of  the  Issuer  to pay  any  Indebtedness  within  any
applicable  grace period after final  maturity or the  acceleration  of any such
Indebtedness  by the holders thereof because of a default if the total amount of
such  Indebtedness  unpaid or  accelerated  exceeds $10.0 million or its foreign
currency  equivalent,   (vii)  certain  events  of  bankruptcy,   insolvency  or
reorganization  of the  Issuer or any  Significant  Subsidiary  of the Issuer or
(viii) any final  judgment or decree for the payment of money in excess of $10.0
million  (net of any  amounts  with  respect to which a  creditworthy  insurance
company has acknowledged  full liability  (subject to any deductible  amounts of
less than $10.0  million  required  to be paid by the Issuer or the  Significant
Subsidiary of the Issuer in accordance with the applicable insurance policy)) is
rendered  against  the Issuer or any  Significant  Subsidiary  of the Issuer and
either (A) an  enforcement  proceeding  has been  commenced by any creditor upon
such  judgment  or decree or (B) such  judgment  or decree  remains  unpaid  and
outstanding  for a  period  of 60  days  following  such  judgment  and  is  not
discharged, waived or stayed within 10 days after notice. If an Event of Default
occurs  and is  continuing,  the  Trustee  or the  Holders  of at  least  25% in
aggregate  principal amount of the Notes may declare all the Notes to be due and
payable  immediately.  Certain  events of bankruptcy or insolvency are Events of
Default  which will result in the Notes being due and payable  immediately  upon
the occurrence of such Events of Default.

                  Noteholders  may not enforce the Indenture or the Notes except
as provided in the Indenture. The Trustee may refuse to enforce the Indenture or
the Notes  unless it  receives  reasonable  indemnity  or  security.  Subject to
certain limitations,  Holders of a majority in principal amount of the Notes may
direct the  Trustee  in its  exercise  of any trust or power.  The  Trustee  may
withhold from Noteholders  notice of any continuing  Default or Event of Default
(except a Default or Event of Default in payment of principal or interest) if it
determines that withholding notice is not opposed to their interest.

<PAGE>   85
                                       10

15.      Trustee Dealings with the Issuer

                  Subject to certain limitations set forth in the Indenture, the
Trustee under the Indenture, in its individual or any other capacity, may become
the  owner  or  pledgee  of  Notes  and may  otherwise  deal  with  and  collect
obligations  owed to it by the Issuer or its  Affiliates  and may otherwise deal
with the Issuer or its Affiliates  with the same rights it would have if it were
not Trustee.

16.      No Recourse Against Others

                  No director, officer, employee, incorporator or stockholder of
the Issuer,  as such, shall have any liability for any obligations of the Issuer
under the Notes,  the  Indenture or for any claim based on, in respect of, or by
reason of such obligations or their creation.  Each Holder of Notes by accepting
a Note waives and releases all such liability.  This waiver and release are part
of the consideration for issuance of the Notes.

17.      Authentication

                  This Note shall not be valid until an authorized  signatory of
the Trustee (or an authenticating agent acting on its behalf) manually signs the
certificate of authentication on the other side of this Note.

18.      Abbreviations

                  Customary   abbreviations  may  be  used  in  the  name  of  a
Noteholder  or an  assignee,  such  as TEN COM  (=tenants  in  common),  TEN ENT
(=tenants by the entirety),  JT TEN (=joint  tenants with rights of survivorship
and not as tenants in common),  CUST  (=custodian) and U/G/M/A (=Uniform Gift to
Minors Act).

19.      CUSIP Numbers

                  Pursuant to a  recommendation  promulgated by the Committee on
Uniform Security Identification  Procedures, the Issuer has caused CUSIP numbers
to be printed on the Notes and has directed the Trustee to use CUSIP  numbers in
notices of redemption as a convenience to Noteholders. No representation is made
as to the  accuracy  of such  numbers  either  as  printed  on the  Notes  or as
contained  in any notice of  redemption  and  reliance may be placed only on the
other identification numbers placed thereon.
<PAGE>   86
                                       11

20.      GOVERNING LAW

                  THIS NOTE SHALL BE GOVERNED BY, AND  CONSTRUED  IN  ACCORDANCE
WITH,  THE LAWS OF THE STATE OF NEW YORK BUT WITHOUT GIVING EFFECT TO APPLICABLE
PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF
ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

                  The Issuer will furnish to any Noteholder upon written request
and without charge to the Noteholder a copy of the Indenture which has in it the
text of this Note in larger type. Requests may be made to: SpectraSite Holdings,
Inc.,  100  Regency  Forest  Drive,  Suite  400,  Cary,  North  Carolina  27511,
Attention: Chief Financial Officer.

<PAGE>   87
                                       12

                                 ASSIGNMENT FORM

                  To assign this Note, fill in the form below:

I or we assign and transfer this Note to:

-----

-----

-----
(Print or type assignee's name, address and zip code)

(Insert assignee's soc. sec. or tax I.D. No.)

and irrevocably appoint
agent to transfer this Note on the books of the Issuer.  The agent may
substitute another to act for him.

Date:                                       Your Signature:
     -----------------                                     ---------------------
                                                           Sign  exactly as
                                                           your name appears on
                                                           the other  side  of
                                                           this Note.

Signature Guarantee:
                           (Signature  must be guaranteed by a participant  in a
                           recognized  Signature  Guarantee Medallion Program or
                           other   signature    guarantor   program   reasonably
                           acceptable to the Trustee)

In  connection  with any  transfer or exchange of any of the Notes  evidenced by
this  certificate  occurring prior to the date that is two years after the later
of the date of  original  issuance  of such Notes and the last date,  if any, on
which such Notes were owned by the Issuer or any  Affiliate  of the Issuer,  the
undersigned confirms that such Notes are being transferred:

CHECK ONE BOX BELOW:

[ ]      (1)      to the Issuer; or

[ ]      (2)      pursuant to an effective registration statement under the
                  Securities Act of 1933; or
<PAGE>   88
                                       13

[ ]      (3)      inside the United  States to a  "qualified  institutional
                  buyer" (as  defined in Rule 144A under the  Securities  Act of
                  1933) that purchases for its own account or for the account of
                  a qualified  institutional  buyer to whom notice is given that
                  such  transfer is being made in reliance on Rule 144A, in each
                  case  pursuant to and in  compliance  with Rule 144A under the
                  Securities Act of 1933; or

[ ]      (4)      outside the United States in an offshore transaction within
                  the meaning of Regulation S under the Securities Act in
                  compliance with Rule 904 under the Securities Act of 1933; or

[ ]      (5)      pursuant to another available exemption from registration
                  provided by Rule 144 under the Securities Act of 1933.

Unless one of the boxes is checked,  the Trustee  will refuse to register any of
the Notes evidenced by this certificate in the name of any Person other than the
registered holder thereof; provided, however, that if box (4) or (5) is checked,
the Trustee may require,  prior to  registering  any such transfer of the Notes,
such legal  opinions,  certifications  and other  information  as the Issuer has
reasonably  requested to confirm that such transfer is being made pursuant to an
exemption  from,  or  in  a  transaction   not  subject  to,  the   registration
requirements  of the Securities  Act of 1933, as amended,  such as the exemption
provided by Rule 144 under such Act.

Date:                                   Your Signature:
     ------------------                                ------------------------
                                                       Sign  exactly as
                                                       your name appears on the
                                                       other side of this Note.

Signature Guarantee:
                           (Signature  must be guaranteed by a participant  in a
                           recognized  Signature  Guarantee Medallion Program or
                           other   signature    guarantor   program   reasonably
                           acceptable to the Trustee)

<PAGE>   89
                                       14

              TO BE COMPLETED BY PURCHASER IF (3) ABOVE IS CHECKED.

                  The undersigned  represents and warrants that it is purchasing
this Note for its own account or an account  with  respect to which it exercises
sole  investment  discretion  and that it and any such  account is a  "qualified
institutional buyer" within the meaning of Rule 144A under the Securities Act of
1933, as amended,  and is aware that the sale to it is being made in reliance on
Rule 144A and acknowledges  that it has received such information  regarding the
Issuer as the undersigned has requested  pursuant to Rule 144A or has determined
not to request  such  information  and that it is aware that the  transferor  is
relying upon the undersigned's  foregoing  representations in order to claim the
exemption from registration provided by Rule 144A.

Date:
                                              NOTICE:       To be executed by an
                                                            executive officer

                       OPTION OF HOLDER TO ELECT PURCHASE

                  If you want to elect to have this Note purchased by the Issuer
pursuant to Section 4.7 or 4.9 of the Indenture, check the appropriate box:

                  Section 4.7       [ ]

                  Section 4.9       [ ]

                  If you want to elect to have only part of this Note  purchased
by the Issuer pursuant to Section 4.7 or 4.9 of the Indenture,  state the amount
you elect to have purchased (must be integral multiple of $1,000):
$
-----------------

<PAGE>   90
                                       15

                                         [TO BE ATTACHED TO GLOBAL NOTES]

                                 SCHEDULE OF INCREASES OR DECREASES IN GLOBAL NO

                     The  following  increases  or decreases in this Global Note
have been made:

<TABLE>

<S>                       <C>                      <C>                     <C>                      <C>

Date of Exchange           Amount of decrease in    Amount of increase in   Principal Amount         Signature of
                           -----------------------  ----------------------  -----------------------  authorized
                           Principal Amount at      Principal Amount at     at Maturity of this      ----------------------
                           Maturity of this Global  Maturity of this        Global Note              officer of Trustee or
                           Note                     Global                  following such           Notes Custodian
                                                    Note                    decrease or increase

</TABLE>

<PAGE>   91
                                       1

                                                                       EXHIBIT A

                         [FORM OF FACE OF EXCHANGE NOTE
                           [OR PRIVATE EXCHANGE NOTE]]

1

2

3

                                            SPECTRASITE HOLDINGS, INC.

No.__    Principal Amount at Maturity $________________

CUSIP NO.__________

                                        12[ ]% Senior Discount Note Due 2010

                  SpectraSite Holdings,  Inc., a Delaware corporation,  promises
to  pay  to  _____________,   or  registered  assigns,   the  principal  sum  of
__________________ Dollars on March 15, 2010.

<PAGE>   92
                                       2

                  Interest Payment Dates: March 15 and September 15.

                  Record Dates: March 1 and September 1.

                  Additional  provisions of this Note are set forth on the other
side of this Note.

Dated:                                         SPECTRASITE HOLDINGS, INC.

                                               By:
                                                  ----------------------------

                                               By:
                                                  ----------------------------

TRUSTEE'S CERTIFICATE OF
AUTHENTICATION

This is one of the Notes referred to in the Indenture.

UNITED STATES TRUST COMPANY OF NEW YORK
  as Trustee

By:
   -------------------------------------
            Authorized Signatory

<PAGE>   93
                                       3

                     [FORM OF REVERSE SIDE OF EXCHANGE NOTE
                           [OR PRIVATE EXCHANGE NOTE]]

                      12[ ]% Senior Discount Note due 2010

1.       Interest

                  SpectraSite  Holdings,  Inc.,  a  Delaware  corporation  (such
corporation,  and its  successors  and assigns under the  Indenture  hereinafter
referred to, being herein called the "Issuer"),  promises to pay interest on the
principal  amount  of this Note at the rate per annum  shown  above[;  provided,
however,  that if a Registration  Default (as defined in the Registration Rights
Agreement)  occurs,  additional cash interest will accrue on this Note at a rate
of 0.50% per annum from and  including  the date on which any such  Registration
Default shall occur to but excluding the date on which all Registration Defaults
have been cured, calculated on the Accreted Value of this Note as of the date on
which such interest is payable;  provided,  however,  that in no event shall the
aggregate  amount of such  additional  interest  exceed  0.50% per  annum.  Such
interest is payable in addition to any other interest  payable from time to time
with  respect to this Note.  The Trustee  will not be deemed to have notice of a
Registration  Default  until  it  shall  have  received  actual  notice  of such
Registration Default].

                  Until March 15, 2005, the Notes will accrue at a rate of 12[]%
per annum and be compounded semi-annually on each March 15 and September 15 from
March 15,  2000 to March 15,  2010 with  respect  to the Notes,  but,  except as
described herein, will not be payable in cash. Interest on the Accreted Value of
each  Note as of March 15,  2005  will  accrue at the same rate but will be paid
semi-annually  commencing  September 15, 2005, to Holders of record at the close
of business on the March 1 or  September 1  immediately  preceding  the interest
payment  date of March 15 and  September  15 of each year.  The Issuer shall pay
interest on overdue principal at 1% per annum in excess of the rate borne by the
Notes to the extent lawful.  Interest will be computed on the basis of a 360-day
year of twelve 30-day months.

2.       Method of Payment

                  By at least  11:00  a.m.  (New York City  time) on the date on
which any  principal of or interest on any Note is due and  payable,  the Issuer
shall irrevocably  deposit with the Trustee or the Paying Agent money sufficient
to pay such  principal  and/or  interest.  The Issuer will pay interest  (except
defaulted  interest) to the Persons who are  registered  Holders of Notes at the
close of business  on the March 1 or  September 1 next  preceding  the  interest
payment  date even if Notes are  cancelled,  repurchased  or redeemed  after the
record date and on or before the interest  payment date.  Holders must surrender
Notes to a Paying  Agent to collect  principal  payments.  The  Issuer  will pay
principal and interest in money of the United States that at the time of payment
is legal tender for payment of public and private debts. However, the Issuer may
pay  principal  and  interest  by check  payable in such  money.  It may mail an
interest an interest check to a Holder's registered address.

<PAGE>   94
                                       4

3.       Paying Agent and Registrar

                  Initially, United States Trust Company of New York, a national
banking association (the "Trustee"), will act as Paying Agent and Registrar. The
Issuer  may  appoint  and change any Paying  Agent,  Registrar  or  co-registrar
without  notice  to any  Noteholder.  The  Issuer  or  any  of its  domestically
incorporated Wholly Owned Subsidiaries may act as Paying Agent.

4.       Indenture

                  The Issuer  issued the Notes  under an  Indenture  dated as of
March  15,  2000 (as it may be  amended  or  supplemented  from  time to time in
accordance with the terms thereof, the "Indenture"),  between the Issuer and the
Trustee.  The terms of the Notes include those stated in the Indenture and those
made part of the  Indenture by reference to the Trust  Indenture Act of 1939, as
amended  (I5  U.S.C.  ss.ss.  77aaa-77bbbb)  as in  effect  on the  date  of the
Indenture (the "TIA"). Capitalized terms used herein and not defined herein have
the meanings  ascribed  thereto in the  Indenture.  The Notes are subject to all
such terms,  and  Noteholders  are referred to the  Indenture  and the TIA for a
statement of those terms.

                  The Notes  are  unsecured  senior  obligations  of the  Issuer
limited to  $559,800,000  aggregate  principal  amount at  maturity  (subject to
Section 2.7 of the Indenture), all of which are being offered on the Issue Date.

                  This  Note is one of the  Exchange  Notes  referred  to in the
Indenture.  The Notes include the Initial Notes and any Private  Exchange  Notes
and  Exchange  Notes issued in exchange  for the Initial  Notes  pursuant to the
Indenture and the Registration Rights Agreement.  The Initial Notes, the Private
Exchange  Notes  and the  Exchange  Notes  are  treated  as a  single  class  of
securities under the Indenture. The Indenture imposes certain limitations on the
Incurrence of  Indebtedness by the Issuer and its Restricted  Subsidiaries,  the
payment of dividends and other  distributions on the Capital Stock of the Issuer
and its Restricted Subsidiaries,  the purchase or redemption of Capital Stock of
the Issuer and Capital Stock of such Restricted Subsidiaries,  certain purchases
or redemptions of Subordinated  Obligations,  the sale or transfer of assets and
Capital Stock of Restricted Subsidiaries,  the issuance or sale of Capital Stock
of Restricted  Subsidiaries,  the investments of the Issuer and its Subsidiaries
and transactions with Affiliates.  In addition, the Indenture limits the ability
of the Issuer and its  Restricted  Subsidiaries  to restrict  distributions  and
dividends from Restricted Subsidiaries.

<PAGE>   95
                                       5
5.       Redemption

                  Except as set forth in the following paragraph, the Notes will
not be  redeemable  at the  option  of the  Issuer  prior  to  March  15,  2005.
Thereafter, the Notes will be redeemable, at the Issuer's option, in whole or in
part,  at any time or from time to time,  upon not less than 30 nor more than 60
days'  prior  notice  mailed by  first-class  mail to each  Holder's  registered
address,  at the following  redemption  prices (expressed as a percentage of the
Accreted  Value),  plus accrued and unpaid  interest,  if any, on such  Accreted
Value to the  redemption  date (subject to the right of Holders of record on the
relevant record date to receive  interest due on the relevant  interest  payment
date),  if redeemed  during the 12-month  period  commencing  on March 15 of the
years set forth below:

                  Period                                       Redemption Price
               ------------                                 --------------------
                  2005                                                 106.438%
                  2006                                                 104.292%
                  2007                                                 102.146%
                  2008 and thereafter                                  100.000%

                  In addition,  at any time and from time to time prior to March
15,  2003,  the Issuer may redeem in the  aggregate  up to 35% of the  aggregate
principal  amount at  maturity  of the Notes  with the  proceeds  of one or more
Equity  Offerings,  at a redemption  price  (expressed  as a  percentage  of the
Accreted Value thereof) of 112.875% plus accrued and unpaid interest, if any, to
the  redemption  date (subject to the right of Holders of record on the relevant
record date to receive  interest due on the  relevant  interest  payment  date);
provided,  however,  that at least  65% of the  aggregate  principal  amount  at
maturity  of the Notes  must  remain  outstanding  after  each  such  redemption
(excluding  Notes  held  by the  Issuer  or any of its  Subsidiaries);  provided
further,  that such redemption shall occur within 90 days of the date of closing
of such Equity Offering.

6.       Notice of Redemption

                  Notice of  redemption  will be mailed at least 30 days but not
more than 60 days before the redemption date by first-class  mail to each Holder
of Notes to be redeemed at his registered  address.  Notes in  denominations  of
principal  amount  larger  than $1,000 may be redeemed in part but only in whole
multiples of $1,000.  If money  sufficient  to pay the  redemption  price of and
accrued and unpaid interest on all Notes (or portions thereof) to be redeemed on
the  redemption  date is  deposited  with  the  Paying  Agent on or  before  the
redemption  date and certain other  conditions are satisfied,  on and after such
date interest  ceases to accrue on such Notes (or such portions  thereof) called
for redemption.

<PAGE>   96

                                       6

7.       Put Provisions

                  Upon a Change of  Control,  any  Holder of Notes will have the
right to cause  the  Issuer to  repurchase  all or any part of the Notes of such
Holder at a repurchase  price equal to 101% of the Accreted  Value thereof as of
the date of repurchase, plus accrued and unpaid interest, if any, to the date of
repurchase as provided in, and subject to the terms of, the Indenture.

8.       Denominations, Transfer, Exchange

                  The  Notes  are  in   registered   form  without   coupons  in
denominations  of principal  amount of $1,000 and whole  multiples of $1,000.  A
Holder  may  register,  transfer  or  exchange  Notes  in  accordance  with  the
Indenture.  The Registrar may require a Holder,  among other things,  to furnish
appropriate  endorsements  or transfer  documents  and to pay any taxes and fees
required by law or permitted by the  Indenture.  The Registrar need not register
the transfer of or exchange (i) any Notes  selected for redemption  (except,  in
the case of a Note to be  redeemed  in part,  the  portion of the Note not to be
redeemed) for a period beginning 15 business days before a selection of Notes to
be  redeemed  and ending on the date of such  selection  or (ii) any Notes for a
period  beginning 15 business days before an interest payment date and ending on
such interest payment date.

9.       Persons Deemed Owners

                  The registered holder of this Note may be treated as the owner
of it for all purposes.

10.      Unclaimed Money

                  If money for the  payment of  principal  or  interest  remains
unclaimed for one year after the date of payment of principal and interest,  the
Trustee or Paying  Agent  shall pay the money back to the Issuer at its  request
unless an  abandoned  property law  designates  another  Person.  After any such
payment,  Holders  entitled to the money must look only to the Issuer and not to
the Trustee for payment.

11.      Defeasance

                  Subject to certain conditions set forth in the Indenture,  the
Issuer at any time may terminate some or all of its obligations  under the Notes
and the  Indenture  if the  Issuer  deposits  with  the  Trustee  money  or U.S.
Government Obligations for the payment of principal of and interest on the Notes
to redemption or maturity, as the case may be.
<PAGE>   97
                                       7
12.      Amendment, Waiver

                  Subject to certain exceptions set forth in the Indenture,  (i)
the  Indenture  or the Notes may be  amended  with the  written  consent  of the
Holders  of at  least  a  majority  in  principal  amount  at  maturity  of  the
outstanding  Notes and (ii) any default or noncompliance  with any provision may
be waived  with the written  consent of the  Holders of a majority in  principal
amount at maturity of the outstanding  Notes.  Subject to certain exceptions set
forth in the Indenture,  without the consent of any  Noteholder,  the Issuer and
the  Trustee  may  amend  the  Indenture  or the  Notes to cure  any  ambiguity,
omission, defect or inconsistency, or to comply with Article V of the Indenture,
or  to  provide  for  uncertificated  Notes  in  addition  to  or  in  place  of
certificated  Notes, or to add guarantees with respect to the Notes or to secure
the Notes,  or to add  additional  covenants of or  surrender  rights and powers
conferred  on the  Issuer,  or to make any change that does not  materially  and
adversely affect the rights of any Noteholder,  or to comply with any request of
the SEC in connection with qualifying the Indenture under the Act.

13.      Defaults and Remedies

                  Under the Indenture,  Events of Default  include (i) a default
in any payment of interest on any Note when due,  continued for 30 days,  (ii) a
default in the payment of principal of any Note when due at its Stated Maturity,
upon  optional  or  mandatory   redemption,   upon  required  repurchase,   upon
declaration  or  otherwise,  (iii) the  failure by the Issuer to comply with its
obligations under Article V of the Indenture,  (iv) the failure by the Issuer to
comply for 30 days after notice with any of its obligations  under the covenants
described  under Section 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9,  4.10,  4.11 or
4.12 of the  Indenture (in each case,  other than a failure to purchase  Notes),
(v) the failure by the Issuer to comply for 60 days after  notice with its other
agreements  contained  in the  Indenture,  (vi) the failure by the Issuer or any
Significant  Subsidiary  of  the  Issuer  to pay  any  Indebtedness  within  any
applicable  grace period after final  maturity or the  acceleration  of any such
Indebtedness  by the holders thereof because of a default if the total amount of
such  Indebtedness  unpaid or  accelerated  exceeds $10.0 million or its foreign
currency  equivalent,   (vii)  certain  events  of  bankruptcy,   insolvency  or
reorganization  of the  Issuer or any  Significant  Subsidiary  of the Issuer or
(viii) any final  judgment or decree for the payment of money in excess of $10.0
million  (net of any  amounts  with  respect to which a  creditworthy  insurance
company has acknowledged  full liability  (subject to any deductible  amounts of
less than $10.0  million  required  to be paid by the Issuer or the  Significant
Subsidiary of the Issuer in accordance with the applicable insurance policy)) is
rendered  against  the Issuer or any  Significant  Subsidiary  of the Issuer and
either (A) an  enforcement  proceeding  has been  commenced by any creditor upon
such  judgment  or decree or (B) such  judgment  or decree  remains  unpaid  and
outstanding  for a  period  of 60  days  following  such  judgment  and  is  not
discharged, waived or stayed within 10 days after notice. If an Event of Default
occurs  and is  continuing,  the  Trustee  or the  Holders  of at  least  25% in
aggregate  principal amount of the Notes may declare all the Notes to be due and
payable  immediately.  Certain  events of bankruptcy or insolvency are Events of
Default  which will result in the Notes being due and payable  immediately  upon
the occurrence of such Events of Default.

<PAGE>   98
                                       8

                  Noteholders  may not enforce the Indenture or the Notes except
as provided in the Indenture. The Trustee may refuse to enforce the Indenture or
the Notes  unless it  receives  reasonable  indemnity  or  security.  Subject to
certain limitations,  Holders of a majority in principal amount of the Notes may
direct the  Trustee  in its  exercise  of any trust or power.  The  Trustee  may
withhold from Noteholders  notice of any continuing  Default or Event of Default
(except a Default or Event of Default in payment of Principal or interest) if it
determines that withholding notice is not opposed to their interest.

14.       Trustee Dealings with the Issuer

                  Subject to certain limitations set forth in the Indenture, the
Trustee under the Indenture, in its individual or any other capacity, may become
the  owner  or  pledgee  of  Notes  and may  otherwise  deal  with  and  collect
obligations  owed to it by the Issuer or its  Affiliates  and may otherwise deal
with the Issuer or its Affiliates  with the same rights it would have if it were
not Trustee.

15.      No Recourse Against Others

                  No director, officer, employee, incorporator or stockholder of
the Issuer,  as such, shall have any liability for any obligations of the Issuer
under the Notes,  the  Indenture or for any claim based on, in respect of, or by
reason of such obligations or their creation.  Each Holder of Notes by accepting
a Note waives and releases all such liability.  This waiver and release are part
of the consideration for issuance of the Notes.

16.      Authentication

                  This Note shall not be valid until an authorized  signatory of
the Trustee (or an authenticating agent acting on its behalf) manually signs the
certificate of authentication on the other side of this Note.

17.      Abbreviations

                  Customary   abbreviations  may  be  used  in  the  name  of  a
Noteholder  or an  assignee,  such  as TEN COM  (=tenants  in  common),  TEN ENT
(=tenants by the entirety),  JT TEN (=joint  tenants with rights of survivorship
and not as tenants in common),  CUST  (=custodian) and U/G/M/A (=Uniform Gift to
Minors Act).

18.      CUSIP Numbers

<PAGE>   99
                                       9

                  Pursuant to a  recommendation  promulgated by the Committee on
Uniform Security  Identification  Procedures the Issuer has caused CUSIP numbers
to be printed on the Notes and has directed the Trustee to use CUSIP  numbers in
notices of redemption as a convenience to Noteholders. No representation is made
as to the  accuracy  of such  numbers  either  as  printed  on the  Notes  or as
contained  in any notice of  redemption  and  reliance may be placed only on the
other identification numbers placed thereon.

19.      GOVERNING LAW

                  THIS NOTE SHALL BE GOVERNED BY, AND  CONSTRUED  IN  ACCORDANCE
WITH,  THE LAWS OF THE STATE OF NEW YORK BUT WITHOUT GIVING EFFECT TO APPLICABLE
PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF
ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

               The Issuer will furnish to any  Noteholder  upon written  request
and without charge to the Noteholder a copy of the Indenture which has in it the
text of this Note in larger type. Requests may be made to: SpectraSite Holdings,
Inc.,  100  Regency  Forest  Drive,  Suite  400,  Cary,  North  Carolina  27511,
Attention: Chief Financial Officer.

<PAGE>   100
                                       10

                                 ASSIGNMENT FORM

                  To assign this Note, fill in the form below:

I or we assign and transfer this Note to:

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

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

--------------------------------------------------------------------------------
(Print or type assignee's name, address and zip code)

--------------------------------------------------------------------------------
(Insert assignee's soc. sec. or tax I.D. No.)

and irrevocably appoint
agent to transfer this Note on the books of the Issuer.  The agent may
substitute another to act for him.

Date:                                          Your Signature:
     ----------------                                         ------------------
                                                              Sign   exactly  as
                                                              your name  appears
                                                              on the other  side
                                                              of this Note.

Signature Guarantee:
                           (Signature  must be guaranteed by a participant  in a
                           recognized  Signature  Guarantee Medallion Program or
                           other   signature    guarantor   program   reasonably
                           acceptable to the Trustee)

                       OPTION-OF-HOLDER TO ELECT PURCHASE

                  If you want to elect to have this Note purchased by the Issuer
pursuant to Section 4.7 or 4.9 of the Indenture, check the appropriate box:

                  Section 4.7      [ ]

                  Section 4.9      [ ]

                  If you want to elect to have only part of this Note  purchased
by the Issuer pursuant to Section 4.7 or 4.9 of the Indenture,  state the amount
you elect to have purchased (must be integral multiple of $1,000):
$ -------------------------

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