EXHIBIT 10.91
                                MASTER AGREEMENT
                    RELATING TO WIRELESS COMMUNICATIONS SITES
                                     BETWEEN
                             US WIRELESS CORPORATION
                                       AND
                              AMERICAN TOWER, L. P.

This  MASTER  AGREEMENT   RELATING  TO  WIRELESS   COMMUNICATIONS   SITES  (this
"Agreement")  dated May 25, 2000 (the  "Execution  Date"),  is made between U.S.
WIRELESS  CORPORATION,  A Delaware  corporation  having its  principal  place of
business at 2303 Camino Ramon, San Ramon CA 94583,  (hereinafter  referred to as
"USWC") and AMERICAN TOWER L. P., a Delaware Limited Partnership by, through and
under ATC GP, Inc., a Delaware corporation, its sole general partner, a Delaware
corporation,  both having their  principal  place of business at 116  Huntington
Avenue, Boston,  Massachusetts 02116 (hereinafter referred to as "ATC"), for the
performance of services and supply of materials in accordance with the terms and
conditions  hereinafter  set forth.  USWC and ATC are herein  after  referred to
collectively as the "Parties" and individually as a "Party".

         1.       SCOPE OF AGREEMENT.
                  ------------------

         (a) ATC and USWC may  mutually  agree  that ATC shall  provide  certain
services  and  materials   (collectively,   the  "Work")  for  various  wireless
communications  sites located  within the United  States  ("Sites") as set forth
herein  and in Project  Addendums  (as  hereinafter  defined),  and any  written
amendments thereto, executed by both parties from time to time. USWC agrees that
ATC shall have a preferential  right to provide USWC's  services for its network
in accordance with the terms of this Agreement including radio frequency design,
radio  frequency   engineering,   Site  identification,   Site  acquisition  and
development,  Site zoning and permitting,  Site  construction  and  installation
management,  component purchases,  and equipment installation during the Term of
this Agreement.  Notwithstanding  anything to the contrary, this Agreement shall
only be applicable to the  deployment or building out of location  technology by
USWC or its Affiliates  (for use in services which include,  but are not limited
to, caller pinpointing,  location tracking,  vehicle and human tracking, 911 and
411  assistance  and other  geographic  location  needs)  ("Location  Technology
Build-Out").

         (b) When USWC  desires or is in need of any of the  foregoing  types of
services or materials  described in Section 1(a) with respect only to a Location
Technology  Build-Out,  USWC  shall  submit  a  proposed  Project  Addendum  (as
hereinafter  defined) to ATC in the form  attached  hereto as Exhibit A together
with the desired the scope of Work required,  particular equipment  installation
specifications and plans, and the desired schedule for completion.  In the event
that ATC elects to negotiate for the performance of the proposed Work, ATC shall
return a written  notice of its  intention  to  negotiate to perform the Work to
USWC in the form attached hereto as Exhibit B, together with a cost proposal, no
more than twenty  (20) days  following  ATC's  receipt of the  proposed  Project
Addendum request from USWC. For a period beginning on the date that ATC receives
USWC's proposed  Project  Addendum and for 60 days thereafter  unless ATC elects
not to negotiate or does not respond within such twenty (20) day period, ATC and

<PAGE>
USWC agree to negotiate, exclusively and in good faith, the execution of a final
project  addendum setting forth the specific terms relating to the affected MSAs
and/or  RSAs (as  defined by the  Federal  Communication  Commission)  ("Project
Addendum"),  including,  without  limitation,  the scope of Work  which ATC will
provide and the cost of the  services  performed by ATC for the  performance  of
Work. Except as otherwise  expressly provided herein, if any of the terms of any
applicable Project  Addendum(s)  conflict with the terms of this Agreement,  the
Project  Addendum(s)  shall  supersede and control.  Upon execution of a Project
Addendum by authorized  representatives  of both parties to this Agreement,  ATC
shall perform the Work  described  therein in  accordance  with the terms of the
payment  obligations  in Schedule 2 to the applicable  project  Addendum and the
scope of Work outlined in Schedule 1 to the applicable Project Addendum, both of
which shall be attached to each Project Addendum and specifically made a part of
such  Project  Addendum.  ATC and USWC  hereby  acknowledge  and agree  that the
foregoing negotiations shall be arms-length  negotiations and that all Work will
be performed at a market rate. Nothing in this Section 1(b) shall be interpreted
to restrict USWC from meeting with other  companies to educate  itself about the
services industry and USWC agrees that it shall use its reasonable efforts to do
so.

         (c) In the event that the parties hereto are unable to come to a mutual
agreement with respect to a Project  Addendum  after the good faith  negotiation
period set forth in Section  1(b),  USWC shall  provide  copies of all solicited
bids from other  companies for the performance of the identical scope of work to
ATC. In no event shall USWC provide less than two (2) different bids  (excluding
discounts which may be offered by such companies or available from time to time)
for each applicable service category to ATC from qualified companies financially
and  operationally  capable of performing  the  applicable  services in a timely
manner and ATC shall be granted  the  exclusive  right and option to provide the
Work for USWC for the identical scope of work requested by USWC and reflected in
the  applicable  bids for  compensation  that is equal to the  lesser of (i) the
average all such  received  bids (but in no event less than two for each service
category)  plus five percent (5%), or (ii) the lowest price last offered to USWC
by ATC for the applicable  proposed  Project Addendum for the identical scope of
Work  attendant  thereto  (collectively,  "Right of First  Refusal").  ATC shall
exercise its Right of First Refusal rights hereunder by providing written notice
of its acceptance within five (5) business days following its receipt of the bid
amounts and scope of work ("Notice of Exercise").  Upon such Notice of Exercise,
ATC and USWC agree to  diligently  and in good  faith  negotiate  and  execute a
Project  Addendum  with  respect to such Work in  accordance  with the terms and
conditions of this Agreement.  In the event that ATC declines the opportunity to
perform  the Work  pursuant to the Right of First  Refusal,  USWC shall have the
right to engage other contractors to perform the Work, or portion thereof,  with
respect  to the  affected  market so long as the terms  and  conditions  of such
engagement are no less  favorable to USWC than the terms and conditions  offered
to ATC hereunder pursuant to the Right of First Refusal.


         (d) Failure by either USWC or ATC to adhere to the  provisions  of this
Section 1 in good faith shall be deemed a material  default by USWC or ATC under
this Agreement.


<PAGE>
         2.       TERM.  This  Agreement  shall be effective  from the Execution
Date and shall continue in effect for three (3) years, unless sooner terminated
pursuant to Section 10.

         3. PRICE AND  PAYMENTS.  USWC hereby agrees to pay ATC the amounts on a
per-Site  basis  agreed to between  the  parties as set forth in the  applicable
Project  Addendum  executed by both parties hereto and any  additional  payments
pursuant to any  applicable  Project  Addendum  relative to a  particular  Site.
Unless otherwise provided in the applicable  Project Addendum,  ATC shall submit
invoices (in a format reasonably acceptable to USWC) for Work performed incurred
on a monthly or basis with respect to completed  milestones as determined by the
Parties in the applicable  Project  Addendum.  USWC shall remit payment for Work
performed by ATC and for  reimbursable  expenses  incurred by ATC for all excess
Work  authorized by the  applicable  Project  Addendum or as mutually  agreed in
writing  by the  Parties  hereto,  within  thirty  (30) days of  receipt of each
invoice  less any  payments  which are in good  faith  disputed,  which  will be
payable  within 30 days of resolution of such dispute.  ATC shall be entitled to
assess  a one  percent  (1%) per  month  late  fee on all  outstanding  invoices
properly issued, aged over 30 days and not in dispute.

         4.       GENERAL DUTIES AND RESPONSIBILITIES OF CONTRACTOR.
                  -------------------------------------------------

         (a) ATC, at its own cost and expense,  shall  provide all materials and
labor for the  performance of the Work, as set forth in any  applicable  Project
Addendum. Work may include, as further defined in a particular Project Addendum,
any of the  following  or  other  services:  RF  design,  RF  engineering,  site
location;  acquiring or obtaining leases for Sites for USWC; obtaining necessary
governmental  authorizations,  zoning,  and other approvals;  Site  construction
(also known as build-to-suit sites);  construction and installation  management;
provision  of  components,  antennas,  lines and other  equipment;  and shelter,
cabinet and antenna and lines  installation;  and all work  necessarily  related
thereto.

         (b) The services provided hereunder shall be performed by ATC employees
or  qualified  professionals  selected  by ATC;  provided,  however,  that  USWC
reserves the right from time to time, for reasonable  cause, to request that ATC
cease utilizing or not retain any particular company or individual subcontractor
upon written notice to ATC thereof. With respect to subcontractors hired by ATC,
they  shall be paid by ATC or USWC in  accordance  with the  applicable  Project
Addendum  hereto.  All  agreements  between ATC and  entities or  subcontractors
engaged by ATC to perform any services or supply  materials in  connection  with
the Work shall be in  writing,  a copy of which  shall be  provided to USWC upon
USWC's  written  request  with  financial  terms  redacted as deemed  reasonably
necessary or desirable by ATC. ATC shall  coordinate  all Work to be  performed,
testing,  inspections and progress reports with USWC and its  representatives as
set forth in the applicable Project Addendum.

         (c)      ATC's  performance  of the Work hereunder  shall be of good
quality and in  conformance  with the applicable Project Addendum.

         (d) ATC  shall be  responsible  for and  shall  coordinate  all  means,
methods,  techniques,  sequences and procedures, and all portions of the Work in
accordance with the terms of this Agreement and the applicable Project Addendum.

         (e) ATC shall keep USWC  informed  of the  progress  and quality of the
Work.  ATC shall  have sole  responsibility  to  coordinate  the Work and timely
complete the Work in accordance  with the Project  Addendum,  subject to Section
19(i), Force Majeure, set forth herein.


<PAGE>
         (f) ATC shall pay all sales, use, and similar or other taxes imposed on
the Work or any  services or  materials  provided by ATC or obtained by ATC from
third parties; provided, however, that ATC shall not be responsible for any such
taxes with respect to services or materials to be paid for or reimbursed by USWC
pursuant  to the  applicable  Project  Addendum  nor for  USWC's  income  taxes,
franchise  taxes or any  property  taxes  imposed  on Sites as  constructed  and
installed for USWC.

         (g) ATC shall comply with all laws, ordinances,  rules, regulations and
lawful orders of public  authorities  relating to the Work  applicable to ATC in
the performance of its Work hereunder (collectively, "Laws").

         (h) Upon  completion of any Site or upon  termination of this Agreement
(whether  as to any Site or all Sites  under  any  Project  Addendum)  and final
payment by USWC and  following  USWC's  written  request,  ATC shall  return all
Designs  and  Drawings  (as  defined in Section 9),  files,  documents,  written
materials,  drawings,   specifications,   and  information  (including,  without
limitation,  information electronically stored) relating to the Site(s) and Work
that are designated as being  confidential  or  proprietary  in accordance  with
Section 9 to USWC;  provided,  however,  that any such  documents or information
required  by ATC to  perform  Work  under  any  different  Project  Addendum  or
generally  required by ATC to perform Work under this  Agreement may be retained
by it  until  the end of the  term of this  Agreement,  when,  following  USWC's
written request, the same shall be returned by ATC to USWC

         5.       DUTIES AND RESPONSIBILITIES OF USWC.
                  -----------------------------------

         (a) USWC will not  unreasonably  delay any decision to be made by it in
connection  with any approval or direction to ATC pursuant to this  Agreement or
any Project  Addendum  and subject to the  provisions  of Section  8(b).  USWC's
representatives (and other agents of USWC approved by such USWC representatives)
shall be entitled to access to the Site at any time for  inspection or any other
purpose;  provided,  however,  that USWC shall not unreasonably delay, hinder or
interfere with the performance of the Work.

         (b)     USWC shall cooperate with ATC in ATC's performance of the Work.

         6.       SPECIFIC PROVISIONS RELATING TO THE WORK TO BE PERFORMED UNDER
                  ANY PROJECT ADDENDUM.

         (a) The Parties hereto acknowledge and agree that regardless of whether
ATC performs the Work hereunder or in the event that such Work is performed by a
third party or USWC subject to ATC's rights hereunder, tower facilities owned or
leased by ATC shall be USWC's  preferred tower facility  locations and that USWC
(or ATC, if applicable) shall utilize its good faith efforts to maximize the use
of such ATC  facilities  in the  design  of the USWC  location  network  system.
Notwithstanding  anything to the  contrary in this  Agreement,  this  preference
shall not be construed to require USWC to utilize an ATC tower  facility that is
not the best technical choice for USWC, which is at USWC's sole discretion.


<PAGE>
         (b)  Notwithstanding  anything to the contrary in any Project Addendum,
the following  provisions  shall be applicable only to BTS Sites (as hereinafter
defined):

         (i)  Following the  completion of the Work at any Site  designated as a
build-to-suit  site pursuant to the applicable  Project  Addendum,  in which ATC
shall build a Tower for USWC where a structure  does not  currently  exist ("BTS
Site"),  ATC shall deliver to USWC a certificate  based on its good faith belief
that such BTS Site is completed ("BTS Completion Certificate").  USWC shall have
five  (5)  business  days  (the  "Inspection  Term")  after  receipt  of the BTS
Completion Certificate,  to inspect the corresponding BTS Site and to accept and
return the BTS Completion  Certificate to ATC or deliver to ATC a written notice
(the  "Disagreement  Notice")  describing in  reasonable  detail the reasons for
USWC's  good faith  determination  that such BTS Site does not  comply  with the
provisions of this Agreement or the applicable Project Addendum,  indicating the
actual  deviation.  USWC  will be  deemed to have  accepted  the BTS  Completion
Certificate  upon failure to issue a  Disagreement  Notice within the Inspection
Term, and for purposes of this Agreement and the applicable  Site Licenses,  the
License  Commencement  Date shall be the date of  expiration  of the  Inspection
Term.  In the event  that USWC  delivers  to ATC a  Disagreement  Notice and ATC
determines in good faith that the reasons for disagreement  expressed by USWC in
a Disagreement Notice are valid, ATC shall evaluate the deviations  expressed by
USWC in the Disagreement  Notice and shall make the corresponding  modifications
to the BTS Site, if necessary,  within a time period to be determined by ATC and
USWC,  based on ATC's  determination  of the work required.  The applicable site
schedule will be modified accordingly. Upon completion, ATC will issue a new BTS
Completion Certificate to USWC under the terms specified in this subsection.  In
the event  ATC  determines  in good  faith  that the  reasons  for  disagreement
expressed  by USWC in a  Disagreement  Notice are not valid,  the parties  shall
treat the matter as a dispute under Section 12(b).

         (ii)  Notwithstanding  anything to the contrary in this Agreement,  ATC
may elect not to construct any particular BTS Site, for any reason, upon written
notice of such rejection from ATC to USWC within  forty-five  (45) Business Days
following USWC's selection of a BTS Site pursuant to the procedures set forth in
any applicable  Project Addendum.  Further,  ATC may also elect not to construct
any BTS Site at anytime  after USWC has  selected or ATC has  accepted  such BTS
Site but prior to the commencement of construction of the tower structure:

                  (x) in the event that ATC determines,  in good faith, that the
         aggregate  construction  and development  cost (excluding land purchase
         and/or license costs) for such BTS Site may exceed Two Hundred Thousand
         Dollars ($200,000);

                  (y) If ATC is unable, after exercising commercially reasonable
         good faith efforts,  to secure a ground lease that does not provide for
         any form of revenue  sharing  with owner or  payments  based upon third
         party  tenant  leasing  or  contains  adverse  subleasing  restrictions
         (including,  without limitation,  an obligation to obtain prior consent
         from such owner) or a  prohibition  against  subleasing  to third party
         tenants;

                  (z) If  despite  ATC's  diligent  efforts  (including  but not
         limited to the timely filing of all  applications),  zoning approval or
         necessary  permits  are  not  issued  by  the  applicable  governmental
         authorities or cannot be or is not completed within 180 days.
<PAGE>
In the  event  of any  such  rejection,  USWC  will  pay ATC for the  applicable
Milestones  completed as set forth in the applicable  Project  Addendum and at a
time and  materials  rate  for any  uncompleted  Milestones  (but in no event to
exceed the full Milestone  payment  associated  with such Milestone in the event
that it had been  completed).  Any BTS Site  rejected  by ATC  pursuant  to this
Section 6(b)(ii) shall no longer be a Site for the purposes of this Agreement.

                  (iv) ATC may,  in its sole  discretion,  elect to  exceed  any
required  specifications and standards,  at its own cost, so long as such excess
does not  adversely  affect  USWC or the  operation  or  installation  of USWC's
equipment; provided, however, that the parties hereto acknowledge and agree that
each tower structure shall be a multi-tenant  tower or antenna structure capable
of  accommodating  USWC's  equipment  installation  and no less  than  four  (4)
additional  broadband  tenants (unless  otherwise  agreed to by ATC, in its sole
discretion).  In addition to the foregoing,  ATC shall retain the right,  in its
sole  discretion,  to construct  such towers as monopole,  guyed or self support
towers.

         (c) With respect to any Site owned,  operated or under  construction by
ATC  (including  BTS Sites)  that is  selected  by USWC in  accordance  with the
procedures set forth in the applicable  Project  Addendum,  (i) ATC and USWC (or
one of their Affiliates as such term is defined in the MLA) shall execute a site
license for each such Site ("Site  License")  in  accordance  with that  certain
Master Tower Space License Agreement dated May 25, 2000 ("MLA"),  (ii) ATC shall
provide  copies of any  documents  reasonably  requested by USWC with respect to
such  Site  reasonably  in  ATC's  possession,  unless  deemed  confidential  or
proprietary  by ATC,  and (iii) ATC  shall  provide  access to USWC to such Site
prior to USWC's  installations in accordance with the terms as conditions of the
applicable Site License.  In addition to the foregoing,  ATC will notify USWC of
any structural  analysis of or  modifications to the tower structure at any Site
or proposed Site which is owned,  operated or under  construction  by ATC (other
than BTS Sites,  which will not require any such  modifications)  ("ATC Existing
Site") which may be necessary for the  accommodation  of USWC's equipment as set
forth in the applicable Project Addendum prior to the selection of a Site.

         (d) With respect to all Sites,  ATC shall obtain all  necessary  zoning
approvals  and  permits in  accordance  with the  applicable  project  Addendum;
provided,  however, that USWC shall reasonably and promptly cooperate with ATC's
efforts to obtain such approvals and permits, at the request of ATC. The Parties
agree and acknowledge due to the flexibility of the USWC system the objective is
to use Sites that do not require any  approvals  or permits,  and to that extent
Site  selection  should be steered  away from those Site in which  approval  and
permits are necessary.

         7. CHANGES IN THE WORK. Changes in the Work shall be done only pursuant
to a written Change Order (herein so called)  executed by USWC and ATC,  stating
their agreement on all of the following: (i) a change in or addition to the Work
as set forth in the applicable  Project  Addendum and this  Agreement,  (ii) the
amount of adjustment, if any, in the payment due to ATC for the Work thereunder,
and (iii) the extent of adjustment,  if any, in the time for  performance of the
Work.


<PAGE>
         8.       TIME; PENALTY.
                  -------------

         (a) ATC  shall  undertake  the  Work in  accordance  with  the  Project
Addendum scheduling, as expeditiously as is consistent with reasonable skill and
care and orderly progress of the Work.

         (b) If the Work to be undertaken by ATC under this Agreement is delayed
by an act or failure to act by USWC or any separate  contractor engaged by USWC,
or by changes ordered in the Work, in accordance with Section 7 herein,  and not
caused  by an act or  omission  of ATC or any of its  subcontractors,  any dates
specified for  performance  by ATC in the applicable  Project  Addendum shall be
reasonably extended.

         (c) Subject to Section 19(i), a timetable  shall be mutually  agreed to
between ATC and USWC with respect to each Site which  graphically  describes the
time  periods  and  completion  dates for each of the  activities  necessary  to
complete each Site (each a "Site  Schedule"),  as each such Site Schedule may be
amended from time to time in accordance with the provisions of this Agreement or
the applicable Project Addendum If the Parties do not agree on a particular Site
Schedule,  the disagreement shall be resolved as a dispute under this Agreement.
Notwithstanding anything to the contrary, ATC and Client agree that in the event
that a Site can not be completed in accordance  with a particular  Site Schedule
due to a  failure  to  obtain  or a delay in  obtaining  zoning  approvals  from
governmental  authorities,  the applicable Site Schedule shall be  automatically
extended  for so long as ATC  diligently  continues  to attempt  to obtain  such
permit or approval and a reasonable  period of time  thereafter  to complete the
Work required.  In the event of such a delay, ATC and USWC agree to discuss,  in
good faith,  reasonable  changes to the  Specifications,  network  design and/or
ATC's  fees or  rental  terms  with  respect  to such  any such  search  area to
determine  if a  cost-effective  or  more  timely  alternative  location  may be
available.  Any such  changes  agreed  upon  between the parties in an effort to
locate an  alternative  site  location,  if any, shall be evidenced in a writing
signed by both Parties.

                  (d) Subject to Section 19(i),  if ATC fails to complete a Site
in  accordance  with the  completion  date  set  forth  in the  applicable  Site
Schedule,  ATC will have a ten (10) day cure period.  In the event that the Site
is not then  completed  within  such ten (10)  day cure  period,  USWC  shall be
entitled to (i) with respect to ATC Existing Sites and BTS Sites,  two (2) weeks
of rent  abatement and an additional  two (2) weeks of rent  abatement for every
consecutive  period of seven (7) days after the expiration of the foregoing cure
period during which the Site remains  uncompleted (it also being understood that
the monthly license fee with respect to such Site would have otherwise commenced
immediately  following  the  delayed  completion  of such  Site),  and (ii) with
respect to Third Party  Existing  Sites,  the penalty set forth in Schedule 2 of
the applicable Project Addendum.  Notwithstanding  anything to the contrary, the
penalties provided for in this Section 8(d) are not deemed by the parties hereto
to be punitive  in nature but  constitute  liquidated  damages and shall be each
party's sole and exclusive remedy with respect to the circumstances described in
this Section 8(d).

         9.   OWNERSHIP  AND  USE  OF  DOCUMENTS  AND   INFORMATION.   Drawings,
specifications, and other project critical confidential or proprietary documents
and  electronic  data (a) furnished by USWC to ATC, or (b) created by ATC in the
course of performing  the Work and  specifically  related to and  exclusively to
USWC's use of a particular Site  (collectively,  the "Designs and Drawings") are
and shall remain the property of USWC and shall be subject to the  provisions of
Section 4(h) herein. USWC hereby grants a license to ATC to use all such Designs
and Drawings in the  performance of the Work  hereunder  during the term of this
Agreement.


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         10.      TERMINATION.
                  -----------

         (a) If ATC materially fails, defaults or neglects to carry out the Work
in accordance with this Agreement  and/or any Project  Addendum and fails within
ten (10) days after receipt of written  notice from USWC to correct or cure such
default  or  nonconformity  (provided  that  such ten (10) day  period  shall be
automatically  extended for so long as reasonably necessary if ATC commences the
cure during the foregoing  cure period and  diligently  continues to pursue such
correction  or cure) with respect to  twenty-five  percent  (25%) or more of the
Sites subject to the applicable Project Addendum, USWC may, without prejudice to
any other remedy it may have,  terminate the affected Project  Addendum.  In the
event that, during the Term of this Agreement,  USWC has exercised the foregoing
termination right with respect to five (5) or more Project Addendums,  USWC may,
without prejudice to any other remedy it may have, terminate this Agreement.

         (b) If the Work is stopped for a period of thirty (30) days  through no
fault of ATC or because USWC has not made payments  thereon or failed to provide
items as  provided in this  Agreement  or the  Project  Addendum,  then ATC may,
without  prejudice  to any other  remedy it may have,  upon ten (10)  additional
days' written notice to USWC terminate any Project  Addendum and,  together with
any other remedies  available to ATC at law,  recover  payment from USWC for all
completed  Milestones  (as  such  term  is  defined  in the  applicable  Project
Addendum) and based on a time and materials  rate (but in no event to exceed the
applicable  Milestone payment) for Work completed at the time of termination but
associated with an uncompleted Milestone.

     (c) Neither a termination nor the expiration of any Project Addendum,  Site
or this Agreement will affect:

                         (i)  any   duties  or   obligations   for   payment  or
                    performance  that are or become owing hereunder prior to the
                    effective date of such termination or expiration;

                         (ii) any other  duties or  obligations  that  expressly
                    survive the termination or expiration hereof; or

                         (iii) the term of any Site License  entered into by the
                    parties,  which will continue in  accordance  with its terms
                    and  conditions  (provided  that  any  Site  License  may be
                    terminated  in accordance  with its terms),  except for Site
                    Licenses  directly  associated  to  the  specific  event  of
                    default hereunder.

         11. WARRANTY. ATC warrants to USWC that all materials,  equipment,  and
workmanship to be provided by ATC will be new, unless otherwise specified in the
Project Addendum, of good quality, and in conformance with this Agreement.  Work
performed and materials and equipment  supplied by ATC that is not conforming to
these requirements shall be promptly corrected or replaced by ATC. If a warranty
is provided  directly or indirectly by a manufacturer  of an item of material or
equipment utilized in the Work, the  manufacturer's  warranty as to that item is
in addition to the warranty of ATC.  With respect to any  materials  provided by
ATC and to be  subsequently  owned by USWC,  ATC  hereby  agrees to  assign  all
applicable third party warranties to USWC to the fullest extent possible.
<PAGE>
         12.      ARBITRATION.
                  -----------

         (a) Except as otherwise provided in Section 6(b)(i),  in the event that
any dispute  shall arise in  connection  with the Work as to the meaning of this
Agreement,  or to any statement of facts which may arise,  same shall be settled
by the mutual  agreement of both parties;  or if they are unable to agree,  upon
written  request  of either  party,  the  dispute  shall be  subject  to binding
arbitration according to the rules of the American Arbitration Association.  The
arbitration  shall be held in New York,  New York.  The  award  rendered  by the
arbitrator  shall be final,  and judgment  may be entered upon it in  accordance
with applicable law in any court having jurisdiction  thereto.  The fee, if any,
of the arbitrator, shall be shared equally by both parties. Refusal of one party
to arbitrate  shall entitle the  remaining  party to  specifically  enforce this
Agreement in a court of law or equity, and to receive costs of suit,  including,
reasonable  attorney's  fees.  Nothing  herein  shall  preclude,   however,  the
availability of injunctive or other equitable relief in an appropriate case, and
each party  agrees that the other shall be entitled as a matter of right to seek
and obtain an injunction from any court of competent  jurisdiction,  restraining
any further  violation or threatened  violation of any  restriction or agreement
contained  herein  for  which  monetary  damages  are  not an  adequate  remedy,
including,  without  limitation,  any breach by USWC of its  obligations  to ATC
pursuant to Section 1.

         (b) Any dispute  between the parties in connection  with a Disagreement
Notice under Section  6(b)(i) of this Agreement will be resolved by an expert in
telecommunications  or tower  construction,  as applicable,  based solely on the
specifications  and the actual Work performed at the corresponding BTS Site. The
expert shall be appointed by the parties  within a term of fifteen (15) business
days of the date of  delivery  of a  Disagreement  Notice,  or in the  event the
parties may not reach an  agreement,  by the American  Arbitration  Association,
upon the  request  of either  party,  which  appointment  will be binding to the
parties. The expert will examine the BTS Site and will determine whether (i) the
Work performed by ATC complies with the Project Addendum and this Agreement,  in
which  event  the  completion  date  shall  be the  date  set  forth  in the BTS
Completion  Certificate as issued by ATC, or (ii) if additional Work is required
to comply with the Project  Addendum or this Agreement,  in which event ATC will
perform  all  necessary  Work  for  the  BTS  Site  to be  completed  as soon as
practicable and the BTS Completion Date shall be the date in which such Work (as
determined by the expert) is completed.

         13.  INDEMNITY.  Each of the  parties  hereto  (each  an  "Indemnifying
Party") shall hold  harmless,  defend and indemnify the other party hereto,  its
affiliates,   shareholders,   directors,  officers,  advisors,  representatives,
employees,  agents, successors and assigns (collectively,  the "Indemnitees" and
singly, an "Indemnitee") from and against all suits or actions, claims, demands,
damages, settlements, penalties, fines, and costs and expenses of every kind and
description,  including reasonable attorneys' fees and expenses of litigation or
arbitration  (collectively,  "Claims" and singly, a "Claim") to which any or all
of the  Indemnitees  may be  subjected  or put by reason of or arising out of or
related  to  bodily  injury,  sickness,  disease,  or  death  or  injury  to  or
destruction  of  tangible  property,  including  loss  of  use,  resulting  from
negligence or carelessness  or improper  methods of operation on the part of the
Indemnifying Party or any of its employees,  servants, agents, representative or
subcontractors in the performance of its respective rights and obligations under
this  Agreement,  or by or on  account of any  breach of any  provision  of this
Agreement or any Project Addendum. Notwithstanding the foregoing, as a condition
to indemnity  and/or  defense  obligation  hereunder,  the  Indemnitee(s)  to be
indemnified  and/or  defended shall (i) give written notice to the  Indemnifying
Party within thirty (30) days (or such shorter time as shall be necessary to

<PAGE>
avoid  prejudice  to the  rights  of the  Indemnifying  Party,  such as to avoid
default due to failure to timely  respond to a petition or complaint  filed in a
lawsuit)  of its actual  knowledge  of the claim and (ii) upon the  Indemnifying
Party's  request,  execute  documents to assign the defense of such claim to the
Indemnifying Party. The Indemnifying Party shall then be entitled to control the
defense of such claim  provided that counsel  handling such claim is approved by
the Indemnitee(s) being indemnified and/or defended,  which approval will not be
unreasonably withheld, and provided,  further, that the Indemnifying Party shall
not   compromise   or  settle  any  Claim  without  the  prior  consent  of  the
Indemnitee(s)  unless such compromise or settlement involves only the payment of
money by the Indemnifying Party and the claimant provides to all the Indemnitees
a full release from all liability in respect of such Claim. All reasonable costs
and expenses  (including  reasonable legal fees) incurred by an Indemnitee which
are properly  indemnifiable  hereunder shall be paid by the  Indemnifying  Party
within thirty days after written demand  (accompanied  by a reasonably  detailed
statement   of  fees  and  expenses   incurred  to  date)  by  the   Indemnitee.
Notwithstanding  anything  to the  contrary  in this  Agreement,  the MLA or any
Project Addendum, neither party shall be liable to the other for, and waives any
right to recover,  consequential (including lost profits),  punitive,  exemplary
and similar damages.

         14.      INSURANCE; RISK OF LOSS.
                  -----------------------

         (a) Both parties hereto shall obtain and maintain,  at its own cost and
expense, and shall cause all of its respective subcontractors who perform any or
all of the work to obtain and maintain,  the  following  insurance in full force
and effect during the term of this Agreement:

                         (i) Commercial  general liability  insurance  providing
                    coverage for operations and for  contractual  liability with
                    respect to liability  assumed by such party  hereunder.  The
                    limits of coverage for such insurance shall not be less than
                    $1,000,000/$2,000,000  for bodily injury and  $1,000,000 for
                    property damage.

                         (ii)  Comprehensive   automobile   liability  insurance
                    covering the use and maintenance of owned, non-owned,  hired
                    and rented vehicles with limits of coverage of not less than
                    a  combined  single  limit  of  $500,000  or not  less  than
                    $250,000 per person and $500,000 per  occurrence  for bodily
                    injury  and  not  less  than  $300,000  per  occurrence  for
                    property damage.

                         (iii)  Worker's  Compensation  insurance with statutory
                    limits of coverage.

                         (iv) Excess  liability  insurance in the umbrella  form
                    with a combined single limit of $5,000,000.

                         (v)   Employer   liability   policy   with   limits  of
                    $1,000,000.00 and not less than $500,000 per occurrence.


<PAGE>
         Each party shall name the other party hereto as  additional  insured on
all of the above stated policies of insurance  purchased by such party and shall
arrange for its insurer to submit certificates  evidencing such insurance to the
other party upon  request by such party.  Each  insurance  policy shall state by
endorsement that such policy will not be canceled or materially  changed without
at least thirty (30) days' prior written notice to the other party by registered
mail.

         15. PUBLICITY and CONFIDENTIALITY. Neither party hereto shall issue any
press  releases  relating  to the Work  performed  hereunder,  unless  the prior
written  consent is  granted  by the other  party  hereto or as is  required  by
applicable law (of any applicable country),  including the rules and regulations
of the  Securities  and Exchange  Commission,  and the stock  exchange  rules or
regulations.  Each  party  agrees,  for  itself  and  its  directors,  officers,
employees, consultants, representatives,  contractors and agents (a) to maintain
in confidence,  the terms and provisions of this Agreement,  as well as all data
summaries,  reports,  or  information  of all kinds,  whether  oral or  written,
acquired or devised or developed  during the negotiation and  administration  of
this  Agreement,   except  on  a  need-to-know  basis  in  connection  with  the
performance  of this  Agreement,  and (b)  otherwise to reveal the same to other
persons or entities only (i) at the written  direction of the other party;  (ii)
in compliance  with law or the rules of any stock  exchange,  in which event the
disclosing  party shall so notify the other  party as  promptly  as  practicable
(and, if possible,  prior to making any disclosure) and shall seek  confidential
treatment of such  information;  (iii) as part of its normal reporting or review
procedure  to its parent  company,  its auditors  and its  attorneys;  provided,
however,  that such persons or entities  agree to be bound by the  provisions of
this  Paragraph;  (iv) where such  information  is part of the public  domain or
previously disclosed by the other party; (v) to potential investors, insurers or
financing  entities and the agents,  representative and consultants of the same;
provided, however, that such person agrees to be bound by the provisions of this
Paragraph; (vi) in accordance with any offering of securities or other financial
transaction  and, in  connection  therewith,  the  disclosing  party shall first
notify  the  other  party of the  contents  of the  proposed  disclosure  of its
approval,  which  shall  not  be  unreasonable  withheld.   Notwithstanding  the
foregoing,  nothing in this  Section 15 shall be deemed to (i) limit or restrict
ATC's right to market any Sites owned or  operated  by ATC  (including,  without
limitation,  build-to-suit sites) to third parties following the selection of an
such a Site  by  USWC  under  any  Project  Addendum  procedure  (including  the
disclosure or reasonably necessary information regarding the USWC's equipment or
proposed  installation or the frequencies which USWC intends to operate from the
Site),  or (ii)  limit or  restrict  USWC's or ATC's  right to  identify  USWC's
equipment or ATC's facility (or proposed  facility) at any Site in  governmental
filings or marketing materials.

         16. BANKRUPTCY.  Either party may terminate this Agreement by notice in
writing in the event that the other makes a general  assignment  for the benefit
of creditors; is declared insolvent in any state insolvency proceeding;  becomes
the  subject  of an order  for  relief  under  Chapter  7 of the  United  States
Bankruptcy  Code,  11  U.S.C.   ss.101  et.  seq.,  or  successor  statute  (the
"Bankruptcy Code"); becomes a voluntary debtor in a case under Chapter 11 of the
Bankruptcy Code;  becomes an involuntary debtor in a case under either Chapter 7
or 11 of the Bankruptcy Code and fails to achieve a dismissal of the case within
sixty (60) days; or consents to or is subjected to the appointment of a trustee,
receiver, or liquidator with respect to all or substantially all of the Person's
properties.


<PAGE>
         17.  AUDIT.   ATC  shall  maintain   complete   records  of  all  costs
reimbursable by USWC under the terms of this  Agreement.  All such records shall
be maintained in accordance with generally accepted accounting principles.  USWC
shall  have the right upon  reasonable  prior  notice,  through  its  accredited
representatives  and at its sole cost, to examine and audit such records  during
business hours at one or more ATC offices. In the event the correctness of ATC's
billing is  disputed,  USWC may retain an  independent  auditor  and if any such
audit  concludes  that on any month ATC's  calculation of amounts due differs by
more than ten percent (10%) from the actual amount thereof,  ATC shall reimburse
USWC for all reasonable fees, costs and expenses paid for the audit.

         18. INDEPENDENT CONTRACTOR: NO GENERAL CONTRACTOR DESIGNATION.  Neither
ATC nor its subcontractors, nor the employees or agents of any of them, shall be
deemed to be USWC  employees  or agents,  it being  understood  that ATC and its
subcontractors  are independent for all purposes and at all times, and ATC shall
be wholly  responsible for withholding  and payment of all federal,  state,  and
local income and other  payroll taxes with respect to its  employees,  including
contributions  from them and as required by law. ATC and USWC hereby acknowledge
and agree that ATC's  performance  of the Work herein  shall not be deemed to be
services  of a  general  contractor,  as  that  term  is  commonly  used  in the
construction  industry.  ATC's performance of the Work hereunder shall be deemed
performed  by ATC on behalf of USWC,  as  USWC's  representative,  for all Sites
other than Sites to be constructed by ATC for ATC's ownership and operation,  in
which event ATC's  performance  of the Work shall be deemed  performed for ATC's
sole benefit.

         19.      MISCELLANEOUS.
                  -------------

     (a) ENTIRE  AGREEMENT.  Other than that  certain MLA dated as of this date,
this Agreement and the exhibits attached hereto contains the entire agreement of
the parties with respect to the subject  matter  herein and shall not be amended
or modified  without  specific  written  provision to that effect signed by both
parties.  No oral statement of any person  whomsoever  shall modify the terms of
this Agreement.

     (b)  SEVERABILITY.  The  invalidity or  unenforceability  of any particular
provision of this Agreement shall not affect the other  provisions  hereof,  and
the  Agreement  shall  be  construed  in all  respects  as if  such  invalid  or
unenforceable provisions were omitted.

     (c) CHOICE OF LAW. It is understood  and agreed that this Agreement and all
of the rights and obligations of the parties  hereunder shall be governed by the
laws of the  State  of New  York,  except  for any  conflict  of law  provisions
therein.

     (d) WAIVER. No provision of this Agreement shall be deemed waived, amended,
or modified by either party, unless such waiver, amendment or modification be in
writing and signed by the party against whom it is sought to enforce the waiver,
amendment or modification.  Delay in the enforcement by either party of any term
or  condition  hereof or in the  exercise  of any right  hereunder  shall not be
construed as a waiver.


<PAGE>
     (e) ACCORD &  SATISFACTION.  No  endorsement  or  statement on any check or
letter  accompanying  a check for payment of fee or other amount shall be deemed
an accord and  satisfaction,  and ATC may accept  such check or payment  without
prejudice to ATC's right to recover the balance of such fee or other  payment or
to pursue any other  remedy  provided in this  Agreement.  No payment by USWC or
receipt  by ATC of a lesser  amount  than the  amount  invoiced  by ATC shall be
deemed to apply to any amount other than the earliest then  outstanding  payment
due hereunder.

     (f) NOTICE. Any notice to be given under this Agreement by any party to the
other shall be deemed to have been duly given if given in writing and personally
delivered,  sent by nationally  recognized  overnight courier,  or sent by mail,
registered or certified,  postage prepaid with return receipt requested,  at the
address specified below:

<TABLE>
<CAPTION>
         <S>                                                           <C>
         Notices to USWC shall be addressed to:                        U.S. Wireless Corporation
                                                                       2303 Camino Ramon
                                                                       San Ramon, CA 94583
                                                                       Attn: General Counsel

         Notices to ATC shall be addressed to:                         AMERICAN TOWER, L.P.
                                                                       116 Huntington Avenue
                                                                       Boston, MA   02116
                                                                       Attn:  General Counsel

                                    With a copy to:                    The local ATC address set forth in
                                                                       the applicable Project Addendum
</TABLE>
Notices delivered  personally or by courier,  shall be deemed communicated as of
actual receipt;  mailed notices shall be deemed communicated as of 10:00 a.m. on
the third  business  day after  mailing.  Any party may change its  address  for
notice  hereunder by giving notice of such change in the manner provided in this
paragraph.  Refusal to accept  delivery of any notice shall be deemed receipt of
such notice.

                (g) ASSIGNMENT. Any assignment of this Agreement, in whole or in
part, or any other interest  hereunder  without the prior written consent of the
other party hereto shall be void and deemed a material breach of this Agreement;
provided, however, that (i) no such consent shall be required in the event of an
assignment by ATC to a company which is controlled by,  controls or under common
control with ATC  ("Affiliate")  so long as ATC remains liable  hereunder  after
such  assignment,  and  (ii) no  consent  shall  not be  unreasonably  withheld,
conditioned  or delayed with respect to the assignment of this Agreement by ATC,
in  whole  or in  part,  to a  successor  by way of  merger  or  acquisition  of
substantially  all of the  assets or stock of ATC,  though  USWC  shall have the
right to receive business and financial information with respect to the assignee
in accordance with its review. The parties hereto acknowledge and agree that the
BTS Sites  shall be owned  and/or  leased by  American  Tower  Management,  Inc.
("ATMI"),  an  Affiliate  of ATC,  and the license of a portion of ATC  Existing
Sites  and BTS Sites to USWC  hereunder  shall be  between  the  applicable  ATC
Affiliate.  ATC  agrees  to  cause  each of its  Affiliates  to  enter  into the
applicable  Site License with respect to such Sites in accordance with the terms
and  conditions  of this  Agreement  and the MLA. USWC agrees that the foregoing
shall not be deemed an "assignment" for the purposes of this Section 19(g). USWC

<PAGE>
agrees  that  notwithstanding  any  other  provision  in  this  Agreement,   any
agreement,  instrument,  certificate or document  entered into pursuant to or in
connection  with this  Agreement  or the Work  hereunder  and any rule of law or
equity  to  the  contrary,  to  the  fullest  extent  permitted  by  law,  ATC's
obligations  and liabilities  under any this Agreement and all other  agreements
related hereto (excluding  obligations and liabilities  arising solely under the
MLA and any individual  Site License between USWC and ATMI) shall be Nonrecourse
to ATMI.  For the  purposes  of this  paragraph.  "Nonrecourse"  means  that the
obligations  and  liabilities  are limited in recourse to ATC and its applicable
Affiliates other than ATMI and not guaranteed  directly or indirectly by, or the
primary  obligations  of,  ATMI.  Except  with  respect to claims  directly  and
exclusively  arising  from the terms of any  individual  Site  License  (and the
applicable terms of the MLA), USWC hereby  covenants for itself,  its successors
and permitted  assigns that it, its  successors  and permitted  assigns will not
make, bring, claim, commence, prosecute, maintain, cause or permit any action to
be brought, commenced,  prosecuted,  maintained,  either at law or in equity, in
any court in the United States or any state thereof or in any arbitration  forum
against  ATMI  for (i) the  payment  of any  amount  or the  performance  of any
obligation  under  this  Agreement  or (ii) the  satisfaction  of any  liability
arising  in  connection  with any  such  payment  or  obligation  or  otherwise,
including,  without  limitation,  liability  arising in law for tort (including,
without   limitation,    for   active   and   passive   negligence,    negligent
misrepresentation  and  fraud),  equity  (including,   without  limitation,  for
indemnification and contribution) and contract  (including,  without limitation,
monetary damages for the breach of any representation or warranty or performance
of any of the covenants or  obligations  contained in this Agreement or with the
Work contemplated herein or therein

         (h)      SUCCESSORS  AND  ASSIGNS.  This  Agreement  shall  inure to
the  benefit  of,  and  shall  be  binding  upon,  the  parties hereto and their
respective successors and permitted assigns.

         (i) FORCE MAJUERE. An event of "Force Majeure" shall mean the following
events or circumstances, to the extent that they delay the performance by ATC of
any of its duties and obligations under this Agreement, Project Addendum or Site
Schedule:

                         (i) Any acts, omissions,  orders,  actions,  inactions,
                    decisions,  or decrees of any  Governmental  Authority which
                    adversely affects ATC's ability to perform its obligations;

                         (ii)  Changes  in any  federal,  state or  local  laws,
                    ordinances, and regulations effective after the date of this
                    Agreement  which  adversely  affect ATC's ability to perform
                    its obligations;

                         (iii) Acts of God, including, without limitation, rain,
                    snow, extreme temperatures,  tornadoes,  hurricanes, floods,
                    sinkholes,  landslides,  earthquakes,  epidemics, quarantine
                    and pestilence;

                         (iv) Fire and other casualties,  such as explosions and
                    accidents;

                         (v)  Acts  of  war,   terrorism,   effects  of  nuclear
                    radiation,    blockades,    insurrections,    riots,   civil
                    disturbances,  the  combined  action of workers,  failure of
                    transportation,  national or international  calamities,  and
                    other  acts and  circumstances  beyond a party's  reasonable
                    control; and


<PAGE>
                         (vi) any delay  caused by the acts or omissions of USWC
                    or its employees, agents, contractors,  customers or vendors
                    which  adversely   affects  ATC's  ability  to  perform  its
                    obligations.

In the event of an event of force  majeure,  the time for  performance of any of
ATC's  obligations under this Agreement or any affected Site Schedule or Project
Addendum shall only be adjusted to the extent reasonable under the circumstances
for the additional time which will be reasonably required for the performance of
any of the duties or obligations of ATC under this Agreement,  the affected Site
Schedule  or Project  Addendum as a result of such  event.  Notwithstanding  the
above, if the event is  then-continuing  and is directly specific to ATC and the
Work can be performed by USWC or a third party without such  impediment  (except
with  respect  to an  event of  force  majuere  pursuant  to  Section  19(i)(vi)
hereunder),  USWC shall have the right to terminate  the  affected  Site upon no
less than 5 days  notice to ATC (so long as such  event of force  majuere is not
ended  within  such five day period)  and have the Work  performed  by USWC or a
third; provided,  however, that USWC shall pay ATC for the applicable Milestones
completed as set forth in the applicable Project Addendum.

         (j)      THIRD PARTY  BENEFICIARIES.  The parties  hereto do not intend
that any other person or entity be considered to be a third party beneficiary to
 this Agreement.

         (k)  NO  WAIVER  OF   CONTRACTOR'S   RIGHTS  UNDER  OTHER   AGREEMENTS.
Notwithstanding  anything to the contrary,  ATC and USWC hereby  acknowledge and
agree that  nothing  contained  in this  Agreement,  its  exhibits,  any Project
Addendums or any  modifications  or  amendments  thereto shall in any manner (or
shall be deemed or interpreted to) restrict,  limit,  waive, modify or amend any
of the covenants, warranties, representations, rights, obligations or agreements
contained in the MLA, subscription  agreement or any other agreement between the
parties hereto.

         (l)      LANGUAGE.  The  headings  or  articles  and  paragraphs    are
for  convenience  only  and  shall  not modify the rights and obligations of the
parties.

         IN WITNESS WHEREOF,  the parties have executed this Agreement as of the
Execution Date.

<TABLE>
<CAPTION>
<S>                                                          <C>
AMERICAN TOWER, L.P.                                         US WIRELESS CORPORATION
By:  ATC GP, Inc., as its sole General Partner

By:_______________________________                           By:_______________________________
Name:____________________________                            Name:____________________________
                      (Please Print)                                              (Please Print)
Title______________________________                          Title______________________________

</TABLE>