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                                                                   Exhibit 10.73

                              REVOLVING CREDIT NOTE

US$35,000,000                                                December 31, 1996



      FOR VALUE RECEIVED, MICROCELL MANAGEMENT, INC., a Delaware corporation
("Maker"), promises to pay to the order of LCC INTERNATIONAL, INC., a Delaware
corporation ("Holder"), at 2300 Clarendon Boulevard, Suite 800, Arlington,
Virginia 22201, or at such other place as the Holder hereof may from time to
time designate in writing, the principal sum of Thirty-Five Million United
States Dollars (US$35,000,000), or so much thereof as has been or may be
advanced or readvanced to the Maker and remains outstanding pursuant to the
terms and conditions of the Revolving Credit Facility (as hereinafter defined),
together with accrued but unpaid interest thereon at the rate hereinafter
provided, in accordance with the following:

      1.    Interest. Commencing as of the date of each advance under the
Revolving Credit Facility and continuing until repayment in full of all sums due
hereunder, the unpaid principal sum shall bear interest at a rate per annum
equal to the prime rate as published in the Wall Street Journal as in effect
from time to time. Interest shall be computed on the basis of a year of three
hundred sixty (360) days for the actual number of days elapsed.

      2.    Payments and Maturity. The unpaid principal sum, together with
interest thereon at the rate provided above, shall be payable as follows:

            (a) Interest only on the unpaid principal sum shall be due and
payable monthly, commencing on the first day of the month following the month in
which this Revolving Credit Note is made, and on the first day of each month
thereafter to maturity; and

            (b) Unless sooner paid, the unpaid principal sum, together with
interest accrued and unpaid thereon, shall be due and payable upon the
termination of the Revolving Credit Facility.

      The advances made by the Holder to the Maker, all payments made on account
of principal hereof and all conversions of principal hereof, shall be recorded
by the Holder on the grid attached hereto which is a part of this Revolving
Credit Note. The fact that the balance hereunder may be reduced to zero from
time to time pursuant to the Revolving Credit Facility will not affect the
continuing validity of this Revolving Credit Note or the Revolving Credit
Facility, and the balance may be 



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increased to the maximum principal sum of this Revolving Credit Note after any
such reduction to zero.

      3.    Prepayment. The Maker may prepay the outstanding principal sum in
whole or in part at any time and from time to time without notice, premium or
penalty.

      4.    Revolving Credit Facility. This is the promissory note referred to
in the Revolving Credit Facility and Security Agreement dated of even date
herewith by and between the Maker and the Holder (as amended, modified,
restated, substituted, extended and renewed at any time and from time to time,
the "Revolving Credit Facility").

      5.    Events of Default. The occurrence of any one or more of the
following events shall constitute an event of default (individually, an "Event
of Default" and collectively, the "Events of Default") under the terms of this
Revolving Credit Note:

            (a) The failure of the Maker to pay to the Holder when due any and
all amounts payable by the Maker to the Holder under the terms of this Revolving
Credit Note, but only if the Maker fails to cure such default within thirty (30)
days after the Holder shall have sent the Maker written notice of such default
(to the Maker's last known address); or

            (b) The occurrence of an event of default under the Revolving Credit
Facility.

      6.    Remedies. Upon the occurrence of an Event of Default, at the option
of the Holder, all amounts payable by the Maker to the Holder under the terms of
this Revolving Credit Note shall immediately become due and payable. Failure to
exercise this option shall not constitute a waiver of the right to exercise the
same in the event of any subsequent default.

      7.    Security. This Revolving Credit Note is secured pursuant to the
Revolving Credit Facility and reference is made thereto for a statement of the
terms and conditions of such security.

      8.    Waiver. Maker hereby waives demand, presentment, protest, notice of
demand, presentment, protest and nonpaymant. Maker also waives all rights to
notice and hearing of any kind upon the occurrence of an Event of Default prior
to the exercise by Holder of its rights to repossess the Collateral (as defined
in the Revolving Credit Facility) without judicial process or to replevy, attach
or levy upon the Collateral without notice or hearing.

      9.    Miscellaneous.


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            (a) Any term or provision of this Revolving Credit Note that is
invalid or unenforceable in any situation in any jurisdiction shall not affect
the validity or enforceability of the remaining terms and provisions hereof or
the validity or enforceability of the offending term or provision in any other
situation or in any other jurisdiction. If the final judgment of a court of
competent jurisdiction declares that any term or provision hereof is invalid or
unenforceable, the court making the determination of invalidity or
unenforceability shall have the power to reduce the scope, duration, or area of
the term or provision, to delete specific words or phrases, or to replace any
invalid or unenforceable term or provision with a term or provision that is
valid and enforceable and that comes closest to expressing the intention of the
invalid or unenforceable term or provision, and this Revolving Credit Note shall
be enforceable as so modified after the expiration of the time within which the
judgment may be appealed.

            (b) This Revolving Credit Note may not be changed orally but only by
an agreement in writing signed by the party against whom enforcement of any
waiver, change, modification or discharge is sought expressly referencing this
Revolving Credit Note and such party's intent that such waiver, change,
modification or discharge be effected.

            (c) This Revolving Credit Note shall be interpreted in accordance
with the laws of the State of Delaware (other than the laws of the State of
Delaware governing choice of law).

            (d) This Revolving Credit Note is not negotiable.

                                    MAKER:

                                    MICROCELL MANAGEMENT, INC.

                                    By:/S/  ALBERT F. GRIMES
                                       -------------------------- 
                                    Name:    Albert F. Grimes
                                    Title:   President


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                       ADVANCES AND PAYMENTS OF PRINCIPAL

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