Document:

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                                                                   Exhibit 10.12

                                 PROMISSORY NOTE

$285,000                                                           July 30, 2001

         After date, without grace, for value received, HOUSTON AMERICAN ENERGY
CORP., a Delaware corporation having its principal office and place of business
in Harris County, Texas (the "Maker") hereby promises to pay to the order of
JOHN F. TERWILLIGER, an individual having his principal office and place of
business in Harris County, Texas (the "Payee"), the original principal amount of
TWO HUNDRED EIGHTY-FIVE THOUSAND DOLLARS ($285,000), together with interest, as
hereinafter described. This Note is payable in lawful money of the United States
of America at 801 Travis, Suite 1425, Houston, Harris County, Texas 77002, or
such other place as the Payee may designate in writing to the Maker.

         This Note may be assigned at any time without prior notice to Maker.

         This Note shall be due and payable on demand as to both principal and
interest. Interest at a rate of ten percent (10%) per annum shall accrue on the
unpaid principal balance of this Note. If this Note is not paid at maturity,
however maturity may be brought about, all principal due on the date of such
maturity shall bear interest from the date of such maturity at the maximum
contract rate of interest which the Payee may charge the Maker under applicable
law. Interest on this Note shall be computed for the actual number of days
elapsed and on the basis of a year consisting of 360 days.

         If, for any reason whatever, the interest paid on this Note shall
exceed the maximum non-usurious amount permitted by law, the Payee shall refund
to the Maker such portion of said interest as may be necessary to cause the
interest paid on this Note to equal the maximum non-usurious amount permitted by
law, and no more. All sums paid or agreed to be paid to the Payee for the use,
forbearance or detention of the indebtedness evidenced hereby shall to the
extent permitted by applicable law be amortized, prorated, allocated and spread
throughout the full term of this Note until payment in full.

         The Maker shall be entitled to prepay this Note in whole or in part at
any time without the payment of a prepayment premium.

         In the event of default in the payment of this Note or under any
instrument executed in connection with this Note, the Maker agrees to pay on
demand all costs incurred by the Payee (i) in the collection of any sums,
including, but not limited to, principal, interest, expenses, and reimbursements
due and payable on this Note, and (ii) in the enforcement of the other terms and
provisions of this Note, whether such collection or enforcement be accomplished
by suit or otherwise, including the Payee's reasonable attorney's fees.

         Except as otherwise provided for herein, each maker, surety, guarantor
and endorser of this Note expressly waives all notices, including, but not
limited to, all demands for payment, presentations for payment, notice of
opportunity to cure default, notice of intention to accelerate the maturity,
notice of protest and notice of acceleration of the maturity, notice of protest
and notice of acceleration of the maturity of this Note, and consents that this
Note may be renewed and the time of payment extended without notice and without
releasing any of the parties.

         Any check, draft, money order or other instrument given in payment of
all or any portion of this Note may be accepted by the Payee or any other holder
hereof and handled in collection in the customary manner, but the same shall not
constitute payment hereunder or diminish any rights of the Payee or any other
holder hereof, except to the extent that actual cash proceeds of such instrument
are unconditionally received by the Payee or any other holder hereof and applied
to the indebtedness as herein provided.

                                       1

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     This Note shall be governed by and construed in accordance with the laws of
the State of Texas and applicable federal law.

                                         HOUSTON AMERICAN ENERGY CORP.

                                         By /s/ John F. Terwilliger
                                           ----------------------------------
                                           John F. Terwilliger, President

                                       2<PAGE>

                    LEGACY GROUP I LOANS EXTENSION AGREEMENT

         This LEGACY GROUP I LOANS EXTENSION AGREEMENT, dated as of November 15,
2001, is entered into among LogiMetrics, Inc., a Delaware corporation
("LogiMetrics"), mmTech, Inc., a New Jersey corporation ("mmTech" and, together
with LogiMetrics, "Borrowers"), Cramer Rosenthal McGlynn, LLC, as agent (the
"Agent") for the Holders (as defined below), and the other signatories a party
hereto (the "Holders").

         WHEREAS, each of the Holders has previously loaned to Borrowers the
aggregate principal amount set forth opposite such Holder's name on Exhibit A
hereto, on such terms and conditions as are set forth in a 13% Substitute
Negotiable Secured Senior Subordinated Promissory Note originally due July 1,
2000 (each, a "Loan");

         WHEREAS, the Loans are secured by and subject to (i) the Second Amended
and Restated Security Agreement, Intercreditor Agreement, Waiver and Consent
dated on or about August 31, 1999, as amended on December 2, 1999 and February
17, 2000 (the "Security Agreement"), and (ii) the Acknowledgment, Consent and
Waiver dated March 7, 2000 (the "Acknowledgment");

         WHEREAS, each Holder is a party to a Stockholders Agreement dated July
10, 2000, pursuant to which, among other things:

         (a)      the Borrowers paid the Holders all interest previously accrued
                  under the Loans for all periods up to and including July 10,
                  2000; and

         (b)      each Holder agreed to extend the maturity date of its Loan to
                  July 1, 2001;

         WHEREAS, the parties now wish to further extend the maturity date of
the Loans on the terms and conditions set forth herein; and

         WHEREAS, in connection with such extension, L-3 Communications
Corporation, the direct or indirect majority stockholder of the Borrowers
("L-3"), is entering into the Guaranty attached hereto as Exhibit B (the
"Guaranty"), pursuant to which L-3 shall guarantee the payment by Borrowers of
periodic interest accrued under the Loans as and when such interest becomes due
and payable by Borrowers in accordance with the terms hereof.

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

         1. Extension of Maturity Date. Each Holder hereby extends to October 1,
2002 (the "Maturity Date") the final date by which the outstanding principal
amount of the Loan made by such Holder, together with all accrued and unpaid
interest thereon, must be repaid by Borrowers to such Holder.
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                                                                               2

         2. Periodic Interest Payments. The Holders and Borrowers hereby amend
the provisions of the Loans regarding the payment of interest as follows:

              (a) Borrowers hereby jointly and severally agree to pay on January
2, 2002, to each Holder the following:

                   (1) for the period beginning on July 11, 2000 up to and
including July 1, 2001, interest on the outstanding principal amount of such
Holder's Loan at the rate of 13% per annum, calculated on the basis of a 360-day
year for the actual number of days elapsed (such amount, the "Interim Interest
Amount"); and

                   (2) for the period beginning on July 2, 2001 up to and
including January 2, 2002, interest on the outstanding principal amount and
Interim Interest Amount of such Holder's Loan at the rate of 16% per annum,
calculated on the basis of a 360-day year for the actual number of days elapsed.

              (b) Borrowers hereby further jointly and severally agree to pay to
each Holder on each Interest Payment Date (as defined below), interest on the
outstanding principal amount of such Holder's Loan for the applicable Interest
Period (as defined below) at the rate of 13% per annum (calculated on the basis
of a 360-day year for the actual number of days elapsed).

              (c) The following terms, as used in this Section 2, shall have the
following meanings:

                   (1) "Business Day" shall mean any day other than a Saturday,
Sunday or other day on which commercial banks in the State of New York are
authorized or required by law to close.

                   (2) "Interest Payment Date" shall mean the first Business Day
of each month during the period beginning on February 1, 2002 and ending on the
Maturity Date.

                   (3) "Interest Period" shall mean, with respect to each
Interest Payment Date, the period beginning on the day after the prior Interest
Payment Date up to and including the current Interest Payment Date; provided,
that with respect to the initial Interest Payment Date of February 1, 2002,
"Interest Period" shall mean the period beginning on January 3, 2002 up to and
including February 1, 2002.

         3. Default Interest. If the Borrowers fail to pay any amount due under
the Loans, as amended hereby, interest shall thereafter accrue on such overdue
amount at the rate of 16% per annum (calculated on the basis of a 360-day year
for the actual number of days elapsed) until paid in full.

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                                                                               3

         4. Acknowledgment of Prior Interest Payments. Each Holder hereby
acknowledges that Borrowers have paid such Holder for all interest previously
accrued under such Holder's Loan for all periods up to and including July 10,
2000.

         5. Waiver of Past Defaults. Each Holder hereby waives any and all
rights or claims against Borrowers arising out of any default or "event of
default" under such Holder's Loan as a result of the failure of Borrowers to
repay such Holder the outstanding principal amount of such Loan, together with
all accrued interest thereon, as of July 1, 2001, but does not waive any rights
or claims arising out of any default or "event of default" occurring after the
date hereof (a "Future Default"). No delay or failure on the part of any Holder
in exercising any rights or claims arising out of any Future Default shall
operate as a waiver of any such default; not shall any single or partial
exercise of any such rights or claims preclude any other or further exercise of
such rights or claims, or the exercise of any other rights or claims, and no
such waiver whatsoever shall be valid unless in writing, signed by the Holder,
and then only to the extent expressly set forth therein.

         6. Authority of Agent to Accept Guaranty. The Holders hereby authorize
and direct the Agent, in its capacity as agent for the Holders as described in
the Security Agreement, to accept and agree to the Guaranty on behalf of and for
the benefit of the Holders. In the event the Agent receives any payment under
the Guaranty, the parties hereto agree that such payment shall be applied by the
Agent in accordance with the provisions contained in Section 8 of the Security
Agreement as if such payment were the proceeds of the sale of collateral
securing the Loans.

         7. Confirmation of Security Interest. The Borrowers hereby acknowledge
and agree that the security interest in the Collateral (as defined under the
Security Agreement) granted to the Agent under the Security Agreement remains in
full force and effect in accordance with the terms of the Security Agreement and
shall not be effected by the execution of this Agreement.

         8. Miscellaneous.

              (a) This Agreement, the Guaranty and, to the extent not amended by
this Agreement or the Guaranty, (i) the separate 13% Substitute Negotiable
Secured Senior Subordinated Promissory Notes between the Borrowers and each
Holder dated as March 7, 2000, (ii) the Security Agreement, (iii) the
Acknowledgment and (iv) the Stockholders Agreement, together embody the entire
agreement and understanding of the parties hereto in respect of the subject
matter hereof and supercede all prior agreements and understandings, both
written and oral, between the parties with respect to the subject matter hereof.

              (b) This Agreement may be amended, modified or supplemented only
by a written agreement signed by each of the parties hereto and by L-3.

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              (c) This Agreement shall be governed by and construed in
accordance with the laws of the State of New York applicable to agreements made
and to be performed entirely within such State, without regard to the choice of
law principles thereof.

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

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

                                     LOGIMETRICS

                                     By: /s/ Norman M. Phipps
                                        ---------------------------------------
                                         Name:    Norman M. Phipps
                                         Title:   Senior Vice President

                                     MMTECH, INC.

                                     By: /s/ Norman M. Phipps
                                        ---------------------------------------
                                         Name:    Norman M. Phipps
                                         Title:   Assistant Secretary

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                                                                               5

                                     CRAMER ROSENTHAL McGLYNN, LLC, as Agent

                                     By: /s/ Gerald B. Cramer
                                        ---------------------------------------
                                         Name:    Gerald B. Cramer
                                         Title:   Chairman

                                     /s/ Gerald B. Cramer
                                     ------------------------------------------
                                     GERALD B. CRAMER

                                     520 Madison Avenue
                                     New York, New York  10022
                                     Tel:  (212) 838-3830
                                     Fax:  (212) 644-8291

                                     EDWARD J. ROSENTHAL PROFIT SHARING PLAN
                                         AND TRUST

                                     520 Madison Avenue
                                     New York, New York  10022
                                     Tel:  (212) 838-3830
                                     Fax:  (212) 644-8291

                                     By: /s/ Edward J. Rosenthal
                                        ---------------------------------------
                                         Name:  Edward J. Rosenthal
                                         Title:  Trustee

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                                                                               6

                                     CRM 1997 ENTERPRISE FUND, LLC

                                     By:  Cramer Rosenthal McGlynn, Inc.,
                                              Its Managing Member

                                     By: /s/ Gerald B. Cramer
                                        ---------------------------------------
                                         Name:    Gerald B. Cramer
                                         Title:   Chairman

                                     520 Madison Avenue
                                     New York, New York  10022
                                     Tel:  (212) 838-3830
                                     Fax:  (212) 644-8291

                                     CRM PARTNERS, L.P.

                                     By:  Cramer Rosenthal McGlynn, Inc.,
                                              Its General Partner

                                     By: /s/ Gerald B. Cramer
                                        ---------------------------------------
                                         Name:    Gerald B. Cramer
                                         Title:   Chairman

                                     520 Madison Avenue
                                     New York, New York  10022
                                     Tel:  (212) 838-3830
                                     Fax:  (212) 644-8291

                                    CRM RETIREMENT PARTNERS, L.P.

                                     By:  Cramer Rosenthal McGlynn, Inc.,
                                              Its General Partner

                                     By: /s/ Gerald B. Cramer
                                        ---------------------------------------
                                         Name:    Gerald B. Cramer
                                         Title:   Chairman

                                     520 Madison Avenue
                                     New York, New York  10022
                                     Tel:  (212) 838-3830
                                     Fax:  (212) 644-8291

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                                                                               7

                                     CRM MADISON PARTNERS, L.P.

                                     By:  Cramer Rosenthal McGlynn, Inc.,
                                              Its General Partner

                                     By: /s/ Gerald B. Cramer
                                        ---------------------------------------
                                         Name:    Gerald B. Cramer
                                         Title:   Chairman

                                     520 Madison Avenue
                                     New York, New York  10022
                                     Tel:  (212) 838-3830
                                     Fax:  (212) 644-8291

                                     CRM U.S. VALUE FUND, LTD.

                                     By:  Cramer Rosenthal McGlynn, Inc.,
                                              Its General Partner

                                     By: /s/ Gerald B. Cramer
                                        ---------------------------------------
                                         Name:    Gerald B. Cramer
                                         Title:   Chairman

                                     520 Madison Avenue
                                     New York, New York  10022
                                     Tel:  (212) 838-3830
                                     Fax:  (212) 644-8291

                                     A.C. ISRAEL ENTERPRISES, INC.

                                     By: /s/ Jay M. Howard
                                        ---------------------------------------
                                         Name:    Jay M. Howard
                                         Title:   Vice President

                                     520 Madison Avenue
                                     New York, New York  10022
                                     Tel:  (212) 838-3830
                                     Fax:  (212) 644-8291

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                                                                               8

                                     CRM-EFO PARTNERS, L.P.

                                     By:  CRM-EFO Investments, LLC,
                                        ---------------------------------------
                                              Its General Partner

                                     By:  Cramer Rosenthal McGlynn, Inc.,
                                              Its Managing Member

                                     By: /s/ Gerald B. Cramer
                                        ---------------------------------------
                                         Name:    Gerald B. Cramer
                                         Title:   Chairman

                                     520 Madison Avenue
                                     New York, New York  10022
                                     Tel:  (212) 838-3830
                                     Fax:  (212) 644-8291

                                     PAMELA EQUITIES CORP.

                                     By: /s/ Greg Manocherian
                                        ---------------------------------------
                                         Name:    Greg Manocherian
                                         Title:   Vice President

                                     3 New York Plaza
                                     18th Floor
                                     New York, New York  10004
                                     Tel:  (212) 837-4829
                                     Fax:  (212) 837-4938

                                     WHITEHALL PROPERTIES, LLC

                                     By: /s/ Greg Manocherian
                                        ---------------------------------------
                                         Name:    Greg Manocherian
                                         Title:   Vice President

                                     3 New York Plaza
                                     18th Floor
                                     New York, New York  10004
                                     Tel:  (212) 837-4829
                                     Fax:  (212) 837-4938

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                                                                               9

                                     McGLYNN FAMILY PARTNERSHIP L.P.

                                     By: /s/ Ronald H. McGlynn
                                     ------------------------------------------
                                         Name:  Ronald H. McGlynn
                                         Title:  General Partner

                                     520 Madison Avenue
                                     New York, New York  10022
                                     Tel:  (212) 838-3830
                                     Fax:  (212) 644-8291

                                     /s/Fred M. Filoon
                                     ------------------------------------------
                                     FRED M. FILOON

                                     520 Madison Avenue
                                     New York, New York  10022
                                     Tel:  (212) 838-3830
                                     Fax:  (212) 644-8291

                                     /s/Eugene A. Trainor, III
                                     ------------------------------------------
                                     EUGENE A. TRAINOR, III

                                     520 Madison Avenue
                                     New York, New York  10022
                                     Tel:  (212) 838-3830
                                     Fax:  (212) 644-8291

                                     /s/Greg Manocherian
                                     ------------------------------------------
                                     GREGORY MANOCHERIAN

                                     135 Central Park West, Tower Southeast
                                     New York, New York  10023
                                     Tel:  (212) 799-3500
                                     Fax:  (212)  873-2877

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