EXHIBIT 10.8


                                 NORTH FORK BANK

                                    MODIFIED
                              REVOLVING CREDIT NOTE


BORROWER:      LOGIMETRICS, INC. and mmTech, Inc.
PRINCIPAL:     $2,200,000                             Date:  As of April 30,1998

PROMISE TO PAY: The  undersigned  (the  "Borrower"),  for value  received,  does
hereby  promise  to pay to the  order of NORTH  FORK BANK  (the  "Bank")  at its
offices at 245 Love Lane, Mattituck,  New York 11952, or at any of its branches,
the sum of TWO MILLION TWO HUNDRED THOUSAND  ($2,200,000)  DOLLARS plus interest
thereon from the date hereof as set forth herein.

RATE AND PAYMENT:  The Borrower shall pay said sum, or such lesser amount as may
then be the aggregate unpaid principal  balance of all loans made by the Bank to
the  Borrower  hereunder,  (each a "Loan" and  collectively  the  "Loans") on or
before January 2, 1999 (the "Maturity Date").

Notwithstanding  the  foregoing,  the  Borrower  may, at its option,  extend the
Maturity Date to July 1, 1999,  provided that (a) the Borrower shall provide the
Bank with written  notice of said  election no later than ten (10) days prior to
January 2, 1999,  (b) no event of default shall have occurred  hereunder and (c)
the Borrower  shall have received net cash proceeds of not less than Ten Million
($10,000,000)  Dollars  from the private or public sale of  securities  prior to
January 2,1999.

The Borrower also  promises to pay interest  (computed on the basis of a 360 day
year for actual  days  elapsed) at said  office on the unpaid  principal  amount
hereof from time to time  outstanding  at the rate of two (2%) percent per annum
in excess of that rate stated by the Bank to be its Prime Rate from time to time
in effect, payable monthly in arrears on the first day of each month. Prime Rate
as  referred  to  herein  shall  refer to the  rate of  interest  determined  or
announced  by the Bank from time to time as its Prime Rate and the Prime Rate is
not  necessarily  the lowest rate of  interest  charged by the Bank on loans and
other  credit  relationships.  Each  change in the  Prime  Rate  shall  effect a
simultaneous  and  corresponding  change in the interest rate hereunder  without
notice to the Borrower.  Interest  shall be payable  monthly on the first day of
each month  commencing  on the first such day to occur after the date hereof and
upon payment in full of the unpaid principal amount hereof.

In addition to the  foregoing,  there shall be due and payable from the Borrower
to the Bank a  quarterly  fee equal to  one-fourth  of one (1/4%) percent of the
average unused amount of the Commitment during each such quarter, said fee to be
paid to the Bank not  later  than ten (10)  days  after  the end of each  fiscal
quarter.

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Wherever any payment to be made under this Note is required to be paid on a date
that is a Saturday,  Sunday or public holiday, or the equivalent for banks under
the  laws of the  State  of New  York,  such  payment  may be  made on the  next
succeeding  business  day,  and such  extension  of time  shall in such  case be
included in the computation of interest due.

All payments due under the Note shall be made by automatic debit from an account
maintained  by the  Borrower  for such purpose at the Bank in which the Borrower
shall maintain  balances  sufficient to pay each monthly payment due to the Bank
under  the Loan.  In the event  that the money  maintained  in such  account  is
insufficient  for any  payment  due under  this  Note,  the Bank may  charge any
account of the Borrower for any payment due to the Bank under this Note.

The Bank may charge any account of the  Borrower for any payment due to the Bank
hereunder.

DEFAULT  INTEREST RATE: The unpaid  principal sum due under this Note shall bear
interest at a rate equal to five (5%) percent  above the Rate set forth above on
and after the occurrence of any event of default and until the entire  principal
sum hereof has been fully paid,  both before and after the entry of any judgment
with  respect to such event,  but in no event  shall the rate  either  before or
after  the  occurrence  of any  event of  default  exceed  the  highest  rate of
interest,  if any, permitted under applicable New York or Federal Law. Such rate
of interest  shall  continue until such time as any event of default that may be
cured by the Borrower is cured to the  satisfaction  of the Bank,  at which time
the previously  stated  interest rate shall  re-commence.  In no event shall the
rate  either  before or after the  occurrence  of any such  default  exceed  the
highest rate of interest, if any, permitted under applicable New York or Federal
law.

RIGHT OF OFFSET:  If any payment is not made on time,  or if the entire  balance
becomes due and  payable  and is not paid,  all or part of the amount due may be
offset out of any account or other  property  which the Borrower has at the Bank
or any affiliate of the Bank without prior notice or demand.

LATE CHARGES:  The Borrower will pay a charge of five (5%) percent of the amount
of any  payment  which is not made  within ten (10) days of its  respective  due
date,  or, if  applicable,  which  cannot be  debited  from its  account  due to
insufficient balance on the debit date.

SECURITY:  This Note is secured by:

          (1) a security  interest in and  assignment  and pledge of all monies,
deposits,  or  other  sums now or  hereafter  held by the  Bank on  deposit,  in
safekeeping,  transit or otherwise,  at any time credited by or due from Bank to
the Borrower, or in which the Borrower shall have an interest; and

          (2) a continuing  first lien against all assets of the Borrower as set
forth, in part, in that certain Restated and Amended General Security  Agreement
dated of even date herewith.

In  consideration  of the  granting  of the Loans  evidenced  by this Note,  the
Borrower hereby agrees as follows:

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REVOLVING CREDIT COMMITMENT:

          (a) The  Loans  evidenced  by this Note are  available  in one or more
advances  during the period  which  commences on the date hereof and ends on the
Maturity Date (the "Credit Period") in an aggregate  principal amount up to, but
not  exceeding  at any time the  outstanding  principal  sum of Two  Million Two
Hundred  Thousand  ($2,200,000)  Dollars (the  "Commitment").  During the Credit
Period, the Borrower may use the Commitment by borrowing,  prepaying in whole or
in part and reborrowing,  on a revolving basis, all in accordance with the terms
and conditions hereof;  provided,  however, that each Loan or prepayment be in a
minimum amount of $10,000;

          (b)  Notwithstanding  anything to the contrary set forth  herein,  the
outstanding principal balance of the Loans shall at no time exceed the lesser of
the  Commitment  or the  aggregate  amount  available to the Borrower  under the
following Borrowing Base (as such amount shall fluctuate from time to time):

                    (i)  an  amount  equal  to  eighty  (80%)   percent  of  the
          Borrower's "Eligible Accounts  Receivable",  which shall be defined as
          all accounts  receivable  due to the Borrower from persons or entities
          less (A) uncollectible accounts and/or accounts remaining unpaid after
          a date  which is ninety  (90)  days  after  the  invoice  date of said
          account  receivable  and (B) accounts  receivable due from any account
          debtor who has had one-half (1/2) or more of their accounts receivable
          outstanding  for more than  ninety  (90) days (C) amounts due from the
          Borrower to any account receivable debtor; plus

                    (ii)  an  amount  equal  to  fifty  (50%)   percent  of  the
          Borrower's  "Eligible Inventory" on hand. Eligible Inventory shall (A)
          include  only raw  materials,  unfinished  inventory,  components  and
          finished goods (B) exclude work-in-process on existing "systems".  The
          outstanding principal balance of the Loans attributable to fifty (50%)
          percent of the Borrower's  Eligible Inventory as descried herein shall
          not exceed  sixty  (60%)  percent of the total  outstanding  principal
          balance of the Loans thereafter.

          (c) The Borrower  shall submit to the Bank at the time of each request
for a Loan, but not less than one time per month,  a Borrowing Base  Certificate
confirming the calculation of the Borrower's  Eligible  Accounts  Receivable and
Eligible  Inventory  and  calculating  the  amount  available  to  the  Borrower
hereunder.  Said  Borrowing  Base  Certificate  shall be signed by an authorized
representative of the Borrower;

          (d) The date and amount of each Loan and of each  payment of principal
shall be  maintained  by the Bank in its books and  records  at the time of each
Loan or  payment.  Absent  manifest  error  on the  part of the  Bank,  all such

<PAGE>

notations shall be presumed to be correct and the aggregate net unpaid amount of
Loans set forth therein shall be presumed to be the principal balance hereof;

          (e) Each  request for a Loan shall be subject to the  satisfaction  of
the following conditions precedent:

                    (i) The  Borrower  shall have given the Bank  notice of such
          request,  setting forth the amount of the Loan  requested and the date
          thereof. In addition to the aforementioned,  the Borrower shall submit
          to the Bank at the time of each  request,  but in any  event  not less
          than one time per month, a completed Borrowing Base Certificate in the
          form annexed hereto as Exhibit "A"  satisfactory in form and substance
          to the  Bank.  Such  notice  may be  written  or  oral  and  shall  be
          sufficient if received by 1 p.m. of the date the Loan is requested. If
          the  request  is oral,  it shall be  thereafter  confirmed  in writing
          delivered by the Borrower to the Bank;

                    (ii) No Event of  Default,  or event which would be an Event
          of  Default  but for the  giving of notice or the  passage  of time or
          both, has occurred and is continuing;  and all of the  representations
          and warranties  made by the Borrower  herein shall be true and correct
          in all  material  respects on and as of the date of such request as if
          made on and as of such date;

          (f) The  outstanding  principal  balance of the Loans shall at no time
exceed the amount of the Commitment;

          (g) The Borrower acknowledges and represents that the principal amount
of $1,872,383.85  together with interest thereon is outstanding  under the terms
hereof as of April 30, 1998 without offset' defense or counterclaim.

CONDITIONS PRECEDENT:

          The  Borrower  shall  satisfy  the  following   conditions   precedent
including delivery to the Bank of the following:

          (a) An executed copy of this Note;

          (b) The Bank shall continue to maintain its first  perfected  security
interest in certain  assets of the Borrower (the  "Collateral")  pursuant to the
general security agreement (the "Security Agreement") as reaffirmed of even date
herewith;

<PAGE>

          (c) A copy  of the  resolutions  passed  by the  Borrower's  Board  of
Directors  certified by its  Secretary  or Assistant  Secretary as being in full
force and  effect on the date of this  Agreement,  authorizing  the loan  herein
provided for, the execution, delivery and performance of this Note and any other
instrument  or agreement  required  hereunder and  containing a  certificate  of
incumbency  as to the person or persons  authorized  to execute  and deliver the
same; and

          (d) All other  documents  reasonably  required  by the Bank and/or its
counsel in order to  evidence  and/or  secure the Bank's  position  as set forth
herein.

REPRESENTATIONS AND WARRANTIES: The Borrower hereby represents and warrants to
the Bank that:

          (a) The  Borrower  is duly  organized,  validly  existing  and in good
standing  under the laws of the State of its  formation  and is  qualified to do
business and in good standing  under the laws of each state where its failure to
so qualify would have a material  adverse effect on its business,  operations or
properties;

          (b) This Note, the Security Agreement and all other documents executed
and  delivered  herewith have been duly  authorized,  executed and delivered and
constitute  the  valid  and  legally   binding   obligations  of  the  Borrower,
enforceable in accordance with their respective terms, including the granting to
the Bank of a first perfected security interest in the Collateral;

          (c) The  execution and delivery of this Note,  the Security  Agreement
and  all  other  documents  executed  and  delivered  herewith  and  performance
hereunder and thereunder, will not violate any provision of law;

          (d) Except as set forth in the annexed Disclosure Schedule,  there are
no actions or proceedings  pending before any court or  governmental  authority,
bureau or  agency,  with  respect to or  threatened  against  or  affecting  the
Borrower, or any Subsidiary, which if determined adversely would have a material
adverse  effect on the business,  the assets or the  financial  condition of the
Borrower  or  any  Subsidiary.   As  used  herein,   the  term  "Subsidiary"  or
"Subsidiaries"  means any  corporation  or  corporations  of which the  Borrower
alone, or the Borrower and/or one or more of its Subsidiaries, owns, directly or
indirectly,  at least a majority of the securities  having ordinary voting power
for the election of directors;

          (e)  Except  as set  forth in the  annexed  Disclosure  Schedule,  the
Borrower is not in default under, or in violation of, any term of any agreement,
ordinance, resolution, decree, bond, note, indenture, order or judgment to which
it is a party or by which it is  bound,  or by which  any of the  properties  or
assets  owned by or used in the  conduct  of its  business  is  affected,  which
default or violation may have a material adverse effect on its business,  assets
or financial  condition.  The operations of the Borrower  comply in all material
respects with all laws, ordinances and regulations applicable to it;

          (f) The  Borrower  is not a party to or bound  by,  nor are any of the
properties or assets owned by it or used in the conduct of its business affected

<PAGE>

by any agreement, ordinance, resolution, decree, bond, note, indenture, order or
judgment,  or  subject  to any  charter or other  corporate  restriction,  which
materially and adversely affects its business, assets or financial condition;

          (g) All balance sheets, profit and loss statements and other financial
information heretofore furnished to the Bank are complete and present fairly the
financial condition of the Borrower and its Subsidiaries as at the dates thereof
and for the periods covered thereby,  including contingent  liabilities of every
kind, which financial conditions have not materially adversely changed since the
date of the  most  recently  dated  balance  sheet  of the  Borrower  heretofore
furnished to the Bank;

          (h) No part of the  proceeds  of the loan which is  evidenced  by this
Note will be used  directly  or  indirectly  for the  purpose of  purchasing  or
carrying,  or for payment in full or in part of indebtedness  which was incurred
for the purpose of  purchasing  or  carrying,  any margin  stock as such term is
defined in Sec.  221.3 of  Regulation U of the Board of Governors of the Federal
Reserve System;

          (i)  The  Borrower  and  its  Subsidiaries  are in  compliance  in all
material  respects with the  Employees  Retirement  Income  Security Act of 1974
("ERISA") and all rules and regulations thereunder. Neither the Borrower nor any
of its  Subsidiaries  has any unfunded  vested  liability under any type of plan
described in Section 4021(a) of ERISA ("Pension Plan") and no reportable  event,
as set forth in Section  4043(b) of ERISA,  has occurred or is  continuing  with
respect to any Plan.

FINANCIAL STATEMENTS: The Borrower shall deliver to the Bank:

          (a)  Annually,  as soon as  available,  but in any  event  within  one
hundred  twenty  (120)  days  after the last day of each  fiscal  year,  audited
financial statements,  including balance sheets as of the last day of the fiscal
year and  statements  of income and  retained  earnings and changes in financial
condition  for such  fiscal  year each  prepared in  accordance  with  generally
accepted accounting principles, consistently applied ("GAAP") for the period and
prior periods by Deloitte and Touche, LLP, or other independent Certified Public
Accountants  satisfactory  to  the  Bank  and a  complete  signed  copy  of  the
Borrower's Federal Tax Return (and all schedules annexed thereto);

          (b) As soon as  available,  but in any event  within  twenty (20) days
after the end of each  month  (but  forty-five  (45) days  after the end of each
fiscal quarter),  internally prepared financial  statements of the Borrower each
prepared in accordance  with GAAP and  jobs-in-progress  reports for said period
and prior periods;

          (c)  10K and 10Q  reports  and  documentation  within  the  prescribed
reporting period;

          (d) Within a reasonable  time after a written request  therefor,  such
other financial data or information as the Bank may reasonably request from time
to time;

<PAGE>

          (e) At the same time as it delivers the financial  statements required
under the provisions of subsections (a) and (b) hereof, a certificate  signed by
the President or the chief financial, or accounting, officer of the Borrower, to
the effect  that no Event of Default  hereunder  or material  default  under any
other  agreement to which the Borrower or any  Subsidiary is a party or by which
it is bound, or by which any of its properties or assets may be affected, and no
event  which,  with the  giving of notice or the lapse of time,  or both,  would
constitute  such an Event of Default,  has occurred,  except as set forth in the
annexed Disclosure Schedule;

          (f) On a monthly basis,  no later than the twentieth  (20th) day after
each such month,  the Borrowing Base Certificate  referenced  herein and backlog
reports and accounts receivable agings of the Borrower;

          (g) Annual budget at closing and semi-annual budget thereafter on each
January 20 and July 20.

AFFIRMATIVE  COVENANTS:  The Borrower  will, and with respect to  the agreements
set forth in subsections (a) through (f) hereof, will cause each Subsidiary to:

          (a) With  respect to its  properties,  assets and  business,  maintain
insurance  against  loss or damage,  to the  extent  that  property,  assets and
businesses of similar  character  are usually so insured by companies  similarly
situated and operating like  properties,  assets or businesses with  responsible
insurance  companies  satisfactory  to the Bank,  said insurance to indicate the
Bank as an additional insured and loss payee;

          (b) Duly pay and  discharge  all  taxes or other  claims  which  might
become a lien upon any of its  properties  except to the extent  that such items
are being in good faith appropriately contested;

          (c) Maintain, preserve and keep its properties in good repair, working
order and condition, and make all reasonable repairs,  replacements,  additions,
betterments and improvements thereto;

          (d)  Conduct  its  business  in  substantially  the same manner and in
substantially the same fields as such business is now carried on and conducted;

          (e) Comply with all statutes,  rules and  regulations and maintain its
corporate existence;

          (f)  Permit  the Bank to make or cause  to be  made,  inspections  and
audits of any books,  records and papers of the Borrower  and of any  Subsidiary
and each endorser  hereof and to make extracts  therefrom at all such reasonable
times and as often as the Bank may reasonably require;

<PAGE>

          (g)  Immediately  give notice to the Bank that an Event of Default has
occurred or that an event which,  with the giving of notice or lapse of time, or
both,  would  constitute an Event of Default,  has occurred and  specifying  the
action which the Borrower has taken and proposes to take with respect thereto;

          (h) In addition to the  aforementioned,  the Borrower  agrees that the
following  financial  covenants are covenants  upon which the Bank relies in the
extension of the obligation  evidenced  hereby and that any violation or default
under same shall constitute an Event of Default under the terms hereof:

                    (1) at the  end of  each  fiscal  quarter  during  the  term
          hereof,  the Borrower  shall maintain a Tangible New Worth of $846,471
          or greater (as  calculated  in  accordance  with GAAP).  For  purposes
          hereof  "Tangible Net Worth" shall mean, at any date, (i) the net book
          value of assets (other than patents, patent rights, trademarks,  trade
          names, franchises,  copyrights,  licenses, permits, goodwill and other
          intangible  assets  classified as such in accordance  with GAAP) after
          all  appropriate  adjustments  in  accordance  with  GAAP  (including,
          without limitation,  reserves for doubtful receivables,  obsolescence,
          depreciation and amortization) plus (ii) subordinated indebtedness, in
          each case computed in accordance with GAAP;

                    (2) at the  end of  each  fiscal  quarter  during  the  term
          hereof,  the  Borrower  shall report a net income  (gross  income less
          taxes an extraordinary items) of not less than $1.00.

COMPENSATING  BALANCE AND DEFICIENCY  FEE  AGREEMENT:  If at any time during the
term hereof,  the aggregate  average  monthly ledger  balance  maintained in the
non-interest  deposit  accounts  of the  Borrower  at the  Bank  are  less  than
$220,000,  the Borrower shall pay to the Bank an additional fee equal to (a) the
difference  between  $220,00 and the aggregate  average  monthly  ledger balance
maintained in the  non-interest  bearing deposit accounts of the Borrower at the
Bank,  multiplied by (b) a fixed rate (the "Deficiency Rate") equal to four (4%)
percent in excess of the Bank's  Prime Rate,  based on a 360 day year and actual
number of days elapsed. The $220,000  Compensating Balance requirement set forth
herein is  intended  as an  aggregate  requirement  for all  obligations  of the
Borrower to the Bank. The Deficiency  Rate shall be established on the first day
of each January and July and shall be applicable for the immediately ensuing six
(6) moth period.

The fee  defined  herein  shall be due and  payable  within  fifteen  (15)  days
following the end of each calendar quarter and shall be debited by the Bank from
any account  maintained by the Borrower at the Bank. The Borrower shall maintain
sufficient funds in said accounts to permit such debit.

<PAGE>

Nothing  contained herein shall be deemed to require the undersigned to maintain
Demand  Deposit  Balances at the Bank. The  aforementioned  is intended as a fee
only and is neither intended,  nor to be construed as, an imposition of interest
or other charge.

NEGATIVE COVENANTS:The Borrower will not, and will not permit any Subsidiary to:

          (a)  Create,  incur,  assume  or suffer  to exist  any  liability  for
borrowed money, except (i) amounts outstanding under the Borrower's twelve (12%)
percent  Convertible Senior  Subordinated  Debentures,  (ii) amounts outstanding
under the  Borrower's  Amended and  Restated  twelve (12%)  percent  Convertible
Subordinated  Debentures the aforementioned are collectively  referred to herein
as the  "Debentures")  (iii)  indebtedness  to the Bank;  (iv)  existing debt as
reflected  on the most  recent  balance  sheet  provided to the Bank and further
incurred  through the date of this  Agreement,  which further  incurred debt has
been  acknowledged by the Borrower to the Bank in writing prior to the execution
hereof;   and  (v)  other  indebtedness  for  borrowed  money  (whether  or  not
constituting   a  refinancing  of  existing   indebtedness)   so  long  as  such
indebtedness  is not secured by collateral  securing  repayment of this Loan and
the incurrence of which will not cause a default hereunder.  The Borrower agrees
to provide the Bank an opportunity to finance any additional  borrowing needs in
excess of $100,000 during the term of this Note;

          (b) enter into any merger or consolidation  (where the Borrower is not
the surviving entity) or liquidate, wind-up or dissolve itself or sell, transfer
or lease or otherwise dispose of all or any substantial part of its assets;

          (c) lend or  advance  money,  credit or  property  to or invest in (by
capital  contribution,  loan, purchase or otherwise) any firm,  corporation,  or
other person where any event of default has occurred and is  continuing or where
such transaction would cause an event of default hereunder;

          (d) create,  assume or permit to exist, any mortgage,  pledge, lien or
encumbrance  of or upon or security  interest  in, any of its property or assets
now owned or  hereafter  acquired  except  (i)  mortgages,  liens,  pledges  and
security  interests in favor of the Bank; (ii)  subordinate  liens incidental to
the  Debentures or to be granted to MBF Capital Corp. as set forth in subsection
(a)  hereof;  (iii) other  liens,  charges and  encumbrances  incidental  to the
conduct of its  business or the  ownership of its property and assets which were
not  incurred in  connection  with the  borrowing  of money or the  obtaining of
advances  or credit and which do not  materially  impair the use  thereof in the
operation of its business;  (iv) liens for taxes or other  governmental  charges
which are not  delinquent  or which are being  contested  in good  faith and for
which a reserve  shall  have  been  established  in  accordance  with  generally
accepted  accounting  principles;  (v) liens  granted to secure  purchase  money
financing  of  equipment,  provided  such  liens are  limited  to the  equipment
financed;  and (vi) liens granted to refinance  unencumbered  equipment provided
such liens are limited to the equipment  refinanced  and the incurrence of which
will not cause a default hereunder or in any other loan agreements or notes with
the Bank;

<PAGE>

          (e)  assume,  endorse,  be or  become  liable  for  or  guarantee  the
obligations  of any  other  person  except  by  the  endorsement  of  negotiable
instruments for deposit or collection in the ordinary course of business;

          (f) declare or pay any preferred  dividends where any Event of Default
has occurred and is continuing;

          (g) (i)  terminate  any Pension  Plan so as to result in any  material
liability to The Pension Benefit Guaranty  Corporation  established  pursuant to
Subtitle  A of Title IV of ERISA  (the  "PBCG"),  (ii)  engage in or permit  any
person to engage in any "prohibited  transaction"  (as defined in Section 406 of
ERISA  or  Section  4975 of the  Internal  Revenue  Code of  1954,  as  amended)
involving any Pension Plan which would subject the Borrower to any material tax,
penalty  or other  liability,  (iii)  incur or  suffer  to  exist  any  material
"accumulated  funding deficiency" (as defined in Section 302 of ERISA),  whether
or not waived,  involving any Pension Plan, or (iv) allow or suffer to exist any
event or  condition,  which  presents a material  risk of  incurring  a material
liability to the PBCG by reason of termination of any Pension Plan.

COLLATERAL SECURITY:

          (a) As  collateral  security for the payment of any and all sums owing
under this Note and all other obligations,  direct or contingent, joint, several
or  independent,  of the Borrower and of any Subsidiary and each endorser hereof
now or hereafter  existing,  due or to become due to, or held, or to be held by,
the Bank,  whether created  directly or acquired by assignment or otherwise (all
of  such   obligations,   including  this  Note,  are  hereinafter   called  the
"Obligations"),  the Borrower  hereby  grants to the Bank a lien on and security
interest in any and all  deposits  or other sums at any time  credited by or due
from the Bank to the Borrower, whether in regular or special depository accounts
or  otherwise,  and any and all  monies,  securities  and other  property of the
Borrower,  and the proceeds thereof,  now or hereafter held or received by or in
transit to the Bank from or for the Borrower, whether for safekeeping,  custody,
pledge,  transmission,  collection or otherwise,  and any such  deposits,  sums,
monies,  securities and other property,  may at any time after the occurrence of
any Event of Default be set-off,  appropriated  and applied by the Bank  against
any of the  Obligations  whether  or not  such  Obligations  are then due or are
secured  by any  collateral,  or, if they are so  secured,  whether  or not such
collateral held by the Bank is considered to be adequate and with respect to all
collateral security the Bank shall have all the rights and remedies available to
it under the Uniform Commercial Code of New York and other applicable law;

          (b) This Note is also secured by the Collateral.

EVENTS  OF  DEFAULT:  If any one or more of the  following  events  ("Events  of
Default")  shall occur the Borrower  shall be in default  hereunder  and, at the
option of the Bank,  the entire unpaid  balance of the principal of and interest
on the Obligations shall immediately become due and payable:

<PAGE>

          (a)  Failure to pay any amount  required  by this Note within ten (10)
days of its  respective  due date, or any other  obligation  owed to the Bank by
Borrower, or, if applicable, failure to have sufficient funds in its account for
loan payments to be debited on the due date;

          (b) Failure to perform or keep or abide by any  negative or  financial
covenant  set forth  herein  contained  in this Note,  or any other  document or
instrument given to the Bank in connection with this loan;

          (c) Failure to perform or keep or abide by any other  term,  covenant,
or condition  contained in this Note, or any other document or instrument  given
to the Bank in connection with this Loan,  said failure  continuing for a period
of thirty (30) days after written notice thereof;

          (d) Payment Default by the Borrower or any declared  default  pursuant
to the Debentures;

          (e) The Borrower  makes an assignment  for the benefit of creditors or
admits in writing its  inability to pay its debts  generally as they become due;
or an order, judgment or decree is entered adjudicating the Borrower as bankrupt
or  insolvent;  or any order for relief with  respect to the Borrower is entered
under the United States Bankruptcy Code; or the Borrower petitions or applies to
any tribunal for the appointment of a custodian, trustee, receiver or liquidator
of the Borrower or of any  substantial  part of the assets of the  Borrower,  or
commences  any  proceeding  relating  to  the  Borrower  under  any  bankruptcy,
reorganization,  arrangement,  insolvency,  readjustment of debt, dissolution or
liquidation  law of any  jurisdiction;  or any such petition or  application  is
filed, or any such proceeding is commenced,  against the Borrower and either (i)
the Borrower by any act indicates its approval  thereof,  consents  thereto,  or
acquiesces  therein or (ii) such  petition,  application  or  proceeding  is not
dismissed within sixty (60) days;

          (f) The happening of any event which,  in the  reasonable  judgment of
the Bank,  adversely affects the Borrower's ability to repay or the value of any
collateral;

          (g) If any material written  representation or material statement made
to the Bank by the Borrower is untrue when made;

          (h) The occurrence of a default under any other document or instrument
given to the Bank in connection with this loan;

          (i) Failure to provide any financial  information on request or permit
an examination of books and records;

          (j) In the event that any person or "group"  (as defined in Rule 13d-S
promulgated  under the Exchange  Act),  acquires or otherwise  obtains the right
(whether by contract,  through the  ownership of  securities  or pursuant to any
proxy or consent  arrangement,  voting trust or otherwise) to appoint,  elect or
cause the election of a majority of the Board of Directors of the Company;

<PAGE>

          (k) if any order is  entered  by any court or  tribunal,  at law or in
equity, by or against any of the Obligors for the appointment of any receiver or
any  trustee for any of the  Obligors  and said Order is not  discharged  within
sixty (60) days from the entry thereof.

ATTORNEYS  FEES:  In  the  event  the  Bank  retains  counsel  with  respect  to
enforcement of this Note or any other document or instrument  given to the Bank,
the Borrower agrees to pay the Bank's reasonable  attorneys fees (whether or not
an action is commenced and whether or not in the court of original jurisdiction,
appellate court, bankruptcy court, or otherwise).

SUBSEQUENT  AGREEMENTS:  The Borrower shall be bound by any agreement  extending
the time or modifying the above terms of payment made by the Bank without notice
to the Borrower, and the Borrower shall continue to be liable to pay all amounts
due hereunder,  but at an interest rate not exceeding the rate set forth herein,
according to the terms of any such agreement of extension or modification.

MISCELLANEOUS:

          (a)  Only  those  agreements,   representations  and  warranties  made
expressly  herein shall survive the delivery of this Note.  The Borrower  waives
trial by jury,  set-off and  counterclaim  of any nature or  description  in any
litigation in any court with respect to, in connection  with, or arising out of,
this  Note or any  instrument  or  document  delivered  pursuant  hereto  or the
validity, protection, interpretation, collection or enforcement hereof;

          (b) No  modification  or waiver of or with respect to any provision of
this Note,  or consent to any departure by the Borrower from any of the terms or
conditions hereof, shall in any event be effective unless it shall be in writing
and signed by the Bank,  and then such waiver or consent shall be effective only
in the specific  instance  and for the purpose for which given.  No notice to or
demand on the Borrower in any case shall, of itself,  entitle it to any other or
further notice or demand in similar or other circumstances;

          (c) Each and every right  granted to the Bank  hereunder  or under any
other document delivered hereunder or in connection  herewith,  or allowed it by
law or equity,  shall be cumulative  and may be exercised  from time to time. No
failure on the part of the Bank or the holder of this Note to  exercise,  and no
delay in exercising,  any right shall operate as a waiver thereof, nor shall any
single or partial  exercise of any right  preclude any other or future  exercise
thereof or the exercise of any other right;

          (d) In the event that this Note is placed in the hands of an  attorney
for collection by reason of any default  hereunder,  the Borrower  agrees to pay
reasonable  attorney's  fees  so  incurred.  The  Borrower  promises  to pay all
reasonable  out-of-pocket  expenses of any nature as soon as incurred whether in
or out of court and whether  incurred before or after this Note shall become due
at its maturity date or otherwise and Costs which the Bank may deem necessary or
proper  in  connection  with  the   satisfaction  of  the  indebtedness  or  the

<PAGE>

administration, supervision, preservation, protection (including but not limited
to maintenance of adequate insurance) of or the realization upon the collateral;

          (e) The  Borrower  hereby  waives  presentment,  demand  for  payment,
protest,  notice of protest, notice of dishonor, and any or all other notices or
demands except as otherwise expressly provided for herein;

          (f) All accounting terms not otherwise defined in this Note shall have
the meanings ascribed thereto under generally accepted accounting principles;

          (g) Delay or failure of the Bank to exercise  any of its rights  under
this Note shall not be deemed a waiver  thereof.  No waiver of any  condition or
requirement  shall operate as a waiver of any other or  subsequent  condition or
requirement.  The Bank or any other  holder of this  Note  need not  present  it
before  requiring  payment.  The  Borrower  waives  trial by jury,  offset,  and
counterclaim with respect to any action arising out of or relating to this Note.
This Note may not be modified or terminated orally.  This Note shall be governed
by the laws of the State of New York  without  regard to its  conflicts  of laws
rules.  The Borrower  irrevocably  consents to the jurisdiction and venue of the
New York State Supreme Court, Suffolk County in any action concerning this Note.
This Note is binding upon the Borrower, its heirs, successors and assigns;

          (h) The Borrower expressly warrants and represents that no statements,
agreements or  representations,  whether oral or written,  have been made by the
Bank,  or by any  employee,  agent or  broker of the Bank  with  respect  to the
obligation  or debt  evidenced  by this Note.  The  Borrower  further  expressly
warrants and represents that (i) no oral commitment has been made by the Bank to
extend or  continue  any  credit to the  Borrower  or any  party  other  than as
expressly  stated  herein or in those certain  documents  executed in connection
herewith, (ii) no representation or agreement has been made by or with the Bank,
or any employee,  agent or broker of the Bank, to forebear or refrain in any way
from exercising any right or remedy in its favor  hereunder or otherwise  unless
expressly set forth herein,  and (iii) the Borrower has not and will not rely on
any  commitment  to extend or  continue  any  credit,  nor on any  agreement  to
forebear or refrain from exercising rights or remedies unless such commitment or
agreement shall be in writing and duly executed by an authorized  officer of the
Bank.

NOTICES: All notices,  requests and other  communications  pursuant to this Note
shall be in writing,  either by letter  (delivered  by hand or sent by certified
mail, return receipt requested) or telegram, addressed as follows:

                  (a)      if to the Borrower:

                           c/o Logimetrics , Inc.
                           50 Orville Drive
                           Bohemia, New York 11716
                           Attention: Norman Phipps, President

<PAGE>

                  (b)      if to the Bank:

                           North Fork Bank
                           275 Broad Hollow Road
                           Melville, New York 11747

                           Attention Joseph Walsh, Senior Vice President

          Any notice, request or communication hereunder shall be deemed to have
been  given when  deposited  in the mails,  postage  prepaid,  or in the case of
telegraphic  notice,  when  delivered  to the  telegraph  company,  addressed as
aforesaid.  Any party may  change  the  person or  address  to whom or which the
notices are to be given  hereunder,  but any such notice shall be effective only
when actually received by the party to whom it is addressed.

          IN WITNESS  WHEREOF,  the Borrower has signed this Note as of the 30th
day of April, 1998.

                                             LOGIMETRICS, INC.


                                              By:/s/Norman Phipps
                                                 _______________________________
                                                 Norman Phipps
                                                 President


                                              mmTech, Inc.


                                              By:/s/Charles S. Brand
                                                 _______________________________
                                                 Charles S. Brand
                                                 President

<PAGE>

STATE OF NEW YORK                )
                                 ) ss.:
COUNTY OF NASSAU                 )

          On this day of March,  1997,  before me personally came Norman Phipps,
to me known,  who,  being by me duly  sworn,  did  depose and say that he has an
address at c/o  LOGIMETRICS,  INC.,  121-03 Dupont Street,  Plainview,  New York
11803, that he is the President of LOGIMETRICS,  INC., the corporation described
in, and which executed,  the foregoing  instrument;  and that he signed his name
thereto by order of the Board of Directors of said corporation.

                                               _________________________________
                                               NOTARY PUBLIC


STATE OF NEW YORK                )
                                 ) ss.:
COUNTY OF NASSAU                 )

          On this day of March,  1997,  before me  personally  came  Charles  S.
Brand, to me known,  who, being by me duly sworn, did depose and say that he has
an address at c/o LOGIMETRICS,  INC., 121-03 Dupont Street,  Plainview, New York
11803,  that he is the President of mmTech,  Inc. the corporation  described in,
and which  executed,  the  foregoing  instrument;  and that he  signed  his name
thereto by order of the Board of Directors of said corporation.

                                               _________________________________
                                               NOTARY PUBLIC


<PAGE>

                                   EXHIBIT "A"

                           BORROWING BASE CERTIFICATE

The undersigned hereby certifies that:

          1. The undersigned has performed and complied in all respects with the
agreements,  covenants and  conditions of those  certain loan  agreements  dated
April 30, 1998 between North Fork Bank and the undersigned; and

          2. On the date hereof,  there exists no event of default or default as
defined in the  aforementioned  agreements,  and no material  adverse change has
occurred to the financial  condition of the Borrower  between April 30, 1998 and
the date hereof; and

          3. The following information relating to the Borrowing Base as defined
in the agreement is true and accurate and  represents  fairly and completely the
status of the stated information as of the date hereof.

Eligible Inventory                                         _______x 50% ______

Eligible Accounts Receivable                               _______x 80% ______

Total Eligible Inventory and Accounts Receivable

         Less Outstanding Loan (A)                            __________

         Remaining Eligibility (B)                            ==========

             (A + B not to exceed the sum of  $2,200,000 or such maximum
             available as is defined herein)



                                             LOGIMETRICS, INC.


                                              By:
                                                 _______________________________
                                                 Norman Phipps
                                                 President