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                                                                 Exhibit 10 (ll)
                              STATE OF SOUTH DAKOTA
                          BOARD OF ECONOMIC DEVELOPMENT

                                                        REDI LOAN NUMBER 02-18-A

                                 PROMISSORY NOTE

                                                        YANKTON, SOUTH DAKOTA

$296,000                                                DECEMBER 19, 2002

         For value received, the undersigned M-TRON INDUSTRIES, INC. OF 100
DOUGLAS AVENUE, YANKTON, SOUTH DAKOTA 57078 promises to pay, in lawful money of
the United States of America, to the order of SOUTH DAKOTA BOARD OF ECONOMIC
DEVELOPMENT at the offices of its Loan Servicing Agent, BankWest Inc., at P.O.
Box 998, City of PIERRE, State of SOUTH DAKOTA or at holder's option, at such
other place as may be designated from time to time by the holder TWO HUNDRED
NINETY-SIX THOUSAND AND NO/100 DOLLARS, ($296,000) with interest on unpaid
principal computed from the date of each advance to the undersigned at the rate
of three percent per annum, payment to be made in installments as follows:

         By paying 59 equal monthly installments, in the amount of $1,642.00,
         (based on a level 240 month amortization), beginning thirty (30) days
         from the date of this Promissory Note, with the final balloon payment
         of principal and interest due at the end of 60 months/years from the
         date of this Promissory Note.

         This Promissory Note is issued pursuant to that certain Revolving
Economic Development and Initiative Fund (REDI) Loan Agreement dated the date
hereof by and between the Borrower and BED (the "Loan Agreement"), the terms and
provisions of which are hereby incorporated by reference, pursuant to SDCL
Chapters 1-16G and 1-33, as amended, and Rules and Regulations Article 68:02,
Administrative Rules South Dakota (ARSD).

         This Promissory Note is secured by:

                   [X] Mortgage of even date.

         If any sum payable hereunder is not paid when due or in the event of a
default upon any term, covenant or condition of any of the Loan Documents, then
the entire outstanding principal balance shall thereafter bear interest until
paid or until the default is cured to BED's satisfaction at a fixed rate three
percentage points higher that the prime rate of interest published weekly in the
Wall Street Journal, as published a the time of the default.

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         The Borrower shall have the option of prepaying any installment of
principal or interest owing on this Promissory Note prior to the maturity date
thereof without penalty. If prepayments are made, such payment will include
accrued interest to the date of the prepayment on the amount of principal
prepaid, and principal payments shall be reduced in inverse order of maturity.
Such prepayments shall not in any way alter or suspend any obligations of the
Borrower under the terms of this Promissory Note or the Loan Agreement.

         In the event of default in the payment of this Promissory Note, the
Borrower agrees to pay all costs of collection, including reasonable attorney
fees.

         The Borrower hereby waives presentment for payment, demand, notice of
nonpayment, protest, notice of protest, and notice of dishonor.

         This Promissory Note and all instruments or documents securing the same
shall be governed by and construed in accordance with the laws of the State of
South Dakota.

         Signed and sealed this 19th day of December, 2002.

                                                  M-TRON INDUSTRIES, INC.

       (SEAL)                                     BY:  /s/ Robert R. Zylstra
                                                       ---------------------
                                                  ITS: President & CEO

ATTEST:

BY: /s/ David L. Rein
    -----------------
ITS: Secretary

NOTE: Corporate Borrowers must execute Promissory Note, in corporate name, by
duly authorized officer, and seal must be affixed and duly attested.

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                         DECLARATION OF BUSINESS PURPOSE

         The undersigned has applied to BED for credit in the amount not to
exceed $296,000. The undersigned warrants and represents that the credit will be
used primarily (50% or more) for the business or commercial purpose described in
the Loan Agreement, and will not be used primarily for personal, family or
household purposes. This declaration is to confirm that no disclosures are
required under the Federal Truth in Lending law and Regulations.

         Dated at Yankton, South Dakota, this 19th day of December, 2002.

                                                  M-TRON INDUSTRIES, INC.

         (SEAL)                                   BY:  /s/ Robert R. Zylstra
                                                       ---------------------
                                                  ITS: President & CEO

ATTEST:

BY: /s/ David L. Rein
    -----------------
ITS: Secretary

NOTE: Corporate Borrowers must execute Declaration, in corporate name, by
duly authorized officer, and seal must be affixed and duly attested.

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