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                                                                    Exhibit 10.1

                       FOURTH AMENDMENT TO LOAN AGREEMENT

          THIS Amendment to Loan Agreement made this 30th day of June,  2007, by
and between M-TRON  INDUSTRIES,  INC., a Delaware  corporation  ("M-TRON"),  and
PIEZO TECHNOLOGY,  INC., a Florida corporation (collectively,  the "Borrowers"),
and FIRST NATIONAL BANK OF OMAHA (the "Bank"),  a national  banking  association
established at Omaha, Nebraska.

          WHEREAS,  M-TRON has  existing  term loans with the Bank  evidenced by
term note number  855891-1  with a due date of October 14, 2007,  pursuant to an
existing  additional  loan agreement  with the Bank,  which shall remain in full
force in accordance with its terms; and

          WHEREAS, M-TRON has an existing revolving line of credit with the Bank
evidenced by  revolving  note number  855893-1  with a due date of June 30, 2008
pursuant to an existing  additional loan agreement with the Bank, which shall be
paid in full from the proceeds of the Revolving Note; and

          WHEREAS,  the Bank is willing to provide such credit facilities to the
Borrowers upon the terms and conditions herein set forth.

          WHEREAS,  BANK and BORROWER  executed a written Loan  Agreement  dated
October 14, 2004 which was subsequently  amended May 31, 2005, June 30, 2006 and
October  3, 2006 (the Loan  Agreement  together  with all  amendments  is herein
called the "AGREEMENT"); and

          WHEREAS, the parties hereto desire to amend the AGREEMENT.

          Now,  therefore,  in consideration of the AGREEMENT,  and their mutual
promises made herein, BANK and BORROWERS agree as follows:

          1. Terms which are typed herein as all  capitalized  words and are not
          defined  herein shall have the same meanings as when  described in the
          AGREEMENT.

          2. Article I Section 1.01 Defined Terms  "Borrowing  Base"  subsection
          (b) of the AGREEMENT is hereby amended to read, effective immediately:
                   The term  "Tangible  Net  Worth" of the  AGREEMENT  is hereby
          amended to read, effective immediately:
                              "Tangible Net Worth" means total assets less total
          liabilities (but excluding  Subordinated  Debt existing on the Closing
          Date, in an amount of not less than $4,200,000).

          3. Article I Section 1.01.  Defined Terms  "Revolving Loan Termination
          Date"  (a) of the  AGREEMENT  is  hereby  amended  to read,  effective
          immediately:

               (a) June 30,  2008,

          4. Article II Section  2.12,  Repayment  of  Revolving  Note is hereby
          amended to read, effective immediately:

                   2.12 The Revolving  Note shall be due and payable on June 30,
                   2008. Interest only shall be payable monthly on the Revolving
                   Note. All outstanding principal and interest shall be due and
                   payable on June 30, 2008.

          5.  BORROWER  certifies  by  its  execution  hereof  that  all  of the
          representations  and warranties set forth in the AGREEMENT are true as
          of this date, and that no EVENT OF DEFAULT under the AGREEMENT, and no
          event  which,  with the  giving of notice or  passage of time or both,
          would  become such an EVENT OF DEFAULT,  has  occurred as of execution
          hereof, except as disclosed to BANK. All other terms and conditions of
          the  AGREEMENT not affected or amended by this  AGREEMENT,  are hereby
          ratified and confirmed.

          8. GUARANTOR acknowledges and consents to the foregoing amendment, and
          agrees  and  confirms  that  his  separate   guarantee  of  BORROWER's
          obligations  to BANK  are,  and  continue  to be,  valid  and  binding
          obligations of GUARANTOR.

          9. Except as herein amended,  the AGREEMENT continues to be the valid,
          binding obligation of BORROWER.

          IN WITNESS  WHEREOF,  the parties  have caused  this  Agreement  to be
executed by their respective officers thereunto duly authorized,  as of the date
first above written.

M-TRON INDUSTRIES, INC.                             FIRST NATIONAL BANK OF OMAHA

By:  /s/ David Rein                                 By:  /s/ Justin Mahoney
     -----------------------                             -----------------------

Its:  VP                                            Its:  Justin Mahoney
     -----------------------                             -----------------------

PIEZO TECHNOLOGY, INC.

By:  /s/ David Rein
     -----------------------

Its:  VP
     -----------------------

ACKNOWLEDGED BY GUARANTOR:

LYNCH CORPORATION

By:  /s/ Steve Pegg
     -----------------------
Its: Chief Financial Officer
     -----------------------
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