Exhibit 2.2

           FIRST AMENDMENT TO ASSET PURCHASE AGREEMENT




     This First Amendment To Asset Purchase Agreement
("Amendment") is entered into effective as of November 1, 1997,
among BOATRACS, INC., a California corporation ("Purchaser"), MED
ASSOCIATES, INC., a Mississippi corporation (the "Company"),
CHARLES J. DROBNY, JR., an individual ("CD"), and PAMELA M.
DROBNY, an individual ("PD") (CD and PD, collectively, "Drobny"),
who agree to amend that certain Asset Purchase Agreement dated as
of November 1, 1997 among them (the "Agreement") as follows:


1.  Recital.
            By this Amendment,
          
          
Purchaser, the Company and Drobny intend to amend certain
provisions of the Agreement to more accurately reflect the
agreement of the parties.  Capitalized terms used in this
Amendment, and not defined in this Amendment, shall have the
meaning set forth in the Agreement.


2.  Deferred Contingent Payment.
  Paragraph 4.3(c) of the Agreement is hereby deleted in its
entirety and replaced with the following new paragraph:

          "(c)   Issuance to the Company, subject to the
   option set forth below, of Three Hundred Thousand
   (300,000) shares of common stock of Purchaser (the
   "Issued Stock").  The certificates representing the
   Issued Stock shall contain the following legend and
   shall be physically held by Purchaser and not released
   to the Company or Drobny until the time for the exercise
   of such option has expired:

          `THE SHARES REPRESENTED BY THIS CERTIFICATE
          ARE SUBJECT TO AN OPTION TO PURCHASE BY
          BOATRACS, INC. ON TERMS SET FORTH IN THAT
          CERTAIN ASSET PURCHASE AGREEMENT DATED AS OF
          NOVEMBER 1, 1997, AS AMENDED.
          
          THESE SHARES HAVE NOT BEEN REGISTERED UNDER
          THE SECURITIES ACT OF 1933, HAVE BEEN TAKEN
          FOR INVESTMENT PURPOSES ONLY AND NOT WITH A
          VIEW TO THE DISTRIBUTION THEREOF, AND NEITHER
          SUCH SHARES NOR ANY INTEREST THEREIN MAY BE
          SOLD, TRANSFERRED, ASSIGNED OR PLEDGED UNLESS
          THERE IS AN EFFECTIVE REGISTRATION STATEMENT
          UNDER SUCH ACT COVERING SUCH SECURITIES, OR
          BOATRACS, INC. RECEIVES AN OPINION OF
          COUNSEL, THAT SUCH SALE, TRANSFER, ASSIGNMENT
          OR PLEDGE IS EXEMPT FROM THE REGISTRATION AND
          PROSPECTUS DELIVERY REQUIREMENTS OF SUCH
          ACT.'"
          

3.  Option To Purchase.
  Paragraph 4.3.1 of the Agreement is hereby deleted in its
entirety and replaced with the following new paragraph:

          "4.3.1. The Company hereby grants to Purchaser the
     option to purchase all of the Issued Stock if Net
     Income From Operations (as defined below) for the
     calendar year ended December 31, 1998 is less than
     Three Hundred Thousand Dollars ($300,000), then
     Purchaser shall have the option to purchase one share
     of the Issued Stock for each dollar by which Net Income
     From Operations for the calendar year ended December
     31, 1998 is less than Three Hundred Thousand Dollars
     ($300,000).  The purchase price pursuant to such option
     shall be $0.001 per share of the Issued Stock.  Such
     option shall be binding upon both Company and Drobny,
     and their successors and assigns.  Until the time for
     the exercise of such option has expired, neither
     Company nor Drobny may assign or transfer any rights or
     interests in or to the Issued Stock.  Purchaser may
     exercise such option by giving Drobny or the Company
     written notice on or before the date which is 12 months
     after the Closing Date. As an example of the number of
     shares of Issued Stock Purchaser is entitled to
     purchase pursuant to this paragraph, if Net Income From
     Operations for the year ended December 31, 1998 is
     $200,000, then Purchaser would be entitled to purchase,
     and the Company would be obligated to sell to
     Purchaser, 100,000 shares of the Issued Stock."


     4.  Additional Corrections. Paragraph 4.4 of the Agreement
is hereby deleted in its entirety and replaced with the following
new paragraph:

     
     "4.4. The purchase price for the Assets shall be
     allocated as set forth on Schedule 4.4 and all tax
     returns filed by the parties shall be consistent with
     such allocation.  Schedule 4.4 shall be subject to the
     review and approval of Purchaser's auditors within a
     reasonable time after the Closing.  The Company and
     Purchaser shall each prepare IRS Form 8594 in
     accordance with such allocation and consistent with one
     another and in accordance with applicable law and
     regulations.  Such Forms shall be delivered to one
     another for review prior to filing with the IRS."

Paragraph 5.25 of the Agreement is hereby deleted in its entirety
and replaced with the following new paragraph:

          "5.25 The Company (a) has a preexisting business
     relationship with Purchaser, or by reason of its
     business or financial experience, is capable of
     evaluating the risks and merits of an investment in the
     Issued Stock and of protecting its own interests in
     connection with the investment; (b) has received and
     reviewed all information it considers necessary or
     appropriate for deciding whether to accept the Issued
     Stock as a portion of the purchase price for the
     Assets; (c) has had an opportunity to ask questions and
     receive answers from the Purchaser and its officers,
     directors, and employees regarding the business,
     financial affairs, and other aspects of the Purchaser
     and has further had the opportunity to obtain all
     information which it deems necessary to evaluate the
     investment and to verify the accuracy of information
     otherwise provided it; and (d) is acquiring the Issued
     Stock for its own account and not with a view to their
     distribution within the meaning of Section 2(11) of the
     Securities Act."



5.  Amendment.
 The Agreement shall remain in full force and effect and, except
as expressly amended by this Amendment, unmodified.


6.  Waiver.
  Any party may waive compliance by another with any of the
provisions of this Amendment.  No waiver of any provisions shall
be construed as a waiver of any other provision.  Any waiver must
be in writing.
                                                                 

7.  Miscellaneous.
             The headings contained in this Amendment are for
reference purposes only and shall not affect in any way the
meaning or interpretation of this Amendment. This Amendment may
be executed in several counterparts, each of which shall be
deemed an original, and all of which shall constitute one and the
same instrument.  This Amendment shall be governed in all
respects, including validity, interpretation and effect, by the
laws of the State of California, applicable to contracts made and
to be performed in California.  This Amendment shall be binding
upon and inure to the benefit of the successors and assigns of
the parties hereto. The obligations of Drobny under this
Amendment shall be the joint and several obligations of CD and
PD.

                             BOATRACS, INC., a California
                             corporation
                             
                             
                             By: /s/ JON GILBERT
                                     Jon Gilbert, Chief
                                     Executive Officer and
                                     President
                             
                             MED ASSOCIATES, INC., a Mississippi
                             corporation
                             
                             
                             By: /s/ CHARLES J. DROBNY, JR.
                                     Charles J. Drobny, Jr.,
                                     Chief Executive Officer
                             
                            
                             /s/  CHARLES J. DROBNY, JR.
                             
                             /s/  PAMELA M. DROBNY