SC 13D/A

              SECURITIES AND EXCHANGE COMMISSION
                    Washington, D.C. 20549





                         Schedule 13D
           Under the Securities Exchange Act of 1934
                       (Amendment No. 4)

                        Metricom, Inc.
                       (Name of Issuer)

                         Common Stock
                (Title of Class of Securities)

                          591596-10-1
                        (CUSIP Number)

                      Brian L. Blomquist
                7711 Carondelet Ave., Suite 700
                      St. Louis, MO 63105
                         (314) 727-5305
         (Name, Address and Telephone Number of Person
       Authorized to Receive Notices and Communications)

                       October 12, 1997
             (Date of Event which Requires Filing
                      of this Statement)


If the filing person has previously filed a statement on
Schedule 13G to report the acquisition which is the subject
of this Schedule 13D, and is filing this schedule because of
Rule 13d-1(b)(3) or (4), check the following box  [ ]


 2
       This Amendment No. 4 to Schedule 13D is being filed by
Ryback Management Corporation, a Michigan corporation
("Ryback") in order to amend Item 6 in its entirety.  Item 6
is hereby amended to read as follows:

Item 6.  Contracts, Arrangement, Understandings or
Relationships with Respect to Securities of the Issuer.

       On October 10, 1997, the Trust and Vulcan Ventures,
Inc. ("Vulcan"), agreed to terminate the Stock Purchase
Agreement, dated as of September 25, 1997, relating to the
purchase by Vulcan from the Trust of 2,583,500 shares of
common stock of Metricom.  Effective on October 12, 1997, the
Trust entered into a new Stock Purchase Agreement (the
"Agreement") with Vulcan, pursuant to which the Trust has
agreed to sell, and Vulcan agreed to buy, all of the
2,583,500 shares of Common Stock of Metricom owned by the
Trust.  Completion of the sale is subject to expiration of
the waiting period under the Hart-Scott-Rodino Antitrust
Improvements Act of 1976, as amended.  The Board of Directors
of Metricom has approved the purchase by Vulcan in order to
exempt such purchase from the provisions of Section 203 of
the Delaware General Corporation Law.  The Agreement may be
terminated by the Trust if the sale does not occur by
December 31, 1997, and the Trust may also terminate the
Agreement two business days after giving notice of
termination to Vulcan, any time after the commencement of a
tender offer for all of the outstanding Common Stock of
Metricom by any Person that is not an Affiliate of Vulcan,
unless within such two business day time period Vulcan agrees
in writing to pay the Trust for the Shares the same amount
offered per share in such tender offer.  A copy of the
Agreement is attached as Exhibit 6.2 hereto.

Item 7.  Material Required to be Filed as Exhibits.

Exhibit No.  Description
- -----------  ------------
   6.2       Stock Purchase Agreement, dated as of October
             13, 1997, between Lindner Investments, on behalf
             of Lindner Dividend Fund, Lindner Growth Fund
             and Lindner Bulwark Fund and Vulcan Ventures,
             Inc., a Washington corporation.

                           SIGNATURE

       After reasonable inquiry and to the best of my
knowledge and belief, I certify that the information set
forth in this statement is true, complete and correct.

                           RYBACK MANAGEMENT CORPORATION

Date: October 17, 1997     By: /S/ LAWRENCE G. CALLAHAN
                              Lawrence G. Callahan
                              Vice President

EX-6.2

 1
                STOCK PURCHASE AGREEMENT

        This Stock Purchase Agreement (this "Agreement") is
made as of the 12th day of October, 1997 by and between
Vulcan Ventures, Inc., a Washington corporation ("Buyer"),
and Lindner Investments, a Massachusetts business trust, on
behalf of Lindner Dividend Fund, Lindner Growth Fund and
Lindner Bulwark Fund ("Seller").

        WHEREAS, Seller is the record and beneficial owner of
2,583,500 shares (the "Shares") of the common stock of
Metricom, Inc., a Delaware company ("Metricom");

        WHEREAS, Seller desires to sell the Shares to Buyer,
and Buyer desires to purchase the Shares from Seller, upon
the terms and subject to the conditions hereinafter set
forth; and

        WHEREAS, the Board of Directors of Metricom has
approved the purchase of the Shares by Buyer for purposes of
Section 203 of the Delaware General Corporation Law.

        NOW THEREFORE, in consideration of the foregoing
premises, and for other good and valuable consideration the
receipt and sufficiency of which are hereby acknowledged,
Buyer and Seller hereby agree as follows:

1.     PURCHASE AND SALE

       1.1 Purchase and Sale. Upon the terms and subject to
the conditions of this Agreement, Seller agrees to sell to
Buyer, and Buyer agrees to purchase from Seller, the Shares
at the Closing. The purchase price for the Shares (the
"Purchase Price") is $18,084,500, the aggregate of seven (7)
dollars per share, in cash. The Purchase Price shall be paid
as provided in Section 1.2. 

       1.2 Closing. The closing (the "Closing") of the
purchase and sale of the Shares hereunder shall take place at
the offices of Irell & Manella LLP, 1800 Avenue of the Stars,
Los Angeles, CA, 90067, as soon as possible, but in no event
later than five (5) business days, after satisfaction of the
conditions set forth in Section 3, or at such other time or
place as Buyer and Seller may agree. At the Closing:

       (a) Buyer shall deliver to Seller $18,084,500 in 
immediately available funds by wire transfer to an account 
of Seller with a bank designated by Seller, by notice to 
Buyer, not later than two (2) business days prior to the 
Closing; and

       (b) Seller shall deliver to Buyer evidence
satisfactory to Buyer of the transfer of the Shares to Buyer
or its designee by a book entry at the Deposit Trust Company.


2.     REPRESENTATIONS AND WARRANTIES

       2.1 Representations and Warranties of Seller. Seller
represents and warrants to Buyer that as of the date hereof
and as of the Closing: 

       (a) Existence and Power. Seller is a business trust
duly incorporated and validly existing under the laws of the
Commonwealth of Massachusetts and has all powers and all
governmental licenses, authorizations, permits, consents and
approvals required to carry on its business as now conducted.

       (b) Authorization. The execution, delivery and
performance by Seller of this Agreement and the consummation
of the transactions contemplated hereby are within Seller's
powers and have been duly authorized by all necessary action
on the part of Seller. This Agreement constitutes a valid and
binding agreement of Seller, enforceable in accordance with
its terms. 

       (c) Ownership of Shares. Seller is the record and
beneficial owner of the Shares, free and clear of all liens
and encumbrances and any other limitation or restriction
(including any restriction on the right to vote, sell or
otherwise dispose of the Shares), and will transfer and
deliver to Buyer at the Closing valid title to the Shares
free and clear of any lien, encumbrance or any such
limitation or restriction.

       2.2 Representations and Warranties of Buyer. Buyer
represents and warrants to Seller, as of the Closing, as
follows:

       (a) Corporate Authorization. The execution, delivery
and performance by Buyer of this Agreement and the
consummation of the transactions contemplated hereby are
within Buyer's corporate powers and have been duly authorized
by all necessary corporate action on the part of Buyer. This
Agreement constitutes a valid and binding agreement of Buyer,
enforceable in accordance with its terms.

3.     CONDITIONS PRECEDENT

       3.1 Conditions to Obligation of Buyer. The obligation
of Buyer to Purchase the Shares is subject to the
satisfaction (or waiver by Buyer) of the conditions set forth
below:

       (a) The representations and warranties made by Seller
in this Agreement shall be true and correct in all material
respects on and as of the date hereof and as of the Closing
with the same effect as if made on and as of the Closing.
Seller shall have performed and complied With all agreements,
covenants and conditions on his part required to be performed
or complied  with on or prior to the Closing in all material
respects.

       (b) Any applicable waiting period under the Hart-
Scott-Rodino Antitrust Improvements Act of 1976, as amended
(the "HSR Act") relating to the transactions contemplated
hereby shall have expired or been terminated. 

       3.2 Conditions to Obligation of Seller. The obligation
of Seller to sell to Buyer the Shares shall be subject to the
satisfaction (or waiver by Seller) of the conditions set
forth below:

       (a) The representations and warranties made by Buyer
in this Agreement shall be true and correct in all material
respects on and as of the Closing with the same effect as if
made on and as of the Closing. Buyer shall have performed and
complied with all agreements, covenants and conditions on the
part of such entity required to be performed or complied with
on or prior to the Closing in all material respects.

       (b) Any applicable waiting period under the HSR Act
relating to the transactions contemplated hereby shall have
expired or been terminated.

4. ADDITIONAL COVENANTS AND AGREEMENTS OF THE PARTIES. 

       4.1 Approvals. Buyer and Seller agree to use their
best efforts and to cooperate with each other to obtain the
approvals necessary to effect the transactions hereunder.

       4.2 Transfer Taxes. The parties acknowledge and agree
that all transfer, stamp, recording and similar taxes
assessed or otherwise payable by reason of the conveyance
contemplated hereby shall be for the account of and paid by
Seller.

       4.3 Additional Deliveries; Further Assurances. After
the Closing, each party to this Agreement shall, at the
request of the other, furnish, execute, and deliver such
documents, instruments, certificates, notices or other
further assurances as the requesting party shall reasonably
request as necessary or desirable to effect complete
consummation of this Agreement and the transactions
contemplated hereby.

5. TERMINATION.

       If, on or prior to December 31, 1997 (a) the Closing
has not occurred (or been extended in writing by mutual
consent of Buyer and Seller), or (b) the conditions contained
in Section 3 of this Agreement have not been satisfied or
waived, then this Agreement shall, on such date,
automatically and without further action by either party,
terminate and have no further force and effect. In addition,
if any representation or warranty made by any party herein
shall prove to have been false, inaccurate or misleading in
any material respect when made, then the party to whom such
representation or warranty is made may terminate this
Agreement by notice to the breaching party any time prior to
the Closing. Further, the Seller may terminate this
Agreement, prior to the closing, two (2) Business Days after
the giving of notice to Buyer, any time after the
commencement of a tender offer ("Tender Offer") for all of
the outstanding shares of common stock of Metricom by any
Person (as defined in the Securities Exchange Act of 1934, as
amended) that is not an Affiliate (as defined in the
Securities Act of 1933, as amended, and the rules promulgated
thereunder) of the Buyer prior to the waiting period under
the HSR Act unless within such two Business Day time period
Buyer agrees in writing to pay Seller for the Shares the same
amount offered per share in the Tender Offer.

6.     MISCELLANEOUS.

       6.1 Changes, Waivers, etc. Neither this Agreement nor
any provision hereof may be changed, waived, discharged or
terminated except in writing (including facsimile
communication).

       6.2 Payment of Fees and Expenses. Each of the parties
hereto shall pay its own respective fees and expenses
incurred in connection herewith. 

       6.3 Notices. All notices, requests, consents and other
communications required or permitted hereunder shall be in
writing and shall be delivered, or mailed first-class postage
prepaid, registered or certified mail, or delivered via
overnight courier;

       If to Buyer: Vulcan Ventures, Inc. 
                    110 110th Avenue NE
                    Suite 550
                    Bellevue, WA 98004
                    Facsimile: (425) 453-1985 
                    Attention: William Savoy, President 
       with copy to: Irell & Manella LLP
                     1800 Avenue of the Stars 
                     Suite 900
                     Los Angeles, CA 90067 
                     Facsimile: (310) 203-7199 
                     Attention: Al Segel

       If to Seller: Lindner Investments
                     7711 Carondelet Avenue 
                     P.O. Box 16900
                     St. Louis, MO  63105
                     Facsimile: (314) 727-3877 
                     Attention: Larry Callahan 
       with a copy to: Dykema Gossett PLLC 
                       400 Renaissance Center 
                       Detroit, MI  48243 
                       Facsimile: (313) 568-6915 
                       Attention: Paul Rentenbach 

Such notices and other communications shall for all purposes
of this Agreement be treated as being effective or having
been given on the date of delivery, if delivered personally,
one (1) day following the date of delivery, if delivered by
overnight courier or facsimile transmission or, if sent by
mail, five (5) days thereafter.

       6.4 Entire Agreement. This Agreement, including the
exhibits which are incorporated into and made an integral
part of this Agreement by reference, set forth the entire
understanding of the parties and supersede all prior
agreements of the parties with respect to the subject matter
hereof. 

       6.5 Survival of Representations and Warranties, etc.
All representations and warranties contained herein shall
survive the execution and delivery of this Agreement.

       6.6 Counterparts. This Agreement may be executed in
any number of counterparts (including facsimile
transmissions) and by the parties hereto in separate
counterparts, each of which when so executed shall be deemed
to be an original and all of which taken together shall
constitute one and the same agreement. A faxed signature
shall have the same validity as an original signature.

[Signature page follows]



       IN WITNESS WHEREOF, the undersigned have caused this
Agreement to be duly executed and delivered as of the date
and year first above written. 

VULCAN VENTURES, INC.

By: William Savoy
    -----------------
Title: Vice President


LINDNER INVESTMENTS

By: Larry Callahan
    -----------------
Title: Vice President

                                       S-1