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                                                                    Exhibit 4.23

                               DMG LEGACY FUND LLC
                        DMG LEGACY INSTITUTIONAL FUND LLC
                          DMG LEGACY INTERNATIONAL LTD.
                              c/o DMG Advisors LLC
                        One Sound Shore Drive, Suite 202
                               Greenwich, CT 06830

                                 April 26, 2002

Speedcom Wireless Corporation
1748 Independence Boulevard, D-4
Sarasota, Florida 34243

     RE:  Letter Loan Agreement
          ---------------------

Ladies and Gentlemen:

     1.   Loan. This letter when fully executed will constitute a loan agreement
          ----
(the "Agreement") among DMG Legacy Fund LLC, DMG Legacy Institutional Fund LLC,
and DMG Legacy International Ltd. (collectively, the "Lenders"), and Speedcom
Wireless Corporation, a Delaware corporation ("Borrower"), pursuant to which
Lenders, on the terms and conditions provided herein, shall agree to make one or
more loans to or for the benefit of Borrower hereunder (each a "Loan" and
collectively, the "Loans"), provided the aggregate principal amount of all Loans
shall not exceed One Million Dollars ($1,000,000.00). The day on which Lenders
make a Loan is referred to herein as a "Closing Date." The initial Closing Date
shall be the date hereof and the initial Loan shall be for the principal amount
of $750,000.00. The second Closing Date shall be within five (5) days of the
date hereof and the second Loan shall be for the principal amount of
$250,000.00. Each Lender's obligation to make a Loan is subject to the
Borrower's fulfillment of each of the applicable conditions set forth in Section
4 hereof.

     2.   Loan Documents.
          --------------

          a.   Notes. The Loans shall be evidenced by separate promissory notes
               -----
issued to the Lenders in the principal amount of each such Loan in the form
attached hereto as Exhibit A (together with any replacements and substitutes
                   ---------
therefor, the "Notes"). The principal amount of the Loans and interest thereon,
calculated at the rate of 15% per annum as provided in the Notes, shall be
payable as set forth more particularly therein.

          b.   Security Agreement. The Loans shall be secured by a continuing
               ------------------
security interest in all of the property and assets of the Borrower pursuant to
the terms of a security agreement in the form attached hereto as Exhibit B (the
                                                                 ---------
"Security Agreement").

          c.   Letter Agreement. So long as the Loans are outstanding, Michael
               ----------------
McKinney shall not sell or transfer any of the shares of common stock of the
Borrower

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beneficially owned or held of record by him, including, without limitation, any
shares under his control, pursuant to the terms of a letter agreement by and
among Michael McKinney and the Lenders in the form attached hereto as Exhibit C
                                                                      ---------
(the "Letter Agreement").

          d. Agreement to Vote Shares. Michael McKinney shall vote all of the
             ------------------------
shares of common stock of the Borrower beneficially owned or held of record by
him, including, without limitation, any shares under his control, for any Change
in Control Transaction (as defined below) which has been approved by the
Borrower's Board of Directors, pursuant to the terms of an Agreement to Vote
Shares in the form attached hereto as Exhibit D (the "Agreement to Vote
                                      ---------
Shares").

          e. This Agreement, the Notes, the Security Agreement, the Letter
Agreement, the Agreement to Vote Shares and each other document which evidences
and/or secures the Loans are hereinafter collectively referred to as the "Loan
Documents."

     3.   Term and Termination. Subject to Section 7 hereof, the aggregate
          --------------------
principal amount of the outstanding Note and all accrued and unpaid interest
thereon and other sums owing hereunder and thereunder shall be due and payable
on the earliest (the "Maturity Date") of: (i) ninety (90) days following the
                      -------------
execution of a definitive agreement with respect to a bona fide merger, stock
sale or sale of all or substantially all of the Borrower's assets with an
acquiror acceptable to the Lenders which would result in a change in control of
the Borrower (a "Change in Control Transaction"); (ii) July 31, 2002, if a
                 -----------------------------
Change in Control Transaction has not occurred; or (iii) the acceleration of the
obligations as contemplated by this Agreement. The Maturity Date may be extended
as agreed upon in writing between the parties.

     4.   Conditions Precedent.
          --------------------

          a. Documents to be Delivered. The obligation of each Lender to make
             -------------------------
any Loan is subject to the due execution and delivery by Borrower (or Borrower
causing the due execution and delivery) to each Lender of each of the following
(all documents to be in form and substance satisfactory to each Lender and their
counsel):

             i.   This Agreement, the Notes, the Security Agreement, the Letter
Agreement, the Agreement to Vote Shares and each other instrument, agreement and
document to be executed and/or delivered pursuant to this Agreement and/or the
instruments, agreements and documents referred to in this Agreement.

             ii.  A certified copy of the resolutions of the Board of Directors
(or if the Board of Directors takes action by unanimous written consent, a copy
of such unanimous written consent containing all of the signatures of the
members of the Board of Directors) of the Borrower, dated as of the initial
Closing Date, authorizing the execution, delivery and performance of the Loan
Documents.

             iii. A certificate, dated as of the applicable Closing Date, signed
by an executive officer of the Borrower to the effect that: (i) the
representations and warranties set forth in Section 5 of this Agreement are true
and correct as of the applicable Closing Date, (ii) it is the intention of the
Borrower to comply with the covenants set forth in Section 6 of this Agreement
and the Borrower has no reason to believe that it will not be able to comply
with the covenants.

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             iv. The Borrower shall have filed all UCC financing statements in
form and substance satisfactory to the Lenders at the appropriate offices to
create a valid and perfected security interest in the Collateral (as defined in
the Security Agreement).

             v.  As a condition to the second Closing, the Employment Agreement
Amendments (as defined in Section 6(a) hereof) shall have been executed and
delivered to the Lenders.

          b. Absence of Certain Events. The following events shall not have
             -------------------------
occurred or be occurring as of any Closing Date: (i) the occurrence of a
Material Adverse Effect (as defined below), or (ii) the inability to comply with
the covenants.

    5.    Representations and Warranties.  To induce each Lender, severally and
          ------------------------------
not jointly, to make the Loan, Borrower hereby represents and warrants to each
Lender that at and as of the date hereof:

          a. The Borrower has been duly incorporated and is validly existing and
in good standing under the laws of the state of Delaware, with full corporate
power and authority to own, lease and operate its properties and to conduct its
business as currently conducted. The Borrower is duly qualified as a foreign
entity to do business and is in good standing in every jurisdiction in which its
ownership of property or the nature of the business conducted by it makes such
qualification necessary and where the failure so to qualify would have a
Material Adverse Effect. "Material Adverse Effect" means any material adverse
effect on the ability of the Borrower to perform its obligations hereunder or on
the business, operations, properties, prospects or financial condition of the
Borrower.

          b. Each of the Loan Documents has been duly authorized, validly
executed and delivered on behalf of the Borrower and is a valid and binding
obligation of the Borrower enforceable against the Borrower in accordance with
its terms, subject to limitations on enforcement by general principles of equity
and by bankruptcy or other laws affecting the enforcement of creditors' rights
generally, and the Borrower has full power and authority to execute and deliver
this Agreement and the Loan Documents and to perform its obligations hereunder
and thereunder.

          c. The execution, delivery and performance of this Agreement and the
Loan Documents will not (i) conflict with or result in a breach of or a default
under any of the terms or provisions of, (A) the Borrower's certificate of
incorporation or by-laws, or (B) any material provision of any indenture,
mortgage, deed of trust or other material agreement or instrument to which the
Borrower is a party or by which it or any of its material properties or assets
is bound, (ii) result in a violation of any material provision of any law,
statute, rule, regulation, or any existing applicable decree, judgment or order
by any court, Federal or state regulatory body, administrative agency, or other
governmental body having jurisdiction over the Borrower, or any of its material
properties or assets or (iii) result in the creation or imposition of any
material lien, charge or encumbrance upon any material property or assets of the
Borrower or any of its subsidiaries pursuant to the terms of any agreement or
instrument to which any of them is a party or by which any of them may be bound
or to which any of their property or any of them is subject.

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          d. No consent, approval or authorization of or designation,
declaration or filing with any governmental authority on the part of the
Borrower is required in connection with the valid execution and delivery of this
Agreement or the Loan Documents.

All representations and warranties made by Borrower under or in connection with
this Agreement shall survive the making of the Loans and issuance and delivery
of the Note to Lenders, notwithstanding any investigation made by Lenders or on
Lenders' behalf. All statements contained in any certificate or financial
statement delivered by Borrower to Lenders under this Agreement or any other
Loan Document shall constitute representations and warranties made by Borrower
hereunder.

     6.   Affirmative Covenants.  To induce each Lender, severally and not
          ---------------------
jointly, to make the Loan, Borrower hereby covenants to each Lender as follows:

          a. On or before the second Closing, the employees of the Borrower
listed on Schedule 6(a) hereto shall enter into and execute amendments to their
          -------------
respective employment agreements which shall state that such employees shall
remain employed by the Borrower through any transition period until at least
December 31, 2002 regardless of the parties involved in the Change in Control
Transaction (the "Employment Agreement Amendments"). The Employment Agreement
                  -------------------------------
Amendments shall be in a form satisfactory to the Lenders. The employees listed
on Schedule 6(a) hereto shall use their best efforts to assist in the transition
   -------------
of operations of the Borrower and to provide the time and service necessary for
the integration of the business and operations of the Borrower into the newly
formed or combined entity.

          b. Michael McKinney shall vote all of the shares of common stock of
the Borrower beneficially owned or held of record by him, including, without
limitation, any shares under his control, which shares are listed on Schedule
                                                                     --------
6(b) hereto, for any Change in Control Transaction which has been approved by
----
the Borrower's Board of Directors. Furthermore, Michael McKinney shall use his
best efforts to cause his former spouse to vote her shares for such Change in
Control Transaction.

          c. Borrower shall apply $40,400.00 of the proceeds resulting from the
issuance of the Note on the second Closing Date for payment to IW Miller and
travel expenses to further develop the Borrower's potential transactions with
Waverider Communications Inc., Malibu Networks and any other transaction that
Lenders may approve. Such $40,400.00 includes $20,000.00 to be paid by the
Lenders to Michael Sternberg for consulting services rendered to the Borrower
for April 2002 in payment of any fees currently invoiced to the Borrower by
Michael Sternberg. The balance of the proceeds received by the Borrower shall be
used for general corporate purposes as set forth in the spreadsheets attached
hereto as Exhibit E. All applications of proceeds pursuant to this Section 6(c)
          ---------
shall be approved by the Borrower's Board of Directors.

          d. The term of all outstanding Series B Warrants of the Borrower dated
August 23, 2001 shall be extended until the Maturity Date.

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     7.   Events of Default; Remedies. Upon the occurrence of any of the
          ---------------------------
following (each, an "Event of Default"):

          a. the Borrower shall fail to make the payment of any amount of any
principal outstanding after the date such payment shall become due and payable
hereunder; or

          b. the Borrower shall fail to make any payment of interest after the
date such interest shall become due and payable hereunder; or

          c. any representation, warranty, covenant or certification made by the
Borrower herein, in the Notes, any other Loan Document or in any certificate or
financial statement shall prove to have been false or incorrect or breached in a
material respect on the date as of which made; or

          d. the Borrower or any of its subsidiaries shall (i) default in any
payment of any amount or amounts of principal of or interest on any indebtedness
for borrowed money (the "Indebtedness") (other than the Indebtedness hereunder)
                         ------------
the aggregate principal amount of which Indebtedness of all such persons is in
excess of $100,000, whether such Indebtedness now exists or shall hereinafter be
created, and such default entitles the holder thereof to declare such
indebtedness to be due and payable, and such indebtedness has not been
discharged in full or such acceleration has not been stayed, rescinded or
annulled within twelve (12) business days of such acceleration, or (ii) default
in the observance or performance of any other agreement or condition relating to
any Indebtedness in excess of $100,000 or contained in any instrument or
agreement evidencing, securing or relating thereto, or any other event shall
occur or condition exist, the effect of which default or other event or
condition is to cause, or to permit the holder or holders or beneficiary or
beneficiaries of such Indebtedness to cause with the giving of notice if
required, such Indebtedness to become due prior to its stated maturity; or

          e. A judgment or order for the payment of money shall be rendered
against the Borrower or any subsidiary in excess of $100,000 in the aggregate
(net of any applicable insurance coverage) for all such judgments or orders
against all such persons (treating any deductibles, self insurance or retention
as not so covered) that shall not be discharged, and all such judgments and
orders remain outstanding, and there shall be any period of thirty (30)
consecutive days following entry of the judgment or order in excess of $100,000
or the judgment or order which causes the aggregate amount described above to
exceed $100,000 during which a stay of enforcement of such judgment or order, by
reason of a pending appeal or otherwise, shall not be in effect; or

          f. the Borrower shall (i) apply for or consent to the appointment of,
or the taking of possession by, a receiver, custodian, trustee or liquidator of
itself or of all or a substantial part of its property or assets, (ii) admit in
writing its inability to pay its debts as such debts become due, (iii) make a
general assignment for the benefit of its creditors, (iv) commence a voluntary
case under the Bankruptcy Code or under the comparable laws of any jurisdiction
(foreign or domestic), (v) file a petition seeking to take advantage of any
bankruptcy, insolvency, moratorium, reorganization or other similar law
affecting the enforcement of creditors' rights generally, (vi) acquiesce in
writing to any petition filed against it in an involuntary case under the
Bankruptcy Code or under the comparable laws of any jurisdiction (foreign or
domestic), or (vii) take any action under the laws of any jurisdiction (foreign
or domestic) analogous to any of the foregoing; or

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           g. a proceeding or case shall be commenced in respect of the Borrower
or any of it's subsidiaries without its application or consent, in any court of
competent jurisdiction, seeking (i) the liquidation, reorganization, moratorium,
dissolution, winding up, or composition or readjustment of its debts, (ii) the
appointment of a trustee, receiver, custodian, liquidator or the like of it or
of all or any substantial part of its assets or (iii) similar relief in respect
of it under any law providing for the relief of debtors, and such proceeding or
case described in clause (i), (ii) or (iii) shall continue undismissed, or
unstayed and in effect, for a period of thirty (30) consecutive days or any
order for relief shall be entered in an involuntary case under the Bankruptcy
Code or under the comparable laws of any jurisdiction (foreign or domestic)
against the Borrower or any of its subsidiaries or action under the laws of any
jurisdiction (foreign or domestic) analogous to any of the foregoing shall be
taken with respect to the Borrower or any of its subsidiaries and shall continue
undismissed, or unstayed and in effect for a period of thirty (30) consecutive
days; or

           h. The occurrence of any event which has a Material Adverse Effect.

         THEN, Lenders may, at their election and without demand or notice of
any kind, which are hereby waived, declare the unpaid balance of the Notes, and
accrued interest thereon, immediately due and payable, proceed to collect the
same, and exercise any and all other rights, powers and remedies given it by
this Agreement, the Notes and the other Loan Documents or otherwise at law or in
equity.

     8.    Miscellaneous.
           -------------

           a. The representations and warranties of Borrower contained herein
shall survive the making of the Loans and shall remain effective until all
indebtedness contemplated hereby shall have been paid by Borrower in full.

           b. This Agreement shall be governed by and construed in accordance
with the laws of the State of New York without giving effect to the choice of
law provisions. This Agreement shall not be interpreted or construed with any
presumption against the party causing this Agreement to be drafted.

           c. Each of the Borrower and each Lender (i) hereby irrevocably
submits to the jurisdiction of the United States District Court sitting in the
Southern District of New York and the courts of the State of New York located in
New York county for the purposes of any suit, action or proceeding arising out
of or relating to this Agreement or the Loan Documents and (ii) hereby waives,
and agrees not to assert in any such suit, action or proceeding, any claim that
it is not personally subject to the jurisdiction of such court, that the suit,
action or proceeding is brought in an inconvenient forum or that the venue of
the suit, action or proceeding is improper. Each of the Borrower and each Lender
consents to process being served in any such suit, action or proceeding by
mailing a copy thereof to such party at the address set forth in Section 8(j)
below and agrees that such service shall constitute good and sufficient service
of process and notice thereof. Nothing in this Section 8(c) shall affect or
limit any right to serve process in any other manner permitted by law.

           d. Any forbearance, failure, or delay by a Lender in exercising any
right, power, or remedy shall not preclude the further exercise thereof, and all
of such Lender's rights,

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powers, and remedies shall continue in full force and effect until specifically
waived in writing by such Lender.

           e. This Agreement may be executed in two or more counterparts, all of
which shall be considered one and the same agreement and shall become effective
when counterparts have been signed by each party and delivered to the other
party.

           f. The headings of this Agreement are for convenience of reference
and shall not form part of, or affect the interpretation of, this Agreement.

           g. If any provision of this Agreement shall be invalid or
unenforceable in any jurisdiction, such invalidity or unenforceability shall not
affect the validity or enforceability of the remainder of this Agreement or the
validity or enforceability of this Agreement in any other jurisdiction.

           h. Borrower shall reimburse Lenders, on demand, for all reasonable
fees and costs incurred by Lenders (including reasonable fees and costs of
Lenders' counsel) in connection with the enforcement of Lenders' rights and
remedies thereunder.

           i. This Agreement and the instruments referenced herein contain the
entire understanding of the parties with respect to the matters covered herein
and therein. No provision of this Agreement may be waived or amended other than
by an instrument in writing signed by the party to be charged with enforcement.

           j. Any notices, demands or waivers required or permitted to be given
under the terms of this Agreement shall be in writing and shall be sent by
certified or registered mail (return receipt requested) or delivered personally
or by courier (including a recognized overnight delivery service) or by
facsimile and shall be effective five (5) days after being placed in the mail,
if mailed, or upon receipt, if delivered personally or by courier, or by
facsimile (if received during normal business hours), in each case to the
address of the party to receive such notice, demand or waiver as set forth
below:

              If to Borrower:

                     Speedcom Wireless Corporation
                     7020 Professional Parkway East
                     Sarasota, Florida 34240
                     Attention:  Sara Byrne, Secretary
                     Fax No.: (941) 907-2394

              If to any of the Lenders:

                     c/o DMG Advisors LLC
                     One Sound Shore Drive
                     Suite 202
                     Greenwich, CT 06830
                     Attention: Andrew Wilder
                     Fax No.: (203) 629-0345

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                         with a copy to:

                            Jenkens & Gilchrist Parker Chapin LLP
                            The Chrysler Building
                            405 Lexington Avenue
                            New York, New York 10174
                            Attention:  Christopher S. Auguste
                            Tel. No.: (212) 704-6000
                            Fax No.:  (212) 704-6288

     Each party shall provide notice to the other party of any change in
address, such notice to become effective upon receipt.

           k. This Agreement shall be binding upon and inure to the benefit of
the parties and their successors and assigns. Borrower shall not assign this
Agreement or any rights or obligations hereunder without the prior written
consent of Lenders. Notwithstanding the foregoing, each Lender may assign its
rights hereunder to any other person or entity without the consent of Borrower.

           l. This Agreement is intended for the benefit of the parties hereto
and their respective permitted successors and assigns, and is not for the
benefit of, nor may any provision hereof be enforced by, any other person.

           m. All remedies of Lenders (i) are cumulative and concurrent, (ii)
may be exercised independently, successively or together against Borrower, (iii)
shall not be exhausted by any exercise thereof, but may be exercised as often as
occasion therefor may occur, and (iv) shall not be construed to be waived or
released by Lenders' delay in exercising, or failure to exercise, them or any of
them at any time it may be entitled to do so.

                            [Signature Page Follows]

                                        8

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         By executing the appropriate signature line below, Borrower, intending
to be legally bound hereby, agrees to the terms and conditions of this Agreement
as of the date appearing opposite Borrower's signature.

                               Very truly yours,

                               DMG LEGACY FUND LLC


                               By: ______________________________________
                                     Name:
                                     Title:


                               DMG LEGACY INSTITUTIONAL FUND LLC


                               By: _____________________________________
                                     Name:
                                     Title:


                               DMG LEGACY INTERNATIONAL LTD.


                               By: _____________________________________
                                     Name:
                                     Title:



SPEEDCOM WIRELESS CORPORATION


By: ________________________________________
         Name: Michael McKinney
         Title:   Chief Executive Officer

                                       9

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                                    Exhibit A
                                    ---------
                                  Form of Note

                                       10

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                                    Exhibit B
                                    ---------
                           Form of Security Agreement

                                       11

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                                    Exhibit C
                                    ---------
                            Form of Letter Agreement

                                       12

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                                    Exhibit D
                                    ---------
                        Form of Agreement to Vote Shares

                                       13

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                                    Exhibit E
                                    ---------
                          Use of Proceeds Spreadsheets

                                       14

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                                  Schedule 6(a)
                                  -------------

         William R. Davis
         Patrick Pacifico
         Michael McKinney
         Philip Decker
         Sara Byrne

                                       15

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                                  Schedule 6(b)
                                  -------------

Shares directly owned by Michael McKinney: 1,849,995

Shares owned by Michael McKinney as custodian for Molly Michel McKinney: 321,780

Shares owned by Michael McKinney as custodian for Ryan Lewis McKinney: 321,780

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