EXHIBIT 10.43

      THIS MORTGAGE, made this 16th day of April 2001, Between LINDA J.
ISAACSON, with a notification address at 38 Jordan Road, Brookline,
Massachusetts (the "Mortgagor"), and AMBIENT CORPORATION, a Delaware Corporation
with a principal place of business located at 1033 Beacon Street, Brookline, MA
02446-5654 (the "Mortgagee").

                               W I T N E S S E T H

            That to secure the payment of an indebtedness in the sum of One
Million Nine Hundred and Ninety Dollars ($1,990,000) Dollars lawful money of the
United States, without any interest thereon, which sum the Mortgagor hereby
promises to pay in one installment of $1,990,000 Dollars, such payment to be
made on the date which is ten (10) years from the date first set forth above
according to a certain bond, note or obligation bearing even date herewith (the
"Note") the Mortgagor hereby Mortgages to the Mortgagee and with MORTGAGE
COVENANTS, the following described premises:

            See Schedule "A" annexed hereto and made a part hereof.

            TOGETHER with all rights, title and interest of the Mortgagor in and
to the land lying in the streets and roads in front of and adjoining said
premises;

            TOGETHER with all fixtures, chattels and articles of personal
property now or hereafter attached to or used in connection with said premises,
including but not limited to furnaces, boilers, oil burners, radiators and
piping, coal stokers, plumbing and bathroom fixtures, refrigeration, air
conditioning and sprinkler systems, wash-tubs, sinks, gas and electric fixtures,
stoves, ranges, awnings, screens, window shades, elevators, motors, dynamos,
refrigerators, kitchen cabinets, incinerators, plants and shrubbery and all
other equipment and machinery, appliances, fittings, and fixtures of every kind
in or used in the operation of the buildings standing on said premises, together
with any and all replacements thereof and additions thereto;

            TOGETHER with all awards heretofore and hereafter made to the
Mortgagor for taking by eminent domain the whole or any part of said premises or
any easement therein, including any awards for changes of grade of streets,
which said awards are hereby assigned to the Mortgagee, who is hereby authorized
to collect and receive the proceeds of such awards and to give proper receipts
and acquittance therefor, and to apply the same toward the payment of the
Mortgage debt, notwithstanding the fact that the amount owing thereon may not
then be due and payable under the Note; and the said Mortgagor hereby agrees,
upon request, to make, execute and deliver any and all assignments and other
instruments sufficient for the purpose of assigning said awards to the
Mortgagee, free, clear and discharged of any encumbrances of any kind or nature
whatsoever.

            AND the Mortgagor covenants with the Mortgagee as follows:


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            1. That the Mortgagor will pay the indebtedness as hereinbefore
provided. Notwithstanding the foregoing, it is specifically understood and
agreed that the obligations of Linda J. Isaacson hereunder shall be limited to
the extent of her interest in the premises. Nothing herein shall be construed as
applying to any party other than Linda J. Isaacson.

            2. That the Mortgagor will keep the buildings on the premises
insured against loss by fire for the benefit of the Mortgagee; that he will
assign and deliver the policies to the Mortgagee; and that Mortgagor will
reimburse the Mortgagee for any premiums paid for insurance made by the
Mortgagee on the Mortgagor's default in so insuring the buildings or in so
assigning and delivering the policies.

            3. That no building on the premises shall be altered, removed or
demolished without the consent of the Mortgagee.

            4. That the whole of said principal sum and any interest shall
become due at the option of the Mortgagee; after default in the payment of any
installment of principal or of interest for ten (10) days; or after default in
the payment of any tax, water rate, sewer rent or assessment for thirty days
after notice and demand; or after default after notice and demand either in
assigning and delivering the policies insuring the buildings against loss by
fire or in reimbursing the Mortgagee for premiums paid on such insurance, as
hereinbefore provided; or after default upon request in furnishing a statement
of the amount due on the Mortgage and whether any offsets or defenses exist
against the Mortgage debt, as hereinafter provided. An assessment which has been
made payable in installments at the application of the Mortgagor or lessee of
the premises shall nevertheless, for the purpose of this paragraph, be deemed
due and payable in its entirety on the day the first installment becomes due or
payable or a lien.

            5. That the holder of this Mortgage, in any action to foreclose it,
shall be entitled to the appointment of a receiver.

            6. That the Mortgagor will pay all taxes, assessments, sewer rents
or water rates, and in default thereof, the Mortgagee may pay the same.

            7. That the Mortgagor within five (5) days upon request in person or
within ten (10) days upon request by mail will furnish a written statement duly
acknowledged of the amount due on this Mortgage and whether any offsets or
defenses exist against the Mortgage debt.

            8. That notice and demand or request may be in writing and may be
served in person or by certified mail, return receipt requested.

            9. That the Mortgagor warrants the title to the premises.

            10. That the fire insurance policies required by Paragraph 2 above
shall contain the usual extended coverage endorsement; that in addition thereto
the Mortgagor, within thirty (30) days after notice and demand, will keep the
premises insured against all risk and any other hazard that may reasonably be
required by the Mortgagee. All of the provisions of Paragraphs 2 and 4 above
relating to fire insurance and the provisions of Section 254 of the Real
Property Law construing the same shall apply to the additional insurance
required by this paragraph.


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            11. That in case of a foreclosure sale, said premises, or so much
thereof as may be affected by this Mortgage, may be sold in one parcel.

            12. That if any action or proceeding be commenced (except an action
to foreclose this Mortgage or to collect the debt secured thereby), to which
action or proceeding the Mortgagee is made a party, or in which it becomes
necessary to defend or uphold the lien of this Mortgage, all sums paid by the
Mortgagee for the expense of any litigation to prosecute or defend the rights
and lien created by this mortgage (including reasonable counsel fees), shall be
paid by the Mortgagor, together with interest thereon at the rate of five (5%)
percent, per annum, and any such sum and the interest thereon shall be a lien on
said premises, prior to any right, or title to, interest in or claim upon said
premises attaching or accruing subsequent to the lien of this Mortgage, and
shall be deemed to be secured by this Mortgage. In any action or proceeding to
foreclose this Mortgage, or to recover or collect the debt secured thereby, the
provisions of law respecting the recovering of costs, disbursements and
allowances shall prevail unaffected by this covenant.

            13. That the Mortgagor hereby assigns to the Mortgagee the rents,
issues and profits of the premises as further security for the payment of said
indebtedness, and the Mortgagor grants to the Mortgagee the right to enter upon
and to take possession of the premises for the purpose of collecting the same
and to let the premises or any part thereof, and to apply the rents, issues and
profits, after payment of all necessary charges and expenses, on account of said
indebtedness. This assignment and grant shall continue in effect until this
Mortgage is paid. The Mortgagee hereby waives the right to enter upon and to
take possession of said premises for the purpose of collecting said rents,
issues and profits, and the Mortgagor shall be entitled to collect and receive
any rents, issues and profits until default under any of the covenants,
conditions or agreements contained in this Mortgage, and agrees to use such
rents, issues and profits in payment of principal and interest becoming due on
this Mortgage and in payment of taxes, assessments, sewer rents, water rates and
carrying charges becoming due against said premises, but such right of the
Mortgagor may be revoked by the Mortgagee upon any default, on five days,
written notice. The Mortgagor will not, without the written consent of the
Mortgagee, receive or collect rent from any tenant of said premises or any part
thereof for a period of more than one month in advance, and in the event of any
default under this Mortgage will pay monthly, in advance to the Mortgagee, or to
any receiver appointed to collect said rents, issues and profits, the fair and
reasonable rental value for the use and occupation of said premises or of such
part thereof as may be in the possession of the Mortgagor, and upon default in
any such payment will vacate and surrender the possession of said premises to
the Mortgagee or to such receiver, and in default thereof may be evicted by
summary proceedings.


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            14. That the whole of said principal sum and any interest shall
become due at the option of the Mortgagee: (a) after failure to exhibit to the
Mortgagee, within ten (10) days after demand, receipts showing payment of all
taxes, water rates, sewer rents and assessments; or (b) after the actual or
threatened alteration, demolition or removal of any building on the premises
without the written consent of the Mortgagee; or (c) after the assignment of the
rents of the premises or any part thereof without the written consent of the
Mortgagee; or (d) if the buildings on said premises are not maintained in
reasonably good repair; or (e) after failure to comply with any requirement or
order or notice of violation of law or ordinance issued by any governmental
department claiming jurisdiction over the premises within three months from the
issuance thereof; or (f) if on application of the Mortgagee two or more fire
insurance companies lawfully doing business in the State of New York refuse to
issue policies insuring the buildings on the premises; or (g) in the event of
the removal, demolition or destruction in whole or in part of any of the
fixtures, chattels or articles of personal property covered hereby, unless the
same are promptly replaced by similar fixtures, chattels and articles of
personal property at least equal in quality and condition to those replaced,
free from chattel Mortgages or other encumbrances thereon and free from any
reservation of title thereto; or (h) after thirty (30) days notice to the
Mortgagor, in the event of the passage of any law deducting from the value of
land for the purposes of taxation any lien thereon, or changing in any way the
taxation of mortgages or debts secured thereby for state or local purposes; or
(i) if the Mortgagor fails to keep, observe and perform any of the other
covenants, conditions or agreements contained in this Mortgage.

            15. That the Mortgagor will, in compliance with Section 13 of the
Lien Law, receive the advances secured hereby and will hold the right to receive
such advances as a trust fund to be applied first for the purpose of paying the
cost of the improvement and will apply the same first to payment of the cost of
the improvement before using any part of the total of the same for any other
purpose.

            16. Mortgagor may not convey or transfer its interest in the subject
premises, unless the balance of the Mortgage obligation, including interest, is
paid in full.

            17. Mortgagor represents that it has not and will not execute any
other mortgages of any type on the premises, without the prior written consent
of the Mortgagee. In the event consent is granted by Mortgagee, such other
Mortgages shall be subordinate to this Mortgage.

            18. That the Holder of this Mortgage, in any action to foreclose
same, shall be entitled to reasonable attorney's fees to be fixed by the Court.

            19. That in the event of a default under this mortgage, and if the
mortgaged premises shall be abandoned or vacated by the Mortgagor, or any
successors in title, the Mortgagee shall be entitled to take possession of the
premises and to take whatever steps necessary to protect and conserve the
Mortgagee's security.

            20. Mortgagor shall indemnify, defend and hold Mortgagee harmless
from and against any claim brought or threatened against Mortgagee by Mortgagor,
any guarantor or endorser of the Note, or by any governmental agency or
authority or any other person (as well as from reasonable attorneys' fees and
expenses in connection therewith) on account of the presence of Hazardous
Material or oil on the premises or other property of Mortgagor held as
collateral by Mortgagee, or the failure by Mortgagor to comply with the terms
and provisions of any Hazardous Waste Law (each of which claims may be defended,
compromised, settled or pursued by Mortgagee with counsel of Mortgagee's
selection but at the expense of Mortgagor). This indemnification shall survive
payment of the Note and/or any termination, release or discharge executed by
Mortgagee in favor of Mortgagor.


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      B. As used herein:

            (i)   The term "Hazardous Materials" shall mean and include
                  asbestos, polychlorinated biphenyls ("PCB's"), other
                  carcinogens, oil and other petroleum products, and any other
                  hazardous or toxic materials, wastes and substances which are
                  defined, determined or identified as such under New York Law,
                  CERCLA, or any other applicable federal, state or local laws,
                  rules, codes or regulations or any judicial or administrative
                  interpretation thereof; and

            (ii)  The term "Hazardous Waste Law" shall mean all federal, state
                  or local laws, rules, codes or regulations, or any judicial or
                  administrative interpretation thereof, including, without
                  limitation, all orders, decrees, judgments and rulings imposed
                  through any public or private enforcement proceedings relating
                  to Hazardous Materials or the existence, use, discharge,
                  release, containment, transportation or disposal thereof.

            21. That this is a Purchase Money Mortgage given to secure all or a
portion of the purchase price for the premises.

            22. Mortgagee is required, within fifteen (15) days of written
notice from Mortgagor, to provide a written certification (estoppel letter) duly
acknowledging the amount due on this mortgage.

            23. This Mortgage may not be changed or terminated orally. The
covenants in this Mortgage shall run with the land and bind the Mortgagor, the
heirs, personal representatives, successors and assigns of the Mortgagor and all
subsequent owners, encumbrancers, tenants and subtenants of the premises, and
shall enure to the benefit of the Mortgagee, the personal representatives,
successors and assigns of the Mortgagee and all subsequent holders of this
mortgage. The word "mortgagor" shall be construed as if it read "Mortgagors" and
the word "Mortgagee" shall be construed as if it read "Mortgagees" whenever the
sense of this Mortgage so requires.

            24. The premises are improved by:

            1 or 2 family dwelling


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            IN WITNESS WHEREOF, this Mortgage has been duly executed by the
Mortgagor.

IN THE PRESENCE OF:

                                     /S/ Linda Isaacson
                                     ---------------------------
                                     LINDA J. ISAACSON

STATE OF            )
                    : ss.:
COUNTY OF           )

      On this 16th day of April in the year 2001, before me, the undersigned,
personally appeared Linda J. Isaacson, personally known to me or proved to me on
the basis of satisfactory evidence to be the individual whose name is subscribed
to the within instrument and acknowledged to me that she executed the same, and
that by her signature on the instrument, executed the instrument.


                                          ------------------------
                                          Notary Public
                                          My Commission Expires


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