Microwave Listener System

[Zerothe...@webtv.net]

I am interested in the specifications on the microwave surveillance
systems used by the government and others to monitor room sounds from a
remote location. These systems are similar in principle to the laser
window bounce listener systems that are well known, but because they are
utilizing microwaves or millimeter waves they can and do penetrate solid
barriers and so do not require a window for operation.

I only have an interest in the type of microwave/millimeterwave passive
reflector that does not require the implantation of a resonant cavity or
other similar device in the area of interest to be able to function.

These devices have existed for over 3 decades, but specific information
such as exact carrier frequencies, power output levels, etc, are very
hard to obtain. I know that commercial units, even from the early or mid
70’s were very small, only several inches by several inches in size.
This small unit performed both the transmit & receiver demodulation
function. I call it “ sound radar .”

I think the units that operate without a planted resonator are utilizing
a principle where by standard everyday objects in the dwelling to be
monitored, including the people themselves, modulate a continues wave
microwave or millimeter wave carrier with the amplitude as well as the
frequency of the audio sounds produced in the dwelling of interest. This
now modulated carrier wave is then bounced back to the transmit/receiver
unit and then demodulated as an AM or possibly a PM signal.
There are government people, others etc...that will claim a device like
this cannot work with out a purpose built resonant cavity being planted
in the area to be monitored. This kind of claim is either propaganda to
keep the reality of such devices hidden, or is made out of ignorance.

I would like to obtain brand & model names, companies that sell the
units, as well as full specifications as detailed in manufactures
product manuals etc. Any information would be appreciated.

[Don K.]

Zerothe...@webtv.net wrote:
> I would like to obtain brand & model names, companies that sell the
> units, as well as full specifications as detailed in manufactures
> product manuals etc. Any information would be appreciated.

That is old technology which is easily defeated by wearing aluminum foil
over your head and humming.
I think Radio Shack still sells them.

Don
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[VortexOne]

If I remember correctly during the cold war, the Soviets gave the American
as "friendship" gesture a beautiful carving of the US coat of arms to be
hanged in the US embassy in Moscow. Unbeknown to the Americans, hidden in
the coat of arms, there was a passive microwave microphone
reflector/resonator. I do not remember how long it was operating before the
US contra-intelligence finally found it and remove it.
Perhaps a search on Google will give you some info and some links.
VortexOne

[VortexOne]

From: http://www.etext.org/CuD/NFX/nfx-2

(Quote):.....
Another example in the history of passive audio bugs is the device
hidden in the American embassy in the Soviet Union in the '50s. Apparently,
the Soviets had placed a tuned resonant cavity with a diaphragm and antenna
inside a carefully-carved wooden presidential seal given as a gift to a new
American ambassador, who mounted it in his office unknowingly. The Soviets
aimed a high-power microwave beam at the antenna (as a matter of fact, the
beam was powerful enough to injure some embassy personnel) and bounced it
back to a receiver. The modulation of the beam caused by hitting the
antenna
picked up the sound in the room. The principle of the above two bugs is
similar: if you have a substance that can act as a diaphragm, or something
that will vibrate when sound waves hit it, you can bug it. A rather
esoteric
example invented in the '60s is going up to the roof of the building to bug
and lowering a microphone into the toilet air pipe (no kidding). Since any
sort of sound in the room would, of course, vibrate the water, and then
vibrate the air in the pipe, it should actually work rather well. If the
pipe is the right length, you might not even need the microphone, due to the
principles of open-air resonance. The best way to counter this type of
listener would be to simply go to the bathroom, which would disturb the
water
and mask whatever sort of conversation you're having in the bathroom.
Probably not a bug that's used often. .....
--
VortexOne