Invention: Wall-beating bugging

Invention: Wall-beating bugging

"So the new "through-the-wall audio surveillance system" uses a powerful beam of very high frequency radio waves instead of light. Radio can penetrate walls – if they didn't, portable radios wouldn't work inside a house.

The system uses a horn antenna to radiate a beam of microwave energy –between 30 and 100 gigahertz – through a building wall. If people are speaking inside the room, any flimsy surface, such as clothing, will be vibrating. This modulates the radio beam reflected from the surface.

Although the radio reflection that passes back through the wall is extremely faint, the kind of electronic extraction and signal cleaning tricks used by NASA to decode signals in space can be used to extract speech."

http://www.newscientist.com.nyud.net:8090/article.ns?id=dn8208

""between 30 and 100 gigahertz "" oo:

Last I heard that was not safe to be around, at least not in high powers.

Radio waves sure are some interesting things,
everything from radar, to talking to the other side of the planet with HAM radios.

Have you heard about the invention that allows you to see through walls???
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It's called a WINDOW!!

Good one Roy


Btw, hasn't lasers been used to detect the vibration in windows caused by people talking? Or maybe this was just something I saw in a movie and that can not be done in real life.

I like spy stuff, so I keep an eye out for this type of thing.

There are systems that use a laser to 'read' the vibrations of a window. They work especially well for industrial espianage since the bigwigs get the offices with windows.

Other clever tricks.....

The LED on some phone systems are powered by the same voltage that powers the phone's microphone. The LED's brightness is modulated by the speaker's voice. A telescope and simple amplifier has been used to "bug" a conversation on such a phone.

The Russian boy scout equivilent presented the American embassador in Moscow with a wooden plaque. The plaque had the amercan eagle carved on it. It also had a tuned cavity that resonated when hit by microwaves. The ambasador mounted it above the desk in his office. It was, in effect, a wood microwave powered passive audio transmitter.

Scientists (just recently) recorded the sounds of people typing and decoded the keystrokes based on the timing and volume of the clicking keys. I think that was done over a phone line.

It's possible to use an antenna to "read" the varying radio noise created by your computer monitor. That noise can be decoded to provide an accurate image of the screen.

There are, literally, a million of them.