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Old October 10th 06, 03:56 PM posted to comp.sys.ibm.pc.hardware.storage,alt.comp.hardware,sci.electronics.equipment,rec.radio.amateur.misc
Joey Joey is offline
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First recorded activity by RadioBanter: Oct 2006
Posts: 12
Default How detect if MP3 player is recording in your room? [OT]

"Joey" wrote in message

Suppose someone visited your office or home and tried to make a
voice recording using a hidden recorder.

If they used a older-style dictation machine based on tape then
you could detect the electromagnetic transmissions from the
dictation machine when it was recording.

But how would you detect if someone was secretly recording with an
MP3 player that recorded to flash memory?

Is there some transmission which could be detected?
Perhaps some low power ultra high frequency from chip refresh
cycles?


On 10 Oct 2006, Ken Maltby wrote:

What is done is to generate a pattern of sound, only
part of which is audible, and then detect the low level
IF and RF that any sound equipment emits. Then follow
the signal detected to its source.

Luck;
Ken



Generate a pattern of sound part of which is inaudible?

IF and RF?