Arno Wagner wrote:

In comp.sys.ibm.pc.hardware.storage Joey wrote:

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?


Not really. You could maybe detect that it was turned on with
an RF scanner. But if it is low power enough (most MP3 players
are, since they are optimised for that) and well shielded, you
would likely get nothing in today's RF polluted environment.
In addition the attacker may just add some more shielding to be
sure. I think you can basically forget about this, unless you
can take the devices away from people.

Arno
i have seen a device used by an electrical instructor at a trade school.
he does not like any Cell, recorders or electronic devices active while
in his class.
this device will buzz and vibrate in his pocket as he walks around
the class, he can walk right up to the student that has something on..
it works by detecting a variation of known R.F. frequencies that helps
him decide on an LCD screen of the device what it could be, and then it
has wide band detection of any R.F. generation..
as you know, most devices do generate some R.F. of some freq..
i've seen it in use and its on the market... all i can say is by
his words, "it works very good"


--
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5