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?

"Joey" wrote in message
...
Suppose someone visited your office or home and tried to make a voice
recording using a hidden recorder.

Tad paranoid here.

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.

Yep

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?

Close. There are devices that are around that do exactly what you want.
Security firms and such use them to verify a room is bug free, etc.

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.

In practice that was always a lot easier to say than to do.

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

In theory any electronic device will produce some
EM so at least in theory that can be detected.

In practice there is so much of that stuff in any
normal room anyway that its just not feasible.

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

Fraid not.

On Mon, 09 Oct 2006 22:23:22 +0100, Joey
wrote:

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


Ok, why do you care?
Don't have sensitive conversations with anyone you can't
trust, if you're going to be saying anything that shouldn't
be recorded.


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.

Doubtful, and not worth the bother when you could just scan
them or search them physically.



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

Scan them or search them.
What makes you think you should detect it?
Don't they have a right to a recording of any conversation
they're participating in?


Is there some transmission which could be detected?

Do you mean "wild hypothetical way that some future
technology or extremely expensive equipment and controlled
environment could detect", or do you mean, practically
speaking?


Perhaps some low power ultra high frequency from chip refresh cycles?

.... and you're discriminate this from everything else, all
other HF noise, how? Get a baseline maybe, but noise is
random unless a controlled environment.

You just need to have everyone strip down nude and then do
body cavity searches, X-Rays, exploratory surgery, then
never let them leave so it doesn't really matter if anything
was recorded so long as the environment has sufficient RF
shielding.

Joey wrote in :

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?


There probably is a little electro magnetic energy leaving the device, but
what frequency would you try to find it on? Other electronic things such
as computers, printers, etc in the office most likely emit far more RF
noise than the MP3 device. It would be hard to find it. Eventually, the
power would run down and the thing would stop recording. Someone would
have to come by again and pick up the recorder. So your best bet is to be
on the lookout for any suspicious recorder placement and pick up activity.

Or just buy as stereo for your office and play it real loud all the time.

Maybe belch and fart a lot too.

SC

Joey wrote in :

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

That should be the least of your worries. What can you do to stop "them"?
One word: 'Faraday cage hats'.


--
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vbaabgriragurtbireazragnertbaanfgbclbhabjohgnerlbh ernqlgborurnegoebxra

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

On Tue, 10 Oct 2006 01:08:40 GMT, Slow Code wrote:

Maybe belch and fart a lot too.

Or a noisy computer placed close to where the suspected mp3 recorder
would be. I have an ancient 286 whose 80MB hard drive sounds like
it's about to take off and its fan is second only to vacuum cleaner on
the noise level.
--
When you hear the toilet flush, and hear the words "uh oh", it's already
too late. - by anonymous Mother in Austin, TX
Spam block in place, no emil reply is expected at all.

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?


3 AM with the right equipment it would be findable , now are you serious
or just another one of "them"?

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 sure if you could find it with a metal detector, but probably


NT