On 09 Oct 2006, kony wrote:

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.

I say things in my conversation which i do not want to be broadcast in
the public media.




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.


You say, "search them physically"? I have to tell you that I don;'t
work in the sort of environment where that kind of behaviour is
considered acceptable!



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?

They have the right to record themselves. I have the right not to have
my words broadcast. Unfortunately obtaining redress can be expensive.
So prevention is beter than cure.


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?

The latter. I am talking practicalitites ere.


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.

If necessary I could have my PC turned off and my phone put further
away. But is there any leakage from solid MP3 recorders?



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.