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

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

In comp.sys.ibm.pc.hardware.storage Jamie t wrote:
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"

That sounds like BS to me. Of course cellphones are very easy to
detect that way, and I expect that is what he is showing off. Forget
about non-woreless devices. They have several orders of magnitude
less RF emanations. This guy is likely demonstrating with
cellphones and then claiming he can detect the other things
without ever demonstrating.

Arno

Arno Wagner wrote:

In comp.sys.ibm.pc.hardware.storage Jamie t wrote:

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"


That sounds like BS to me. Of course cellphones are very easy to
detect that way, and I expect that is what he is showing off. Forget
about non-woreless devices. They have several orders of magnitude
less RF emanations. This guy is likely demonstrating with
cellphones and then claiming he can detect the other things
without ever demonstrating.

Arno

maybe you should step out of the dark and into the real world.
have you ever use a service monitor to scan a wide spectrum of
frequencies?
i can tell you that wide band receivers on a mini board exist and
are very sensitive to external R.F. when your standing beside the person
with in 3 feet of them.
most devices these day's involve embedded processes which also uses
R.F. clock devices. it would take a very high priced unit with proper
casing and shielding to reduce the emissions low enough for this device
to not detect it. most consumer electronics is very sloppy in the area.
in fact, there has been cases where cheaply made devices that xfer lets
say audio information in a digital format causes their internal osc's to
be unstable enough when voice is passing through the mic/pre'amp
circuits, that some one with a high gain FM receiver can detect clear
enough audio from a distance before it even gets encoded digitally for
final destination.
the average joe wouldn't even think of this let alone attempt to
waste their time in trying it how ever, there are people out there that
spend a lot of time investigating consumer devices just for the purpose
of simple wireless taps and detection of use.




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

In comp.sys.ibm.pc.hardware.storage Jamie t wrote:
Arno Wagner wrote:

In comp.sys.ibm.pc.hardware.storage Jamie t wrote:

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"


That sounds like BS to me. Of course cellphones are very easy to
detect that way, and I expect that is what he is showing off. Forget
about non-woreless devices. They have several orders of magnitude
less RF emanations. This guy is likely demonstrating with
cellphones and then claiming he can detect the other things
without ever demonstrating.

Arno

maybe you should step out of the dark and into the real world.
have you ever use a service monitor to scan a wide spectrum of
frequencies?

I have used a spectrum analyser. I admit I am not an EMI expert.
However cellphone detection is far simpler than detection of other
devices....

i can tell you that wide band receivers on a mini board exist and
are very sensitive to external R.F. when your standing beside the person
with in 3 feet of them.
most devices these day's involve embedded processes which also uses
R.F. clock devices. it would take a very high priced unit with proper
casing and shielding to reduce the emissions low enough for this device
to not detect it. most consumer electronics is very sloppy in the area.
in fact, there has been cases where cheaply made devices that xfer lets
say audio information in a digital format causes their internal osc's to
be unstable enough when voice is passing through the mic/pre'amp
circuits, that some one with a high gain FM receiver can detect clear
enough audio from a distance before it even gets encoded digitally for
final destination.
the average joe wouldn't even think of this let alone attempt to
waste their time in trying it how ever, there are people out there that
spend a lot of time investigating consumer devices just for the purpose
of simple wireless taps and detection of use.

Oh, I know. But I was pointing out that the guy described does not need
to have what he claimed. And in addition, how do you separate, e.g., the
crystal in a high-powerd pocket calculator from the one in the MP3
recorder? Detecting RF energy is not that difficult. It becomes
difficult if you have a lot of background noise or need an identification
in addition.

Arno

Jamie t wrote:
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"

Trouble is that he cant know about the devices his doesnt detect.