cellphone qu estion

The phone is periodically querying its environment as it programmed to do. No, on a practical basis, the audio that you could record is not useful.

Well this answer is similar to your question..

I have a friend who lives close to an AM band radio station. If he turns his computer speakres on they will faintly pick up the radio station near by. It is kind of coo.. I would immagine if cell phones were still analog you could probably hear a conversation the same way.

- Mike

I don't know how many current phones still do, but both my phones have both analog and digital capability. FM not AM analog.

The basic problem with AM is AM. Amplitude modulation. Aircraft radio's use some AM, but most communication services are FM or now digital. Analog cell phones are some type of FM.

Strong FM and television stations can easily demod into active devices, but not always audible.

If you use one of those Led phone blinkers that work from radiation, you will see the same thing occuring before a ring or when the phone is communication with a tower.

greg

If a cell phone is in a roaming area, and especially if its in a remote area, the phone needs to transmit on high power, where if it has good signal strength, it transmits on low power. It makes a huge difference in battery charge time, in standby mode. On roaming mode, it will tend to communicate with the tower much more often, than being in a home area.

greg

Typical example of "topic drift":

"If one were to record this sound with a microphone at 11 or 22Khz, would it be possible to obtain any information (usable signal) from the recorded audio?"

The basic answer is still "NO."