I saw a demonstration of an RF detector being brought close to a mobile phone. As the detector was moved away, the number on it dropped to zero. How can that be? Shouldn’t there be some RF signal from the phone all the way to the cell tower, so that the phone can communicate with the tower?

Question

I saw a demonstration of an RF detector being brought close to a mobile phone. As the detector was moved away, the number on it dropped to zero. How can that be? Shouldn’t there be some RF signal from the phone all the way to the cell tower, so that the phone can communicate with the tower?

In: Technology

Answer 1

Squelch. We are constantly bombarded by RF. Radio and TV stations broadcast thousands of times more powerful signals than phones. The detector is tuned to ignore a certain level of background rf, and only reports a level of energy above that threshold.