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

One thing to mention – the RF detector like any measurement device will have a finite sensitivity, and signals below some level will measure ‘zero’. But the signal may still exist. In the case you described the signal *does* exist, at a power level that is lower than what could be measured with that equipment.