How do spy bug scanners work?

[bluedolphin]

How do they work. What does the scanner actually scan for. Must the bugs be wireless? Or can they find a microphone leading into another room? How about video...must it be wireless to be detectable or can they pick up an ordinary handycam?

[djg23]

As I understand it they just scan certain radio frequencies typically used by bugs for any radio transmissions. Apparantly you can use a standard fm radio to scan for bugs. It goes something like this: Play some music in the room you think is bugged. Go into another room with a radio and tune through the full range of frequencies. If there is a bug transmitting on a radio frequency, you should be able to tune the radio in to it an hear the music you have playing in the other room!