Find a vehicle tracking device

Most tracking devices use an integrated SIM card which emits a GSM frequency signal and it is that signal that can be detected by equipment called Radio Frequency Detectors or otherwise referred to as 'Bug Detectors'.

Even if a tracking device is not moving, a GSM burst signal is sent out to the networks once every say 15 minutes and it is also when that happens that a decent RF Detector can detect this signal.

As trackers also require a GPS signal (the signals obtained from the satellites orbiting our Earth = 31 of them at last count) they will not be placed near an engine area or underneath a car in the centre. Along the edges or in the boot area are favoured places.

So, either a decent Bug Detector or a sharp eye will find one.