Mobile Phone signal jammer

[Odie]

Does anyone know if their is a way of checking if a mobile phone signal jammer is in use somewhere?

[Soovy]

See if people's phones work?

[RDM]

http://www.himfr.com/d-p1115529368027100225-Signal...

If this works it may tell you..

[Kindersley]

As used in many a hotel years ago ! I know because we use to fit them . Owners made a fortune on room call charges. They are a real nightmare now.... cheaper than those in the link. A small 10-20 meter one with remote can be had for £48.00 in the UK. Fitted to a timer and hidden in a car or office is dirty trick !