A bloke who is miffed at getting stuck in a bus or a train with people shouting into mobiles has built a device which creates a mobile phone dead zone.

A reporter for NBC10 in Philadelphia recently tracked down the man, who was using a mobile phone jammer on the bus to block riders' phone reception. He said that he turns on the illegal device whenever other passengers talk too loudly and bother him.

The man, identified as Eric, told NBC reporters: "I guess I'm taking the law into my own hands, and quite frankly, I'm proud of it." A jammer is the size of a walkie-talkie. Its job is to jam, block or interfere with wireless communication including Wi-Fi, mobile phone reception, GPS and police radar.

It is illegal to own one in the US but they are possible to build or buy if you know where to look. However word has got out that for some reason using a mobile on Philadelphia public transport is almost as bad as trying to use an iPhone 4 without a rubber band.

More here.