Tyne and Wear / Northumberland Fire Brigade

Low band AM VHF radios are used in the 70 MHz band to provide very wide coverage for vehicle to base comms. For on site incident comms UHF FM handsets are used in the 457 MHz band.

The VHF system utilises a quasi-synchronous transmission technique whereby a number of transmitters simultaneously relay the signal from different transmission sites. Each transmitter is tuned a few KHz lower or higher than the others. As a result the signals do not interfere but the radios used must have a wider receive bandwidth.

When you listen on your scanner which has quite a tight bandwidth, you may hear the signal apparently fading in and out. This is caused by these multiple signals cancelling each other out.

I have been informed that Northumberland Fire and Rescue are using a new zoned radio system using a number of FM frequencies. Known frequencies are listed below, but there may be more, so get scanning and post them on the forum!