Leaky feeder

A leaky feeder is a communications system used in underground mining and other tunnel environments. It consists of a cable run along drivages which emits and receives radio waves. The system has a limited range and because of the high frequency it uses, transmissions cannot pass through solid rock, which limits the system to a line of sight application. It does, however, allow two-way mobile communication.

This system is also used for underground mobile communication in mass transit railways. In Hong Kong the leaky feeder aerial was incorporated in the specification of the capital project and installed during construction. This allows emergency services seamless mobile communication from the underground to the surface.

In London, London Underground use a leaky feeder system for their internal communication network. The emergency services' communications system however is not compatible and does not work underground. That this situation continued to exist after the 1987 King's Cross fire was criticised in reports into the 7 July 2005 London bombings, where it hampered rescue efforts.

ee also

Tunnel transmitter