Unable to afford the expensive Rescue Radios (for surface work) and Mole-phones (for underground use) we were forced to compromise (although we have since been lucky enough to purchase a Heyphone since our radio experiments started - see below).
CB Radios & Guide Wire
Several Club Members had CB radios (working on 27MHz), but these were only any good for line of sight work - and no good underground.
However, a chance observation during a rescue practice, when someone was at the bottom of a ladder pitch, that they could still talk to the surface, lead to a range of experiments with 'guide wires' for the radio signals.
Picture: Peter Eggleston
Heyphone Pictures: Kelvin Lake & Alan Robinson