Main Gadgets

 

Based on an induction loop transmitter (placed underground) and a receiver (moved about on the surface), working at a frequency of 3kHz, the system can fairly accurately relate underground positions to the surface by exploring for 'nulls' in the signal.

The proto-type uses computer ribbon cable for the transmitter and receiver aerials.

Picture: Peter Eggleston

 

After spending endless hours of fun tramping across the countryside trying to work out exactly where underground workings were in relation to the surface, the Club's electronics expert developed the first stage of his through-rock communication system, to help pin-point the cavities.

Locator receiver in use