Radio Propagation Testing in Lava Tubes

By Jansen Cardy, ZL1AAB

Cave Research Foundation Volunteer, Lava Beds National Monument

http://www.caves.org/section/commelect/splncs/splncs27.pdf

Firstly, the CB radios had a significantly longer

range when transmitting in these particular caves than our VHF radios did. The 27 MHz signal either travels directly through

these lava tubes more efficiently, or perhaps it penetrates the relatively shallow overburden and travels longer distances above the

surface before being received by the other underground station. S