Two-way communication with an earth penetrator


  • Thurlow W. H. Caffey


A telemetry link capable of communicating from a depth of 50 m to the surface is described. The buried package fits within a diameter of 100 mm and provides a bit error rate of less than 10−4 at a rate of 1000 bits per second while consuming 8 w. A control link capable of turning on and off the buried telemetry transmitter from the surface is also described together with results from typical tests in a three-layer soil. The included propagation analysis is intended for use at frequencies below 100 kHz.