Conduction Current Signaling Through Sea Water and Wet Sand

摘要

A communication system employing conduction currents through coastal waters and wet sand is described. Design details of the high efficiency battery-operated inverters used as signal sources for the experiments are given. The detection circuits used to receive underwater electrical current signals through high levels of interference are also shown. Results of tests conducted at Sandy Hook, N. J. indicated that it is possible to communicate over distances of 200-700 meters using powers of 120-300 watts. The method of communication described is not new, but the utilization of very efficient DC-AC solid-state inverters as signal sources makes earth current systems operationally attractive. Although the communication ranges are short compared to high frequency radio communications, earth current communications may prove useful for certain applications. (Author)