Radio Transmission Between Two Submerged Submarines

Experiments have been conducted with two submerged submarines which demonstrate that a radio wave propagation path is possible, involving transmission over the horizontal distance above the surface instead of directly through the sea water to the submerged receiver, which holds the prospect of communication over militarily useful distances. Without special transmitting, receiving, or antenna coupling equipment, and without optimum design of antennas or choice of frequency, a transmission distance of 3000 yards was realized, at which point the signal was weaker than the high local noise.