Science: High-Tension for Telephones

The General Electric Co. last week proposed the use of the thousands of miles of U.S. high-tension electric power lines in civilian defense. The network could be used for large-scale air-raid warnings, could control colored lights to warn air-raid wardens, start pumps at pumping stations in case of fires, operate traffic signals, give telephone service in remote areas where telephone lines do not reach and cannot now be built.

The high-frequency signal currents merely ride on the high-power current like waves on a river. The vibrations are drawn off at any point by a condenser or antennae system. This does not affect the power circuit which thus acts much like a special track for radio waves. As in radio, many frequency channels are available so that several conversations or signals could be carried by the same wire at the same time. By eliminating the need for separate telephone lines, many tons of aluminum, copper and steel could be saved. Chief obstacle: lack of materials for telephone instruments.