Use of high-frequency currents for control

Chester Lichtenberg: One thing that is disturbing to the designers, as well as the operators, is the high cost of the equipment required for carrier-current supervisory control. At present the cost of wires is large, however, the terminal apparatus required for radio supervisory equipment is also large. It is therefore necessary to make a quite careful analysis of the situation before a reasonable conclusion can be drawn as to whether or not it is cheaper to use supervisory equipment employing wires or supervisory equipment using carrier current. From some studies which we have made, the wires seem more economical for distances up to about 25 mi., beyond that distance however, the carrier-current design becomes feasible.