Amplification of Power-Line Carrier Signals at Intermediate Stations

On long power-line carrier circuits used for telemetering and automatic control, the signal-to-noise ratio during foul weather may become too low for reliable operation. Where the carrier circuit passes through an intermediate switching or transformer station, amplification of the signal is possible. This paper describes an investigation of the limitations on the gain of an amplifier inserted directly in a carrier by-pass cable. An amplifier with 20-db (decibel) gain installed near the middle of a 260-mile carrier circuit used for telemetering and control functions is described. Power requirements and reliability considerations in this amplifier are also discussed in the following paper.