Power Supplies for Microwave Relay Systems

The establishment of microwave relay systems, carrying large numbers of separate telegraph communication channels on a single radio circuit and having relay stations located every 30 or 40 miles, usually in remote country districts, has put a premium on dependability of power supplies, This paper describes the facilities that have been provided for regular and fallback power supplies for the Western Union radio-beam triangle which interconnects New York, Washington, and Pittsburgh. Interruption of the regular commercial a-c supply at any point causes the radio beam to be switched, without any effect on its operation, to a-c power supplied from battery-fed vibrators. Simultaneously, an engine generator unit is started and takes over the load automatically as soon as it has reached a steady operating condition. The paper includes a brief discussion of operating experience.