Line filter for program system

Open wire circuits recently have been developed for transmitting radio broadcast programs with greater naturalness and over greater distances than heretofore (see companion paper “Wide-Band Open-Wire Program System” in this issue). The simultaneous utilization of these circuits for the transmission of broadcast programs and carrier telephone messages requires the use of line filters to restrict the program and carrier currents to the proper circuits. The low pass line filter developed for the program circuits and its contribution to the maintenance of good quality in the programs transmitted are described in this paper.