Coaxial Cable System for Television Transmission

HE reports which have been made on the progress in television development increase the expectation t h a t the broadcasting of visual programs will soon be realized. In anticipation of that result, the Bell Laboratories has been engaged for some time in the development of wire line circuits for transmitting television signals between studios and broadcasting transmitters, or between cities, as may some day be required if television follows in the footsteps of sound program broadcasting. The wide frequency bands required for television and the dearth of available frequencies appear to force the broadcasting of television signals into the ultra-high frequency range. At these high frequencies, the coverage which can be obtained from a broadcasting station is very limited as compared to that obtainable in the sound broadcasting frequency range. Hence, if television programs are to reach large sections of the country simultaneously, the provision of interconnections between large numbers of television broadcasting transmitters will become even more important than it is today for sound broadcasting. Coaxial cables have received much publicity as transmission lines for television. The original conception and use of the coaxial form of cable was first as a low frequency submarine conductor and later as a lead-in for radio antennas. The idea of a coaxial cable or other medium for the transmission of very broad frequency bands originated in the course of telephone development in America.