Hi-Fi TV Soundtracks (pre 1978) - Why?

[Mi40793]

Network audio nationally was always just single ‘5khz’ equalized circuits to the local stations, for both the radio and tv networks.

Telcos provided special ‘local loops’ for example, studio to transmitter 15 khz equalized lines, but you paid dearly for these, and you’d better check that response yourself.

In 1978 two FM subcarriers were added above the network video channels at about 5-5.5 MHz. These were typically Farinon units and were flat to 15kHz. ATT’s network video channel was wide enough to carry the two added FM subcarriers above the video bandwidth.

Local tv stations always had the capability, and were required to be capable of transmitting 15kHz audio, same as any FM station, but not all program sources were 15khz audio. Particularly network audio until the above system was installed.