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

[Mi40793]

The quoted May 13, 1978 NYT article on DATE says 62 stations had bought receive equipment. It was an expensive box .

DATE was 4 audio channels, 15 kHz, 16bit, mux’d onto ~5.5 Mhz QPSK carrier, intended to ride above the video.

To my knowledge DATE was never used on the ATT terrestrial microwave system used for PBS video. ATT would not allow DATE on the terrestrial microwave links, serving a limited number of PBS stations, as it ‘violated ATT tariffs’.

This dispute led to PBS obtaining money from CPB to build their own complete network satellite distribution system, in service Sept 1978. It included over 300 downlink dish/antenna receivers (FM video and one channel FM subcarrier for mono 15khz audio) and a ground uplink station Springfield, Va., and leasing Western LC Union satellite transponders. This allowed PBS stations to receive stereo programs (not all programs were stereo) via DATE if they purchased a decoder, or FM mono if not. NPR used the other two DATE channels. The cost of the complete PBS satellite system was equivalent to 10 years of ATT microwave line charges at 1978 rates.

The ‘big three’ networks used 5kHz telephone circuits for audio until ~1978 when ATT added FM subcarriers providing 15kHz audio. ATT used Farinon FM modulators above the video at about 5-5.5 MHz.

Quad tape audio at 15 ips would do 15 kHz.
16mm television film projectors, ~6 or 7 kHz (best I ever saw)
TV station audio transmitter, audio path, etc., 15 kHz, same as any FM radio station required.

Working at two networks, everything audio was kept as flat a response as possible, with agc and peak limiting at transmitters.