Quote:
Originally Posted by JGlenn
I did a little searching and it was actually a primitive pay tv service in that started in the 50s and never really caught on. I guess there would be a box that got some signal over the air
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There were those supressed horizontal sync scrambled TV stations, usually up at the upper end of the UHF TV band. We had one in the NYC area on channel 68, here's the box you rented from the service
The missing horiz sync signal was added to the audio subcarrier, along with the soundtrack modulated as a double sideband suppressed AM carrier at around 31KHz (twice the horiz frequency), a lot like FM stereo is done where the soundtrack would be the L-R signal, and a "barker" (someone telling how great the movie service is) sound on the baseband mono audio, to be heard by people tuning the channel without the decoder on their TV sets. Then the box would add the missing horiz sync back to the video, and send that to the TV set. You'd see tons of pirate decoder boxes at swap meets and such, most not working all that well.
Building such a decoder box using tube technology would be rather expensive, similar to a TV set but without the CRT and deflection circuits. That's probably why it bombed, that much investment would have to be paid off in a couple of years and then getting movies that just finished their runs in movie houses but before they hit regular TV would be expensive too. "Wometco Home Theatre" lasted about 12 years before it folded.