During the early days of cable TV, has there been a time where cable networks have to share the same channel spot(s)?
Oh, my, yes. Ignoring pairs like Nickelodeon/Nick-at-Nite and Cartoon Network/Adult Swim (which are basically just separate programming blocks on the same channel run by the same company), the 1970s and 1980s certainly did have shared channels. Bravo and A&E are two that come to mind immediately, but there were others. It was very expensive back then to run a 24-hour cable network, to acquire and/or produce programming, run the satellite uplink service, and so on, and so forth. I was born in 1982, and I remember when a good number of cable networks used to sign off every night just like the broadcast channels did. (Yes, really!!) Other channel numbers were split between two networks, so that when one went off the air, the other went on. This decision was usually made by the two networks to coordinate their time, share transponders, and so on. But, even then, there were still plenty (given the far lower amount of channels available at the time) of 24-hour cable networks.
I'm trying to think... when we first got cable in the 1980s, the channels went as high as 64, I think, but with plenty of gaps in between, so we probably had only 50 or so channels available. However, we had fewer at my house, since the only premium channel we subscribed to was HBO.
When my area was served by Paragon Cable, three networks had to share the same spot: Prevue Channel, Sneak Prevue (for PPV promos), and Playboy TV. Here's how it was arranged on Ch. 24 on a daily basis: From 5AM to 11PM, they have The Prevue Channel showing in its entirety in its first and last hours. From 6AM to 9PM, Sneak Prevue would occupy the :10-:22/:40-:52 slots with The Prevue Channel showing in the remaining slots. The final 15 minutes of Prevue Channel were scrambled at 10:45PM to switch over to Playboy TV from 11PM to 5AM. It's kinda confusing, but that was their arrangement up until 1999 when Prevue/TV Guide Channel finally had its own spot.
Good heavens! That seems needlessly confusing, not to mention irritating if you were a late-night channel surfer trying to find one of the few good shows to watch that late. My cable company always had Prevue on its own channel, Sneak Prevue was on the next channel, and we never had Playboy. However, the second of the two PPV channels (the first being "Viewer's Choice" and the second, I believe, called "Spice") showed pornography overnight.
