We used to run two small cable systems at work, one at Bakewell, VHF 405 and radio only, and one at Matlock, which also had 625 line TV, down converted to VHF from UHF (channels A, D, and H - I can still remember!). Both systems were really old, and all valve!, very unreliable, and if there was a power cut it took about two days to get it settled down again!.
Anyway, moral of the story! - we had reports of the Bakewell one giving poor pictures on a certain section - so we went out to have a look. Some guy had illegally connected himself, but rather than connecting to the tapped off output, he'd connected directly to the main high level line.
He admitted what he had done (couldn't really deny it!) and signed up for the service, so we connected him properly - however, the TV needed the front end valves replacing - either they were duff before, or the excessively high input had damaged them.
To be honest, I call them unreliable, but most problems were caused by power cuts, or by people cutting the cables - I really learned to hate JCB drivers :lol: The one at Bakewell was particularly troublesome, because the cables were underground (installed as the estate was being built) - unfortunately the hillside it was built on was subsiding (sliding down to the river!), and this was stretching and snapping the cables.
The main lines came out of the ground on each house, into a tapoff box, and back down into the ground again - the tapoff boxes were fitted about three feet off the ground, screwed to the wall. We went out once for a large failure, went to check on the tapoff box - and it wasn't there!, the subsidence had ripped it off the wall, and we dug down to find it four feet underground!.
We were really pleased when local TV relay transmitters eventually opened, and we ripped the systems out with great glee :lol: