Good grief. Permanently on the output !? (During ad breaks too ?) The only permanent tones in that era
were transmitter status/anti piracy stuff up at 23 kHz, so totally inaudible (by humans !)
Whatever, I'd have pursued that via the IBA until it had been sorted. Totally unacceptable
Yes it was permanent. It was there from when the channel opened as well - I noticed it almost immediately but was told I was making it up as a kid(!). I blamed C4 for many years but it must have been either TTT or IBA transmitters responsible. And yes it was present on the ads as well, although there it was drowned out by the tape noise of Tyne Tees's ACR players.
If you'd reported it to the IBA at Winchester, they'd have leapt on the problem, and had it sorted within hours, whoever was to blame. 0962 822444 almost made it onto my 'Friends and Family' discount list !
I'm amazed however no one at the IBA ROC at Emley noticed the problem !
I guess from the fact that it lasted so long, that (a) no-one, the viewing public, the IBA, C4 or TTT, gave a monkey's about it, and (b) it must have been meeting minimum broadcast standards (as the idea that no-one but Si-Co and me noticed it, is completely absurd).
Hence my initial thought that it must have been deliberate in some way!