[Deejay]

They shared presentation areas (and still do). If you were the director looking after the children’s channels you’d also be looking after BBC Three and Four from the same positions as CBeebies/CBBC. There was a dynamic switch that took place at the actual service providers (I.e. downstream of the BBC) which changed the channel numbers so that the output from the pres suites stopped being available on CBeebies and became available on BBC Three. Etc. It was supposed to be fully automatic and happen at a fixed clock time.

But in the early days it went wrong a few times and the BBC was rightly sensitive about some of the content that was being promoted for the evenings schedule being seen still, because of the error, on the children’s channels. The engineer had a bank of off air boxes for DSAT and DTT to check that the children’s channels had gone off air and Three/Four had become receivable correctly.

Yes. I do have vague memories of the switching interval being increased, I’m not sure it was ever 15 minutes but I may be wrong.

These days it’s about a minute I think. Incidentally, if you’re directing BBC Three’s CatchUp, and you’re on at 7pm, you’ll see the end of CBBC on your network output, then the slides, fade to black etc while the switch happens, before you go on air.