Launch BBC One North

[technologist]

In the analogue era,  a BBC English region could opt on BBC 1 or BBC 2, but not both at the same time (although I think Bristol  could)?

I think Leeds, Newcastle and Manchester managed it once, with the SuperLeague Show and the regional politics programmes going out at the same time. I suspect Manchester Comms (as was) fed the SuperLeague Show as though it was the network feed leaving the regional infrastructure to opt out and do the politics progs.

Most regions could opt in both networks at the same time …
The key issue was that one may be a non sync opt.
Often a regional would lock to BBC one and then synchronously opt.
So to opt simultaneously  on BBC two would meant that station output was non sync
To BBC 2 …..
also besides have synchronisers and being able to put them in the right place,
Which was not that straight forward even when you had them.  

The opt was actually in the DCSIS domain Which meant  having a coder  available.
This was not a problem in the as any cut in the DCSIS was non sync in NICAM 
Even if it were sync in video. 
(DCSIS was not locked to video at all 
and the emitted NICAM subcarrier was locked to incoming NICAM clock )
And so there was full reframing  at the transmitter,
So that the receivers always got continuous NICAM sequence. So no audio splats.
It also meant the strictly speaking lip sync was lost ….
But as the audio was being delayed by 16ms in average (ideally less and rarely 32ms)
It sort if compensated for a field delay  in the video ….

All regions had two operational opt chains and a spare one on the shelf
Except Southampton who installed it !
The Nations had 4 sets of equipment usually all installed.

I’m certain the BBC 2 super league Manchester Comms diverted the network feed….
Using the spare kit ( they actually has a further set on the shelf for MR LS NT )
Birmingham had a spare as it was the alternate network playout …
but it basically used both existing opt chains and just changed the network source identity
In the ITS test waveform to spoof London . This mean you knew it was working …
Kit for standby use often does nit work when you need it
Red Bee and ch4 spring to mind …..