and yes there were means in the VBI to ident the source so the transmitter would accept the signal ...... very useful for RBS at main stations
as well as The normal RBL at main relays ..
and it told Douglas to take Manchester not Carlisle / Newcastle for the regional opt ... Caldbeck was a better signal than Winter Hill so was used for Network programmes
Wasn't there a similar arrangement for Sutton Coldfield to be able to signal Oxford to switch from RBL of SC to it's RBS source so that Sutton could then take Oxford as it's RBS? I think that was done with inaudible tones rather than VBI.
This and my u link pulling is BBC as it owned it’s distribution..
Under normal conditions Oxford Was fed by microwave from wipsnade which took CP .... under “all uk RBS “. Sutton Coldfield RBS from Oxford...
And it may be that Oxford if it had lost the microwave would RBS from HAnnington ..
But that had to change itself round to RBS feed from CP rather than RBL Rowridge ... so that Hannington was Rowridges RBS source ... that was a commonly known situation...
Itv if course had it easy as the only link required to broadcast
was from The contractor to the IBA transmitter site ..
..and that was the IBAs problem I think !
I remember being phoned in the office by Plymouth saying that they had been putting out pulse and bar on BBC2 as that is what was in the incoming feed from BT .... they had phoned Bristol and CAR who had no advice !!!
I just said pull the output U links ..that took all SW transmitters RBS until some one could sort it all out .....
so I phoned the Duty Engineer to tell him a)what seemed to have occurred and would he tell transmitters etc and EID .
b) what I told PY to do and c) I would walk down the road to CAR to help them out ..but a BS-PY reverse contribution circuit seemed a good idea and opt out in PY (or over plug at the BT bays )
...which had been done by the time I got there !