21-05-2024, 07:25 PM
(21-05-2024, 06:48 PM)AvroVulcanXH607 Wrote: The BBC therefore used a special data signal which was mixed in with the "Insertion Test Signal" (basically a one-line test card in the Vertical Blanking Interval). This signal identified what region each video feed originated from.
From then on, the transmitters didn't check for syncs, they checked for this address - and if it wasn't either it's own regions or London's, it would not radiate it - essentially treating it as no signal at all.
In Northern Ireland, right up until closedowns stopped in the late 1990s, BBC Scotland was sometimes up later than when BBC-1 and BBC-2 Northern Ireland closed. In those situations, RBS kicked in, and BBC Scotland was rebroadcast on NI transmitters.
In 1994, when the power supply to Divis went down (on a weekday afternoon), BBC-1 and BBC-2 was still available in at least some parts of Northern Ireland because BBC Scotland was rebroadcast. UTV and Channel 4 had no such arrangement and were off air completely.