IS
I watched the events last night... It was interesting how everyone was saying it would happen at midnight - and then never happened until 00:50! Also worthy of note was that ALL channels went off air (I thought each channel had its own seperate transmission equipment so only BBC2 and ITV1 would go off) but I guess that was the main switch being thrown (like the footage we saw from the Whitehaven switch over).
Yes, each channel has it's own set of transmitters (with older equipment like Beacon Hill each will have 2 audio and 2 video) but they will share aerials, combiners, feeders (the cabling to the aerials) and the main power supply.
I assume that last night the new DTT transmitter had to be 'plumbed in' to the feeders/combiners/aerial system which means taking everything else down. Also if any work needs to take place to the aerials or mast then they must go off air for safety reasons. It's a lot easier and less likely to cause damage in general if stuff is switched off before plugging/unplugging equipment, especially at the powers involved.
The actual switch of the BBC2 analogue transmitters to ITV1 would have been fairly simple. It should just invole unplugging the feed of BBC2 and replacing it with ITV1's - the transmitter isn't fussy what video is going into it. Channels come in to transmitter sites via a distribution board which has all the electronics and decoders/encoders to provide a finished signal before it goes into the transmitter. However because of the old BBC/IBA and latterly Crown Castle/NTL split it's likely that the BBC and ITV equipment will be in different rooms or even different buildings so the difficult bit would be to physically get the ITV feed to the BBC2 transmitter
I watched the events last night... It was interesting how everyone was saying it would happen at midnight - and then never happened until 00:50! Also worthy of note was that ALL channels went off air (I thought each channel had its own seperate transmission equipment so only BBC2 and ITV1 would go off) but I guess that was the main switch being thrown (like the footage we saw from the Whitehaven switch over).
Yes, each channel has it's own set of transmitters (with older equipment like Beacon Hill each will have 2 audio and 2 video) but they will share aerials, combiners, feeders (the cabling to the aerials) and the main power supply.
I assume that last night the new DTT transmitter had to be 'plumbed in' to the feeders/combiners/aerial system which means taking everything else down. Also if any work needs to take place to the aerials or mast then they must go off air for safety reasons. It's a lot easier and less likely to cause damage in general if stuff is switched off before plugging/unplugging equipment, especially at the powers involved.
The actual switch of the BBC2 analogue transmitters to ITV1 would have been fairly simple. It should just invole unplugging the feed of BBC2 and replacing it with ITV1's - the transmitter isn't fussy what video is going into it. Channels come in to transmitter sites via a distribution board which has all the electronics and decoders/encoders to provide a finished signal before it goes into the transmitter. However because of the old BBC/IBA and latterly Crown Castle/NTL split it's likely that the BBC and ITV equipment will be in different rooms or even different buildings so the difficult bit would be to physically get the ITV feed to the BBC2 transmitter
