Power outage at BBC Wales

Just seems surprising that such a system would route the clean feed rather then Net1, unless it's an equivalent of the system that prevented RBS during regional opts on analogue.

It might have been Net 1 initially, but then a seamless router switch (in a controlled manner), to a clean feed later?

The holding animation after the Six suggests otherwise?

I don't recall anything in the analogue days that would go into bypass in a total power failure, unless it was post mid 1990s.
The problem would be that all incoming circuits would be equalised and then be bought back up to line level by a line amplifier. With no power that doesn't work. The line send amplifiers were on the outgoing circuits.
Simply connecting the co-ax together would produce a mismatch - so SiS probably wouldn't decode for example.
Maybe there was a UPS introduced on that kit (with its own potential issues).
Plus of course it is not just the feed to their local transmitters, but also onpassing the network feed to the next site.

When I was working one day at the London Switching Centre, a lot of phones rang at the same time - never a good sign.
BBC 1 and BBC 2 to Manchester had been lost. I couldn't get hold of Birmingham.
Eventually Pebble Mill Comms Centre rang me on the DEL. They had had a power failure and had been ringing BT to take them out of circuit to restore BBC 1 and 2 to the local Midlands tx and lines north and east, and the reverse contribution back to me from Manchester.
A very manual process indeed. This would have been around 1989.
The feed up country north of Oxford had reverted to RBS while this happened - via the weak Oxford > Sutton Coldfield link.

At a place I worked a while back we had a rather limited UPS backup which would only keep us up and running for half hour (depending on how much load we were drawing), just enough to (hopefully) be able to de-power everything essential. But our broadcast network was a loop around sites so it passed through us and had it's own seperate battery back up UPS which, as it was just powering a few bits of kit.

Maybe that's the same in this case, there's a seperate backup power just enough to maintain distribution circuits into and back out of the building?

Well, by clean feed I was thinking of what Red Bee normally send down the pipe to the nations, programmes interspersed by holding animations?

I didn't realise the distribution was daisy chained through each centre, I had assumed it was DA'd by BT at their NSCs, and tromboned through each centre on local ends.

Yes, you're quite right, I'd forgotten you'd have DAs to Eq the outgoing lines, so some form of juice is still required.
Then the first line of defence back in the analogue era would have been RBS at the primary transmitter

Don't forget back in those days it was possible to use the Network Distribution circuits to carry programme material to other regions out of programme hours (radiating local test signals while this happened).
Therefore Birmingham could feed Manchester or Norwich, so the network had to pass through Pebble Mill.

Yes. How responsive were the various BT NSCs to switching round problems for you, (presumably they
were relatively close at hand, because of the ITV switching they were routinely doing ?)

BT were excellent, we would have control lines to our local exchange, in my case BT Tower, Pebble Mill to BT Birmingham NSC (and possibly Anchor exchange too).
They would be very quick to react, especially when there was a fault condition.
Bear in mind that we would also be booking Protection circuits with them when the permanent BBC circuits were overbooked.

UPS have become much more manageable these days, so essential kit can be kept running, although the kit itself is now more power hungry than the old line recieve and line send amplifiers back in the 1980s.
What sort of site vere you working in ( an island site for example)?

It was part of a fibre ring, so all that was needed was to keep the traffic moving around that. Doesn't take much power