Emergency Broadcasts

The satellite broadcasts would continue, though whether they'd have anything being uplinked to them and for how long is another matter in that scenario.

There did use to be the rebroadcast test that the BBC did once or twice yearly at like silly o'clock in the morning but that was in the analogue days and I don't know if it still applies in the digital world.

Some of the ITV regions are fed from outside London so presumably the entire lot wouldn't fall off the air if the transmitters are working. However by this point we'd probably all be running around doing Corporal Jones impressions if truth be told...

Wait… is that Last of the Summer Wine?!

The digital equivalent of the old RBS system involves the transmitter switching to a satellite feed.

I believe it is still tested occasionally overnight, but rather than just cutting to a testcard they just put a white square in a corner on the main feed so it can be identified when the transmitter switches to a satellite feed.

If London was taken out then there wouldn't be much TV to broadcast as the vast majority of it originates from there. Though I doubt most of it would be of interest in such circumstances!

I suppose that's one advantage of the recent decentralisation of BBC TV - a lot of what was once done at TV Centre is now in various locations outside London which presumably makes things more resilient. Only one service was moved out of London though - 5 Live


However in such an event TV wouldn't be as much of a factor, for obvious reasons radio would be the more important medium. There are various facilities and procedures for radio to get the messages out in an event like that. All highly secret of course.

And if the uplink isn't in the area affected. Some channels are uplinked from the London area, there's a couple of big teleports in Hampshire which uplink a lot of services

That wasn't really to do with this sort of scenario though. It was a backup feed to individual transmitters should it lose its normal line feed.

As mentioned there is an equivalent today

Yes the TV RBS test was done that way because it was convenient to test the whole country at once.

FM radio going to RBS across the country is a fallback position for the NICAM distribution failing, as happened a few years ago when an aircon failure in an apps room somewhere exposed a single point of failure.

Yeah, it's very well connected up. The cameras are not always live shots, by the way. NHK have a network of cameras across the entire country (600 or so?) which operate in "skip back" mode when requested from NHK control. They will play the last few minutes. It's like a DVR.

A national test of the Emergency Alert System (EAS) in November 9, 2011, which went wrong:

Sounds more like a Dashcam

The alert captions are generated by the earthquake early warning system (緊急地震速報). They are shown nationwide on NHK and on all local stations within the warning area. Along with the warning from the stations, data is transmitted and even if data services are switched off, as is visible in the third video, a small banner saying 'Early Earthquake Warning' appears, giving an extra few seconds.I believe this may, although I'm not entirely sure, also show on stations where no warning is displayed (Cartoon Network, Disney Channel... etc)

There is a similar system to the USA in France called Alerte Enlèvement (Abduction Alert) and it's bloody terrifying.

This is a template one but it isn't really less scary...

I visited the TSW studios in Derry's Cross back in the summer of 1992 and I happened to raise the question about facilities for emergency broadcasts. The answers were:

1. They have the facility to interrupt transmission or overlay a caption onto a programme after receiving information by the government or the police that must be broadcast urgently.

2. Emergency broadcasts can originate in the form of a networked programme. If a local programme is being shown then it will immediately be interrupted and switched over to the emergency broadcast.

3. Pre-recorded idents existed for use when interrupting a transmission.

4. Warnings can also be issued on teletext.

Of course, things have moved on dramatically since then with 24 hour news broadcasts and the like, but facilities to issue emergency broadcasts on the main channels are built into the software controlling the TV network.