BBC 1 & 2 Engineering Closedowns

I think it's because ITV is notionally a regional broadcaster, and back in the day Belmont losing its feed and rebroadcasting Sutton would have been a big deal in terms of advertising revenues etc.

There have been occasions during ITV Nightscreen in London when the picture goes fuzzy for a litle while and Teletext switches to ITV SOUTH being fed from Rowridge... Someone can correct me if I'm wrong, but I believe it's actually the backup feed from Croydon being tested when that happens?

There used to be (and for all I know may still be) a small white marker inserted bottom right or left in the BBC One feed from Sandy Heath when BBC Cambridge were testing opt-out switching. (It was placed bottom of screen rather than top so as not to mask cue-dots - not that they are used in the same way any more)

Unlike most analogue regions, you can also spot the Sandy Heath switch because it is accompanied by a significant frame delay being added and removed.

I suspect this is the reason - as in the days of regional ITV Companies, they considered themselves pretty independent - and the idea of rebroadcasting a neighbouring franchise would not really have been an option to be considered.

There is also the issue that BBC One is deemed to be the "most important" network - and in times of national emergency, when regional stations and network feeds may be interrupted, an automatic rebroadcast chain that works may be deemed of national importance?

CP is also deemed to be one of the most important transmitters in the UK - because the feed to it is important (though if it is knocked out, if network reaches other transmitters the rebroadcast chain still works)

Speaking of closedowns, nice one on BBC2 last night with the announcer saying you can fall asleep on the sofa with some christmassy ceefax music! (although IMHO the music was horrible)

The reason for annual RBS tests, as with Network Recall and Radio NICAM ones really stems from Engineers influence in the old days. You know when Technical Quality was considered important by the mandarins.

you wait, once siemens empire grows they'll charge them out of existence!



CP has several differently routed feeds, and all are unlikely to be knocked out. The normal Network distribution is point to multi-point so the next one up in the RBS chain would take over. Having said that there is also a continguency plan to inject into Network distribution if BC & TVC are knocked out.

Yep - I should have said "feeds"!

do they perform network recall tests?

There used to be a test with a "BM" dog added to ceefax - which was to test routing network via Pebble Mill.

I'm not aware of one having been done for years, and the infrastructure for London to "force" back a Nation no longer exists. Not sure about regions, my guess is that they could force back the analogue feed but not the digital one.

The official ones always used to get cancelled cos someone always managed to create an impromptu one by leaning on the button in London.....

Edit : DTT has the BNCS to do Network Recall, and DSAT will follow.

There's something odd about a system which allows non-BBC staff to take control of BBC output and out of the hands of BBC staff. Or perhaps the oddity is the bigger picture.