Really interesting nations opts and network chatter.

OK, so there's all of about 2 seconds of TCG on that recording of TCG in the BBC Yorkshire region.

This is the version of TCG from the BBC Yorkshire recording:

http://thetvroom.com/images/pool-z/z-051/main-000-63.jpg

...and the music playing is from the 'Sunflower' tape. So this is almost certainly a TCG transmission during a programme transfer. I believe BBC Midlands and BBC Glasgow used the Sunflower tape. We know it's not Scotland's TCG because of the narrower font used for the 'BBC2' text. This is the same font that network BBC Two used on TCG. But network's TCG has the vertical black reflection line (above one of the black rectangles near the top of the circle) slightly further to the right, as we see here:

http://thetvroom.com/tvf/bbc2-tcg-001.png

That image is taken from this YT clip I posted a page or two back....which is probably the closest evidence we've got to a programme transfer. Note the music is faded out and switched to tone on the stroke of 4pm, when the programme transfer would normally start in 1983.

The embed problem is because your site isn't https compatible.

Ah ok. Thanks. Will have to make do with URL links for now then.

Crystal Palace had a dedicated feed from TVC/BH so there was no need for it to have TCG, it could stay with TCF coming from presentation. Each of the feeds from LO SWC was opted out individually, so only the feed that needed to be switched was.

Anywhere fed via Birmingham could have got a test card generated there, that's no in doubt. Manchester, Leeds, Newcastle, Scotland, Birmingham etc could all have had a Birmingham TCG.

The assumption at the moment is the programme material being sent down the line is predominantly news-related stuff - clean clips of interviews etc. I just automatically assumed that BBC Two Pres played out this programme transfer material on the usual network feed of BBC Two and that the feed to the Crystal Palace transmitter was switched to something else (e.g., TCF or TCG) whilst this was happening. What pushes me towards this theory was that in that YT clip, why would Pres in London bother fading out the music at 4pm and replace it with tone? It's as if they were readying themselves for something and were perhaps in control of what was about to be sent down the line to the regions. Pure speculation.

But with respect to transmitters beyond the reach of Crystal Palace and prior to Birmingham in the chain, I'm curious about what happened there. From Charles' letter, it sounds as though BBC Wales intervened where BBC West was concerned.

Whilst I get that everything technically "fed" out of Birmingham could conceivably receive Birmingham's TCG, what happened here still amounts to unusual activity. By that I mean, in normal circumstances, any local output from Birmingham was confined to that BBC region. For the purposes of the "programme transfer" exercise, Birmingham effectively replaced the network feed of BBC Two to any transmitters that it fed directly or that followed it in the transmission chain (i.e., generally northwards up the country).

Why would you not!? Thanks

Edit; oh this was a very late reply

So via a contact who got in touch with a former CAR engineer. Re the BBC Two programme transfers:

"It was for feeding future network programmes to the regions when they opted out of the network and showed programmes at a later time. As far as I can remember it was done using the opt-out switches at SWC. CAR just fed the prog to SWC. Scotland were the biggest user, and it usually only involved the north distribution. It wasn't used often, only if the Rev Contrib to the north was busy. I think BM provided the Test card."

So, I assume the North Distribution started at Birmingham? Given this statement, it doesn't seem to make much sense for BBC Scotland to override Birmingham's TCG - and for Scotland to send on their TCG to NI. Why not just let Birmingham's TCG pass through Scotland and NI? Although I'm still convinced that I spotted Scotland's TCG in NI (I recall the bolder font on the channel ID), it may well have been on a very small number of occasions - and possibly for reasons other than programme transfer. Given some of the recent explanations of distribution configs, I can't think why Scotland would've put up their TCG during the programme transfer window and for that to be passed to NI (replacing a test card with another test card - doesn't seem logical).

From a technical perspective, it seems to make more sense that both NI and Scotland would receive Birmingham's TCG. After the bit of detective work in the last couple of days, it seems that Birmingham's TCG channel ID text was identical to that on network's TCG and the only discernible difference between these two TCG units was the vertical black reflection test line. And I do recall seeing that difference (live) back in 1983 when feeds were switched. Just can't remember if the channel ID font was identical. It was a very long time ago and it is a pretty obscure subject!

Still to figure out how southern distribution was dealt with during these transfers and how that fits in with what Charles has described. Hopefully a bit of input from some people in Cardiff and Belfast by next week. Have asked some additional questions of the CAR engineer too - if I get a response, hopefully that'll shed some additional light on this.

The North distribution started at LO SWC and went Birmingham, Manchester up to Glasgow. It sounds like Manchester would have had to generate a test card too (to TX locally and send on to Leeds etc). Glasgow would have had to generate their own too. NI would have received Manchester's test card rather than Birmingham's.

Remember that we're taking about the comms centres/CTAs in these places, not the regional news galleries.

Apologies gents - but not being a broadcast techie is putting me at a real disadvantage here. I'm beginning to feel utterly thick.

So, let me try and get this straight in my head. And please correct me where I'm talking nonsense (which may well be right from the start). In late-1970s and early-1980s terms...

- There are two key items here: (a) Network Distribution Feeds (NDF); (b) What gets sent out from the transmitter sites. From what I can glean, there is a main and reserve NDF. Both main and reserve NDFs are channelled through each BBC regional centre across the country. Ordinarily, the main NDF will carry Network BBC One and Network BBC Two output. As our CAR engineer hinted at, the reserve NDF could, theoretically be used for other purposes (such as programme transfer material. However, he suggests that if the reserve NDF is "busy" (not sure what kind of content it would've been carrying), then the main NDF would have to be used for programme transfers.

- The London Switching Centre - which is what I assume LO SWC stands for (pardon my ignorance) - can presumably switch the content of the NDF to any part of the country? So, if for example, LO SWC changed the main NDF to Birmingham to carry a programme that needs to be recorded in certain regional centres, every other regional centre that follows Birmingham in the NDF chain would also receive that programme on their NDF?

- Because the main NDF of BBC One and BBC Two is generally what is routed to transmitters across the country, some sort of intervention needs to occur to prevent the "programme transfer" material (which is now being sent down the NDF) being seen by viewers at home. Our CAR engineer mentioned LO SWC having "opt-out" capabilities. So: (a) could LO SWC also switch the transmitter output in those affected regions to a different source (say a Test Card G, originating in Birmingham); (b) is it only at the regional centres that the output from the transmitter can be overridden (in the same way that they do for a local news opt)?

I'll preface this by saying I'm not an engineer, just an technically minded anorak.



Yes and no - because Birmingham also had various feeds leaving it and could switch different things onto them. So for the example of a programme being sent up to Glasgow, Birmingham would put TCG onto the feeds to Nottingham and its local transmitters, eg Sutton Coldfield, but leave the network feed on the route to Manchester.

Manchester would send its own test card to Winter Hill and to Leeds, (and depending on the era also to Newcastle), but leave network going north to Glasgow and NI.

This is where the confusion comes in around Carlisle and the switching facility there. How did they put a test card on the feed to NI while leaving the network output on the feed to Glasgow?



I think in this sense the opt-out referred to LO SWC opting out of network output at their end on the feeds to certain parts of the country only, rather than remotely causing it to happen "up country". There were fully staffed switching centres around the country doing this kind of thing routinely so there was no need to automate it.

When we're talking about these opt outs, and I must confess I haven't read the whole thread, was it possible that network could go to pages from ceefax, but Birmingham could send a programme to Glasgow for later broadcasting, and thus opt out of pages from ceefax for a period of time to allow the programme to be sent?

Before all of this (TCG), I can remember as a wee 10-year old anorak ('71), flipping between BBC1UHF Belmont, Emley Moor and Bilsdale. Sometimes there'd be a change, where (say) BBC1 Bisdale would go to bars and tone, whereas Emley and Belmont would stay with TCF and music.

Presumably, this was because the microwave cct up to Newcastle was needed to send material from Leeds, Manchester or London, and that an engineer at (BBC) Newcastle or Pontop Pike had made the switch from line to local pattern generator.

From the era, or a little later, there's something that I could never get my head around.

ITV's TCF came off slide-scanners in the main regional transmitter sites. So, Blisdale's would have come from Burnhope to Pontop Pike, and then RBR's to Bilsdale. Emley Moor naturally had its own slide-scanner, and Belmont's TCF came from Mendlesham (microwave) to Tacolneston and RBL via Massingham/Winceby.

OK. But after '74 Belmont was re-assigned to Yorkshire Television.

It couldn't have RBR'd Emley Moor's TCF because local Belmont content was originated from YTV (7 mins in Calendar and the Belmont Weather Forcast**). (** Itself one of these contributions that would have taken ITV/IBA resource to transfer via the PO London, Birmingham and Manchester switching matrices hopefully straight from the studio floor in Norwich to a VT machine at YTV.)

This meant that Belmont *had* to be microwave fed. So, how did Belmont get TCF?

Did Emley Moor trombone Belmont's feed back to Tinshill, then Upton/Farley? Even though Emley is a massive stable structure, and los to Belmont, I can't believe that the IBA had their own microwave route (single-hop) Emley Moor to Belmont. Or, perhaps YTV fed Belmont directly, and the IBA used a remote switch at Belmont to take Emley via an off-air receiver and thus show TCF?