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Really interesting nations opts and network chatter.

Can you tell I really don't know what to call this topic. (January 2018)

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MM
MMcG198
TonyCurrie posted:
Oh, and to go back to the prehistoric days before anoraks had been invented, Northern Ireland's programme vision feed in the early '50s was an RBL from Kirk o'Shotts, and in the very early days of Glencairn (the temporary site for Belfast before Divis was completed) Ko'S* had to radiate Test Card 'C' out of normal hours to give Glencairn some pictures for their test transmissions. Initially, the first NI programme "Ulster Mirror" was shot on film (NI had no studios), then sent to Glasgow for playout via KoS. So Scottish viewers saw the programme as well. Audio, however was distributed by BT.

*Until UHF came along, most main 405 line stations had either a slide scanner or a monoscope to radiate their own test card. Shotts initially had a Cathodeon Monoscope, especially necessary as they only took network programmes in afternoons and evenings and didn;t take any Trade transmissions in the mornings until the South - North link was properly completed.


Nice info Tony. Before the anorak was invented you say. Wink

I always thought that 'Ulster Mirror' was shown across the whole BBC network in its early days?
SP
Steve in Pudsey
Could it be that the off-air BBC Scotland which was available at Divis was routed to Belfast BH via the circuit used for OB contributions?

Apparently at one time there was a test card with an electronically generated BBC WALES ident. Enterprising engineers in Cardiff CTA found that each letter was generated by a different add-on card, so amused themselves with "BBC ALES"
MM
MMcG198
Steve in Pudsey posted:
Could it be that the off-air BBC Scotland which was available at Divis was routed to Belfast BH via the circuit used for OB contributions?


Possible Steve. I suspect it's going to be difficult to get a definitive answer on this as many of the people who were involved in this type of thing will have left the BBC. But, I'm doing a bit of digging. I'm glad I brought up the subject again after all these years. I feel I'm getting closer to the facts now.

Steve in Pudsey posted:
Apparently at one time there was a test card with an electronically generated BBC WALES ident. Enterprising engineers in Cardiff CTA found that each letter was generated by a different add-on card, so amused themselves with "BBC ALES"


I'm enquiring about how BBC Wales handled the programme transfers. They definitely had their own TCG generator and I've seen mocks online where a 'BBC Wales' ID is displayed. More hopeful of getting a definitive answer re BBC Wales.
DE
deejay
Can I just say, hope you don’t mind
BEST THREAD ON HERE IN YEARS

Thankyou.

Wasn’t the Carlisle studio (which I think ended up as a DTL contribution studio) the last to have the 1999 (?) Lambie-Nairn cream window on the world set still to be seen on air?
CO
commseng
MMcG198 posted:
Would you say this is a fair assessment of what happened during the 'programme transfer' process on BBC Two:

BBC Birmingham fed their version of Test Card G + music to all transmitter sites in England.
BBC Wales fed their version of Test Card G + music to all transmitter sites in Wales.
BBC Scotland fed their version of Test Card G + music to all transmitter sites in Scotland and Northern Ireland.

Presumably part of the reasoning behind this weird set-up is the fact that the SE of England was effectively served by the network feed 24x7. And if that feed was being used to send programme material, there needed to be some way of preventing viewers in the SE seeing that. Having Birmingham send their output to all transmitter sites got around that presumably? I'm assuming TVC couldn't send anything other than network feed to transmitters in the SE? If they could, I can't understand why each region couldn't just opt in to BBC Two, put out their own test card (assuming they had a generator and music - and perhaps this was also part of the problem), and record what was coming in on the network feed? Perhaps a lack of resourcing for BBC Two opts in regional centres also had a part to play - don't know. But it would be good to understand the rationale behind this.

And re your point about if a switch occurred at Carlisle, it would probably look messy. Well, I saw that switch at 4pm in 1983 in Northern Ireland on a number of occasions - and it was actually reasonably tidy. Just a slight picture hiccup. I kick myself now because if I had looked at the VBI at the time, that might've told me a bit more about where the Test Card was coming from.

Just going back to an earlier question, it has just occurred to me that the bit about Pebble Mill being able to feed all the transmitters in England is probably a reference to the Network tests when it was simulated that London was unavailable.
This would have been later once the Energis distribution was in place and could be reconfigured if required.

Before then when it was still on BT, there was one vision circuit from Birmingham to London, which could be either routed by London Switching Centre at LBH to either or both networks. Or could have been overplugged at BT Tower. This would allow for failure at both TVC and LBH - an unlikely scenario unless you imagine a major disaster. At which point there may not be a BT Tower either......
The more realistic set of circumstances was a part evacuation of TVC, in which case network could be sourced from News in the Spur via lines to LO SWC. If TVC was completely unavailable (power failure for example) then Lime Grove could be routed via the Loco to LBH (one line only). If that was also impractical, then LO SWC would keep the networks up with our local pulse and bar, and then hand over to Pebble Mill when they were able to take over.
These contingency plans were in place, but not used that I am aware of.
All of this is now long gone of course.

This is very different to using the network distribution when it wasn't in use for programme service to move programmes between BBC sites for later transmission.
MMcG198, Steve in Pudsey and Markymark gave kudos
MA
Markymark
TonyCurrie posted:
The BBC Scotland generator came into service in early 1970 I think. The choice of ident was a BBC modification, so I don;t know if other PM5544 generators were similarly modified.


The BBC applied a few modifications to the PM5544. They used to love to apply (or request to have applied) modifications to kit back then !

https://www.radios-tv.co.uk/Pembers/Test-Cards/Test-Card-Technical.html#PM5544
MA
Markymark
MMcG198 posted:

Your videotape comment got me thinking. I don't think it was videotape actually - the tape would've been well worn.


I can't imagine there'd have been any routine instances of originating at test signal off tape. Using a VTR back then had a 'cost', and no broadcaster would have tied up resources in that manner. Also, the signals off tape would be totally invalid as test signals. There are far cheaper methods (tone and black/bars) to keep a circuit or transmitter alive out of programme hours.
CO
commseng
So, no VT channels tied up, no extra lines rented (protection circuits) as both would cost.
If BBC Scotland's test signals ended up on BBC NI's transmitters the only option would have been a network switch at Carlisle.
We would need someone on here from Manchester CTA back in the 1980s who could confirm if this was possible on the remote unit. Plus the real concern as to what would happen if it it didn't switch back.
It would also tie up the outgoing line from Glasgow to all points south.
If I get time I will see if I can find any notes from back then as to if the contribution network is as I remember it.
I still think the most likely scenario is simply that Belfast had their own generator.
TC
TonyCurrie
commseng posted:
So, no VT channels tied up, no extra lines rented (protection circuits) as both would cost.
If BBC Scotland's test signals ended up on BBC NI's transmitters the only option would have been a network switch at Carlisle.
We would need someone on here from Manchester CTA back in the 1980s who could confirm if this was possible on the remote unit. Plus the real concern as to what would happen if it it didn't switch back.
It would also tie up the outgoing line from Glasgow to all points south.
If I get time I will see if I can find any notes from back then as to if the contribution network is as I remember it.
I still think the most likely scenario is simply that Belfast had their own generator.


But remember the PM5544 generators were hugely expensive bits of kit. I take on board the idea that there would not have been 'routine' instances of originating test card off VT but it's not impossible as the odd one-off. I very much doubt that an RBL link would have been used for the test card so that leaves us with the circuit theory, which seems the most plausible.
TC
TonyCurrie
Don't know if I should post this link but it takes you to Gary Platten's colossal job of restoring the dead BBC Scotland PM5544. http://www.forum.radios-tv.co.uk/viewtopic.php?f=5&t=7998
JA
james-2001
Of course you should post it, it's very interesting!
MM
MMcG198
TonyCurrie posted:
Don't know if I should post this link but it takes you to Gary Platten's colossal job of restoring the dead BBC Scotland PM5544. http://www.forum.radios-tv.co.uk/viewtopic.php?f=5&t=7998


Absolutely fantastic! Thanks for posting this Tony.

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