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Markymark6,726 posts since 13 Dec 2004
Meridian (North) South Today

It was called RBS, the BBC’s main transmitters had ( where possible) and alternative source. My local Tx Hannington which was off air fed by Rowridge, had Crystal Palace as an RBS source ( for the BBC, and Mendip for C4)

Lower order transmitters and relays had no back up source should the parent die.


ITV and C4 used to have a backup transmitter for London/SE at Croydon in the event of failure at Crystal Palace. IIRC it was actually fed from one of the Meridian transmitters (possibly Hannington?) as on occasions when it was tested you would get ITV/C4 South Teletext and pressing Reveal on P100 would show the Rowridge three letter transmitter code.


Right, now, hold tight. You're quite right there were back up analogue transmitters for ITV and C4 at Croydon (later, from about 2006 for BBC1/2 too, but that's another story). Because the Teletext Ltd (from now on in this post, referred to as 'Teletext') server/inserter for London was at Crystal Palace, that would obviously vanish in the event of a catastrophe at CP. Therefore at Croydon there was a data bridge, that took the Teletext data from the Hannington RBS receiver, and inserted it into the incoming video feed from LNN.
If both LNN and CP were to ever both suffer a catastrophe ! then Hannington became the video source (same mirrored arrangement for C4 of course)

Hannington itself, that was line fed for the Meridian North region, had a data bridge that took Teletext data from the Rowridge RBS receiver, and added it to the incoming video feed from line.

If Rowridge suffered a power glitch, the Teletext server there appeared to have no UPS, because it would take 10 mins or so for the carousel of pages to rebuild again from scratch. I think the servers were fed from Teletext HQ in Fulham by 9.6k data lines ? Cool
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Si-Co2,122 posts since 2 Oct 2003
Tyne Tees Look North (North East)
Nothing particularly interesting here, except the generic branding on the breakdown slide suggests that Carlton or LWT are playing this out to the entire network. This was before the days of shared continuity, but after networked ECPs were introduced (so everything passed through LNN who sent out a not-quite-clean feed to all stations). I assume that once this new networking arrangement came in, it was no longer the responsibility of a local station to cover a breakdown.

Much has been discussed about the networking arrangements in the early 90s and before, and the post-2002 arrangements, but not about the period in between (roughly equating to the “hearts era”) which seemed to be a combination of traditional networking arrangements and local/semi-local presentation along with centralised playout and some shared presentation/ECPs etc.

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Steve in Pudsey9,988 posts since 4 Jan 2003
Yorkshire Look North (Yorkshire)

Therefore at Croydon there was a data bridge, that took the Teletext data from the Hannington RBS receiver, and inserted it into the incoming video feed from LNN.


Was there anything to prevent the wrong subtitles going out if Meridian were showing something different? Or was the correct ITV provided p6xx Ancillary magazine (which had nothing to do with Teletext Ltd) available?
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Technologist37 posts since 10 Oct 2018
London London
The different teletext services were on diferent tv lines so you just did not bridge those lines.
E.g. Itv subtitles were in line 335 only
Likewise the Teletext ltd service was only added on its tv lines,
while the feed from the local station carried its 6xx and subtitles on their lines 21-334 & 22. And 335

Actually you could have a clever data bridge such as the BBC had which could filter by magazine number and then output that on certain tv lines
There is a lot about these and other strange teletext engines
In a SMPTE event ..
the slides are at https://www.smpte.org/sections/united-kingdom/events/untold-stories-teletext-celebrating-40-years-digital-broadcasting

And there is a code of practise on allocation of VBI space
https://www.etsi.org/deliver/etsi_tr/101200_101299/101233/01.01.01_60/tr_101233v010101p.pdf
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bluecortina835 posts since 26 Jul 2012
I'll d

The different teletext services were on diferent tv lines so you just did not bridge those lines.
E.g. Itv subtitles were in line 335 only
Likewise the Teletext ltd service was only added on its tv lines,
while the feed from the local station carried its 6xx and subtitles on their lines 21-334 & 22. And 335

Actually you could have a clever data bridge such as the BBC had which could filter by magazine number and then output that on certain tv lines
There is a lot about these and other strange teletext engines
In a SMPTE event ..
the slides are at https://www.smpte.org/sections/united-kingdom/events/untold-stories-teletext-celebrating-40-years-digital-broadcasting

And there is a code of practise on allocation of VBI space
https://www.etsi.org/deliver/etsi_tr/101200_101299/101233/01.01.01_60/tr_101233v010101p.pdf


The document you point to also answers a point that I think we discussed some time ago - Line 22. I thought it was used as a quiet line with no information on it, you thought it was used for teletext.

Referring to page 15:

" ....Lines 21/335 were selected to maximize the amount of space available for Teletext services, whilst leaving a blank line pair 22/335 for the use of test signals on point-to-point links in the TV distribution system. ...".

So it would seem that Line 22 was indeed a quiet line between ITV studio centres, but could be modulated with teletext on transmission feeds. In effect, we are both right!! I remember only looking at Line 22 in MCR so it would have been looking directly at incoming ITV network feeds.
Technologist37 posts since 10 Oct 2018
London London
The annex B describes the BBC operation which had the one line ITS ...... Whuch is described in the text

The BBC specified that mixers ( or at least the studio ) passed lines 20/333 subtitles - 21/334 ITS and then 22/335 normally empty ...

Itv and ch 4 used line 335 for subtitles with lin 22 blank most of the time ...and lin 21/334 having the ancillary mag 6xx service which was in theory able to be filled with the ancillary service or other things ..
for instance it was used for the AudeTel experiment of audio descriptions with CELP encoded audio ....

Thus it is likely that you saw line 22 as a blank line.

Because if the BBC requirement to show a (super) efficient use if the vbi hence ceefax outputting In 14 1/2 line pairs but being emitted on 13 line pairs it had the kit to mux AD celp and subtitles on the same lines .... in part because the CELP was only one packet / frame and tha ad and subs tend Not to happen at the same time!
But it was started in line 22/335 actually in 335 so we could tell,which network we were looking at ! A single teletext line is about 8 kbit /s
Si-Co2,122 posts since 2 Oct 2003
Tyne Tees Look North (North East)
Some of the above may be going somewhat over my head, however I recall from the Oracle days that when Thames were behind the network with Coronation Street (in late 1984), subtitles for the Thames broadcast were carried on P399 in London only (with the “wrong” subtitles being networked on P199). Evidently Thames couldn’t - or didn’t - opt out of the networked subtitles.
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JAS843,902 posts since 26 Aug 2010
Yorkshire Look North (E.Yorks & Lincs)
Nothing particularly interesting here, except the generic branding on the breakdown slide suggests that Carlton or LWT are playing this out to the entire network. This was before the days of shared continuity, but after networked ECPs were introduced (so everything passed through LNN who sent out a not-quite-clean feed to all stations). I assume that once this new networking arrangement came in, it was no longer the responsibility of a local station to cover a breakdown.

Much has been discussed about the networking arrangements in the early 90s and before, and the post-2002 arrangements, but not about the period in between (roughly equating to the “hearts era”) which seemed to be a combination of traditional networking arrangements and local/semi-local presentation along with centralised playout and some shared presentation/ECPs etc.

https://www.youtube.com/watch?v=p3rRnEX-aWs
An England match, and was that the Finland manager we see at the end? If so, this was a Saturday, 24 March. So it would be LWT.

https://en.wikipedia.org/wiki/England_national_football_team_results_(2000%E2%80%9319)#2001
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Lewismpsmith68 posts since 12 May 2018
Meridian (South East) South East Today
Nothing particularly interesting here, except the generic branding on the breakdown slide suggests that Carlton or LWT are playing this out to the entire network. This was before the days of shared continuity, but after networked ECPs were introduced (so everything passed through LNN who sent out a not-quite-clean feed to all stations). I assume that once this new networking arrangement came in, it was no longer the responsibility of a local station to cover a breakdown.

Much has been discussed about the networking arrangements in the early 90s and before, and the post-2002 arrangements, but not about the period in between (roughly equating to the “hearts era”) which seemed to be a combination of traditional networking arrangements and local/semi-local presentation along with centralised playout and some shared presentation/ECPs etc.

https://www.youtube.com/watch?v=p3rRnEX-aWs
An England match, and was that the Finland manager we see at the end? If so, this was a Saturday, 24 March. So it would be LWT.

https://en.wikipedia.org/wiki/England_national_football_team_results_(2000%E2%80%9319)#2001


Actually this was from Wednesday 28th February where England played Spain that evening.

Ehiogu had just scored for England before the directors cut to the breakdown slide.

How do I know this? Well.



Last edited by Lewismpsmith on 9 July 2019 4:29am - 2 times in total
Si-Co2,122 posts since 2 Oct 2003
Tyne Tees Look North (North East)
OK, so it appears the voice over the breakdown slide is a Carlton announcer. As I said above, the interesting part for me is that the breakdown slide and announcement appears to be networked along with the programme, which was never the case in the early 90s and before. I’m not sure if UTV, STV and GPN took this generic caption - I’m sure they had the same feed as everyone else, but I don’t know what their stance was about ITV-branded content in those days.

I may be wrong, and Carlton (or whatever region this is) just happens to be using a generic caption and transmitting it locally, but I doubt it.
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