SP
Presumably the Channel Islands analogue services won't be taking part in this test, as they're fed from DSAT nowadays
MA
And it's meaningless for some transmitters at the end of cul-de-sac distributions.
Redruth has no other option than its normal RBL feed from Caradon Hill. Much the same applies for transmitters north and west of Rosemarkie. Although of course picture quality will drop owing to the RBS feeds upstream.
My own local Tx Hannington is interesting. Normally RBL Rowridge, which is often quite a ropey signal. For RBS it switches to Crystal Palace, and the picture noticeably improves
Steve in Pudsey posted:
Presumably the Channel Islands analogue services won't be taking part in this test, as they're fed from DSAT nowadays
And it's meaningless for some transmitters at the end of cul-de-sac distributions.
Redruth has no other option than its normal RBL feed from Caradon Hill. Much the same applies for transmitters north and west of Rosemarkie. Although of course picture quality will drop owing to the RBS feeds upstream.
My own local Tx Hannington is interesting. Normally RBL Rowridge, which is often quite a ropey signal. For RBS it switches to Crystal Palace, and the picture noticeably improves
NG
My own local Tx Hannington is interesting. Normally RBL Rowridge, which is often quite a ropey signal. For RBS it switches to Crystal Palace, and the picture noticeably improves
Though it then broadcasts BBC London not BBC South - which is presumably the reason for the lower quality feed being use?
noggin
Founding member
Markymark posted:
My own local Tx Hannington is interesting. Normally RBL Rowridge, which is often quite a ropey signal. For RBS it switches to Crystal Palace, and the picture noticeably improves
Though it then broadcasts BBC London not BBC South - which is presumably the reason for the lower quality feed being use?
IS
And it's meaningless for some transmitters at the end of cul-de-sac distributions.
Redruth has no other option than its normal RBL feed from Caradon Hill. Much the same applies for transmitters north and west of Rosemarkie. Although of course picture quality will drop owing to the RBS feeds upstream.
Just because they're at the end of the distribution doesn't mean that testing them is pointless. There are still viewers who are served by them even if there are no further dependant transmitters
My own local Tx Hannington is interesting. Normally RBL Rowridge, which is often quite a ropey signal. For RBS it switches to Crystal Palace, and the picture noticeably improves
ITV and Channel 4 (AFAIK not the BBC) from Crystal Palace use Hannington as RBS should the feed to it go down. I assume there's some system to prevent some sort of RBS feedback loop between the 2!
Markymark posted:
And it's meaningless for some transmitters at the end of cul-de-sac distributions.
Redruth has no other option than its normal RBL feed from Caradon Hill. Much the same applies for transmitters north and west of Rosemarkie. Although of course picture quality will drop owing to the RBS feeds upstream.
Just because they're at the end of the distribution doesn't mean that testing them is pointless. There are still viewers who are served by them even if there are no further dependant transmitters
Quote:
My own local Tx Hannington is interesting. Normally RBL Rowridge, which is often quite a ropey signal. For RBS it switches to Crystal Palace, and the picture noticeably improves
ITV and Channel 4 (AFAIK not the BBC) from Crystal Palace use Hannington as RBS should the feed to it go down. I assume there's some system to prevent some sort of RBS feedback loop between the 2!
MA
My own local Tx Hannington is interesting. Normally RBL Rowridge, which is often quite a ropey signal. For RBS it switches to Crystal Palace, and the picture noticeably improves
ITV and Channel 4 (AFAIK not the BBC) from Crystal Palace use Hannington as RBS should the feed to it go down. I assume there's some system to prevent some sort of RBS feedback loop between the 2!
That might be right, though there'd be no risk of feedback. ITV Hannington is line fed, C4 is RBL Rowridge. ITV RBS for Hannington is Rowridge, C4 RBS is Mendip. There is risk of feedback with the BBC, because in an RBS condition, Rowridge takes Hannington.
However, I think some of that has recently changed to using D-Sat 28E feeds as RBS sources for ITV/4, that way those all important regional ads still come out in the correct place ?
Inspector Sands posted:
Markymark posted:
My own local Tx Hannington is interesting. Normally RBL Rowridge, which is often quite a ropey signal. For RBS it switches to Crystal Palace, and the picture noticeably improves
ITV and Channel 4 (AFAIK not the BBC) from Crystal Palace use Hannington as RBS should the feed to it go down. I assume there's some system to prevent some sort of RBS feedback loop between the 2!
That might be right, though there'd be no risk of feedback. ITV Hannington is line fed, C4 is RBL Rowridge. ITV RBS for Hannington is Rowridge, C4 RBS is Mendip. There is risk of feedback with the BBC, because in an RBS condition, Rowridge takes Hannington.
However, I think some of that has recently changed to using D-Sat 28E feeds as RBS sources for ITV/4, that way those all important regional ads still come out in the correct place ?
JV
James Vertigan
Founding member
That test that happens occasionally on ITV/C4 in the middle of the night is, I believe, the backup link at Croydon being tested in case CP ever fails.
When they are broadcasting on the backup from Croydon you will notice that the Teletext signal switches to "ITV South" or "C4 South" from Rowridge - I think that's probably where the teletext signal is fed from, but you could be right about the actual broadcast signal coming from Hannington.
When they are broadcasting on the backup from Croydon you will notice that the Teletext signal switches to "ITV South" or "C4 South" from Rowridge - I think that's probably where the teletext signal is fed from, but you could be right about the actual broadcast signal coming from Hannington.
MA
This is ringing some bells now. I think the Teletext data does indeed come from Hannington, but I've got a feeling the video/audio still comes from the 'London ITV' output of LNN-Southern Playout Centre and C4 HFR.
Remember that ITV and C4 Teletext servers are sited at each primary regional transmitter (NOT at any ITV/C4 building). Therefore if Crystal Palace suffers a power failure etc, off goes the Teletext server for London too.
If Croydon has to step in and replace CP for whatever reason, it still takes audio and video from the normal sources, but Teletext has to be provided from the Rowridge server (via RBS Hannington).
I suspect the the lines from LNN and HFR to CP, 'loop through' Croydon, but that's pure speculation.
James Vertigan posted:
That test that happens occasionally on ITV/C4 in the middle of the night is, I believe, the backup link at Croydon being tested in case CP ever fails.
When they are broadcasting on the backup from Croydon you will notice that the Teletext signal switches to "ITV South" or "C4 South" from Rowridge - I think that's probably where the teletext signal is fed from, but you could be right about the actual broadcast signal coming from Hannington.
When they are broadcasting on the backup from Croydon you will notice that the Teletext signal switches to "ITV South" or "C4 South" from Rowridge - I think that's probably where the teletext signal is fed from, but you could be right about the actual broadcast signal coming from Hannington.
This is ringing some bells now. I think the Teletext data does indeed come from Hannington, but I've got a feeling the video/audio still comes from the 'London ITV' output of LNN-Southern Playout Centre and C4 HFR.
Remember that ITV and C4 Teletext servers are sited at each primary regional transmitter (NOT at any ITV/C4 building). Therefore if Crystal Palace suffers a power failure etc, off goes the Teletext server for London too.
If Croydon has to step in and replace CP for whatever reason, it still takes audio and video from the normal sources, but Teletext has to be provided from the Rowridge server (via RBS Hannington).
I suspect the the lines from LNN and HFR to CP, 'loop through' Croydon, but that's pure speculation.
JV
This is ringing some bells now. I think the Teletext data does indeed come from Hannington.....
Sorry Mark, should that not be Rowridge?
James Vertigan
Founding member
Markymark posted:
This is ringing some bells now. I think the Teletext data does indeed come from Hannington.....
Sorry Mark, should that not be Rowridge?
MA
This is ringing some bells now. I think the Teletext data does indeed come from Hannington.....
Sorry Mark, should that not be Rowridge?
Yes, that's where the Teletext data is generated, at the server there. Hannington picks this up on an RBL link, and it's Data Bridged onto the audio/video line feed it receives (aka ITV Thames Valley-South from LNN).
Croydon therefore picks Hannington's Teletext data up, and Data Bridges this onto the LNN/HFR line feeds.
James Vertigan posted:
Markymark posted:
This is ringing some bells now. I think the Teletext data does indeed come from Hannington.....
Sorry Mark, should that not be Rowridge?
Yes, that's where the Teletext data is generated, at the server there. Hannington picks this up on an RBL link, and it's Data Bridged onto the audio/video line feed it receives (aka ITV Thames Valley-South from LNN).
Croydon therefore picks Hannington's Teletext data up, and Data Bridges this onto the LNN/HFR line feeds.
IS
Remember that ITV and C4 Teletext servers are sited at each primary regional transmitter (NOT at any ITV/C4 building). Therefore if Crystal Palace suffers a power failure etc, off goes the Teletext server for London too.
Not every main transmitter, I think it's only about 25 of them (at least it was at launch) this means that they can split the service 25 ways, but some transmitters can't have their own. Hannington is one of these - it takes the output of Rowridge's teletext server.
The subtitles, PDC and the ancillary services (now gone) do come straight from ITV/C4 the only time I've seen a Croydon or a RBS in London I didn't get a chance to check page 600 to see what happened to that
No idea either, but for resiliance and to avoid a single point of failure they'd need to have one path going TX-Croydon-CP and the other going TX-CP-Croydon. So if something major happened at Croydon; CP would still get a feed and vice versa.
Reminds me of a story i heard about OnDigital - their lines from Battersea to Crystal Palace were designed with 2 totally diffrent routes for resiliance.... except someone had decided they should both cross the Thames by the same bridge!
Markymark posted:
Remember that ITV and C4 Teletext servers are sited at each primary regional transmitter (NOT at any ITV/C4 building). Therefore if Crystal Palace suffers a power failure etc, off goes the Teletext server for London too.
Not every main transmitter, I think it's only about 25 of them (at least it was at launch) this means that they can split the service 25 ways, but some transmitters can't have their own. Hannington is one of these - it takes the output of Rowridge's teletext server.
The subtitles, PDC and the ancillary services (now gone) do come straight from ITV/C4 the only time I've seen a Croydon or a RBS in London I didn't get a chance to check page 600 to see what happened to that
Quote:
I suspect the the lines from LNN and HFR to CP, 'loop through' Croydon, but that's pure speculation.
No idea either, but for resiliance and to avoid a single point of failure they'd need to have one path going TX-Croydon-CP and the other going TX-CP-Croydon. So if something major happened at Croydon; CP would still get a feed and vice versa.
Reminds me of a story i heard about OnDigital - their lines from Battersea to Crystal Palace were designed with 2 totally diffrent routes for resiliance.... except someone had decided they should both cross the Thames by the same bridge!
MA
Remember that ITV and C4 Teletext servers are sited at each primary regional transmitter (NOT at any ITV/C4 building). Therefore if Crystal Palace suffers a power failure etc, off goes the Teletext server for London too.
Not every main transmitter, I think it's only about 25 of them (at least it was at launch) this means that they can split the service 25 ways, but some transmitters can't have their own. Hannington is one of these - it takes the output of Rowridge's teletext server.
That's why I said every primary regional tx
i.e Sutton Coldfield, but not Ridge Hill and The Wrekin. But as you say there's about 25, so some sub regional primaries have them, Dover and Waltham for instance.
I suspect the the lines from LNN and HFR to CP, 'loop through' Croydon, but that's pure speculation.
No idea either, but for resiliance and to avoid a single point of failure they'd need to have one path going TX-Croydon-CP and the other going TX-CP-Croydon. So if something major happened at Croydon; CP would still get a feed and vice versa.
Reminds me of a story i heard about OnDigital - their lines from Battersea to Crystal Palace were designed with 2 totally diffrent routes for resiliance.... except someone had decided they should both cross the Thames by the same bridge!
And of course the now infamous Aug 5th BBC Radio distribution debacle
http://www.lamont.me.uk/broadcast/
Inspector Sands posted:
Markymark posted:
Remember that ITV and C4 Teletext servers are sited at each primary regional transmitter (NOT at any ITV/C4 building). Therefore if Crystal Palace suffers a power failure etc, off goes the Teletext server for London too.
Not every main transmitter, I think it's only about 25 of them (at least it was at launch) this means that they can split the service 25 ways, but some transmitters can't have their own. Hannington is one of these - it takes the output of Rowridge's teletext server.
That's why I said every primary regional tx
i.e Sutton Coldfield, but not Ridge Hill and The Wrekin. But as you say there's about 25, so some sub regional primaries have them, Dover and Waltham for instance.
Inspector Sands posted:
Markymark posted:
I suspect the the lines from LNN and HFR to CP, 'loop through' Croydon, but that's pure speculation.
No idea either, but for resiliance and to avoid a single point of failure they'd need to have one path going TX-Croydon-CP and the other going TX-CP-Croydon. So if something major happened at Croydon; CP would still get a feed and vice versa.
Reminds me of a story i heard about OnDigital - their lines from Battersea to Crystal Palace were designed with 2 totally diffrent routes for resiliance.... except someone had decided they should both cross the Thames by the same bridge!
And of course the now infamous Aug 5th BBC Radio distribution debacle
http://www.lamont.me.uk/broadcast/
SP
Remember that ITV and C4 Teletext servers are sited at each primary regional transmitter (NOT at any ITV/C4 building). Therefore if Crystal Palace suffers a power failure etc, off goes the Teletext server for London too.
Not every main transmitter, I think it's only about 25 of them (at least it was at launch) this means that they can split the service 25 ways, but some transmitters can't have their own. Hannington is one of these - it takes the output of Rowridge's teletext server.
That's why I said every primary regional tx
i.e Sutton Coldfield, but not Ridge Hill and The Wrekin. But as you say there's about 25, so some sub regional primaries have them, Dover and Waltham for instance.
Are you sure Ridge Hill doesn't? Pressing reveal on ITV1 Teletext P100 brings up 'RID'.
Markymark posted:
Inspector Sands posted:
Markymark posted:
Remember that ITV and C4 Teletext servers are sited at each primary regional transmitter (NOT at any ITV/C4 building). Therefore if Crystal Palace suffers a power failure etc, off goes the Teletext server for London too.
Not every main transmitter, I think it's only about 25 of them (at least it was at launch) this means that they can split the service 25 ways, but some transmitters can't have their own. Hannington is one of these - it takes the output of Rowridge's teletext server.
That's why I said every primary regional tx
i.e Sutton Coldfield, but not Ridge Hill and The Wrekin. But as you say there's about 25, so some sub regional primaries have them, Dover and Waltham for instance.
Are you sure Ridge Hill doesn't? Pressing reveal on ITV1 Teletext P100 brings up 'RID'.