Digital Spy

Search Digital Spy
 

DS Forums

 
 
 

COM7 mux, Al Jazeera HD - LCN 108


Reply
Thread Tools Search this Thread
Old 08-11-2013, 11:51
OwenSmith
Forum Member
 
Join Date: Nov 2003
Location: Cambridge, UK
Posts: 1,774
But why would DigitalUK see a benefit in providing that? It would be of little interest to the trade (who would be likely to be interested in their own region), of no interest to the public at large, and as such DUK would be unlikely to perceive it as being of benefit.
Digital UK must have the complete information themselves somewhere so what is the difficulty in publishing it? I suspect they are scared of what we will find.
OwenSmith is offline   Reply With Quote
Please sign in or register to remove this advertisement.
Old 08-11-2013, 12:03
mossy2103
Forum Member
 
Join Date: Aug 2005
Posts: 57,003
Digital UK must have the complete information themselves somewhere so what is the difficulty in publishing it? I suspect they are scared of what we will find.
As I said, they probably don't see the need (within their operating remit) to do so.

Why not suggest it to them and see what they say?

http://www.digitaluk.co.uk/contactus
mossy2103 is online now   Reply With Quote
Old 08-11-2013, 13:28
technologist
Forum Member
 
Join Date: Feb 2004
Location: London
Posts: 5,947
I'd say a more relevant point is that we should be able to download a single document that gives all the transmitters, frequencies, powers and coverage information for the entire UK.
What about this from ofcom who have to know it all
http://stakeholders.ofcom.org.uk/bro...-guidance/?a=0
technologist is offline   Reply With Quote
Old 08-11-2013, 13:34
kruador
Forum Member
 
Join Date: Feb 2011
Location: Reading
Posts: 449
I'd say a more relevant point is that we should be able to download a single document that gives all the transmitters, frequencies, powers and coverage information for the entire UK.
Ofcom: UK Digital Terrestrial Television Transmitter Frequency and Site Data

Ofcom: UK Digital Terrestrial Television: International Coordination Agreements

Doesn't yet include COM7, but I'm sure it will a month or so after it launches.

The radiation patterns of the main sites are apparently a state secret: Ofcom do not want to compromise possible negotiations with neighbouring countries by admitting what we're actually using, rather than what we've asked for.

However, Brian Butterworth at ukfree.tv did manage to get a restricted set of data through a Freedom of Information request.

In addition, Arqiva's Reference Offers for television transmission usually include suggested radiation patterns, but there is no guarantee that what ultimately goes up is what was suggested. Arqiva are required to publish a Reference Offer for any new multiplexes, under the agreement that was reached when they purchased National Grid Wireless' half of the transmitter network.
kruador is offline   Reply With Quote
Old 08-11-2013, 14:50
Mark C
Forum Member
 
Join Date: Dec 2001
Location: Hampshire
Posts: 4,797
But why would DigitalUK see a benefit in providing that? It would be of little interest to the trade (who would be likely to be interested in their own region), .
No, not so. 'Trade' in terms of a local bloke with ladder, who just serves his town, OK, but many 'trade' organisations install RF distribution systems nationally, and need to have just that level of information, in order to design and specify complex systems. Good job Bill Wright of Yorkshire's
Wrightsaerials isn't a member of this forum, you'd have been well and truly flamed for that
Mark C is offline   Reply With Quote
Old 08-11-2013, 15:19
mossy2103
Forum Member
 
Join Date: Aug 2005
Posts: 57,003
Note that I did qualify that by saying that they would be likely to be interested in their own region.

But you do have a point. Perhaps you should contact DUK and suggest it to them.
mossy2103 is online now   Reply With Quote
Old 08-11-2013, 16:56
jimbo
Forum Member
 
Join Date: Mar 2000
Posts: 3,227
As MUX 7 is meant to be starting at Winter Hill on 26 November, why have we not see ANY test transmission on channel 31 yet? Anyone know?
jimbo is offline   Reply With Quote
Old 08-11-2013, 17:08
jimbo
Forum Member
 
Join Date: Mar 2000
Posts: 3,227
Ofcom: UK Digital Terrestrial Television Transmitter Frequency and Site Data

Ofcom: UK Digital Terrestrial Television: International Coordination Agreements

Doesn't yet include COM7, but I'm sure it will a month or so after it launches.

The radiation patterns of the main sites are apparently a state secret: Ofcom do not want to compromise possible negotiations with neighbouring countries by admitting what we're actually using, rather than what we've asked for.

However, Brian Butterworth at ukfree.tv did manage to get a restricted set of data through a Freedom of Information request.

In addition, Arqiva's Reference Offers for television transmission usually include suggested radiation patterns, but there is no guarantee that what ultimately goes up is what was suggested. Arqiva are required to publish a Reference Offer for any new multiplexes, under the agreement that was reached when they purchased National Grid Wireless' half of the transmitter network.
A bit off topic, but thank you - because I have been looking for that spreadsheet for ages.

I was under the impression that

Douglas had ITV Granada a their service now, not Border England) This changed after DSO.

That there was at least one transmitter in the Lake District with BBC North West and ITV Tyne Tees. I was staying iat Conniston at the time a few years ago. This spreadsheet says it is BBC North West and ITV Border.

So what is correct? Thanks.
jimbo is offline   Reply With Quote
Old 08-11-2013, 18:41
kruador
Forum Member
 
Join Date: Feb 2011
Location: Reading
Posts: 449
Douglas had ITV Granada a their service now, not Border England) This changed after DSO.
Yes, that is the case. It's an error in the spreadsheet.

That there was at least one transmitter in the Lake District with BBC North West and ITV Tyne Tees. I was staying iat Conniston at the time a few years ago. This spreadsheet says it is BBC North West and ITV Border.
There, the spreadsheet is correct.

The problem is that ITV essentially merged Border with Tyne Tees to save money. They are now required to resurrect it.

Kendal and all its children carry BBC North West rather than BBC North East and Cumbria, for historical reasons. (The BBC 405-line NW service reached that far north, ITV's didn't.) This required promoting Kendal to a full Service Insertion Point for digital TV, where it had previously just been a relay.

The spreadsheet actually should have Kendal as a separate Transmitter Group and the Primary Transmitter cell set to 1, not 0.
kruador is offline   Reply With Quote
Old 08-11-2013, 18:53
kruador
Forum Member
 
Join Date: Feb 2011
Location: Reading
Posts: 449
Yes I've seen that before, but I don't know how accurate it is. The official document suggested HP only, and the DUK site is only showing COM7 for HP, which is now leading me to believe that it will only be HP.
Arqiva's Reference Offer suggested that the S2 antenna would be used. This is the COM antenna. It has both horizontal and vertical elements; less power is fed to the horizontal elements than the vertical, for the COM services, resulting in 200kW ERP for VP, and 50kW for HP.

It's not clear where the power division takes place, whether it's in the array itself, some elements on the mast but not actually in the array, or on the ground. If it's somewhere up the mast, VP will happen. If it's on the ground, it'll be optional.

Ofcom's statement awarding the band indicates that Rowridge is cleared for 200kW power on both H and V polarization. The allowed radiation pattern is omnidirectional on C31, and basically firing to the north only on C37. The S2 antenna already has that restriction (panels are only fitted on the north corner, firing north-west and north-east).

The problem for the COM4-6 multiplexes on horizontal polarization is that they're co-channel with Crystal Palace. That isn't a problem for COM7 and COM8. On VP there are no interactions: the only other VP transmitters are Sheffield, Fenton and Fenham.

Really the only answer is: are Arqiva going to spend the money? Or, rather, can they persuade the broadcasters to spend a little more for a little more power? Given the general level of power increases, I would tend to think the answer was Yes.
kruador is offline   Reply With Quote
Old 08-11-2013, 19:16
Mark C
Forum Member
 
Join Date: Dec 2001
Location: Hampshire
Posts: 4,797
Kendal and all its children carry BBC North West rather than BBC North East and Cumbria, for historical reasons. (The BBC 405-line NW service reached that far north, ITV's didn't.)
Up until 1982 Kendal and its dependants did actually carry Granada. The distribution matched that of the BBC's. Kendal was a relay of Morecombe Bay for BBC 405 lines (it still is for FM radio) and a relay of Lancaster for BBC and ITV UHF.

However, in order to bolster Border's potential audience, Border lobbied the IBA successfully to have Kendal and the South Lakeland relays reallocated from Granada to them.

At the same time some relays on the Yorks /Lancs border
were swapped between YTV and Granada (I can't remember which ones, or which way) Buxton was also reallocated from ATV and BBC Midlands to Granada and BBC North West.
Mark C is offline   Reply With Quote
Old 08-11-2013, 19:18
Colin_London
Forum Member
 
Join Date: Jul 2003
Location: Essex
Posts: 2,758
As MUX 7 is meant to be starting at Winter Hill on 26 November, why have we not see ANY test transmission on channel 31 yet? Anyone know?
Patience! There is no real need for extended tests - you can test a transmitter into a dummy load and the antenna system overnight in a few hours. It might well be sitting there tested, ready for switch on already.
Colin_London is offline   Reply With Quote
Old 08-11-2013, 19:25
Mark C
Forum Member
 
Join Date: Dec 2001
Location: Hampshire
Posts: 4,797
Note that I did qualify that by saying that they would be likely to be interested in their own region.

But you do have a point. Perhaps you should contact DUK and suggest it to them.
I did recently, never received even an acknowledgement, though shortly after, the Ofcom spreadsheet appeared. They had a similar, and just as useful spreadsheet ever since Ofcom were created; for radio, they inherited that from The Radio Authority, which I take partial credit for, because I buttonholed one of the RA's engineering staff at an industry do, and suggested the idea, it was just as the internet started to become really popular
Mark C is offline   Reply With Quote
Old 08-11-2013, 19:56
kurgan2
Forum Member
 
Join Date: Oct 2002
Location: Crystal Palace Transmitter
Posts: 376
Having read this post and then gone back to look at your earlier ones I have visited a couple of people I know with Vestel boxes and can confirm they both behave exactly as you describe. One is a Bush DVB 680 on software V2.47, the other a Technika STBHDV2010 on software V2.44.
Thanks for the confirmation. So there was an update to 2.47 at some point?
kurgan2 is offline   Reply With Quote
Old 12-11-2013, 11:29
Greebo
Forum Member
 
Join Date: Feb 2003
Posts: 937
C31 just (up by 11:13am) fired up from Winter Hill - my tvcard is getting the full SIG CARR VIT SYNC LOCK from it! No idea what is there yet, nothing being detected in the NITs on the other 7 muxes. Manual scan on my Humax Fox T2 finds no channels but does show a good strong signal strength. More info as/when but if anyone else wants to take a look (especially if you happen to have test gear), help yourselves now while it is up...

Update: pidscan shows that it is full of null packets to start with, only PID 8191 in use, running at approx 40232 kbit/s.
Greebo is offline   Reply With Quote
Old 12-11-2013, 11:59
reslfj
Forum Member
 
Join Date: Jun 2007
Posts: 1,809
Update: ..... running at approx 40232 kbit/s.
This is the expected bitrate for a UK-standard - 256-QAM 32ke PP7 CR=2/3 no TR PAPR reduction - DVB-T2 mux.

TR PAPR reduction would reduce the bitrate by 1 Mbps.
I think, however, it should allow the RF power amplifiers to operate at a higher power level - increasing the ERP by 1-2 dB ?

Lars
reslfj is offline   Reply With Quote
Old 12-11-2013, 12:18
Greebo
Forum Member
 
Join Date: Feb 2003
Posts: 937
It looks like they've powered it down again now.
Greebo is offline   Reply With Quote
Old 12-11-2013, 12:45
djmark
Forum Member
 
Join Date: Oct 2007
Location: Essex
Posts: 228
Much better signal quality today on 108, about 6/10. Has CP power been turned up?
djmark is offline   Reply With Quote
Old 12-11-2013, 13:37
Greebo
Forum Member
 
Join Date: Feb 2003
Posts: 937
This is the expected bitrate for a UK-standard - 256-QAM 32ke PP7 CR=2/3 no TR PAPR reduction - DVB-T2 mux.
TR PAPR reduction would reduce the bitrate by 1 Mbps.
I think, however, it should allow the RF power amplifiers to operate at a higher power level - increasing the ERP by 1-2 dB ?
Sadly my USB T2 stick is very 'auto' when it comes to tuning parameters, and is very good at reporting back to you the parameter you requested rather than the one actually detected. So I can't really comment on the mode. The kbit/s rate was from a doing "dvbsnoop -s bandwidth 8191 -crc" and then letting it settle and picking a typically reported value, so the errors are bigger than if I'd averaged over a 5 minutes sample or somesuch - but it gives an indication.
Greebo is offline   Reply With Quote
Old 12-11-2013, 14:24
kasg
Forum Member
 
Join Date: Oct 2002
Location: West Sussex (Crystal Palace)
Posts: 2,626
Much better signal quality today on 108, about 6/10. Has CP power been turned up?
Quite the opposite here, it's been absolutely fine but now zero signal, surely the CP mux has been turned off?
kasg is offline   Reply With Quote
Old 12-11-2013, 18:46
kasg
Forum Member
 
Join Date: Oct 2002
Location: West Sussex (Crystal Palace)
Posts: 2,626
Hmmm, I'm getting a bit worried now nobody else has commented. Can anyone else confirm that the new Crystal Palace HD mux is off the air, because I am still getting absolutely nothing.
kasg is offline   Reply With Quote
Old 12-11-2013, 18:49
Greebo
Forum Member
 
Join Date: Feb 2003
Posts: 937
Hmmm, I'm getting a bit worried now nobody else has commented. Can anyone else confirm that the new Crystal Palace HD mux is off the air, because I am still getting absolutely nothing.
Sorry kasg can't help from here. I can state that Winter Hill C31 COM7 only lit up for the one hour as far as I detected, and is still off - not much help for CP though.
Greebo is offline   Reply With Quote
Old 12-11-2013, 18:55
kasg
Forum Member
 
Join Date: Oct 2002
Location: West Sussex (Crystal Palace)
Posts: 2,626
OK, thanks, it's just that it's been on the air continuously (AFAIK) for nearly a month and I've had faultless reception. Hopefully djmark can comment as it was he who posted earlier that reception had improved.
kasg is offline   Reply With Quote
Old 12-11-2013, 19:20
jimbo
Forum Member
 
Join Date: Mar 2000
Posts: 3,227
Sorry kasg can't help from here. I can state that Winter Hill C31 COM7 only lit up for the one hour as far as I detected, and is still off - not much help for CP though.
I missed it then did I? When was Winter Hill Mux 7 on and what date?
jimbo is offline   Reply With Quote
Old 12-11-2013, 19:25
Greebo
Forum Member
 
Join Date: Feb 2003
Posts: 937
I missed it then did I? When was Winter Hill Mux 7 on and what date?
Today - approx 11:10 -> 12:10 - see upthread post #265 onwards. You didn't miss any channels, it was all power and null packets - worked very nicely for me though, better signal strength than BBCB reported by my Humax HD T2, probably a function of my wideband aerial.

(and strictly it is COM7 - it will be our eighth mux
Greebo is offline   Reply With Quote
 
Reply



Thread Tools Search this Thread
Search this Thread:

Advanced Search

 
Forum Jump


All times are GMT +1. The time now is 09:51.