Is Kippure not transmitting on CH61?

keithoh · 16-04-2010 09:07AM #1

Has Kippure stopped transmitting on CH61? I was getting no signal on my PZ81B last night. In the tuning menu I could see that CH54 was at full strength, but I didn't want to do a rescan as I'm not sure whether RTENL are transmitting with the setting that the PZ81B's don't understand.

16-04-2010 09:55AM

yup 61 is off as of now-just checked.

54 is 3 rock I presume ?
Thats on,I have 40% strength and 10% quality on that one.
We have weak 3 rock analogue here west of Arklow believe it or not [also get good 98fm but only here-drive about and you lose it] and thats despite all the wicklow mountains being in the way!

They are probably working on the tx-I'd expect it back on by the days end.
They did this with mt leinster during the week also.

keithoh · 16-04-2010 11:39AM

Thanks Black Briar

Thoie · 16-04-2010 11:10PM

Mine seems to be half back - in that I'm getting about half the screen, but not much more. I thought with digital you either received it perfectly, or not at all - are they likely to be running half a test?:rolleyes:

SRB · 17-04-2010 10:30PM

Kippure originally came on using Ch61, with Three Rock on 54, they switched last year, with Kippure using 54 and Three Rock 61. Since late last year I've been watching Kippure on 54, with Three Rock on 61 during lift conditions. There was talk of an SFN testing on both channels.

keithoh · 17-04-2010 10:48PM

Does anyone know if it's safe to rescan with the PZ81B at present, or are RTENL broadcasting with the setting that wont store the channels on the PZ81B?

pa990 · 17-04-2010 11:50PM

is it possible to do a scan without deleting what u already have ?

SRB · 18-04-2010 08:24AM

If it's any help, two of the boxes I have, which wouldn't store the channels last year (when the descriptor first changed) are both storing them fine - just re-scanned them. (Ch 54)

18-04-2010 12:56PM

Are you telling me that the ch61 that I've been picking up all along down in Arklow was actually 3 rock?

keithoh · 18-04-2010 03:29PM

SRB wrote: »

If it's any help, two of the boxes I have, which wouldn't store the channels last year (when the descriptor first changed) are both storing them fine - just re-scanned them. (Ch 54)

Thanks SRB, I'll try a rescan later today

SRB · 18-04-2010 10:20PM

Deleted User wrote: »

Are you telling me that the ch61 that I've been picking up all along down in Arklow was actually 3 rock?

When Three Rock came on it was orginally on 54, also appeared on 61 towards the end of last year. Kippure was on 61 but moved to 54. Now, if they were running an SFN, Three Rock was would still have been running on 54.
The signal levels and direction of the signal I was receiving on 61 until the end of last week would point to 61 coming from Three Rock.
I'm in Portaferry Co. Down.

19-04-2010 09:15AM

So no one except RTENL knows then for sure?

Both tx's are about the same area just one is a few miles further inland than the other.

I definitely should not in my opinion be receiving dtt from 3rock amp less.
I should be able to pick it up from kippure though.I've great VHF tv from there and vhf radio services and better uhf than I do for 3 rock.

SRB · 19-04-2010 11:19AM

Someone on here mentioned they were running an SFN on 54 from Three Rock and Kippure, so I take it that is/was on air. As for 61, I can only go on the signal levels where I am and it was consistant with the power from Three Rock. It's possible they had another TX on Kippure with power restrictions Northwards, but that would be a bit strange given the signal on 54 from the same site...
Are you getting anything on 54 at the moment ?
I suppose an e-mail to RTE NL would solve the mystery, lol.

fat-tony · 19-04-2010 11:54AM

Three Rock has been transmitting on CH54 and Kippure on CH61. At the moment(11.50) Three Rock is on and Kippure is off.

SRB · 19-04-2010 12:22PM

Kippure was/is on 54 too Tony. It's been there since the end of last year when all it's muxes were active for an afternoon.

19-04-2010 12:59PM

I'm beginning to think theres confusion here.
ch61 up to the other day must have been kippure.

If kippure and 3rock were both on 54 at the same time,that would be absolutely pointless.
Nothing would be received as they are only a couple of miles apart and both are in line of sight through most of Dublin and beyond to the north of Dublin.

The Cush · 19-04-2010 01:55PM

Deleted User wrote: »

If kippure and 3rock were both on 54 at the same time,that would be absolutely pointless.
Nothing would be received as they are only a couple of miles apart and both are in line of sight through most of Dublin and beyond to the north of Dublin.

They will be operated as a Single Frequency Network (SFN). DAB operates this way.

SRB · 19-04-2010 02:09PM

Yup, if you remember just over a year ago, there were timing issues with the SFN, Three Rock then ran on 54, Kippure came up on 61. It moved back to 54 towards the end of last year and as far as I know was running along side Three Rock on 54. On the day Kippure moved to 54, it was on and off over the afternoon, the signal on 54 with me was as normal for Three Rock, then shot up to the same level as the signal I had been receiving on 61. 61 then dropped to the level that I would expect from Three Rock and stayed that way.
As I say, an e-mail to RTE NL would clear this up.

19-04-2010 04:15PM

This appears to be supposition.

If an sfn is possible with dtt [I know that cofdm cannot cope with strong co channel-presely Vs Mt Leinster is an example] then the whole country should be on ch 39.

Where is mrdtv when we need him

Yes someone email RTEnl.

keithoh · 19-04-2010 04:19PM

Deleted User wrote: »

Yes someone email RTEnl.

I sent them an email today asking about Kippure and Three Rock, I'll post the reply if I get one

SRB · 19-04-2010 04:32PM

Deleted User wrote: »

This appears to be supposition.

If an sfn is possible with dtt [I know that cofdm cannot cope with strong co channel-presely Vs Mt Leinster is an example] then the whole country should be on ch 39.

Where is mrdtv when we need him

Yes someone email RTEnl.

Honestly, it is perfectly possible and there was one running on 54. (It may well still be running on 54 - anyone in the Three Rock area who can't "see" Kippure should be able to confirm this if they are getting a strong signal, it'll be Three Rock). An SFN is not the same as two different services on the same channel, which is the issue with Wales and Mt Leinster.

The Cush · 19-04-2010 05:09PM

Deleted User wrote: »

This appears to be supposition.

If an sfn is possible with dtt [I know that cofdm cannot cope with strong co channel-presely Vs Mt Leinster is an example] then the whole country should be on ch 39.

Attached is some info I think I posted previously.

In Spain the four commercial multiplexes operate as nationwide SFNs, UHF Channels 66 - 69. The national PSB mux operates as an MFN. On the Isle of Man 3 relays I believe operate as an SFN.

This was a discussion on SFNs over in the DS forum last year http://www.digitalspy.co.uk/forums/showthread.php?t=1035699

Antenna · 19-04-2010 05:33PM

In the Cork area, Spur Hill and Crosshaven were at one stage planned to operate on the same channels as a SFN , though that plan has gone out the window.
So too has Kippure and Three Rock in the Dublin area (a similar distance apart) with the new plan (see below) they are no longer to use the same channels.

https://us.v-cdn.net/6034073/uploads/attachments/10144/108434.pdf
Third column is Channel number

Kippure DTT is now allocated channels 29, 33, 35, 37, 55, 59, 62, 65
Three Rock DTT is allocated 23, 26, 30, 34, 54, 58, 61, 64
none are co-channel.
(attachment originally posted by The Cush)

The Cush · 19-04-2010 08:46PM

Antenna wrote: »

In the Cork area, Spur Hill and Crosshaven were at one stage planned to operate on the same channels as a SFN , though that plan has gone out the window.
So too has Kippure and Three Rock in the Dublin area (a similar distance apart) with the new plan (see below) they are no longer to use the same channels.

https://us.v-cdn.net/6034073/uploads/attachments/10144/108434.pdf
Third column is Channel number

Kippure DTT is now allocated channels 29, 33, 35, 37, 55, 59, 62, 65
Three Rock DTT is allocated 23, 26, 30, 34, 54, 58, 61, 64
none are co-channel.
(attachment originally posted by The Cush)

That document is the DTT plan from RRC-06 but its not written in stone. Following the conference countries can enter into bilateral agreements with other countries to amend or change an assignment. This is what happened to Three Rock/Kippure. Kippure has been assigned the same frequencies as Three Rock to become an SFN.

Since 2007 the Three Rock/Kippure SFN has been part of the Irish DTT plan, see Comreg document 07/65.

Don't know why this was done, maybe it was done because of the close proximity of the two main transmitters and to develop the expertise and knowledge in building SFNs, maybe it was done to free up these frequencies for use in relays (low power sites were not allocated frequencies at RRC-06), maybe it was done in coordination with Ofcom/Arqiva as a trade off somewhere else.

SRB · 19-04-2010 09:26PM

The MUX I'm sitting monitoring tonight, on CH 54, is not from Three Rock. Three Rock analogue is totally unwatchable with me this evening, hardly any trace of a signal at all (TG4). The signal on 54 has to be coming from Kippure.

lawhec · 19-04-2010 09:39PM

DVB-T Single Frequency Networks are in place in several countries. As The Cush points out, there is a national 4 Multiplex SFN in Spain (using frequencies E66, E67, E68 and E69). IIRC in Portugal the RTP (public) multiplex was to be a national SFN as well but I don't know if it was implemented as such.

Several countries have regional SFNs including (off the top of my head) the Netherlands, Germany, Belgium & Switzerland. In these cases there is either one main high powered transmitter with on-channel low powered filler transmitters (sometimes with opposite polarity) or they can work as mid to low powered transmitters as a cellular style network. The Digital Spy post mentioned that there is a small SFN multiplex in northern France for the TF1 Multiplex. In Australia, SBS operates a SFN multiplex in the South-East Queensland region involving IIRC seven transmitters all on-frequency. In the UK digital rollout, SFNs are being kept to some small scale areas of low-powered relays each using similar frequencies - there's one on the Isle of Man, I think there's also SFNs planned for part of the Channel Islands and in parts of southern England, but I'll need to double check.

In theory the whole of the Irish Republic could be covered by a SFN at least for a public broadcasting multiplex that didn't need to be regionalised, however it would need to be engineered in a different fashion to that for a multi-frequency network which is what RoI has planned through its allocations (as does the UK in general) not to mention that it may require some viewers to need different UHF aerials compared to their current one required for analogue broadcasts (though this is the case anyway for Mt. Leinster and Spur Hill).

Country-wide Single Frequency Networks don't lend themselves well to the current analogue VHF/UHF TV network of having several transmitters with high powers spaced quite widely apart. Even using the 8K COFDM mode with a long guard interval only gives some protection, receiving a distant transmitter from a distance greater than the guard allows adds or interferes to the signal destructively rather than constructively, not to mention a reduced data-rate available for the multiplex. As an example though not using DVB-T but DAB, the BBC National Multiplex on 12B is a UK-wide SFN, however ERP powers are limited to 10kW maximum so that the signal from each transmitter doesn't travel too far away into the coverage area of another distant transmitter broadcasting the same content to cause destructive interference and hence reduce the coverage area of distant transmitters.

There is a Javascript calculator here that allows you to configure different DVB-T parameters that translate into transmission details of data rates, guard intervals etc. for a DVB-T transmitter (there's an experimental DVB-T2 calculator there as well) that shows how different parameters set up for a DVB-T transmitter can be configured to give required data, coverage and network planning results and the trade offs required.

whizbang · 19-04-2010 11:20PM

CH 61 is Greystones relay i believe..
Also (a bit late!) kippure apparently is lower power to the east, on analog anyway.

mrdtv2010 · 20-04-2010 09:11AM

SFN's are possible with DVB-T1 and DVB-T2. The maximum allowable distance between the transmitters varies between 2k and 8k DVB-T1 COFDM depending on the mode chosen, error correction used and data rate. Large area SFNs such as those used in Spain have lower data rates than that used in the UK or Ireland via DVB-T1. DVB-T2 uses 32k COFDM and can have much larger SFNs with much bigger distances. (This is one of the reasons why it was developed.) In SFNs the data transmitted is identical and signals add constructively whereas in the case of uncorrelated sources of roughly equal signal strength transmitting different data you get destructive interference and no pictures as is the case with Preseli COM muxes and Mount Leinster.
I have been away, but I have noticed, that as expected Irish commercial DTT has again fallen by the wayside. For the nth time. When are they going to change the regulatory structure and business model?

You can find out all about SFNs by googling the technical literature.There are too many parameters to discuss in an Internet post!

20-04-2010 11:40AM

SRB wrote: »

The MUX I'm sitting monitoring tonight, on CH 54, is not from Three Rock. Three Rock analogue is totally unwatchable with me this evening, hardly any trace of a signal at all (TG4). The signal on 54 has to be coming from Kippure.

not a good guide.
I've bad kippure uhf analogue here[west of Arklow] on a grid thats pointed to mt leinster .
I could only ever see tv3 actually.
No tg4.
VHF on the other hand from there is perfect.

Up untill the other day I had good dtt on ch61 which I always took to be kippure.
I've nothing today on either 61 or 54.

SRB · 20-04-2010 12:31PM

Deleted User wrote: »

not a good guide.
I've bad kippure uhf analogue here[west of Arklow] on a grid thats pointed to mt leinster .
I could only ever see tv3 actually.
No tg4.
VHF on the other hand from there is perfect.

Up untill the other day I had good dtt on ch61 which I always took to be kippure.
I've nothing today on either 61 or 54.

Actually it is, if you've a steady enough but weakish UHF analogue, you can be sure you'll have a steady signal on DTT.
VHF reception is very, very different.
I've OK UHF and analogue VHF from Kippure (apart from TG4 which is wiped by co-channel from Belfast), Three Rock (where I am) is very much weather dependant and the DTT, even going back to the MPEG 2 trial from Three Rock, is exactly the same. Incidently, this afternoon, the signal I'm getting on 54 is the same level I'd expect from Three Rock, so I take it Kippure is off altogether.
There was a new caption on the RTENL testcard yesterday evening - it was in Irish though, so no idea if it was pointing to an outage.

The Cush · 20-04-2010 01:32PM

SRB wrote: »

There was a new caption on the RTENL testcard yesterday evening - it was in Irish though, so no idea if it was pointing to an outage.

Tarchur Digiteach (Digital Transmission). Back to Digiteach (Digital) only today.

Is Kippure not transmitting on CH61?

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