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Northern Ireland "mini multiplex" (NIMM)

I have added information to the UK Free TV database to cover the so-called mini-multiplex that will carry three Irish channels, TG4, RTE1 and RTE2 in a very special multiplex from three transmitters in Northern Ireland.

I have added information to the UK Free TV database to cover th
published on UK Free TV

A special service for 80%-90% of households in Northern Ireland will see three Freeview additional channels being available. These will be:



Some homes will be able to receive the services directly from the Saorview transmitters in the RoI (see SAORVIEW - Ireland's free digital television service ), and others will, from the digital switchover date of Wednesday 24th October 2012, have a service provided from three Freeview transmitters in Northern Ireland.



Northern Ireland RTE1 RTE2 TG4 minimux transmitters

However, you will not be able to view these services using a standard-definition Freeview receiver - a Freeview HD box or set will be required. It is not known at this time if the NIMM will carry RTE2 in HD, as per the Saorview service. TG4 and RTE1 are broadcast in standard definition at the moment.

The requirement for a Freeview HD receiver is because the services are being broadcasting in "D-Book Option 11", which uses the DVB-T2 standard ("a new mode, option 11, is being planned for a multiplex in Northern Ireland. Receivers should be able to switch between these automatically", D-Book 7, DTG164 is defined in appendix G as: FFT size 32k, 16QAM modulation, 1/128 guard interval, PP7, FEC 64800). Digital Television - Technical guidance on the availability of TG4 in Northern Ireland after digital switchover says that Option 11 is: DVB-T2 16QAM FEC 1/2.

Update: DVB-T2 16QAM FEC 1/2 provides a bitrate for the multiplex of 12.77Mb/s.

Update: DVB-T2, QPSK modulation, FEC 2/3, 32K carriers, 9.954 Mbit/s.

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Comments
Monday, 6 February 2012
Briantist
sentiment_very_satisfiedOwner

8:13 AM

Carl: All my information is from official sources.

I was referring to the Saorview satellite service. As it's not on Astra 2A/B/D/1N, a Soarview satellite user will NOT be viewing Freesat channels, at least not without a second dish and receiver.

If you can get a service from Claremont Cairn, you will get a wider selection of channels (including the News and Kids' offerings) than you would from the NIMM.

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Briantist's 38,908 posts GB flag
Tuesday, 7 February 2012
P
Peter Henderson
sentiment_satisfiedSilver

12:36 AM

"it is now Feb and the DSO is months away"

Digital Dave should be making an appearance soon Carl !

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Peter Henderson's 240 posts GB flag
P
Peter Henderson
sentiment_satisfiedSilver

12:41 AM

but the soarview signal in the north seems "to be restricted"

I have been reliably informed on Boards.ie (by Saorview Brian) that Clermont Cairn will increase power to the north on 24th October 2012.

There will also be a change of channel from 53 to 52, so anyone currently receiving Saorview from Clermont Cairn will have to do a retune on that date.

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Peter Henderson's 240 posts GB flag
Briantist
sentiment_very_satisfiedOwner

8:08 AM

Peter Henderson: I have heard the same about the change of C53 to C52, and the removal of restrictions to improve coverage. I'm not sure if the restrictions only apply to the multiplex with TG4, RTE1 and RTE2 on it, or if other services will be available to the north. I would guess not.


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Briantist's 38,908 posts GB flag
P
Peter Henderson
sentiment_satisfiedSilver

11:32 AM

Brian: All Saorview channels from Clermont Cairn are currently on channel 53, as far as I'm aware, including TV3, RTE news now, and all the radio channels.

I would imagine when the restriction is lifted it will apply to all the channels, not just RTE 1, RTE 2, and TG 4 (at least that was the impression I was given by Saorview Brian).

I think Truskmore is also on reduced power for similar reasons to Clermont Cairn.

The change of channel from 53 to 52 is definitely going ahead on 24th October, according to Saorview.

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Peter Henderson's 240 posts GB flag
Briantist
sentiment_very_satisfiedOwner

12:15 PM

Peter Henderson: Yes, ooking at Coverage Map | SAORVIEW it does show "CLERMONT CARN Channel: 53, changing to 52 at Oct 2012 Polarization: V".

I was thinking that there was more than one multiplex for Saorview, but actually it's just the one at the moment, I suppose once the analogue services are turned off then there might be more multiplexes?

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Briantist's 38,908 posts GB flag
T
The Cush
2:19 PM

A second PSB Mux licence was issued to RT in May 2011 by Comreg. The Dept of Communications requires RT2 HD and RTjr/RT1+1 to move to this mux when operational. There is no official start date for this mux yet - http://www.boards.ie/vbul…=312

4 further national multiplexes have been planned and coordinated with the UK for commercial DTT and will be awarded by the BAI (Boadcasting Authority of Ireland) at some point in the future (after ASO) - Digital Terrestrial Television « Broadcasting Authority of Ireland Frequencies not known.

A further 2 multiplexes are in the planning and coodination stage according to Comreg. Frequencies not known.

Clermont Carn is restricted to the north until ASO - http://www.boards.ie/vbul…451. The 2 PSB Muxes should be unrestricted north after ASO, any encrypted commercial multiplexes may not be (unknown at this stage).

After ASO RT estimates 60% population coverage from Saorview transmitter overspill increasing to over 90% population coverage when the mini-mux is launched. Saorsat should increase RT/TG4 coverage closer to 100%.

Saorview ASO 24th Oct 2012 retune information - http://www.rtenl.ie/wp-co….pdf

Saorview Mux 1 Sites, Frequencies, EPR - http://www.rtenl.ie/wp-co….pdf

Regarding RT2 on the mini-mux RT has said all services will be in SD only. The multiplex may be required to carry one further TV and radio service.

The contract to run the mini-mux should be awarded by the end of March. Tender currently underway.

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The Cush's 5 posts IE flag
M
Mike Dimmick
sentiment_very_satisfiedPlatinum

2:46 PM

- http://www.rtenl.ie/wp-co….pdf lists the frequencies and powers used by Saorview transmissions at present. It appears (from comments on other boards) that they use 64QAM 2/3 8K 1/32 mode as used by the UK PSBs. The second multiplex is already broadcasting, but only carrying test loops.
Ireland actually received 8 UHF channels per site at the Geneva 2006 Regional Radio Conference, they aren't short of frequencies. Some of the assignments were above C60, which will be cleared in Ireland as it will here.
DTT was going to be mostly-pay in Ireland, as it was originally launched here, but the credit crunch hit them hard. Three different operators were awarded the licences before pulling out. They'd also be entering a market where Sky and cable providers are already hugely dominant; it didn't work here, where Sky's digital service and DTT launched at nearly the same time (although our low-power DTT and poor initial planning meant that getting all services was difficult for many viewers).

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Mike Dimmick's 2,486 posts GB flag
M
Mike Dimmick
sentiment_very_satisfiedPlatinum

3:10 PM

Carl: Different DVB-T and DVB-T2 modes require greater or lesser amounts of signal, relative to the noise and interference on that channel. The ratio required depends on how much line-of-sight is available between the transmitter and the receiving aerial, and the amount of reflected signal that arrives at the receiver as well. The specifications give three scenarios: direct line-of-sight with no reflections and random noise; mostly line-of-sight with some reflection; all reflections and no line-of-sight.

The mode selected for the mini-mux requires 10.7 dB less signal (compared to noise + interference) in the first case, 11.1 dB less in the second, and 12.8 dB in the third, comparing to the mode used for UK PSBs. That makes it approximately equivalent to a PSB transmission with 11.7-19 times the power. It still puts Black Mountain NIMM well down on Divis PSBs (which will be at 100 kW), but in the direction of maximum power, actually not far off COMs, which now require 1.5 - 3 dB more than (1.4 - 2x) the PSBs. Brougher Mountain's coverage will be at least as good as the PSB multiplexes and far better than the COMs, while Carnmoney Hill's will be much greater.

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Mike Dimmick's 2,486 posts GB flag
Briantist
sentiment_very_satisfiedOwner

3:49 PM

The Cush/Mike Dimmick: Thanks for the detailed information and links.

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Briantist's 38,908 posts GB flag
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