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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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Saturday, 10 March 2012

8:46 PM

Peter Henderson: You can now see the Whitehead transmitter's radiation pattern here - Whitehead digital switchover date | - independent free digital TV advice

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Briantist's 38,915 posts GB flag
Wednesday, 14 March 2012
Ronan o dwyer
7:57 PM

2 analogue channels from 3 rock mountain still open..
ch 33(RTE2)and ch 35 (TV3).

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Ronan o dwyer's 1 post IE flag
Thursday, 12 April 2012
Mike Dimmick

2:30 PM

There are some coverage maps in the Republic's Competition Authority's review statement. (The TCA were required to review the joint venture between RT and TG4, as both sell advertising.)

See….pdf , annex 1 and 3 specifically.

Ronan o dwyer: Analogue switch-off on the island of Ireland is not until 24 October. All four services are still broadcasting from Three Rock, RT One on C29, RT Two on C33, TV3 on C35 and TG4 on C55, all at 25 kW. Three Rock broadcasts the first Saorview multiplex on C54 at 63 kW, quite an increment when digital services are usually considered equivalent at one-fifth to one-tenth the power of analogue!

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Mike Dimmick's 2,486 posts GB flag
Friday, 13 April 2012
7:13 AM

Six months to go until DSO in Northern Ireland region. Does anyone know anything further comcerning the NI mini-multiplex (RTE channels)arrangements. Specifically, channel allocations and polarisation at Black Mountain, Carnmoney Hill and Brougher Mountain? Indeed, if these are still the proposed transmitting sites?
Will need to consider the aerial here (Bangor, Co Down) sometime over the summer.

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Iderown's 2 posts GB flag
Mike Dimmick

2:33 PM

Iderown: The map I pointed to suggests that the NIMM will cover Bangor. For the full range of UK services you will need to point the aerial to Divis. If you already get a good Channel 5 analogue service from Black Mountain, you're probably good for the NIMM.

We don't yet know which channel will be used, unfortunately, so you may have to gamble on wideband.

If you're the same Iderown on, you should be good to stick with your Group C/D on Clermont Carn. Saorview from there will be 160kW digital after analogue switch-off, which is approximately equivalent to 800kW analogue using the scaling factors that the UK uses to set the digital power level. The current analogue output at Clermont Carn is 250kW. Saorview signals are currently restricted to the north, that restriction is lifted on 24 October. It will replace RT One on C52, so if you have good reception of that already, you'll probably get good results from Saorview directly.

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Mike Dimmick's 2,486 posts GB flag
5:43 PM

Thank you for that Mike Dimmick. Yes, I am the same Iderown. Reception from Clermont Carn (analogue) is marginal to reasonable at Bangor (North Down).
I will most likely hedge the bets, leave the group C/D (V) aerial on the chimney, and keep the diary empty for a few days at the end of October!
It will be an interesting time.

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Iderown's 2 posts GB flag
Peter Henderson

11:34 PM

If you can't get the NIMM from Black Mountain Iderown, you may be able to receive it from Carnmoney Hill which is only across the lough.

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Peter Henderson's 240 posts GB flag
Peter's: mapP's Freeview map terrainP's terrain plot wavesP's frequency data P's Freeview Detailed Coverage
Tuesday, 29 May 2012

6:56 PM

UPDATE from BBC News - RTE channels will go on Freeview in Northern Ireland :

RTE channels will go on Freeview in Northern Ireland

People in Northern Ireland will be able to watch RTE TV channels on Freeview following digital TV switchover, the government has confirmed.

Three channels - RTE One, Two and TG4 - will be available.

Freeview delivery of the channels will be supplemented by overspill coverage from Saorview, its equivalent in the Republic.

Digital switchover is to be completed in Northern Ireland on 24 October of this year.

Minister of State for Northern Ireland Hugo Swire said:"This announcement is the culmination of a great deal of work involving the UK and Irish governments, the broadcasters themselves and the regulatory bodies.

"I'm pleased to welcome this important practical step, which will increase the coverage of RTE1 and 2 and importantly of TG4 following digital switchover later this year."

Communications Minister Ed Vaizey said: "I'm delighted that the digital future for TG4, RTE One and RTE Two in Northern Ireland is now strengthened and secure.

"Today's announcement is good news for viewers and continues our delivery on commitments set out in the Good Friday agreement."

Irish Minister for Communications Pat Rabbitte added: "This announcement means that from Analogue Switch-off on 24 October, over 90% of viewers in Northern Ireland will be able to receive TG4 and the two primary RTE channels in digital.

"It is a hugely positive result in terms of practical cooperation resulting from the Good Friday Agreement."

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Briantist's 38,915 posts GB flag
Peter Henderson
11:23 PM

At last, something official Brian !

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Peter Henderson's 2 posts GB flag
Thursday, 31 May 2012
Mike Dimmick

2:45 PM

Information on the NI mini-mux is now on Digital UK's postcode checker. The selected mode is DVB-T2, QPSK modulation, FEC 2/3, 32K carriers.


Carnmoney Hill on C48 at 16 watts
Black Mountain on C39+ at 1kW/2kW (directional)
Brougher Mountain on C30- at 1kW

No information on the Guard Interval, but since the obvious pairing of Carnmoney Hill and Black Mountain are on different frequencies, I expect it'll be 1/128. Similarly it will probably use Pilot Pattern 7 to match the HD mode. The recommended configuration in the DVB-T2 Implementation Guide gives 9.954 Mbit/s (the frame lengths can also be altered in T2). Using this mode requires 2.6 - 2.8 dB less signal, compared to the noise level, than the 16QAM 1/2 mode previously suggested, and 14.7 - 15.8 dB less than the HD mode. That's equivalent to broadcasting at 29.5x - 38x the power of the HD mux.

The change in mode could be down to the power level permitted at Brougher Mountain, which is half that previously indicated (i.e. 3 dB less).

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Mike Dimmick's 2,486 posts GB flag
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