NI DTT frequency reshuffle for 700MHz clearence (aka DSO2)

TAFKAlawhec

The Digital UK reception predictor database has been updated in the last couple of days, finally showing up what frequencies are planned to be used at transmitter sites & relays to clear UHF channels E49 - E60 for cellular 4G/5G use. I've compiled a list of changes for sites in Northern Ireland that are listed below. In general the changeover to new frequencies are expected to take place during the third quarter of 2019, so that leaves just over 18 months notice.

* Divis & Brougher Mountain will remain on Group A frequencies with the exception of COM7 & COM8 from Divis that will be shifted further up the band until they are closed.

* Limavady will use Group B frequencies.

* No current Group A relays will switch to out-of-band frequencies. Some Group B relays will move to Group A frequencies (notably Derry & Strabane relays). Most Group C/D relays are moving to Group B frequencies, though a few are moving to Group A.

* The COFDM modes used on all multiplexes will remain the same.

* The maximum ERPs of transmitters & relays shifting multiplexes to new frequencies are all the same power as their old/current frequency, though this may not take into account possible changes in TX aerial patterns nor possible new interference to services reducing the quality of reception in places - the exception is the L-BFT multiplex that carries NVTV in Belfast, it will change from E30 to E36 with a power increase from 5kW to 10kW with probably a slightly more relaxed directional coverage area as well if postcode searches are anything to go by.

* The bulk of frequency changes is scheduled for Q3 of 2019 but there are a couple of planned exceptions. The Bellair relay on the Antrim coast between Carnlough & Glenarm will have their PSB1 mux moved from E56 to E39 during Q3 of 2018 with the remaining PSB2 & PSB3 muxs moving on Q3 2019. At Divis on Q3 2019 the COM7 and COM8 multiplexes will move from E33 & E34 to E51 & E60 (as opposed to the rest of this network in Britain which will shift them straight away to E55 & E56 when their time comes - it shouldn't take a genius to work out why E55 & E56 are not being used straight away at Divis on that day). In Q1 2020 these muxs will shift again to E55 & E56, presumably after the ROI has done their own 700MHz clearing. COM7 & COM8 are assumed to be closing later on in 2020, with the second quarter being likely.

I've no info as yet as to what Comreg or 2RN are looking at for rearranging frequencies on DTT/Saorview in the Republic, but the behaviour of the COM7 & COM8 muxs at Divis suggest that clearance should be completed there by the end of 2019. Most certainly the likes of Clermont Carn, Truskmore, Kippure, Maghera & Spur Hill will have to shift as well as current Group C/D relays. Wouldn't rule out the likes of Group B sites like Carin Hill also adjust frequencies.

*** MAIN TRANSMITTERS ***

Site            PSB1    PSB2    PSB3    COM4    COM5    COM6    NOTES

Brougher Mt        28        22        25        21        24        27        Now
                29        31        37        21        24        27        After retune
                
Divis            27        21        24        23        26        29        Now
                27        21        24        23        26        30        After retune
                
Limavady        50        59        55        54        58        49        Now
                41        44        47        40        43        46        After retune - Group C/D -> B
                

                
*** RELAY STATIONS ***

--- BROUGHER MT GROUP ---

Site            PSB1    PSB2    PSB3    NOTES

Belcoo            44        47        41        Now
                44        47        41        After retune - no change

Castlederg        54        58        49        Now
                40        43        46        After retune - Group C/D -> B

Claudy            57        53        60        Now
                39        42        45        After retune - Group C/D -> B

Derrygonnelly    44        41        47        Now
                44        41        47        After retune - no change

Ederney            58        54        49        Now
                40        43        46        After retune - Group C/D -> B

Glenelly Valley    26        29        23        Now
                26        30        23        After retune - no change

Gortnalee        28        25        22        Now
                28        25        22        After retune - no change

Lisbellaw        49        54        58        Now
                40        43        46        After retune - Group C/D -> B

Muldonagh        27        24        21        Now
                27        24        21        After retune - no change

Plumbridge        54        58        49        Now
                40        43        46        After retune - Group C/D -> B

Strabane        45        42        39        Now
                32        34        35        After retune - Group B -> A


--- DIVIS GROUP ---

Site            PSB1    PSB2    PSB3    NOTES

Armagh            44        41        47        Now
                44        41        47        After retune - no change

Banbridge        40        43        46        Now
                41        44        47        After retune

Bangor            50        55        59        Now
                41        44        47        After retune - Group C/D -> B

Bellair            56        48        52        Now
                39        48        52        After retune - Q3 2018 - Group C/D -> B
                39        42        45        After retune - Q3 2019

Benagh            28        25        22        Now
                28        25        22        After retune - no change

Black Mt        45        42        49        Now
                41        44        47        After retune

Camlough        55        59        50        Now
                40        43        46        After retune - Group C/D -> B

Carnmoney Hill    46        40        43        Now
                46        40        43        After retune - no change

Conlig            45        42        49        Now
                32        34        35        After retune - Group B -> A

Cushendall        46        40        43        Now
                46        40        43        After retune - no change

Cushendun        27        21        24        Now
                27        21        24        After retune - no change

Draperstown        45        42        49        Now
                32        34        35        After retune - Group B -> A

Dromore            59        55        50        Now
                41        44        47        After retune - Group C/D -> B

Glenariff        49        54        58        Now
                39        42        45        After retune - Group C/D -> B

Glynn            50        55        59        Now
                41        44        47        After retune - Group C/D -> B

Kilkeel            45        42        39        Now
                40        43        46        After retune

Killowen Mt        27        21        24        Now
                27        21        24        After retune - no change

Larne            45        42        39        Now
                45        42        39        After retune - no change

Leitrim            58        54        49        Now
                32        34        35        After retune - Group C/D -> A

Moneymore        46        43        40        Now
                41        44        47        After retune

Newcastle        50        55        59        Now
                40        43        46        After retune - Group C/D -> B

Newry Nth        43        46        40        Now
                22        25        28        After retune - Group B -> A

Newry Sth        44        41        47        Now
                44        41        47        After retune - no change

Newtownards        50        55        59        Now
                32        34        35        After retune - Group C/D -> A

Rostrevor Fst    39        42        45        Now
                23        26        30        After retune - Group B -> A

Whitehead        52        51        56        Now
                39        42        45        After retune - Group C/D -> B

                
--- LIMAVADY GROUP ---

Site            PSB1    PSB2    PSB3    NOTES

Ballintoy        52        51        56        Now
                39        42        45        After retune - Group C/D -> B

Ballycastle        45        42        49        Now
                23        26        30        After retune - Group B -> A

Buckna            44        41        47        Now
                29        31        37        After retune - Group B -> A

Bushmills        44        41        47        Now
                29        31        37        After retune - Group B -> A

Derry/L'derry    44        41        47        Now
                29        31        37        After retune - Group B -> A

Gortnageeragh    45        42        39        Now
                29        31        37        After retune - Group B -> A
                
                
*** RNI1 MULTIPLEX NETWORK ***

Site            RNI1    Notes

Black Mt        39        Now
                33        After retune - will bring mux within Divis aerial group (A)
                
Brougher Mt        30        Now
                30        After retune - no change
                
Carnmoney Hill    48        Now
                48        After retune - no change
                

*** COM7/8 NETWORK ***

Site            COM7    COM8    Notes

Divis            33        34        Now
                51        60        After retune - Q3 2019 - Temp require Group T or W aerial
                55        56        After retune - Q1 2020
                **        **        Muxs likely to close around Q2 2020
                

*** LOCAL TV NETWORK (NVTV BELFAST) ***

Site            L-BFT    Notes

Divis            30        Now
                36        After retune - Maximum ERP increased from 5kW to 10kW

Sorry, the table of frequencies hasn't come out as I expected, but hopefully it isn't too hard to read.

The Cush

TAFKAlawhec wrote: »

In general the changeover to new frequencies are expected to take place during the third quarter of 2019, so that leaves just over 18 months notice.

The Dept of Communications published some details of the migration plan for the 700 MHz band almost 12 months ago

- 4th September 2019 is the agreed and fixed coordinated start date for clearance of the band for the island of Ireland
- In NI all broadcasting in the band will cease within a number of weeks
- In Ireland this will be the start of the simulcast phase which will allow affected Saorview users time to make the necessary aerial upgrades. The simulcast phase ends 4th March 2020

https://www.boards.ie/vbulletin/showthread.php?p=102073966

https://www.dccae.gov.ie/documents/Minister%27s%20Letter%20to%20RTÉ%20Chair%20setting%20out%20Act%20of%20Entrustment_Redacted.pdf
https://www.dccae.gov.ie/en-ie/communications/topics/spectrum/digital-dividend/Pages/700-MHz-Migration.aspx
https://www.dccae.gov.ie/en-ie/communications/publications/Pages/Migration-from-700-MHz-Spectrum-Band.aspx

TAFKAlawhec wrote: »

I've no info as yet as to what Comreg or 2RN are looking at for rearranging frequencies on DTT/Saorview in the Republic, but the behaviour of the COM7 & COM8 muxs at Divis suggest that clearance should be completed there by the end of 2019. Most certainly the likes of Clermont Carn, Truskmore, Kippure, Maghera & Spur Hill will have to shift as well as current Group C/D relays. Wouldn't rule out the likes of Group B sites like Carin Hill also adjust frequencies..

Back at the end of March last, Comreg published a range of documents which gave us an update on the 700 MHz band migration plan. They include the coordinated bilateral agreement on the band, signed off between Comreg and Ofcom on March 24th - https://www.comreg.ie/publication/mo...-ofcom-comreg/.

Go to the end of the agreement and click on the embedded links to access Annex 3 & 4
Annex 3 - Record of the co-ordination spreadsheet for the 700 MHz DTT clearance for Ireland - Tech03 IRL Final Rev65
Annex 4 - Record of the co-ordination spreadsheet for the 700 MHz DTT clearance for the United Kingdom - Tech04 UK Final 7v019

Doesn't contain information for all Irish sites, only those requiring coordination with the UK but does include the main high power sites.

Clermont Carn will use the following channel configuration: 42, 45 for the 2-MUX plan; 39, 42, 45 for the 3-MUX plan and 39, 42, 45, 36 for the 4-MUX plan. Ireland intend to use channel 48 only in a 6-MUX Plan implementation.

https://www.boards.ie/vbulletin/showthread.php?p=103087933
https://www.comreg.ie/publication/progress-update-dtt-migration-700-mhz-band-international-coordination-irelands-dtt-spectrum-plan/

Annex 2 of the agreement details the Ireland/UK Planning Principles for the 700 MHz DTT Clearance

Irish planners have completed replanning to clear TV from the channels 49-60. They worked in conjunction with their UK colleagues on this task. On the whole the plan has 9 UHF channel groups, each with 3 channels. The Department expects that TV services will clear the channels 49-60 by April 2020, creating a second digital dividend. Associated with that will be much tighter reuse of frequency channels. The Department does not guarantee reception of TV services outside their core service area. Some households currently receiving UK TV signals from Northern Ireland or Wales will no longer be able to do so. This is because of transmissions from Irish TV transmitters in neighbouring areas.

https://www.dccae.gov.ie/en-ie/communications/topics/spectrum/digital-dividend/Pages/DTT-Spectrum.aspx

12 months before the agreement with the UK the WEDDIP multilateral cross-border spectrum coordination group, of which Ireland and the UK are members, signed a final agreement on the revised DTT frequency plan for the 470-694 MHz band for the main interfering sites, after 18 months of technical planning and bilateral meetings. This plan was the basis for the finalisation of bilateral agreements on field strengths, interference levels, technical characteristics and transitional arrangements.

https://www.boards.ie/vbulletin/showthread.php?p=99656082

Johnboy1951

I wonder if these changes could affect some users who have band-specific aerials and are maybe at the limit of coverage?

kazoo106

Moving Divis 29 to 30 will have a huge impact, unless of course 3rock is going to move too

StreetLight

Three Rock is staying put on 30 and 33.

kazoo106

Rostrevor forest moving to be right on top of divis makes me question the authenticity of their research, 26 and 30 are used by Divis, are the relays fed over point to point? if not, how would the feed be delivered with MUXes on the same channels? - this will also make 26 and 30 both unusable on the north Cooley peninsula

TAFKAlawhec

kazoo106 wrote: »

Rostrevor forest moving to be right on top of divis makes me question the authenticity of their research, 26 and 30 are used by Divis, are the relays fed over point to point? if not, how would the feed be delivered with MUXes on the same channels? - this will also make 26 and 30 both unusable on the north Cooley peninsula

In the original DSO in the UK, some relays (without being redesignated as such) went from actually relaying an off-air signal to being line or SHF fed. It's possible that this could happen with more sites with the 700 MHz clearence.

Another possibility is that instead of directly relaying Divis, it may relay from another site - Camlough appears to give good coverage near the Rostrevor Forest site.

http://www.digitaluk.co.uk/coveragechecker/main/trade/BT34+3AA/NA/0/NA

Thurston?

kazoo106 wrote: »

Rostrevor forest moving to be right on top of divis makes me question the authenticity of their research, 26 and 30 are used by Divis, are the relays fed over point to point? if not, how would the feed be delivered with MUXes on the same channels?

Maybe there's enough isolation between their transmitting & receiving aerials, that they don't need to worry about their feed being polluted by their own adjacent channel transmissions?

SFN could be a possibility too, it was done with Three Rock and Kippure before ASO.

The Cush

Karsini wrote: »

SFN could be a possibility too, it was done with Three Rock and Kippure before ASO.

Not in the case above, the frequencies at Divis are used for the commercial muxes but at Rostrevor they are used for the PSB muxes.

As posted above Rostrevor is probably well shielded from Divis and that combined with the lower power commercial muxes from Divis means no interference.

Looking at the radiation pattern for Rostrevor it will only be restricted for a few degrees towards Three Rock.

kazoo106

There will be a problem with people above Omeath (even around Flagstaff which is in NI) with the COM Muxes on Divis when this happens

Thurston?

Yeah, it seems to be a pretty clear-cut case of people losing out due to the constriction in available frequencies.

In the absence of alternative freqs., I suppose there isn't really anything they can do short of maybe re-siting the Rostrevor tx, as Camlough seems to duplicate a lot of its coverage, so it could probably get the places Camlough can't get without affecting Divis users further west.

I can't get 23 & 26 from Divis due to CCI from Mt Leinster. When 29 goes to 30 I might lose that too due to potential 3R interference.

coylemj

Will this potentially mean that people who currently use a wideband rooftop aerial will need to change it to a group aerial to avoid interference from 4G/5G masts?

TAFKAlawhec

coylemj wrote: »

Will this potentially mean that people who currently use a wideband rooftop aerial will need to change it to a group aerial to avoid interference from 4G/5G masts?

Probably not. If you are currently affected by 4G LTE interference from BTS stations it's possible to get a low-pass filter to knock out (or at least heavily reduce) reception above channel 60. I'd assume something similar will be available once the 700MHz band is cleared and either LTE or 5G networks get going there.

TAFKAlawhec

Viewers receiving from the Bellair relay station in Co. Antrim, serving Glenarm, Carnlough & surrounding areas, will need to retune on Wednesday 5th September as the PSB1 multiplex (containing the BBC SD TV & radio services) will change frequency from E56 to E39.


http://www.digitaluk.co.uk/__data/assets/pdf_file/0019/94204/700MHz_clearance_Q3_2018_UTV.pdf


(There's a mistake in the above link, Bellair's future aerial group will be "B", not "A".)


After this there's no more expected retuning for any NI transmitter or relay until September 2019.

TAFKAlawhec

I've recently found out that the RNI_1 multiplex that carries RTÉ1, RTÉ2 & TG4 is SD will have a fourth transmission site come September as the Armagh relay site will be carrying the multiplex on channel E48 with an ERP of 24 watts, the same as the other three PSB muxs at the same site.


Don't know if any more will be added, I'll try and mention them if I come across them ASAP unless someone else gets to it first!

Antenna

TAFKAlawhec wrote: »

I've recently found out that the RNI_1 multiplex that carries RTÉ1, RTÉ2 & TG4 is SD will have a fourth transmission site come September as the Armagh relay site will be carrying the multiplex on channel E48 with an ERP of 24 watts, the same as the other three PSB muxs at the same site.

Is this because there is going to be some deterioration in the coverage of Saorview transmissions from across the border in the future due to everything associated with 700MHz clearances/repacking?

The Cush

Antenna wrote: »

Is this because there is going to be some deterioration in the coverage of Saorview transmissions from across the border in the future due to everything associated with 700MHz clearances/repacking?

Clermont Carn remains at vertical polarisation and 160 kW ERP, UHF 42 & 45. Restricted to the SE (110-170 deg) only, after the 700MHz clearance. Also Monaghan, which appears to be the recommended transmitter for Armagh city, is unrestricted after clearance on UHF 40 & 43.

At Clermont Carn there's a restriction on UHF 48, where it'll only be used for a 6 mux plan and only then with 2 years advance notice to the UK.

I wonder what Saorview coverage is like in and around Armagh city now?

http://www.digitaluk.co.uk/coveragechecker/main/trade/+BT61+9BE/NA/0/NA

Antenna

Both Monaghan and Clermont Carn are moving down to channels which are ADJACENT to the existing UK MUXs from Armagh relay.

receiving adjacent channels in itself is OK provided there is not too much of a difference in signal strength,

however.....

To attempt to combine signals then would require wideband instead of grouped combiners. Wideband combiners (compared to grouped combiners) will introduce a few dB of extra signal loss for signals received (applicable to both aerials), not good news if either signal is not 'strong' to start with.

Secondly the Saorview aerial might pickup distant co-channel interference (some, if not all, of the time) that affects the Freeview aerial (and vice versa) especially high probability of this where one is horizontal polarized and the other is vertical polarised.
Grouped combiners attenuated the 'opposite' grouped aerial sufficiently (and the aerials themselves were more than likely grouped), however this is gone out the window with wideband combiners and adjacent signals.

Possible solutions to such difficulties might include:

(1) running two seperate downleads and the viewer going to the trouble of using an 'A-B' switch to switch from one aerial to the other. (and avoiding any auto tuning in standby) -

(2) Satellite Diseqc style switching for terrestrial aerials ?? (Do any such receivers exist??)

(3) Terrestrial Receivers with two aerial inputs and can select one or the other ???

(4) switching from Freeview to Freesat for UK channels and just have an aerial purely for saorview


I expect the only reason for this Armagh RTÉ/TG4 relay availability is to mitigate loss of Saorview for a portion of NI viewers which will happen with the 700 MHz clearance changes (viewers will of course most notably loose the VM channels if they have to switch to this relay as well as RTE not being HD).

The Cush

Bitrate monitoring of the NI Mux from Black Mountain via digitalbitrate.com commenced yesterday - http://www.digitalbitrate.com/dtv.php?liste=1&live=19&lang=en&mux=NIMUX-BLACK-MOUNTAIN

Digifriendly

The Cush wrote: »

Clermont Carn remains at vertical polarisation and 160 kW ERP, UHF 42 & 45. Restricted to the SE (110-170 deg) only, after the 700MHz clearance. Also Monaghan, which appears to be the recommended transmitter for Armagh city, is unrestricted after clearance on UHF 40 & 43.

At Clermont Carn there's a restriction on UHF 48, where it'll only be used for a 6 mux plan and only then with 2 years advance notice to the UK.

I wonder what Saorview coverage is like in and around Armagh city now?

http://www.digitaluk.co.uk/coveragechecker/main/trade/+BT61+9BE/NA/0/NA

There are a lot of aerials for Cairn Hill in and around Armagh city as well as quite a few aerials for Clermont Carn.

TAFKAlawhec

The 700MHz clearence event is now scheduled to take place in Northern Ireland on Wednesday 4th September 2019, according to Digital UK.

http://www.digitaluk.co.uk/operations/700mhz_clearance/clearance_events_in_2019

Details on frequency & power changes, where applicable, are listed in the PDF linked below...

http://www.digitaluk.co.uk/__data/assets/pdf_file/0020/95033/700MHz_Clearance_Q3_2019_UTV.pdf

The COM7 & COM8 multiplexes will be subject to a further frequency change in around March 2020.

Presumably there will be concurrent action taken by 2RN to start broadcasting Saorview multiplexes on new frequencies at the designated transmission stations where appropriate for a simulcast length of ~6 months, either on the same day or very shortly afterwards.

TAFKAlawhec

In addition to the Armagh relay station mentioned earlier in this thread, the NI Mux carrying RTÉ1, RTÉ2 & TG4 will also commence broadcasting on 4th September...



Divis (?) - E48, 10W
Armagh - E48, 24W
Newcastle - E48, 200W
Whitehead - E48, 2.4W
Strabanistan - E40, 20W

The Cush

TAFKAlawhec wrote: »

The 700MHz clearence event is now scheduled to take place in Northern Ireland on Wednesday 4th September 2019, according to Digital UK.

...

The COM7 & COM8 multiplexes will be subject to a further frequency change in around March 2020.

Presumably there will be concurrent action taken by 2RN to start broadcasting Saorview multiplexes on new frequencies at the designated transmission stations where appropriate for a simulcast length of ~6 months, either on the same day or very shortly afterwards.

Yes, confirmed by the Dept of Communications back in Dec 2016, 4th September 2019 was the agreed and fixed Ireland/UK coordinated start date for clearance of the band on the island of Ireland.

Simulcast here will be 6 months, ending 4th March 2020, allowing for any changes to the COM 7/8 muxes after that date.

https://www.boards.ie/vbulletin/showthread.php?p=102073966