DTT Mt Leinster, Ch45 blocking Presely in the South East

mrdtv2010

Deleted User wrote: »

I'm guessing and this is only a guess that they are taking down the extra mux tx equipment in preparation for using it for some of the many infill relays.

I shall have the ear of one of the engineers in the next week in the flesh which could be a very interesting chat!

RTENL will have to be told that ch39 is the only practical solution to the widespread usage of presely.
I can get ch45 here no bother if I unplug presely but I won't be doing that.

If they don't do something on that front aswell,RTE in this household and TV3 will be restricted to one tv at a time via sky.
Another solution would be to separately wire a mt leinster aerial to a decoder and pipe this receiver without rf pass through to other tv's.
I'm not sure how you would do that and it would be just simpler if RTENL switched to 39.

Economic realpolitik may finally be intervening. It makes the greatest sense if Saorview one mux only (and I think that is what is affordable ONLY) is launched that Mt Leinster Irish DTT should be on E39. Reasons are straightforward:

a) E39 is completely clear of Preseli in SE Ireland

b) Slots in neatly with Preseli Freeview services in MPEG2 if you have an MPEG4 box.

c) Preseli T2 starts in two weeks time which means that anybody with a T2 box or TV will get Saorview as a bonus for nothing on top of UK FTA HD services.

Is it too much to hope that consumer, commercial and economic pragmatism will finally hold sway? We will see...

Sponge Bob

mrdtv2010 wrote: »

Is it too much to hope that consumer, commercial and economic pragmatism will finally hold sway? We will see...

It is far too much.

That is if you ever heard of Eamon Ryan the sole shareholder in RTE and thereby RTENL and of course he who appoints the Board of the Broadcasting quango that awards commercial DTT licences.

mrdtv2010

Sponge Bob wrote: »

It is far too much.

That is if you ever heard of Eamon Ryan the sole shareholder in RTE and thereby RTENL and of course he who appoints the Board of the Broadcasting quango that awards commercial DTT licences.

We'll see. I think economics in the current EU situation will be decisive: its a great leveller and will kill off projects which are now unviable and kill off unnecessary operating costs.

lawhec

Deleted User wrote: »

I'm guessing and this is only a guess that they are taking down the extra mux tx equipment in preparation for using it for some of the many infill relays.

I shall have the ear of one of the engineers in the next week in the flesh which could be a very interesting chat!

RTENL will have to be told that ch39 is the only practical solution to the widespread usage of presely.
I can get ch45 here no bother if I unplug presely but I won't be doing that.

If they don't do something on that front aswell,RTE in this household and TV3 will be restricted to one tv at a time via sky.
Another solution would be to separately wire a mt leinster aerial to a decoder and pipe this receiver without rf pass through to other tv's.
I'm not sure how you would do that and it would be just simpler if RTENL switched to 39.

Considering that any commercial pay-DTT operation is now effectively mothballed, would it not make more sense to instead transmit a Saorview multiplex from Mt. Leinster on E30 or E34? Both frequencies are cleared for use at the location, both fall within the current UHF analogue aerial group (TV3 & TG4) from the site (meaning viewers in the area have less headaches with possibly needing a new UHF aerial) which would allow a proper diplexed aerial set-up rather than in the case of using E39 relying on viewers picking up the signal off the side of an aerial directed eastwards across the water?

E45 made a little sense when there was still a possibility of a commercial operation using another three multiplexes before an analogue shut down, but it makes none now. Maybe the DTT aerials on the mast would require adjustment?

mrdtv2010

lawhec wrote: »

Considering that any commercial pay-DTT operation is now effectively mothballed, would it not make more sense to instead transmit a Saorview multiplex from Mt. Leinster on E30 or E34? Both frequencies are cleared for use at the location, both fall within the current UHF analogue aerial group (TV3 & TG4) from the site (meaning viewers in the area have less headaches with possibly needing a new UHF aerial) which would allow a proper diplexed aerial set-up rather than in the case of using E39 relying on viewers picking up the signal off the side of an aerial directed eastwards across the water?

E45 made a little sense when there was still a possibility of a commercial operation using another three multiplexes before an analogue shut down, but it makes none now. Maybe the DTT aerials on the mast would require adjustment?

These are interesting considerations. However with the local high power Mount Leinster ( I am assuming circa 50kW ERP) transmissions side beam COFDM reception will be fine with Group B aerials used for Preseli so only one aerial would be needed. Therefore E39 makes a lot of sense. Also with newer smarter tuning DTT boxes E39 would be loaded BEFORE the Preseli channels. The use of Group A channels would mean diplexers would be needed and you need to know where the frequency cut would be made. Certainly lone radiation on E45 makes no sense as this will be wrecked by Preseli in overlap areas. The entire trial at Mount Leinster has proved one thing conclusively: overlapping cochannel DTT allocations cannot work with overspill. This will be bad news for the Drogheda relay which will get zapped by the Divis analogue and DSO signals (going up by a factor of nearly twentyfive to fifty depending on mux allocation.)

mrdtv2010

mrdtv2010 wrote: »

These are interesting considerations. However with the local high power Mount Leinster ( I am assuming circa 50kW ERP) transmissions side beam COFDM reception will be fine with Group B aerials used for Preseli so only one aerial would be needed. Therefore E39 makes a lot of sense. Also with newer smarter tuning DTT boxes E39 would be loaded BEFORE the Preseli channels. The use of Group A channels would mean diplexers would be needed and you need to know where the frequency cut would be made. Certainly lone radiation on E45 makes no sense as this will be wrecked by Preseli in overlap areas. The entire trial at Mount Leinster has proved one thing conclusively: overlapping cochannel DTT allocations cannot work with overspill. This will be bad news for the Drogheda relay which will get zapped by the Divis analogue and DSO signals (going up by a factor of nearly twentyfive to fifty depending on mux allocation.)

Would the way it is now on e45 have a major signal impact on the reception of preslie frequencies - so if rte was on e39 instead teh preslie channels would come through alot stronger?

Gerry Wicklow

To my mind the fact that RTÉNL insisted on using 45 instead of 39 just goes to prove that it is deliberate jamming. I can only assume they got their diplomatic skills in Israel, 'it's legal so we will bloody well use it regardless of who we p**s off!' Whether it works or not is beside the point.:mad:

Gerry Wicklow

Gerry Wicklow wrote: »

To my mind the fact that RTÉNL insisted on using 45 instead of 39 just goes to prove that it is deliberate jamming. I can only assume they got their diplomatic skills in Israel, 'it's legal so we will bloody well use it regardless of who we p**s off!' Whether it works or not is beside the point.:mad:

isnt there supposed to be co-ordination between european states in regards to frequencies used?

watty

Yes there is.

That would very much apply to Strabane and Longford.

watty

watty wrote: »

Yes there is.

That would very much apply to Strabane and Longford.

there are other spill over areas as well as just those two -

watty

Yes, that just came to mind as very solid both ways along there.

mrdtv2010

warlikedave wrote: »

Would the way it is now on e45 have a major signal impact on the reception of preslie frequencies - so if rte was on e39 instead teh preslie channels would come through alot stronger?

Yes. The Preseli PSB channels are 43, 46 and 50 (active from 29 June with HD services) and the COM channels are 42, 45 and 49. If Mount Leinster was on E39 or even E30 or E34 there would be no interference whatsoever. If both transmitters use E45 and you get signals above the decode threshold then you get nothing. A similar problem is occuring in South and East Down where the high power Caldbeck COM muxes are cochannel with some of the current low power Divis DTT muxes. In lift conditions or with misaligned aerials this is knocking out Divis. The moral of the story is don't use the same channel allocations on adjacent sea paths as COFDM propagates much better than PAL TV with ruinous consequences all round.

lawhec

watty wrote: »

Yes there is.

That would very much apply to Strabane and Longford.

I'm lost here.

Both Strabane and Carin Hill (Longford) broadcast in the UHF Group B bands, but use differing frequencies for analogue broadcast & planned digital broadcasts.

Strabane analogue - E39, E42, E45 & E49. Strabane digital (when due) - E42, E45 & E49 (Strabane is only planned to be a Freeview Lite TX).

Carin Hill analogue - E40, E43, E46 & E50. Planned digital allocations - E41, E44, E47 & E51 with analogue allocations available after switch-over.

So there's no planned case of possible co-channel interference between the two transmission sites not to mention that the two sites use different polarisations in any case

I've never seen a Strabane/Carin Hill duplexed set-up here in Tyrone for analogue either.

watty

Exactly, my point.

Working Frequency co-ordination.

Since Presli & Mt Leinster are "adjacent" (only sea between), they should be on differing channels & Polarisation like Strabane & Longford.

Anyone with Radio planning expertise can see there will be often problems.

Spain was only an occasional issue, but that was VHF. It's too much sea to worry about.

mrdtv2010

watty wrote: »

Exactly, my point.

Working Frequency co-ordination.

Since Presli & Mt Leinster are "adjacent" (only sea between), they should be on differing channels & Polarisation like Strabane & Longford.

Anyone with Radio planning expertise can see there will be often problems.

Spain was only an occasional issue, but that was VHF. It's too much sea to worry about.

They were warned about this in a number of EBU/ERO reports and the trainwreck between Down/Cumbria and Wicklow/Wales was entirerly predictable with COFDM cochannel allocations where these services would be used on either side of the sea.

lucernarian

mrdtv2010 wrote: »

These are interesting considerations. However with the local high power Mount Leinster ( I am assuming circa 50kW ERP) transmissions side beam COFDM reception will be fine with Group B aerials used for Preseli so only one aerial would be needed. Therefore E39 makes a lot of sense. Also with newer smarter tuning DTT boxes E39 would be loaded BEFORE the Preseli channels. The use of Group A channels would mean diplexers would be needed and you need to know where the frequency cut would be made. Certainly lone radiation on E45 makes no sense as this will be wrecked by Preseli in overlap areas. The entire trial at Mount Leinster has proved one thing conclusively: overlapping cochannel DTT allocations cannot work with overspill. This will be bad news for the Drogheda relay which will get zapped by the Divis analogue and DSO signals (going up by a factor of nearly twentyfive to fifty depending on mux allocation.)

I would have thought the problem would be the reverse??? That reception from one of the Divis PSB muxes will be destroyed by a relay on top of that hospital? The places in Drogheda which are poor for TV reception don't have a hope of picking up Divis, considering there are a couple of 100 ft masts along the river just to pick up Divis analogue currently.

Divis is not going to interfere with anyone using the Drogheda relay, as the relay is designed to make up for CC coverage in parts of the town. You can't get good Divis if you can't get good CC.

lawhec

mrdtv2010 wrote: »

These are interesting considerations. However with the local high power Mount Leinster ( I am assuming circa 50kW ERP) transmissions side beam COFDM reception will be fine with Group B aerials used for Preseli so only one aerial would be needed. Therefore E39 makes a lot of sense. Also with newer smarter tuning DTT boxes E39 would be loaded BEFORE the Preseli channels. The use of Group A channels would mean diplexers would be needed and you need to know where the frequency cut would be made. Certainly lone radiation on E45 makes no sense as this will be wrecked by Preseli in overlap areas. The entire trial at Mount Leinster has proved one thing conclusively: overlapping cochannel DTT allocations cannot work with overspill. This will be bad news for the Drogheda relay which will get zapped by the Divis analogue and DSO signals (going up by a factor of nearly twentyfive to fifty depending on mux allocation.)

While DVB-T (and DVB-T2) has mechanisms allowing for off-beam reception to be more forgiving in reception compared to analogue broadcasts (resilience to multipath, lower S/N levels required etc.), relying on receiving a signal off-beam is simply poor aerial installation practice. This brings in a set of scenarios that aren't often considered including hoping that the direction of the Mt. Leinster signal going to the Presely aligned aerial corresponds to a favourable side-lobe and not (at worst) a deep notch in the polar pattern.

Even allowing for high powered DTT to reach places better than analogue did, considerations into receiving sites that may be difficult to receive Mt. Leinster from (with no other RTÉ DTT transmitter available) because of terrain, local objects etc. which would require a separate aerial aimed there alongside one for Welsh reception. Also, with the UK plan to reassign channels E61 and E62 for EU co-ordinated use (possibly mobile phone use) and to reintroduce E39 and E40 back into the UK DTT broadcasting plan, future use of E39 from a UK based transmitter (be it Presely or another transmitter that could be received in lift conditions) that could be received on the SE coastline could interfere co-channel, particularly vulnerable when the RTÉ DTT signal is off-beam.

This also doesn't take into account Mt. Leinster viewers who receive no (direct) UK DTT signals - in terms of Mt. Leinster's geographical coverage, those that can also receive Welsh DTT signals only cover a minority part of it. Therefore those who have a VHF/UHF set up may have to change their UHF aerial - that'll depend on individual circumstances.

IMO E34 would be better - it falls just outside the coverage bandwidth of modern Group B aerials (E35-53) (whereby aiming a Group B aerial at such a TX should still give acceptable results) in the case of single aerial off-beam reception, and falls into all Group A aerials aimed at Mt. Leinster for currently receiving TV3 & TG4 (analogue), with viewers avoiding possibly having to have their UHF aerial updated simply for one multiplex. In the case of UHF diplexers, the lowest channel cut-off I've seen on any is E21-E34.

As for the Drogheda scenario, my understanding is that current analogue reception from Divis in the town is unusable and since the Drogheda "relay" plans to use vertical polarisation, it may not prove to be a big problem at least in its target area. Drogheda's potential overspill may be more of a problem to potential fringe viewers in Louth & Meath.

lucernarian

Just for the record, about 25-30% of Drogheda has Divis aerials. From what I've seen, reception is somewhat snowy especially on Channel 4 and BBC1 but usually a bit better than houses picking up Kilkeel. I also know of the odd home which can pick up one or two freeview muxes. I wouldn't say Divis is unsuable by any stretch. When the transmitter is within a mile of a couple of thousand houses and a few more thousand within 3 miles, it almost won't matter what polarisation it is as cross-polar rejection (e.g of 20 dB) would be insufficient to counteract the far stronger signal strength. ERP will be 130W.

The rest of Louth (e.g. Ardee, Dunleer, Dundalk) should not be affected that much due to the higher ground to the north of Drogheda. More parts of Meath could suffer issues however.

lawhec

watty wrote: »

Exactly, my point.

Working Frequency co-ordination.

Since Presli & Mt Leinster are "adjacent" (only sea between), they should be on differing channels & Polarisation like Strabane & Longford.

Anyone with Radio planning expertise can see there will be often problems.

Spain was only an occasional issue, but that was VHF. It's too much sea to worry about.

I misread your main point then, apologies.

Getting Preseli or Mount Leinster to use vertical polarisation wasn't likely to happen, especially in the former case. The UK as a rule don't do vertical polarisation for its "main" transmission sites (Rowridge will be an exception, if only because some one there knew of potential co-channel interference problems) and again, at least in the UK, the main point for the digital switch-over is that at least for the PSB multiplexes, viewers won't have to change their aerials in almost all cases (a few tiny relays excepted).

Saying that, I remember in the ICDG days when some forum members in Wicklow/Wexford had OnDigital subscriptions, points were made that Mt. Leinster's then DTT allocations co-channelled with Presely. When the ITU conference came about in 2006, I was surprised they agreed to such allocations myself.

lawhec

To_be_confirmed wrote: »

Just for the record, about 25-30% of Drogheda has Divis aerials. From what I've seen, reception is somewhat snowy especially on Channel 4 and BBC1 but usually a bit better than houses picking up Kilkeel. I also know of the odd home which can pick up one or two freeview muxes. I wouldn't say Divis is unsuable by any stretch. When the transmitter is within a mile of a couple of thousand houses and a few more thousand within 3 miles, it almost won't matter what polarisation it is as cross-polar rejection (e.g of 20 dB) would be insufficient to counteract the far stronger signal strength. ERP will be 130W.

The rest of Louth (e.g. Ardee, Dunleer, Dundalk) should not be affected that much due to the higher ground to the north of Drogheda. More parts of Meath could suffer issues however.

Hmmm, some headaches and scratching might well ensure. Different ways of tackling that one if you don't want (or at least reduce) a fair proportion of viewers getting wiped out.

mrdtv2010

lawhec wrote: »

While DVB-T (and DVB-T2) has mechanisms allowing for off-beam reception to be more forgiving in reception compared to analogue broadcasts (resilience to multipath, lower S/N levels required etc.), relying on receiving a signal off-beam is simply poor aerial installation practice. This brings in a set of scenarios that aren't often considered including hoping that the direction of the Mt. Leinster signal going to the Presely aligned aerial corresponds to a favourable side-lobe and not (at worst) a deep notch in the polar pattern.

Even allowing for high powered DTT to reach places better than analogue did, considerations into receiving sites that may be difficult to receive Mt. Leinster from (with no other RTÉ DTT transmitter available) because of terrain, local objects etc. which would require a separate aerial aimed there alongside one for Welsh reception. Also, with the UK plan to reassign channels E61 and E62 for EU co-ordinated use (possibly mobile phone use) and to reintroduce E39 and E40 back into the UK DTT broadcasting plan, future use of E39 from a UK based transmitter (be it Presely or another transmitter that could be received in lift conditions) that could be received on the SE coastline could interfere co-channel, particularly vulnerable when the RTÉ DTT signal is off-beam.

This also doesn't take into account Mt. Leinster viewers who receive no (direct) UK DTT signals - in terms of Mt. Leinster's geographical coverage, those that can also receive Welsh DTT signals only cover a minority part of it. Therefore those who have a VHF/UHF set up may have to change their UHF aerial - that'll depend on individual circumstances.

IMO E34 would be better - it falls just outside the coverage bandwidth of modern Group B aerials (E35-53) (whereby aiming a Group B aerial at such a TX should still give acceptable results) in the case of single aerial off-beam reception, and falls into all Group A aerials aimed at Mt. Leinster for currently receiving TV3 & TG4 (analogue), with viewers avoiding possibly having to have their UHF aerial updated simply for one multiplex. In the case of UHF diplexers, the lowest channel cut-off I've seen on any is E21-E34.

As for the Drogheda scenario, my understanding is that current analogue reception from Divis in the town is unusable and since the Drogheda "relay" plans to use vertical polarisation, it may not prove to be a big problem at least in its target area. Drogheda's potential overspill may be more of a problem to potential fringe viewers in Louth & Meath.

Preseli has no planned channel allocations in the E60's so it won't need to change any frequencies now. It operates in truly 'cleared' spectrum irrespective of the 800Mhz debate, which as recent German results show may not be so suitable for mobile broadband. The use of E39 at Mount Leinster is convenient in the SE area and with the powers being pumped out Group A aerials will probably be OK. In West Cornwall I have seen perfect Caradon Hill (Group A COFDM) off Group B Redruth at 175 degree angles because of the powers being pumped out. The SNR, BER and CSI states were perfectly usable. I would be wary also of vertical polarisation CCI issues: topographical scatter may well invert the polarity and cause Drogheda to interfere with Divis losing the DVB-T1/T2 C/I protection of around 20dB for those modes. There is no CCI relationship between Cairn Hill and Strabane (which will behave like Arfon) but there is between Holywell Hill and Brougher: fortunately terrain shielding may be in play but it is still an issue.

mrdtv2010

To_be_confirmed wrote: »

I would have thought the problem would be the reverse??? That reception from one of the Divis PSB muxes will be destroyed by a relay on top of that hospital? The places in Drogheda which are poor for TV reception don't have a hope of picking up Divis, considering there are a couple of 100 ft masts along the river just to pick up Divis analogue currently.

Divis is not going to interfere with anyone using the Drogheda relay, as the relay is designed to make up for CC coverage in parts of the town. You can't get good Divis if you can't get good CC.

I think RTENL have to make a number of quite fundamental decisions now:

a) Do they align their software parameters with NI?

b) Do they use frequency allocations which integrate rather than interfere with UK overspill?

c) Do they try to cash in on 'Tesco DTT economics' ?

These are now the fundamental choices they have to make. To date the calls made have been, to put it politely, sub-optimal. Let's see how the summer pans out for Saorview.

lawhec

mrdtv2010 wrote: »

Preseli has no planned channel allocations in the E60's so it won't need to change any frequencies now. It operates in truly 'cleared' spectrum irrespective of the 800Mhz debate, which as recent German results show may not be so suitable for mobile broadband. The use of E39 at Mount Leinster is convenient in the SE area and with the powers being pumped out Group A aerials will probably be OK. In West Cornwall I have seen perfect Caradon Hill (Group A COFDM) off Group B Redruth at 175 degree angles because of the powers being pumped out. The SNR, BER and CSI states were perfectly usable. I would be wary also of vertical polarisation CCI issues: topographical scatter may well invert the polarity and cause Drogheda to interfere with Divis losing the DVB-T1/T2 C/I protection of around 20dB for those modes. There is no CCI relationship between Cairn Hill and Strabane (which will behave like Arfon) but there is between Holywell Hill and Brougher: fortunately terrain shielding may be in play but it is still an issue.

One provisional plan for reallocation I've seen for reallocating E61 and E62 is for such transmitters to "borrow" frequencies from neighbouring TX's who currently have frequencies in the higher part of the Group B UHF broadcast spectrum. As an example (off my head), Carmel has its COM3 multiplex on E61 at present. To clear this but retune the multiplex to a new channel within the aerial group, it "takes" Presely's E50, with Presely broadcasting PSB3 now on E40. This would obviously require some co-ordination by Ofcom and possibly some new registrations with the ITU as well, but seems inevitable. Only sites currently broadcasting UHF Group A transmissions only would appear to be safe from such retuning. As for German tests, I know ARD/ZDF have concerns mainly regarding the potential swamping of tuners, however I'm pretty convinced that E61-E69 will be "released" from television broadcast use, that piece of spectrum is pretty valuable & suited for mobile use. IMO LTE will be wasted only sitting on 2.6GHz and the 900MHz band may take some time to have GSM off it, UMTS/HSPA certainly isn't doing it.

In terms of aerials, receiving E39 on Group A aerials (especially older ones made before the advent of Channel 5) is fairly unpredictable. The graph below (from aerialsandtv.com) show that grouped yagi aerials have gradual gains going up to their frequency of peak gain before quite quickly dropping off. Modern Group A aerials would probably handle E39 OK, but E34 would provide better reliability. And since an eastwards directed UHF Group B aerial is receiving a signal off beam, all bets are off regarding gain/loss regardless of wherever the multiplex is on either E34 or E39. The Caradon Hill/Redruth example doesn't note of any potential side lobes at the angle specified.



In the case of Drogheda, the potential consequences of what will happen won't be known until something actually happens, given TX siting, ERP, any directional properties and terrain. Freeview reception from Divis along the eastern seaboard is already hampered by co-channel interference on some multiplexes. Those still using terrestrial in Louth/Meath by the time NI DSO comes could be in for an unfortunate awakening.

As for Strabane, as I've said before it was never considered a viable site to singularly cover the West of Northern Ireland on UHF the same way it did for Ulster TV on VHF - it couldn't adequately cover Enniskillen and Derry city (Limavady doesn't either, but it covers the North Coast areas like Coleraine and Ballymoney that Strabane had no hope in reaching). I'm not familiar with Arfon's coverage in Ireland, but Strabane is currently directional towards the south/SSW, and would have significant barriers in terms of the mountains of Donegal as well as hills in south & west Fermanagh, Belleek is about as far as it gets (where it feeds the small Gortnalee relay) though I recall one poster from Leitrim saying that he had reception from Strabane - it's main use for potential Freeview reception will be in East Donegal, and that'll be after if Brougher Mountain or Limavady isn't possible (for the full Freeview service), it's unlikely to be of benefit to anyone else in the Republic, if they get Strabane it likely their get either Brougher Mountain or Divis too. If it somehow made it through the Donegal mountains towards the west coast, co-channel interference with Aranmore could happen.

mrdtv2010

lawhec wrote: »

One provisional plan for reallocation I've seen for reallocating E61 and E62 is for such transmitters to "borrow" frequencies from neighbouring TX's who currently have frequencies in the higher part of the Group B UHF broadcast spectrum. As an example (off my head), Carmel has its COM3 multiplex on E61 at present. To clear this but retune the multiplex to a new channel within the aerial group, it "takes" Presely's E50, with Presely broadcasting PSB3 now on E40. This would obviously require some co-ordination by Ofcom and possibly some new registrations with the ITU as well, but seems inevitable. Only sites currently broadcasting UHF Group A transmissions only would appear to be safe from such retuning. As for German tests, I know ARD/ZDF have concerns mainly regarding the potential swamping of tuners, however I'm pretty convinced that E61-E69 will be "released" from television broadcast use, that piece of spectrum is pretty valuable & suited for mobile use. IMO LTE will be wasted only sitting on 2.6GHz and the 900MHz band may take some time to have GSM off it, UMTS/HSPA certainly isn't doing it.

In terms of aerials, receiving E39 on Group A aerials (especially older ones made before the advent of Channel 5) is fairly unpredictable. The graph below (from aerialsandtv.com) show that grouped yagi aerials have gradual gains going up to their frequency of peak gain before quite quickly dropping off. Modern Group A aerials would probably handle E39 OK, but E34 would provide better reliability. And since an eastwards directed UHF Group B aerial is receiving a signal off beam, all bets are off regarding gain/loss regardless of wherever the multiplex is on either E34 or E39. The Caradon Hill/Redruth example doesn't note of any potential side lobes at the angle specified.



In the case of Drogheda, the potential consequences of what will happen won't be known until something actually happens, given TX siting, ERP, any directional properties and terrain. Freeview reception from Divis along the eastern seaboard is already hampered by co-channel interference on some multiplexes. Those still using terrestrial in Louth/Meath by the time NI DSO comes could be in for an unfortunate awakening.

As for Strabane, as I've said before it was never considered a viable site to singularly cover the West of Northern Ireland on UHF the same way it did for Ulster TV on VHF - it couldn't adequately cover Enniskillen and Derry city (Limavady doesn't either, but it covers the North Coast areas like Coleraine and Ballymoney that Strabane had no hope in reaching). I'm not familiar with Arfon's coverage in Ireland, but Strabane is currently directional towards the south/SSW, and would have significant barriers in terms of the mountains of Donegal as well as hills in south & west Fermanagh, Belleek is about as far as it gets (where it feeds the small Gortnalee relay) though I recall one poster from Leitrim saying that he had reception from Strabane - it's main use for potential Freeview reception will be in East Donegal, and that'll be after if Brougher Mountain or Limavady isn't possible (for the full Freeview service), it's unlikely to be of benefit to anyone else in the Republic, if they get Strabane it likely their get either Brougher Mountain or Divis too. If it somehow made it through the Donegal mountains towards the west coast, co-channel interference with Aranmore could happen.

Interesting post and it does indeed appear that a lot of channels in Group B are going to have to move again, possibly in 2013. This is mentioned in Ofcom's new frequency and power lists for the DSO stations in London, Meridian and Anglia regions, E39 and E40 are going to be given back to broadcasting in the UK as E61 and E62 are ceded to mobile broadband. This was published yesterday. The lists for the NI region are not published yet but would be expected shortly given the release of these frequencies. Preseli could indeed seek to recover E40 as it was originally used for analogue TV. So multiple viewer retunes up to 2014.

As to Divis its COM muxes after DSO are cochannel with Caldbeck and the current Three Rock analogue channels so it will effectively be reduced to a Freeview lite service in the overlap area with Three Rock whilst the analogue service continues and there will, as already seen in East Down, be CCI from Caldbeck. The only clear channels are the three PSB muxes to be on 21, 24 and 27.

Strabane: I agree. Even in the VHF days they had a relay at Ballycastle which has been discussed in other posts.

Kilkeel: This is already experiencing CCI on its analogue channels from PSB muxes at the DSO Moel-y-Parc station.

Satdog

Gerry Wicklow wrote: »

To my mind the fact that RTÉNL insisted on using 45 instead of 39 just goes to prove that it is deliberate jamming. I can only assume they got their diplomatic skills in Israel, 'it's legal so we will bloody well use it regardless of who we p**s off!' Whether it works or not is beside the point.:mad:

I've resorted to using E52 from Ck on Suir as I can't even get E45 Mt Leinster because CCI. I was surprised at first that I could pict up Ck on Suir from Wexford.

Gerry Wicklow

Gerry Wicklow wrote: »

To my mind the fact that RTÉNL insisted on using 45 instead of 39 just goes to prove that it is deliberate jamming. I can only assume they got their diplomatic skills in Israel, 'it's legal so we will bloody well use it regardless of who we p**s off!' Whether it works or not is beside the point.:mad:

RTENL will have to be formally told by aerial installers that ch45 just will not work for the majority of people in co wexford and parts of wicklow that have presely aerials.
It's as easy as twisting a dial for them to go back to ch45.

In other news I've got my hands on a sagem Freeview + hd T2 box.

In theory that would have an epg with the irish and presely channels all recordable like on a sky plus.
I'll test it's mpeg4 abilities when i get it home,I'm not there at the moment.
Clearly i wont have RTE untill they move off ch 45.

mrdtv2010

Deleted User wrote: »

RTENL will have to be formally told by aerial installers that ch45 just will not work for the majority of people in co wexford and parts of wicklow that have presely aerials.
It's as easy as twisting a dial for them to go back to ch45.

In other news I've got my hands on a sagem Freeview + hd T2 box.

In theory that would have an epg with the irish and presely channels all recordable like on a sky plus.
I'll test it's mpeg4 abilit abilties when i get it home,I'm not there at the moment.
Clearly i wont have RTE untill they move off ch 45.

I presume you meant E39. Preseli HD will be live on the 29th, Caradon Hill just started ten days ago.

mrdtv2010

mrdtv2010 wrote: »

I presume you meant E39. Preseli HD will be live on the 29th, Caradon Hill just started ten days ago.

the rte channels have just gone offline in north county wexford at the moment - why do they insist in messing around with transmitters during footy :mad:

looks like they ahve decreased the signal power from what i cna gather - either that or thers some sort of interference coming in but i have no devices beside the antenna

marclt

It could well be atmospheric conditions. The high pressure is allowing signals to travel far further than usual.

Ch.45 from Preseli is causing enough trouble to block out your RTE signal, but not strong enough for the Welsh channels to become visible.

Just another reason to love the summer...

marclt

Satdog wrote: »

I've resorted to using E52 from Ck on Suir as I can't even get E45 Mt Leinster because CCI. I was surprised at first that I could pict up Ck on Suir from Wexford.

The signal seems to run down the Valley quite nicely into Wexford town area. Tipp Fm on 103.9 seems to 'get down' the Suir Valley also.

marclt

marclt wrote: »

It could well be atmospheric conditions. The high pressure is allowing signals to travel far further than usual.

Ch.45 from Preseli is causing enough trouble to block out your RTE signal, but not strong enough for the Welsh channels to become visible.

Just another reason to love the summer...

35 UK channels appear when i point the indoor ariel in the right directon but the signal is just below the viewing threashold i was thinking that could be interferring indeed still point the ariel ina different direction and the rte ones appear good (have had to move it several times at this stage with variable results and it does tend to disappear again after a while) - they really need to change the broadcasting channels for rte so both can operate without interferrence

mrdtv2010

mrdtv2010 wrote: »

I presume you meant E39. Preseli HD will be live on the 29th, Caradon Hill just started ten days ago.

Yeah I meant as easy as pie for them to go back to ch39.
Why won't they?

Going to take the sagem out now and see what happens.
Preseli is on fire strength wise today.
Pity no RTE.
It seems a magic solution as a box with twin tuners that can record RTE aswell as freeview.
Tw'ud be perfect.

marclt

warlikedave wrote: »

35 UK channels appear when i point the indoor ariel in the right directon but the signal is just below the viewing threashold i was thinking that could be interferring indeed still point the ariel ina different direction and the rte ones appear good (have had to move it several times at this stage with variable results and it does tend to disappear again after a while) - they really need to change the broadcasting channels for rte so both can operate without interferrence

I think you must report this sort of thing to RTE. They will only respond if they actually now the level of difficulty this is causing.

Admittedly, the current weather pattern is increasing the distance signals are travelling. On the other side of the water, Ch. 45 is gone for me right now... I'm getting Mt. Leinster is beaming in from the west.

BTW I'm getting 100 % signal and strength on RTE digital from Mullaghanish, along with the analogues on Ch.27 and 31! Result!!!

marclt

marclt wrote: »

I think you must report this sort of thing to RTE. They will only respond if they actually now the level of difficulty this is causing.

Admittedly, the current weather pattern is increasing the distance signals are travelling. On the other side of the water, Ch. 45 is gone for me right now... I'm getting Mt. Leinster is beaming in from the west.

BTW I'm getting 100 % signal and strength on RTE digital from Mullaghanish, along with the analogues on Ch.27 and 31! Result!!!

what department do I report this to? and where do I find contact details about this?

Email rte and tell them you cant get them due to uk interference on ch45 with your loft aerial and this did not happen when they were on ch39 and ask if they could move back to ch 39.

Tell them most of your neighbours who watch welsh digital can't get rte digital since the move from ch 39 to 45.
Tell them,they will not be removing their uk aerials or access to uk channels which are free and popular.

I'm wondering is it the new rte hope,that people will take down their welsh aerials so as to watch rte in wexford aster analogue switch off.

Are we that special down here that they might want to fcuk with us in that way?

jabarrett35

Hi I'm in Tramore Ch 45 is gone but on the other hand I am getting 78 UK DTT channels with amazing strenght and quality signals. I know it's atmospherics but my aerials are pointing away from Presely so if I had a proper aerial and mast head amplifier would I get UK DTT all the time we are very high up and look out straight to sea with no obstruction.

Very possible with the right gear I'd say.

dasilverfox

jabarrett35 wrote: »

Hi I'm in Tramore Ch 45 is gone but on the other hand I am getting 78 UK DTT channels with amazing strenght and quality signals. I know it's atmospherics but my aerials are pointing away from Presely so if I had a proper aerial and mast head amplifier would I get UK DTT all the time we are very high up and look out straight to sea with no obstruction.

yeah i was getting 46 channels including the rte channels, but they disappeared last week. after a retune i'm now getting 78 channels minus the irish ones. got 111 channels yesterday but they must have been from another transmitter as they were the same channels all over again. still no rte though. watching on analogue now.

dasilverfox

dasilverfox wrote: »

yeah i was getting 46 channels including the rte channels, but they disappeared last week. after a retune i'm now getting 78 channels minus the irish ones. got 111 channels yesterday but they must have been from another transmitter as they were the same channels all over again. still no rte though. watching on analogue now.

You need to contact rte and tell them that you were able to receive rte when it was on ch 39 from mt leinster but not anymore as ch45 is unreceivable due to it being co channel with presely.

They may suggest that you disconnect your presely aerial but you just laugh out loud when they say that and tell them you are not disconnecting 78 channels just to pick up 3 channels from rte...
RTE can fix the problem easily by using channel 39.
ch 39 is clear of presely interference and is an ebu allocated channel for mt leinster aswell.

Sponge Bob

Deleted User wrote: »

You need to contact rte and tell them that you were able to receive rte when it was on ch 39 from mt leinster but not anymore as ch45 is unreceivable due to it being co channel with presely.

Tell them to put TV3 on Ch 45

Our man in Havana

LOL!

watty

Oddly I do get TV3 on Ch45.


Analogue in Limerick.
39 = RTE1, 42 = RTE2, 49 = TG4

watty

watty wrote: »

Oddly I do get TV3 on Ch45.


Analogue in Limerick.
39 = RTE1, 42 = RTE2, 49 = TG4

really? or are you referring to the analogue ch45 which you are recieving three on? still think ill do a scan

watty

watty wrote: »

Oddly I do get TV3 on Ch45.


Analogue in Limerick.
39 = RTE1, 42 = RTE2, 49 = TG4

Would dtt at mt leinster on 39 be strong enogh to trouble 39 in limerick?

Deleted User

Deleted User wrote: »

Would dtt at mt leinster on 39 be strong enogh to trouble 39 in limerick?

if uk DTT was being recieve far into the midlands a few days ago - it would make sence that mt leinster could be recived in limerick - whether it would act as interferrence is another question but if they are being broadcast of the same frequencies then i would say it would - thats probably why its on ch45 here (besides the point of them trying to block welsh DTT) and ch39 in limerick

mike65

No TV3 here (no loss admitedly)

watty

Ch39, 42, 45 and 49 are the Analogue channels in Limerick.

There is only a narrow strip of Woodcock receiving Limerick that would get Mt Leinster, and its only rural higher spots. The two paths are at 90 deg approx. The likelyhood of co-channel interference is about Nil.

The city is well shielded in Mt Leinster direction being mostly at sea level. Woodcock Hill is actually in Co. Clare but quite close to the City. Much clearer path to Limerick County than most of Clare.

Woodcock Digital
47 41 44 51

Looks to me like 44 is in use only for DTT
I think pointing an aerial SW I'm getting weak DTT on 45.

Just Analog spectrum analyser.

razor_ryan

warlikedave wrote: »

if uk DTT was being recieve far into the midlands a few days ago - it would make sence that mt leinster could be recived in limerick - whether it would act as interferrence is another question but if they are being broadcast of the same frequencies then i would say it would - thats probably why its on ch45 here (besides the point of them trying to block welsh DTT) and ch39 in limerick

Which area's were getting UK DTT far into the midlands ?

razor_ryan

razor_ryan wrote: »

Which area's were getting UK DTT far into the midlands ?

it was a rarity - because of the high pressure over the British Isles - i heard it was being recieved in Waterford and a friend in tip was getting it but it disappeared

jabarrett35

High pressure is back and it's not only 1021mb and ch45 strenght is down too 30% and poor quality this co channel interference is a mare!