Welsh digital switch over-Irish reception questions answered

marclt · 05-03-2010 12:41AM

fat-tony wrote: »

Seems to be a lift on all right (pressure's high - 1033). I'm picking up CH58 and CH59 here in Greystones. My wideband aerial is pointed at Blaenplwyf (which I have failed to receive here at any stage). I suspect 58/59 is coming at me from the NorthEast rather than Wales, as I seem to be in a bit of a reception "dip" in that direction.

Hey Tony

What channels are you picking up there??

Marc

05-03-2010 08:55AM

Iirc Tony is in a dip and didn't even have analogue arfon prior to it's aso.
His neighbours do by virtue of tall masts.

fat-tony · 05-03-2010 12:31PM

marclt wrote: »

Hey Tony

What channels are you picking up there??

Marc

On 58 I was getting QVC, Virgin1, bidtv, ITV3, Fiver, Five US, Quest, CNN, G.O.L.D.(encrypted), ESPN(encrypted)

On 59 ITV1, ITV2(+1), CH4, More4, E4, Five

Gone this morning.

mrdtv2010 · 05-03-2010 08:20PM

fat-tony wrote: »

On 58 I was getting QVC, Virgin1, bidtv, ITV3, Fiver, Five US, Quest, CNN, G.O.L.D.(encrypted), ESPN(encrypted)

On 59 ITV1, ITV2(+1), CH4, More4, E4, Five

Gone this morning.

Those are from Winter Hill. No surprise with the direction reported.

mrdtv2010 · 05-03-2010 08:52PM

DigiDec wrote: »

Picking up Preseli tonight, very stable. My location, Finglas on the nothside of Dublin City, setup - wideband attic aerial with masthead amp.

Im getting channels 41, 43, 44, 46

strenght 75%
quality 92%

I just wonder with an outdoor antenna if you couldn't get a regular service from Arfon: its an omnidirectional antenna and the nearest to you. The reason is simple: loft antennas lead to path losses of up to 20dB!

Digifriendly · 06-03-2010 10:22AM

Listening to RTE Radio 1 programme after 8 o'clock news this morning - think programme was called 'Countrywide' and it had a feature on Welsh speaking farmers in the Celtic nations. This will be broadcast on a programme on S4C. Interesting that at the end of the feature the presenter said S4C was available on Sky Ch. 134. No mention whatsoever of those on east coast being able to pick it up via an aerial. RTE don't seem to recognise that Welsh TV is available to thousands of homes along Eastern seaboard via an aerial!

06-03-2010 05:02PM

mrdtv2010 wrote: »

I just wonder with an outdoor antenna if you couldn't get a regular service from Arfon: its an omnidirectional antenna and the nearest to you. The reason is simple: loft antennas lead to path losses of up to 20dB!

Preseli was exceptionally strong last night.
It's normally 80% signal strength here on the humax and it was up at 100% so I'm not surprised it reached north Dublin.

Meanwhile-No blaenplwyf signal at all in Arklow town and thats with a sea view-zero nada nothing so I guess those engineers have got their nulling pretty spot on
We got Arfon working perfectly.
It measured 39db before we put a mast head amp on it and is blasting in.

Interestingly a Grid being used for Mt Leinster was picking up 43 and 46 today from preseli aswell without a masthead amp.

mrdtv2010 · 07-03-2010 12:24PM

Deleted User wrote: »

Preseli was exceptionally strong last night.
It's normally 80% signal strength here on the humax and it was up at 100% so I'm not surprised it reached north Dublin.

Meanwhile-No blaenplwyf signal at all in Arklow town and thats with a sea view-zero nada nothing so I guess those engineers have got their nulling pretty spot on
We got Arfon working perfectly.
It measured 39db before we put a mast head amp on it and is blasting in.

Interestingly a Grid being used for Mt Leinster was picking up 43 and 46 today from preseli aswell without a masthead amp.

Yes, that narrow null in 270-285 degrees towards Arklow is now confirmed. Interestingly it worked perfectly up at Bray which is what you would expect as its outside the null with the North Wales Lleyn peninsula just across the sea. The nulls are now computer controlled in the panels so its very easy to implement cut-outs in an ominidirectional HRP. Still he's got a choice of Preseli or Arfon!

DigiDec · 07-03-2010 02:02PM

mrdtv2010 wrote: »

I just wonder with an outdoor antenna if you couldn't get a regular service from Arfon: its an omnidirectional antenna and the nearest to you. The reason is simple: loft antennas lead to path losses of up to 20dB!

I must give it a shot and see, I remember in the 70's we had BBC Wales and HTV via a massive roof top aerial before cable tv came along.

gtg60 · 07-03-2010 02:51PM

mrdtv2010 wrote: »

Yes, that narrow null in 270-285 degrees towards Arklow is now confirmed.

15 Degrees? I thought it was only supposed to be 5 degrees?

Does this mean the likes of Rathdrum and Wicklow town are likely to be is this restricted area?

Also didn't Black Briar receive B-P? And from the map it definitely looks like he is in the restricted area?

07-03-2010 04:10PM

gtg60 wrote: »

Also didn't Black Briar receive B-P? And from the map it definitely looks like he is in the restricted area?

I did but I don't now.
Sure shows the power of this forum...

Hi engineers ! :rolleyes: Better get working on a few relays on arfons frequencies :rolleyes:

I can also confirm that there is zero Blaenplwyf at castletown which would be 8 miles south of Arklow so a 15 degree null looks likely.

Theres no transmitter in Arklow by the way and no need for one.
At yesterdays location,Kippure and Mt Leinster were blasting in... :rolleyes:

Sam Russell · 07-03-2010 06:01PM

I am trying to figure out which would be the most likely to get in Ballsbridge, if any.

1. Winter Hill is 250km away ffom me.
2. Blaenplwyf is 175km away.
3. LLanddona is 140 km away.

Winter Hill is the highest transmitter in England and is omnidirectional, and very powerful, with all muxes powered, inc HD.

What aerials and polarisation do I need for each one? I am at sea level with the aerial at most 10 - 15 metres up. There are some tall trees around, but not in every direction.

I will try them all with a log periodic wide band first, but if I get nothing, I might try with a better aerial.

Any ideas?

mrdtv2010 · 08-03-2010 11:29AM

DigiDec wrote: »

I must give it a shot and see, I remember in the 70's we had BBC Wales and HTV via a massive roof top aerial before cable tv came along.

I think Arfon might be feasible in parts of Dublin: the transmitter is the highest in Wales with HAAT of 607.4 metres, has an omnidirectional pattern, radiates at 2kW (equivalent to 10kW) PAL, and its channels 41, 44 and 47 have no CCI with TR/KIP or any nearby NI/UK transmitters. It is being received in higher parts of South Down. Its one disadvantage is that its Freeview-lite. The higher you are the better the radio horizon. The antenna would be much smaller than those VHF Channel 10 efforts of yesteryear!

mrdtv2010 · 08-03-2010 11:37AM

gtg60 wrote: »

15 Degrees? I thought it was only supposed to be 5 degrees?

Does this mean the likes of Rathdrum and Wicklow town are likely to be is this restricted area?

Also didn't Black Briar receive B-P? And from the map it definitely looks like he is in the restricted area?

IIRC its 15 degrees. This makes sense if you look at Google maps, the line would be on a bearing just north of towards Enniscorthy to Arklow itself. The null is a 9dB restriction meaning the ERP radiated westward is lower than 5kW and also Blaen Plwyf is ~ 300 m above seal level much less than Arfon's 607m or Preseli's ~ 560 metre. At sea level it will be difficult to get BP with this restriction. North of Arklow you come into the main BP beam serving NW Wales at 40 kW and similarly the SW beam is 40kW which lies below the restriction. This is why you had very good reception of BP in Bray and there is none in or around Arklow. I suspect that BP radiates in a boomerang pattern as there is little point radiating eastward into the mountains.

mrdtv2010 · 08-03-2010 11:55AM

Sam Russell wrote: »

I am trying to figure out which would be the most likely to get in Ballsbridge, if any.

1. Winter Hill is 250km away ffom me.
2. Blaenplwyf is 175km away.
3. LLanddona is 140 km away.

Winter Hill is the highest transmitter in England and is omnidirectional, and very powerful, with all muxes powered, inc HD.

What aerials and polarisation do I need for each one? I am at sea level with the aerial at most 10 - 15 metres up. There are some tall trees around, but not in every direction.

I will try them all with a log periodic wide band first, but if I get nothing, I might try with a better aerial.

Any ideas?

Radio horizons work against you there!

WH: too far away. CCI with Three Rock/Kippure on the HD mux and two of the COM muxes.

BP: Might work but CCI from Divis analogue very possible. Are there any horizontal aerials pointing northwards? BP better from Bray southwards apart from the null.

Llandona: Seems to be a westward null, very low mast on the eastern side of Anglesey and terrain in the way.

I think your best bet could be Arfon as its the nearest, has the highest mast, and is being received along the coast.

08-03-2010 12:11PM

Signal strength on arfon in arklow is 75%.
Quality 100% at saturdays location.

Here presely is varying from above 80% to over 93% strength and 100% quality.

I'm still picking up 63% strength here on ch 27 by the way and 0% quality
Could that be an overspill from Mt Leinster analogue on the adjoining frequency?

mrdtv2010 · 08-03-2010 12:29PM

Deleted User wrote: »

Signal strength on arfon in arklow is 75%.
Quality 100% at saturdays location.

Here presely is varying from above 80% to over 93% strength and 100% quality.

I'm still picking up 63% strength here on ch 27 by the way and 0% quality
Could that be an overspill from Mt Leinster analogue on the adjoining frequency?

The key is to have very high quality. My T2 box works down to 20% signal and still has 100% quality (direct path.) Arfon and Preseli are very good because they are high sites so the radio horizon is big and they work at sea level.

Its possible there could be breakthrough from Channel 26 in which case a variable attenuator will adjust the relative levels so that the DTT works (this was a problem in the early days of DTT as adjacent analogue channels swamped the DTT so you had to attenuate the analogue levels. This is fixed in modern tuners though.) You'll be able to answer this question on Wednesday morning when CH 24 @ 40kW is fired up as are 25, 22+ and 28 at 10kW. You won't see Ch 21+ @ 40kW as that is T2. If the other channels exhibit similar signal strengths but have good quality readings and decode properly then its a channel specific issue. If not then its a path and antenna issue: you are probably on the cusp of the null. In addition as you use Group B there will be a 15dB ish loss in performance for low Group A channels compounded by the fact that your antenna is probably 30 degrees off beam on BP. BP's low height means its radio horizon is lower compared to Arfon and Preseli. BTW I see on another forum that Mount Leinster DTT may be interfering with Preseli Channel 49 on its home turf in Wales, more details awaited with interest.

08-03-2010 12:44PM

ch49 doesn't surprise me.
Whens that going full 20kw erp which will solve the problem?

Currently we can get RTE etc on 49 most of the time here.
42 and 45 have nothing as they are swamped by preseli.

Eagerly awaiting wenesday to see what the story is!

mrdtv2010 · 08-03-2010 01:15PM

Preseli Ch 49 to 10kW (final ERP): Q1 2010. Probably at end of Wenvoe switchover.

Note there is a new newsletter on the BP switchover in which they have a whole discussion of equipment capability for T2. It seems to imply in the table that T2 equipment is BACKWARDS COMPATIBLE with MPEG4 T1, because they compare the receivability of SD and HD services in France and the UK. See:

http://www.digitaluk.co.uk/transmitternetwork/tools__and__resources/almanac/installer_newsletters_transmitter_groups2009_pdfs/Installer_Newsletter_Blaenplywf_1_month_out_FINAL_7_Jan_10.pdf

RTENL are indeed wasting their time and power bills: those with Preseli aerials can't see 42, 45 or possibly 49 and the UK boxes (if MPEG4) will shove the Irish channels into the 800's. I think they should focus on a better strategy: dealing with the unchallengable frequency nemesis in the sky, namely Freesat.

Satdog · 08-03-2010 01:19PM

Deleted User wrote: »

ch49 doesn't surprise me.
Whens that going full 20kw erp which will solve the problem?

Currently we can get RTE etc on 49 most of the time here.
42 and 45 have nothing as they are swamped by preseli.

Eagerly awaiting wenesday to see what the story is!

I use E39 Mt Leinster as there is no CCI from Preseli.

mrdtv2010 · 08-03-2010 01:24PM

Satdog wrote: »

I use E39 Mt Leinster as there is no CCI from Preseli.

Very wise!. There is now CCI from Mount Leinster to the Preseli COM muxes in West Wales: confirmed.

08-03-2010 01:34PM

Yes I use 39 aswell but I mentioned 49 in the above context.

Lol - if you have a few minutes to spare-Read this

If only our current minister was as versed...

mrdtv2010 · 08-03-2010 01:39PM

Deleted User wrote: »

Yes I use 39 aswell but I mentioned 49 in the above context.

Lol - if you have a few minutes to spare-Read this

If only our current minister was as versed...

Yes, I have read this. They need to learn from the lessons of the past. IIRC Mount Leinster used to cause problems with Preseli Channel 8. OneVision reading this board will conclude the SE is a no-receive area for commercial DTT: 'The blue screen of death caused by colliding bits!'

Sam Russell · 08-03-2010 02:15PM

mrdtv2010 wrote: »

Radio horizons work against you there!

Checking the formula for radio horizon, the transmitters are all too far away by at least a factor of 2. Does the sea make a big difference?

I definitely got BP in Bray, but it was so temporary a set up, I could not take measurements. I think there was a lift condition as well. I will try again late next week.

marclt · 08-03-2010 02:56PM

mrdtv2010 wrote: »

Very wise!. There is now CCI from Mount Leinster to the Preseli COM muxes in West Wales: confirmed.

Got any further detail on this MRDTV? I find (even at my location) CH.49 to be the hardest to pick up.

It would be interesting to hear what is happening elsewhere. I guess with the imminent power increase at Preseli, this may restore the balance.

mrdtv2010 · 08-03-2010 03:52PM

Sam Russell wrote: »

Checking the formula for radio horizon, the transmitters are all too far away by at least a factor of 2. Does the sea make a big difference?

I definitely got BP in Bray, but it was so temporary a set up, I could not take measurements. I think there was a lift condition as well. I will try again late next week.

Yes, you have to be high up to get very distant transmitters eg in The Mournes, Wicklow Mountains, or The Cooleys. BP is much closer to Bray. You need to know a) the height of the transmitter b) the receive height and c) seapaths are beneficial to long distance high power DTT. As I said above Arfon is a better bet towards Dublin: north of Dublin by 2012 Divis & Kilkeel will be better as they have clear seapaths on the coast.

mrdtv2010 · 08-03-2010 03:54PM

marclt wrote: »

Got any further detail on this MRDTV? I find (even at my location) CH.49 to be the hardest to pick up.

It would be interesting to hear what is happening elsewhere. I guess with the imminent power increase at Preseli, this may restore the balance.

I'll quote the link later. I think its because Preseli 49 is 2kW: there must be a CCI relationship with Wenvoe or some relay till the switchover which is preventing Preseli 49 from going to 10kW.

Sam Russell · 09-03-2010 01:13PM

mrdtv2010 wrote: »

As I said above Arfon is a better bet towards Dublin: north of Dublin by 2012 Divis & Kilkeel will be better as they have clear seapaths on the coast.

I think Arfon might be a better bet, but it is only Freeview Lite, so no extra channels over Freesat - not worth the effort. I think I am too far, too low to bother trying to get BP in D4. If I succeed in Bray, I'll be happy at that, but disappointed that it is not worth trying at home.:(

mrdtv2010 · 09-03-2010 01:42PM

Sam Russell wrote: »

I think Arfon might be a better bet, but it is only Freeview Lite, so no extra channels over Freesat - not worth the effort. I think I am too far, too low to bother trying to get BP in D4. If I succeed in Bray, I'll be happy at that, but disappointed that it is not worth trying at home.:(

Exactly. Its a simple cost-benefit analysis. If people were getting Welsh analogue off-air then they get a new box or TV and off they go. Ditto when NI switches over in 2012. D4 and higher southern parts of the city can probably get Divis: therefore no BP. Had Arfon been the main station for NW Wales instead of LLanddona that would be a game changer. The one benefit of DTT is its cheaper for multiroom distribution as you can cascade sets off one cable whereas dedicated satellite twin pairs are required per room ( I have both types...). In Bray you are above the Arklow null, out-of-range of Divis (so no CCI), and have a straight sea path. Ideal conditions as you saw last week.

Sam Russell · 09-03-2010 01:50PM

mrdtv2010 wrote: »

Exactly. Its a simple cost-benefit analysis. If people were getting Welsh analogue off-air then they get a new box or TV and off they go. Ditto when NI switches over in 2012.

Yes it would appear that I must wait until 2012 for Divis to switch. Pity, but Freesat will probably have all the channels by then, so I probably will not need it by then. What do you think the chances of Divis will be then?

Welsh digital switch over-Irish reception questions answered

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