Welsh digital switch over-Irish reception questions answered

BowWow

Was on North side of Howth Head yesterday, quite a lot of aerials actually. All point North and vertically polarised, I assume for Kilkeel. Well over 90% of them are small grid type with masthead amps.
Will look at South side of Howth Head next weekend.

mrdtv

BowWow wrote: »

Was on North side of Howth Head yesterday, quite a lot of aerials actually. All point North and vertically polarised, I assume for Kilkeel. Well over 90% of them are small grid type with masthead amps.
Will look at South side of Howth Head next weekend.

Definitely Kilkeel. Its quite a high site and its a straight sea path. Currently four analogue terrestrial channels and from DSO in 2012 3 muxes including HD. Will be easy to receive along the coast as it will have quite high power for a DTT relay vs analogue.

The use of the grids with masthead is obvious: its to rope in Clermont Carn on the same aerial as the grids have wide acceptance angle and the masthead compensates for the low gain from the grid. Will probably provide perfect DTT from both stations because of ability of COFDM to handle reflections and sidepaths on the grid.

marclt

mrdtv wrote: »

DTT behaves differently from analogue terrestrial: it is either perfect, blocky or not there. Those with indifferent analogue will find high power DTT will work extremely well from the same transmitter: this is because if the DTT is above the threshold it will work perfectly. It also requires a much lower signal strength than analogue terrestrial to give a perfect picture: I think this is something which is not widely understood as its counter intuitive but this the way the system works. That is why people are getting excellent Preseli and Arfon DTT in SE Ireland and perfect RTE DTT in mid-Tyrone from Cairn Hill where the analogue is poor. Many people will find out about this through the Internet and word-of-mouth/viral effects.

I never knew it worked like that?!!

I still think that we're looking at a line of reception that extends inland by about 10 to 15 miles hugging the coastline for most. There are very few tv aerials pointing towards Wales in places like Ennsicorthy for example.

To answer your earlier point MRDTV, yes there are online stores like amazon but most people will be unaware and not think any further than the signal is gone. I'd say the figures of those going out and buying a box will be considerably low.

reslfj

marclt wrote: »

....I still think that we're looking at a line of reception that extends inland by about 10 to 15 miles hugging the coastline for most.
To answer your earlier point MRDTV, yes there are online stores like amazon but most people will be unaware and not think any further than the signal is gone. I'd say the figures of those going out and buying a box will be considerably low.

How can you expect people to sign up for a pay DTT service, when they will not even install an aerial, a box and get 15 SD and 4 HD services from Arfon for free?
And from Presely they can get all 40+ Freview services.

Lars

mrdtv

reslfj wrote: »

How can you expect people to sign up for a pay DTT service, when they will not even install an aerial, a box and get 15 SD and 4 HD services from Arfon for free?
And from Presely they can get all 40+ Freview services.

Lars

It is extraordinary that those with digital tv tuners hadn't even though to tune in as described yesterday by Black Briar. But outside Internet reflectors public awareness is very limited: this will change. The true extent of the overspill coverage has yet to be assessed in the South East. As I said in an earlier post good DTT requires about 45dbuV to work well whereas the figure for PAL is 70dBuV.

marclt

marclt wrote: »

I still think that we're looking at a line of reception that extends inland by about 10 to 15 miles hugging the coastline for most. There are very few tv aerials pointing towards Wales in places like Ennsicorthy for example.

In the town? Theres a reason for that.
For a start,Enniscorthy is cabled by UPC whereas Gore has no cable service[I'm not sure about wexford town].
Hence lots of Enniscorthy without aerials.
Sky/freesat is permeating because it is promoted.
Aerial reception isn't and never really has been.

You'll find loads of presely aerials in rural areas outside of Enniscorthy at either side of it and well further inland than 15 miles in wexford.

St Senan

Deleted User wrote: »

In the town? Theres a reason for that.
For a start,Enniscorthy is cabled by UPC whereas Gore has no cable service[I'm not sure about wexford town].
Hence lots of Enniscorthy without aerials.
Sky/freesat is permeating because it is promoted.
Aerial reception isn't and never really has been.

You'll find loads of presely aerials in rural areas outside of Enniscorthy at either side of it and well further inland than 15 miles in wexford.

Presely aerials in Enniscorthy town it's self is a no go the town is in a valley and Vinegar hill towers over the east side thats why Regional relays now Chorus/UPC was origionaly set up to supply the townsfolk with english tv channels

mrdtv

http://www.digitalspy.co.uk/forums/showpost.php?p=36277817&postcount=8

A quick move in Rosslare!

scaller

scaller wrote: »

Presely aerials in Enniscorthy town it's self is a no go the town is in a valley and Vinegar hill towers over the east side thats why Regional relays now Chorus/UPC was origionaly set up to supply the townsfolk with english tv channels

Yeah you are right,I'd forgotten about the reason for that.
It's like Avoca village in that respect except avoca is actually worse.

You don't have to go too far north east south or west of either though before you are into good presely reception again.

gkp1

Arfon ch 41 in Arklow
I can confirm that on a bog standard grid aerial on a chimney with just a standard 3ft pole ,the aerial being in pretty shabby condition in Arklow town [wexford road area],and which is probably slightly out of allignment and actually quite bent up...Arfon signal strenght 71% quality 70%

Analogue reception from arfon on this aerial is pretty poor but watchable.

This is further evidence that anyone that has had half a picture at all from wales in wicklow is going to have crystal clear digital reception and no need for a satelite dish.
I'm impressed.

Great reading here, I have been viewing for a while but this is my first post here.
I am located in Sandyford in Dublin, about the same distance as Arklow is from Arfon (approx 132km). Just wondering what are my chances of picking up Arfon DTT with a roof aerial? I am 107m above sea level according to google earth.

It's worth a try with a grid and masthead amp.
I'd never considered it from there but if theres nothing in the way.. ??


You are definitely in the running for Blaenplwyf when it turns up the juice next march.

mrdtv

gkp1 wrote: »

Arfon ch 41 in Arklow
I can confirm that on a bog standard grid aerial on a chimney with just a standard 3ft pole ,the aerial being in pretty shabby condition in Arklow town [wexford road area],and which is probably slightly out of allignment and actually quite bent up...Arfon signal strenght 71% quality 70%

Analogue reception from arfon on this aerial is pretty poor but watchable.

This is further evidence that anyone that has had half a picture at all from wales in wicklow is going to have crystal clear digital reception and no need for a satelite dish.
I'm impressed.

Great reading here, I have been viewing for a while but this is my first post here.
I am located in Sandyford in Dublin, about the same distance as Arklow is from Arfon (approx 132km). Just wondering what are my chances of picking up Arfon DTT with a roof aerial? I am 107m above sea level according to google earth.

The questions are:

a0 Do you have an unobstructed sea view?

b) Do the neighbours have aerials pointing out to sea?

c) Have any neighbours recently lost off-air UK analogue reception?

If the answer to all three is yes, then as bb says its worth a punt. Your HAASL is advantageous.

bmaxi

Finally getting around to replacing an old grid type aerial in Courtown. I'm heading North tomorrow and was thinking of picking up this http://www.argos.co.uk/static/Product/partNumber/5352069/Trail/searchtext%3ETV+AERIAL.htm and also the Sagem box mentioned earlier in the thread.
Is this a decent enough aerial? Also, with the Sagem box will it be possible to pick up Irish DTT without a second aerial?

reslfj

bmaxi wrote: »

Finally getting around to replacing an old grid type aerial in Courtown. I'm heading North tomorrow and was thinking of picking up this http://www.argos.co.uk/static/Product/partNumber/5352069/Trail/searchtext%3ETV+AERIAL.htm and also the Sagem box mentioned earlier in the thread.
Is this a decent enough aerial? Also, with the Sagem box will it be possible to pick up Irish DTT without a second aerial?

This is a wideband aerial.

Maybe a large group B will be better. Both Arfon and Preseli is in group B.

Remember fitting for vertical mounting for Arfon.

Lars

Sponge Bob

GKP .Top of Killiney hill is higher than you but I think your path is over the top of Ballybrack and therefore it is worth a shot , can you zoom in on the Dublin end of that Google earth image and check against the contours shown here .

http://ims0.osiemaps.ie/website/publicviewer/main.aspx#V1,722460,723791,4

gkp1

Sponge Bob, I think my path would be south of Kiliney Hill...that's a useful site for checking.
No sea view from upstairs window but I think there is from chimney height. A few aerials around area pointing that direction but estate is cabled plus lots of sat dishes so prob just a few enthusiasts. I have an LG PQ3000 with excellent Irish dtt reception so would be great to pull in Uk channels also.

bmaxi

reslfj wrote: »

This is a wideband aerial.

Maybe a large group B will be better. Both Arfon and Preseli is in group B.

Remember fitting for vertical mounting for Arfon.

Lars

What's the difference? I actually Googled for group B and that aerial is one of the ones I came up with.

reslfj

reslfj wrote: »

This is a wideband aerial.

Maybe a large group B will be better. Both Arfon and Preseli is in group B.

Remember fitting for vertical mounting for Arfon.

Lars

In courtown,it's presely he wants -so horizontal.
A grid will work fine there but a group B would work better.

@ GKP

Arfon has a very narrow beam compared to presely, so it is highly intolerant of any obstacle.

We were on arfon here and to get a decent signal we had to rise the aerial 60ft to get above trees and a tiny hill.
At chimney height analogue was very snowy,but once above the tree's and tiny rise of ground to the east,the picture was clean.
So if spending money on that one,be aware of that.
A grid is the cheapest bit of kit to test and can be used for kilkeel and blaenplwyf.

mrdtv

Deleted User wrote: »

In courtown,it's presely he wants -so horizontal.
A grid will work fine there but a group B would work better.

@ GKP

Arfon has a very narrow beam compared to presely, so it is highly intolerant of any obstacle.

We were on arfon here and to get a decent signal we had to rise the aerial 60ft to get above trees and a tiny hill.
At chimney height analogue was very snowy,but once above the tree's and tiny rise of ground to the east,the picture was clean.
So if spending money on that one,be aware of that.
A grid is the cheapest bit of kit to test and can be used for kilkeel and blaenplwyf.

You can't compare analogue and digital pictures. DVB-T works well at 45dbuV whereas analogue PAL requires 70dbuV minimum for a CCIR Grade 5 picture (perfect subjective pictures). This is why people in Ireland are getting perfect Arfon. Arfon DSO has an omnidirectional HRP just like Preseli, but I suspect LLanddona has antenna power restrictions towards Dublin.

It is all about closing the link budget just like in satellite systems:

a) You need to have the minimum field strength of 45dBuV

b) Your C/N must be over 20dB

c) Your post-Viterberi BER should be less than 1 exp-7

Once these three conditions are satisfied you are in business. That is why, I agree trial and error is best, and grids are good starters but they have very poor gain. And COFDM is excellent in time varying and fading RF channel conditions which are encountered over sea paths.

Richard

BowWow wrote: »

Tks Black Briar, have Freesat+ up and running, but would like Dave, Virgin etc. Will have to wait till March. UK Freeview+ box for HD when it launches, coupled with Irish DTT would give me the best of all worlds.

Just to clarify, Freesat+ and Freeview+ aren't HD. The plus means it has an intenal Hard Disk for recorder. For HD, you need Freesat+ HD.

fat-tony

Although Freeview+ was mentioned, I think the poster was referring to the Freeview T2 box, which will display HD on terrestrial once that service is launched. There doesn't appear to be a firm date for consumer kit availability, although HD is due to be launched in London and Granada regions in December.

mrdtv

mrdtv wrote: »

You can't compare analogue and digital pictures. DVB-T works well at 45dbuV whereas analogue PAL requires 70dbuV minimum for a CCIR Grade 5 picture (perfect subjective pictures). This is why people in Ireland are getting perfect Arfon. Arfon DSO has an omnidirectional HRP just like Preseli, but I suspect LLanddona has antenna power restrictions towards Dublin.

It is all about closing the link budget just like in satellite systems:

a) You need to have the minimum field strength of 45dBuV

b) Your C/N must be over 20dB

c) Your post-Viterberi BER should be less than 1 exp-7

Once these three conditions are satisfied you are in business. That is why, I agree trial and error is best, and grids are good starters but they have very poor gain. And COFDM is excellent in time varying and fading RF channel conditions which are encountered over sea paths.

Good post for information.

However I think you took me up wrong:
I wasn't comparing analogue picture quality and digital picture quality-I was giving a rule of thumb which I use as to what to expect.


I'd be advising Gkp to look for arfon analogue in the next forthnight before it goes off and then try digital.
It's easier for a newbie that way.

If your aerial is centred on arfon and you move it 6 inches either side ,you will lose arfon completely.
Thats the same for digital and analogue.

With presely,it's closer to 24 inches before you lose it-thats how strong it is here usually.
The slightest hill practically nulls arfon analogue though whilst a few yards up the road it's perfect.Digital seems to only break up here or go when theres an equivalent signal level to analogue fading out almost entirely or completely.

Now thats good in this location because it happens rarely..but I don't know what is in the path towards arfon from sandyford.
I do suspect it's possible as the montrose hotel beside UCD has a very tall mast with a now disused [I suspect] verticaly polarised quad array pointed to I presume arfon.
It's there with years and must be well over a 100ft high.
Back when I was in UCD,they used have HTV on in there with perfect analogue.

Incidentally, there's an awful lot of houses around sandyford with aerials pointed to kilkeel.
These are group B aerials ,everyone of which could be repointed to arfon if theres nothing in the way yet local installers never did for some reason?
Hopefully not because it was less reliable?

If gkp1 has success ,maybe he could let them know what they are missing!

lucernarian

I thought C/N values varied from mux to mux. What is it for QAM64, 8k with 2/3 FEC and 1/32 guard band??

Edit: Most aerials were pointed there before Freeview came along. I and many others would prefer to watch northie telly over welsh tv any day of the week. Freeview in wales has proper channel 4, so people might get the aerial moved.

I can also vouch for the near total inability for Kilkeel to get over/around small hills. Llanddona definitely has power restrictions towards Dublin, seeing as they're sharing UHF channel allocations!!

mrdtv

Deleted User wrote: »

Good post for information.

However I think you took me up wrong:
I wasn't comparing analogue picture quality and digital picture quality-I was giving a rule of thumb which I use as to what to expect.


I'd be advising Gkp to look for arfon analogue in the next forthnight before it goes off and then try digital.
It's easier for a newbie that way.

If your aerial is centred on arfon and you move it 6 inches either side ,you will lose arfon completely.
Thats the same for digital and analogue.

With presely,it's closer to 24 inches before you lose it-thats how strong it is here usually.
The slightest hill practically nulls arfon analogue though whilst a few yards up the road it's perfect.Digital seems to only break up here or go when theres an equivalent signal level to analogue fading out almost entirely or completely.

Now thats good in this location because it happens rarely..but I don't know what is in the path towards arfon from sandyford.
I do suspect it's possible as the montrose hotel beside UCD has a very tall mast with a now disused [I suspect] verticaly polarised quad array pointed to I presume arfon.
It's there with years and must be well over a 100ft high.
Back when I was in UCD,they used have HTV on in there with perfect analogue.

Incidentally, there's an awful lot of houses around sandyford with aerials pointed to kilkeel.
These are group B aerials ,everyone of which could be repointed to arfon if theres nothing in the way yet local installers never did for some reason?
Hopefully not because it was less reliable?

If gkp1 has success ,maybe he could let them know what they are missing!

The required alignment gadget for £12.99, its used by UK caravanners to align DVB-T signals:

http://www.amazon.co.uk/Philex-SLx-27867R-Digital-Strength/dp/B001GXQUNQ/ref=pd_cp_ce_1/280-6333046-1189546

Works a treat! Note that Arfon will carry Channel 4 as well as S4C when the switchover is completed (but not in HD, it will be S4C HD) on LCN 8, so that will make it attractive. I stayed in the Montrose and yes BBC1 Wales was fine: they've probably switched to NTL or Freesat now.

The trick to align the antenna is to use above meter (or the £300 Horizon TDM for overkill) or do a manual tune on a frequency and use the signal information menu (don't store the channels until you peak the readings): takes five minutes!

Kilkeel was always popular because its a simple install, Clermont can be received as well and you get Channel 4. Its also a high site. From Howth Head you can see Slieve Donard on a clear day and Snowdonia too: so I think Arfon will work, but it needs to be tried out properly

mrdtv

To_be_confirmed wrote: »

I thought C/N values varied from mux to mux. What is it for QAM64, 8k with 2/3 FEC and 1/32 guard band??

Same as for 2k used in pre DSO UK DTT 64QAM! 16QAM is 6dB lower. After DSO all UK MPEG2 stations are 8k 64QAM. DVB-T2 preferred mode is same C/N (to replicate the coverage) but with 40 Mb/s rather than 24Mb/s.

Edit: Most aerials were pointed there before Freeview came along. I and many others would prefer to watch northie telly over welsh tv any day of the week. Freeview in wales has proper channel 4, so people might get the aerial moved.

Yes, Arfon will carry Ch 4 in SD on LCN 8, but neither Arfon or Preseli will carry Channel 4 HD!

I can also vouch for the near total inability for Kilkeel to get over/around small hills. Llanddona definitely has power restrictions towards Dublin, seeing as they're sharing UHF channel allocations!!

We will get final confirmation on Llanddona channel usability in Ireland in a few weeks time.

To_be_confirmed

To_be_confirmed wrote: »

I and many others would prefer to watch northie telly over welsh tv any day of the week. Freeview in wales has proper channel 4, so people might get the aerial moved.

Heretic

Actually the first time I had NI telly down here was with analogue mmds[didn't need it but as ever tried it out since it was available] and then via sky.
We still preferred wales though and still do.
Mind you theres very little difference these days bar the adds and the lack uninists vs nationalists.

Digifriendly

Deleted User wrote: »

Heretic

Actually the first time I had NI telly down here was with analogue mmds[didn't need it but as ever tried it out since it was available] and then via sky.
We still preferred wales though and still do.
Mind you theres very little difference these days bar the adds and the lack uninists vs nationalists.

There is if you're a rugby fan with BBC2W and S4C! Looks like BBC are no longer broadcasting Scrum V (BBC2W) on Friday night on Freeview nationwide via BBCi (302 no longer broadcasts) so being able to get welsh variations is a big advantage for rugby fans like myself although I have to rely on satellite for them.

BowWow

fat-tony wrote: »

Although Freeview+ was mentioned, I think the poster was referring to the Freeview T2 box, which will display HD on terrestrial once that service is launched. There doesn't appear to be a firm date for consumer kit availability, although HD is due to be launched in London and Granada regions in December.

Yes, thats what I meant. Have the Freesat+HD and would like a "T2" Freeview+HD when they are available. T2 should be backwards compatible with Irish DTT so I should be future proofed for a while.

bmaxi

I went North and got the aerial and box, unfortunately weather conditions have prevented the aerial installation, and it is a bit flimsy, but I thought I'd share this info.
Analogue reception from the domestic channels has always been rubbish around here without a roof aerial but when I connected the Sagem box to a €2 rabbit's ears sitting beside the TV, I got perfect reception on all four channels plus the test channel. Signal strength was about 45% but quality was 90%+, what a difference. I hope this is the standard for the future.

timetunnel

gkp1 wrote: »

Sponge Bob, I think my path would be south of Kiliney Hill...that's a useful site for checking.
No sea view from upstairs window but I think there is from chimney height. A few aerials around area pointing that direction but estate is cabled plus lots of sat dishes so prob just a few enthusiasts. I have an LG PQ3000 with excellent Irish dtt reception so would be great to pull in Uk channels also.

hi i live in the gallops beside sandyford,
did you pick up a freeview signal.
how high did you have to go up with your aerial.
what type did you use.
regards
timetunnel