Best Group B Aerial

Galway

Anyone in the trade or the know recommend the best Group B aerial I can get. Am receiving Cairn Hill signal 15 miles north of Galway City - between Galway and Tuam. Can't get all 4 chans similar strength. TG 4 on ch. 50 is worst for noise. RTE 1 and Net 2 not too bad and TV3 okish. Am using standard 18 element UHF aerial - not multi director plus group B masthead amp - 26 db gain and of course low loss cable. Signal seems to come in better lower down 16 foot pole than at top??

Any thoughts & advice appreciated. And where i might get a better aerial - signal is close enough to be brought up to good standard I feel - basic signal is ok. Can't be bothered with Maghera VHF BIII and two aerials!

Thanks in advance

lawhec

Up in Tyrone it's roughly the same RTÉ1 from Carin Hill comes in best with TG4 the worst.

Is there a visible hill between yourself and the transmitter? If so this might explain why your signal is better lower down the pole, as it would end up being knife edge refraction.

I ordered an aerial (Group E) and a masthead amplifier from England last week which should hopefully come in the next couple of days. The aerial is a Triax 18 element model which is recommended to be one of the best. I'll soon know.

Try looking at aerials at Televes (www.televes.com) and you'll come across a monster which has a 20db gain! They have graphs which show the gain over frequency. They also have a log periodic aerial which streches over the entire VHF Band III and UHF bands with a reasonably constant gain and could be a solution to two aerials from Maghera if your signal is reasonably good.

Galway

Thanks, so you reckon the group E would bring up TG4 on ch. 50 more? My experience is that group E will worsen your picture on RTE 1 ch 40 and net 2 on 43. No visible hill but the tx is a good way away in Longford and site height is 916 ft I think. Still id have thought that on 800 Kw of power it would reach me better. Remember Divis on 500kw is picked up deep into the south and even Br Mt on 100kw - not here though!

I fancy trying a XG 18 gr B - Antiference plus my groupised gr b amp. I suppose if i get a more powerful amp i will only end up amplifying noise on the weaker signals.

Anyway let me know how u get on.

lawhec

Originally posted by Northern Correspondent
They also have a log periodic aerial which streches over the entire VHF Band III and UHF bands with a reasonably constant gain and could be a solution to two aerials from Maghera if your signal is reasonably good.

I just remembered that this wouldn't work! Maghera's VHF TV is vertically polarised while the UHF is horizontal. It'd be fine for Turskmore or Kippure but that's not what yer after!

The reason I ordered the Gruop E aerial is to try the Clermont Carn TX which has recently improved is coverage area, but failing that could also be tried for Carin Hill and as a last resort aligned at Truskmore for TV3 and TG4. Channel 5 from Belfast is also an option with the aerial. There's no need for me to have a big group A aerial as I only live a few miles from Brougher Mt. and Divis comes in quite well here.

Looking at a map, are you near Tuam? If so you're closer to Carin Hill than myself and Iv'e seen perfectly working aerials for Carin Hill extend right up to the Tyrone Derry border (though the Sperrins give a good advantage here). I can get Carin Hill with an amplified indoor aerial on RTÉ1 with a snowy picture (no colour lock) but the rest aren't possible.

Galway

Yes, Im 16 miles north of Galway and about 10 or so from Tuam. Its a new house Im getting ready to move into soon and tv reception is always a priority for me! Anyway was there last night and there was some residual impairment on RTE 1 ch 40 (lines), some noise on Net 2 Ch43, TV3 on 46 was actually the best and TG4 on 50 the worst. I suppose that has something with ch 50 being nearer to group C/D channels & at the end of the gr B range. Anyway, the signals are near enough good to hopefully be balanced out by a better multi-director aerial - so thats what im after. I dont really want to try and amplify anymore (using gr. B super fringe amp - the red ones! which gives 26db gain - otherwise i think i'll just get more noise on the pic. have tried a UHF widebide amp at 26db and no difference.

I reckon if I can improve the basic signal with a higher gain aerial and amplify it by the same as before -26db- I should see an improvement. Any thoughts/advice appreciated from those in the know in the field!

Maghera is a pain not just cos of Vhf /uhf thing but channel E RTE 1 seems much lower there than net 2 on H. TV 3 on 66 and TG4 on 68 come booming in as the TX is on 500kw for them! where my parents live 10 mins down road nearer to galway you can get the RTE chans from maghera near perfect on rabbits ears!

Thanks

Originally posted by Galway
and there was some residual impairment on RTE 1 ch 40 (lines), some noise on Net 2 Ch43, TV3 on 46 was actually the best and TG4 on 50 the worst.

Hmmm it's nice to know something interferes with Cairn Hill RTÉ one....in high pressure weather conditions as we have at the moment that could well be presely:D a mean achievement for a tx in pembrokeshire.
Presely shares the same channels as Cairn hill and here in north wexford/south wicklow, it blasts in loud and clear.
But as you go closer to arklow it has a lot of co channel from Cairn hill with TV3 causing the most damage.

I have a triax group B which when swung around to the north west of here brings in fairish Cairn hill with heavy presely co-channel, Swing it back and you get presely with heavy cairn hill co channel.
I would highly reccommend the triax as it brings in the low power Arfon relay from Wales like a mirror albeit with a good seapath...Cairn hill should be moved to the aran islands:D that would hepl...good sea path:D
mm

Galway

Thx any suggestions as to where i could get hold of a triax group B of that type -i.e best possible gain and the likely costs in €?

Hard to think it could be Presely at this distance. How is Ch5 on ch 37 from there? The pain with the welsh trx is S4C! I have it on digital - i brought back my digibox form UK when I moved back

thx

Originally posted by Galway
Thx any suggestions as to where i could get hold of a triax group B of that type -i.e best possible gain and the likely costs in €?

Hard to think it could be Presely at this distance. How is Ch5 on ch 37 from there? The pain with the welsh trx is S4C! I have it on digital - i brought back my digibox form UK when I moved back

thx

Not as unusual as you might think to be getting signals from tx's all that distance when theres an area of high pressure nearby
Channel five on 37 is presely's strongest .
It is powerfull enough at times to come in here on a grid pointed to mt Leinster( for tv3) without a masthead amp!
locally here DTT from presely is possible most of the time-so digital channel four
For Triax-try these people http://www.scantec.org.uk/www/product_list.asp?mc_id=2&sc_id=45

Or contact the manufacturers direct: triax@micro-matic.triax.dk

mm

Galway

is is trade only sales from scantec?? cant see on site if ordinary folk like me can buy from them?

lawhec

Managed to get the Group E aerial last week (18 element Group E Triax yolk with wideband masthead amp & power supply) and I was able to get a snowy but perfectly watchable picture on all four channels. But guess what? I seen those lines on RTÉ1 as well!

Interference from Presely isn't the cause, though Black Hill in central Scotland does come in a few days a year under high pressure conditions. But the weather then wasn't the ideal conditions for it and it doesn't explain why the other three channels were clear of lines.

Unfortunately for myself when the aerial was tried in the attic Carin gave no results - it was at it's best pointed out of a window! My guess is a bigger aerial at group B would do even better, but funds don't allow at the moment alas

I'll try it outdoor later this week - the lines might have gone away then!

Galway

The lines were still there last week - i can get RTe 1 net 2 and Tg4 (no tV3) from the Castlebar relay ch 29, 33 and 23 respectively and no lines there at all on Rte 1. It might be worth giving Rte a buzz - number on page 530 net 2 aertel teletext. If you go to this site
http://www.scantec.org.uk/www/product_list

the price of the triax aerials seems reasonable

Still no-one can tell me if an antiference XG 18 gr B or a triax group B would be better

Galway

did u try the aerial outside yet?how much did it cost u and the amp - wot type? what was delivery charge? thinking of going for triax unix 100 gr. B plus 34 db br. b amp

cheers

lawhec

Did try the aerial outside last week in a field but it didn't help that I was up the wrong side of a hill and the Direction of Carin Hill had tall bushes in the road! Still, I managed to get a four services mostly of equal strength though TG4 perfered to be in a different postition that the other three channels, sometimes that happens. Managed to get colour on all four of them though without an amplifier. We're thinking about getting someone to go on the roof which would then have a clear sight above the bushes.

The lines that plauged RTÉ1 disappeared here anyway. I got the aerial from www.jwhardy.co.uk which also lists delivery charges etc. Unless though you're prepared to pay a fair bit in postage you might have to wait a few days for it though.

Galway

thx i am getting full colour and just a bit of grain on all 4 channels with bog standard 18 element gr B aerial and 26 db gr b amp.

must check for lines - new house havent moved in yet! btw wat did the aerial - was it a triax unix 100?? and amp set u back cost wise? and postage - will be more to down here tho! am thinking of unix 100 grB plus 34 db triax amp.

cheers

tvman

Hello especially 'Galway'

Just a few comments on the various postings. When I got interested in DX (long distance) tv I installed a pair of wideband aerials - one vertically polarised and the other horizontal. Both of them had 18 x type elements and both with a Fringe super uhf amp (22db gain) and were switchable.
The lot was attached to a aerial rotator and always worked fine, as I could receive any stray transmissions that were out there no matter what ae group was being used. The horizontally polarised one was of course used most of the time for UK transmissions - Winter Hill, Caldbeck, Caradon Hill, even Emley Moor to name but a few.
Back to your problem Galway, why not try using a good wideband aerial and a high gain amp or a variable one.

Cairn Hill uses 800 kW but that does not mean it will "reach" further than Divis.
It all depends on how the transmission aerials are configured on installation and the need not to transmit further than required under normal and high pressure conditions.
The Horizontal and Vertical Radiation Patterns (beams are tilted in relation to the horizon) and the power used in both are adjusted to achieve the desired results.
In other words high ERP does not necessarily mean extended coverage.

Good Luck from tvman

Galway

Thx for the info so in your opinion would triax unix 100 gr b or an antiference Xg18 be best?? i plain using a triax gr. B 34 db masthead amp - think i will need PS to deliver 12v at 40 ma too?

Triax has very good rep. the signals are watchable
.- just a little grain on a standard contractor 18 element gr. B plus fringe super grp B amp - 26 db gain.

cheers