UK DTT in North east

towbar

I know its probably been covered but haven't seen any recent posts on this here.

Just installed a sony freeview box and can get the Irish DTT but only Mux C from Divis on channel 48. It comes in at average strength with good quality signal.
I am 2 miles East of Dunleer on reasonably high ground. It looks as if Mux C is at a slighlty higher power than the other Muxes. I did find a link that suggested it was 3.0kw as opposed to the others at 2.3kw. Aerial is a televes dat-75. Cable downlead from attic to tv box may not be great as builder installed - might try upgrading that to see what happens.

What are others in North Esat getting from Divis. Anybody else only getting Mux C?

lawhec

The gain of the Televes DAT-75 on the lower UHF frequencies where the rest of the multiplexes are is lower than that around the middle & higher frequency parts of the UHF band. That is probably one reason.

Another is probably the downlead installed by the builder is just bog-standard "TV cable" and should be replaced by CT-100 style cable (double copper shielded)

Finally, there may be problems with co-channel interference on Muxs 1 & 2 as the same frequencies are used from Three Rock for analogue RTÉ 1 & 2.

towbar

Thanks lawhec,

ThreeRock shouldnt be a problem as the televes is very directional and three rock should be at least 40 mile behind me?

The downlead from aerial into attic is ct100 its just the last bit thats builder installed but it is running alonside mains wires so I think that will have to be replaced somehow. I am going to take a portable up to attic to eliminate the downlead.

For anybody familiar with the televes do you use the MRD as your masthead amp? I have an MRD but dont use it as have a higher gain masthead amp which doesnt pass the DC power onto the MRD. I might try the MRD again but I think its only 13db gain which doesnt seem to be enough.

lawhec

towbar wrote:

Thanks lawhec,

ThreeRock shouldnt be a problem as the televes is very directional and three rock should be at least 40 mile behind me?

Others here in the past have said that Three Rock does affect reception of multiplexes from Divis. It could be hit or miss.

towbar

Made some progress last night with a better downlead and got Mux 1 and 2 temporarily. I think I need to work on the aerial and amp though.

lucernarian

If you're more in Grangebellew than Dunleer then Three Rock will be causing issues to a fair degree. No matter how directional it is, yagis are never brilliant at rejection of signals directly behind it. The DVB-H trial from Three Rock on Ch 26 is extremely resillient and can easily be picked up at the north gable end of the house.

I'm not sure if this will help, but Caldbeck was being received fairly strongly here, 5 miles south of you. It's on Ch 28, 30, 32 and 34. The mornings and evenings are the worst times for it usually. There's no problems right now, so you might want to try it again this afternoon. You may be able to get Mux D.

I know of people with freeview in the area but they never said what muxes they got.

If the MRD is connected, but not powered up, does that weaken the signal? I'd try to use the DAT75 with the MRD and the portable telly in the attic.

towbar

I am more in Tullydonnell but would expect same problems as grangebellew
Apparently the MRD has no degradation when not powered.

Thats interesting about Caldbeck Might try that when I get my ladder back!!
I guess point about 45-50 degrees east of current position towards divis.

SRB

Might be worth pointing out those strong Caldbeck channels are the Analogue service, just in case you're expecting something on the sony box !

towbar

ah right hadnt checked that - well not much use as my analog is reasonable enough from divis.

lucernarian

Just on the caldbeck point:

I've picked up freeview from caldbeck at times, with a mediocre aerial and wrong polarisation. But it completely depends on the weather, and only Mux 1 seems easy to get in the very odd time the weather allows it. Mux 2 and A may be possible, but forget about the other three which will be swamped by Kilkeel analogue.

I should have been clearer. I was suggesting that Caldbeck was stopping you from picking up Mux D from Divis. The afternoons usually don't have the long-distance reception issues. So Mux D on Ch. 34 may work then.


As for the MRD, it adds only a slight amount of noise to the signal (1 dB IIRC) so it might still perform better than the higher-gain masthead amp.

towbar

Ah right had completely misunderstood you - really appreciate all the feedback - given me some good pointers. Hope to get back on the roof next weekend and play around with it.

ZeRoY

Dundalk, Co. Louth --> im using Kaon KTSC- Combo SAT-DVB-T box and can get all UK DTT + Irish DTT from a 14 elements Wideband Areal, lucky isn't it

towbar

Been looking at this again. Fixed downlead and getting closer to signal.
Its clear the sony box tries to get a signal on channel 23 and 29 but gives up.
I'm wondering now is it possible that the Clermont Carn fill in which according to this site http://www.wolfbane.com/articles/eitv.htm
broadcasts on 29 33 23 and 26 would be sufficienct to wipe out my Divis DTT?

If it was three rock wouldn't explain why 23 is wiped?

lucernarian

With a grid aerial, I can pick up perfect TG4 from Mt. Leinster on Ch.23. The same applies to Ch. 29 from Three rock. Though I'm pretty suprised if Mt. Leinster is the cause for Ch. 23. That channel must be QAM64 or on pretty low power.


Only 2 of those channels are working on the Clermont Carn fill-in. I don't know what direction they're pointing in. But three rock is almost definitely responsible for you not picking up Ch. 29.