Full Freeview on the Limavady (Northern Ireland) transmitter

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7:57 PM

seamus o'doherty: If the ground was flat and a radiated the same level of in all directions (omnidirectional), then the coverage area would be a circle. However, the ground isn't flat and the terrain prevents .
Imagine if the signal were light, which isn't too dissimilar as they are both electromagnetic waves. An obstruction like a tree or a building creates a shadow and the same is true of the terrain.
The coverage map takes into account the terrain and shows green where the signal is expected to be available at rooftop height (above the ground).
Look at the map at imagine a line between and town. Along that line, the coverage stops roughly at the top of the "/" in the place name " / Derry".
Referring to a map with contours it is easy to see why this is the case:

NIEA Map Viewer

Loughmore is very high ground and therefore blocks reception!
Theoretically, if you (in Strabane) were to go high enough to "see" over the obstruction, or at least high enough to where there is a bit of signal, then you would be able to receive from Limavady.
Thus, the signal is there, it's just way above you. The coverage map shows what you're interested in which is reception at -top level and not many tens or hundreds of metres above the ground.

Tuesday, 30 October 2012

Brendan
12:11 AM

Hi, do you know if the sdn, arqa and arqb muxes will be boosted or will it remain at 10kw, I am currently receiving the other muxes perfectly but not the ones on lower , I live in in Donegal

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Briantist

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9:11 AM

Brendan: All multiplexes are at their final levels.

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1:02 PM

Brendan: Quite a few transmitters that carry the Commercial (COM) have them at lower than the Public Service (PSB) ones (usually half-power).

Brendan Waters
11:47 PM

Hi, thanks for your replys, I have since retuned my tv again and I am now getting every but not the Film4 etc mux, is there technical reason why this might be happening, I am using a grid type pointed towards . Thanks. Brendan

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Wednesday, 31 October 2012

Ian Drury
7:28 PM

I live in Donegal, and had perfect since last Wednesday, 24th, but since last night BBCB on ch 55 has disapppeared, the HD . The rest are perfect. What happened between Monday and Tuesday? (54.90831,-7.67339)

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7:38 PM

Ian Drury: broadcasts on , albeit vertically.

Thursday, 1 November 2012

Ian Drury
9:47 AM

I know, but I was receiving BBCB Mux ch 55 from perfectly for six days, then nothing, how is that explained? (54.90831,-7.67339)

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11:38 AM

Ian Drury: pictures are an all or nothing sort of thing. There is very little inbetween where they break up a bit. It is said that there is a "cliff edge" over which the can't be resolved.
If it is , for example from , then it could have been that, previously, whilst the picture was "perfect", the was being interfered with, but not to the degree to push you off the cliff.
What this means is that there is only a "slight" change to the level of degradation required to move from "only just" being good enough (which produces a "perfect" picture) to "only just" being not good enough (which produces no picture).
Such a change could have come about due to a change in the Fanad signal (if that is what is the cause) and this may be something that has moved and is causing a reflection in your direction. Or perhaps there was something that was acting to block or reduce the signal from Fanad that has now moved. Or maybe something has acted to reduce the signal from .
I mentioned that Fanad is co- simply as an observation. If you could receive from Fanad (to some degree, even if not watchable, and particularly so on your Limavady ), then this might perhaps add weight to its digital signal being a possible cause of your woes.

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11:57 AM

Ian Drury: Should it prove to be from and you have a grid , such as that shown in this , then perhaps a more directional aerial will be better:

Aerials, TV Aerial and Digital Aerial

Grid aerials have a wide acceptance angle and therefore less than more directional ones. This is because to get more gain, the aerial simply focuses on a narrower "beam".

Both and are on similar bearings and a grid aerial with its wider acceptance angle would therefore be perfect for such an application. However, its wider acceptance angle leaves it open to picking up interference that a more directional would be likely to "reject".

Obviously if the interference is eminating from the direction of the transmitter, then a more directional aerial will still pick it up.