breaking/no picture but sound & subtitles

[Victoria]

I'm confident that the aerial man knows what he is doing. Have used him in the past, and he's used and recommended by others in the area - small villages, limited knowledgeable people.

The coax going to the TV/FVP setup in question is not super super super old, but, thinking about it, it is old. I'm trying to think when we got the tv in the kitchen, as I don't think that cable has been changed. It is also mostly outside. Another thing for me to think about changing! (Current aerial man did not initially split the connections or put that specific cable in. He has changed the coax to the front room which was done in Feb this year. The amplifier power supply is also old. If I remember correctly, it (or one) appeared when we got the RTE aerial, so a long long time ago and that was when we were still using the aerial sockets in the wall!)

Currently looking at the signal quality, it is 100% on both FVPs (on U&Drama).

But as you say @prpr it is kind of futile trying to figure out this issue, especially since switching the FVP boxes they seem to be working fine...
I'll just remain baffled.....

 

[Owen Smith]

The last sentence I wrote in post #10 applies regardless of what anybody writes.

True, it could indeed be anything. Doing a complete audit of everything from the aerial down will usually find the culprit if the person needing help is willing and posts clear enough information, but it is rare people are prepared to do that. They're usually looking for a quick fix. But I'll give Victoria the benefit of the doubt for now.

 

[Owen Smith]

The coax going to the TV/FVP setup in question is not super super super old, but, thinking about it, it is old. I'm trying to think when we got the tv in the kitchen, as I don't think that cable has been changed. It is also mostly outside. Another thing for me to think about changing! (Current aerial man did not initially split the connections or put that specific cable in. He has changed the coax to the front room which was done in Feb this year. The amplifier power supply is also old. If I remember correctly, it (or one) appeared when we got the RTE aerial, so a long long time ago and that was when we were still using the aerial sockets in the wall!)

If the amplifier power supply is old it might not be double screened, which is what should be used for digital TV. For analogue all sorts of rubbish was specified, was the amp installed for analogue TV?

If the coax is outside it could be UV degraded leading to it splitting and water getting in. Water penetration will affect higher frequencies aka higher mux channels more than lower ones, causing attenuation. Are your problems worse when it is raining or shortly after?

When the aerial man changed the coax to the front room do you know what type of coax he put in? It is still possible to buy rubbish "low loss" TV coax and he might have put that in if he thought the signal was strong enough it would still get through. Commercial people trying to make money do all sorts of things that an informed amateur doing work on their own house would not. I used good spec cable in when I put mine in, because I didn't want to have to do it again and I knew some of it was going to be behind a new wall. I also did extra work so none of it would be outside and hence subject to weathering.

 

[prpr]

Doing a complete audit of everything from the aerial down will usually find the culprit if the person needing help is willing and posts clear enough information, but it is rare people are prepared to do that. They're usually looking for a quick fix.

Exactly.
I'm wondering how the aerials are combined (although it's not been explicitly said, I presume they are)? I'm thinking a nasty plastic Y adapter, or, even worse, just paralleled bare ends. Who knows, without pics.

 

[Owen Smith]

I'm wondering how the aerials are combined (although it's not been explicitly said, I presume they are)? I'm thinking a nasty plastic Y adapter, or, even worse, just paralleled bare ends. Who knows, without pics.

You may be right, but I have to say I was assuming at least a proper F connectors 2 way 3db loss splitter being used instead as a combiner which I believe is valid if there are no clashing UHF channels. I haven't checked if the relevant transmitters clash, or can conveniently be combined with something like a Group A and B frequency combiner.

 

[prpr]

I was assuming at least a proper F connectors 2 way 3db loss splitter being used instead as a combiner which I believe is valid if there are no clashing UHF channels. I haven't checked if the relevant transmitters clash

One hopes that is what was used at least. They don't clash, as the coverage from the RTE mast seems deliberately positioned to illuminate the north as well. The relative pickup of the other on each aerial should be very small, assuming something decent has been used, as they are roughly 180 degrees apart.

 

[Owen Smith]

The relative pickup of the other on each aerial should be very small, assuming something decent has been used, as they are roughly 180 degrees apart.

You get some pickup directly to the rear on most aerials. But the Horizontal vs Vertical polarisation should reduce that to virtually nothing, assuming the aerials have been installed correctly. My parents are in the Holmfirth repeater area and there are a few aerials pointing at it aligned horizontally despite the obvious forest of vertical ones on other houses to copy. Even more fun are the people trying to receive Emley Moor with vertical alignment, I doubt that works well.

 

[prpr]

Even more fun are the people trying to receive Emley Moor with vertical alignment, I doubt that works well.

Strangely, the guy who came to do my new one on Mendip a few years back tried that trick. I soon told him what I thought. He blustered his way out of it of course.

 

[Victoria]

Pretty much I don't have any specific information on the aerials, splitters etc. yet. Haven't managed to get up into the attic yet.

I've just had a look outside to see where the cables go. So... what I think happens is: our attic does not go completely across the top of our house. So for the 2 ground floor TVs, the aerial cable comes out of the roof, across the roof and down the outside of the walls. The front room TV, the cable is across about half the roof. The kitchen one it pretty much comes out of the roof and down the wall. The 3 way splitter box is in the attic. (I vaguely remember there being a box in the attic, am assuming it is a splitter box). The upstairs TV, the cable does not go outside.

Once I get up into the attic, I guess I should be able to see how the 2 aerials are combined now, and maybe the splitter box (I so need to tidy the attic, it has got out of hand with stuff!) - it is under some flooring I put down years ago; with carefully cut out piece for the cables to go through and not rub on.

So far this morning: Wed morning. Both TVs and FVPs seem to be working fine, on U&Drama (as that seems to be the most sensitive channel). Stormy weather over the next couple of days so that will give me an idea of.... something! Only been wind so far here, and now the aerials are in the attic, they won't be as susceptible to windy conditions. (Oh, we do live by the sea too, though it is Strangford Lough so we don't view complete open water.)

The 'dodgy' FVP is now in the front room, where the coax was changed in February. Maybe if it continues to work fine in there, then it is the cable in the kitchen that is not working as well as it should, and the 'dodgy' FVP was sensitive to the slightly poorer signal. Though maybe that sensitivity also indicates that that FVP is starting to deteriorate.

If the TV channels start to break up in the front room with the 'dodgy' FVP, then it probably is the 'dodgy' FVP on the way out; especially if there is no channel breakup in the kitchen where the 'not dodgy' FVP now is (where the coax is not brand new).

Yes, I'd really love to be able to get the whole TV aerial and coax system in the house completely refreshed instead of a bit here and there, and then it would all be tidy and I'd know how old every bit it, and where every bit is and what it does.

 

[Owen Smith]

When you do get into the loft please take clear and in focus photos of as much of the system as you can, especially any labelling and model numbers. This includes the aerials and which way up they're mounted, the coax to see what state it is in, the splitter/combiner (now thought to be 3 way) and anything else connected to the aerials or the coax up there. Much easier to take lots of photos on one trip than to go back up into the loft.

 

[prpr]

the splitter/combiner (now thought to be 3 way)

There should be two devices - a (2-way?) combiner to combine the two aerials, and a 3-way splitter to distribute it to the various rooms.
Possibly there is an amp. between these, or possibly it's elsewhere (and maybe a power supply if not integrated) on just one room outlet.

 

[Owen Smith]

There could be an amplified splitter, I have one that is one input with a 13db amp split to 4 outputs. I tried to use it at my brother's place pre DSO, but the analogue signal was so strong it caused visible clipping on the analogue TV picture.