Insane need to maximise analogue equipment

[Griffin NoName]

Analogue TV reception in our block of flats is unwatchable as I have doubtless mentioned before.

It's poor consistently, but every time a new owner moves in they erect their own aerial on the roof and the communal aerial reception worsens into garbage. Several flats suffer as they dont have satellite, cable or freeview and depend only on the communal aerial. Not surprisingly new owners who erect their own equipment deny any culpability and the "evidence" is therefore circumstantial.

Each time the management company pays for dodgy aerial people (a different lot each time in an ever optimistic view that they may know what they are doing). The reception improves slightly but not enough to br viewable.

We've been given every excuse to explain the problem. Like the tree which is actually lower than the aerial and must have magic powers.

The problem is slightly academic as we are due to switch to digital in 2008 but we don't like being fobbed off so we keep trying to get it fixed.

The latest fiasco is yet another newbie installed their own aerial and the communal aerial is even more useless than ever before.

I found a recommended company and they visited last week. They confirmed the tree is a red herring and said that they couldn't find the transducer and needed to unravel the wiring in the whole building.

From the aerial a wire for each flat disappears down into the central service cavity wich is a vertical cavity for the block for all services.

Without knowing much about TV wiring (I know and understand the basics) I was slightly puzzled, thinking that if there were a transducer it would be at the point where the incoming signal was split (there's a booster and a splitter) into separate wires for each block. So I was not convinced by them saying they'd have to get down into the central cavity in which there are individual wires for each flat. It sounded like it might be a money spinner (I wasn't involved in their inspection and the guy was is totally non-technical and so unlikely to have asked them any leading questions).

I decided to see if there were any wiring diagrams for communal aerials but I can't find any.

What I did find were plenty of statements "An antenna or aerial is a transducer designed to transmit or receive radio waves which are a class of electromagnetic waves. "

This would suggest they couldn't find the aerial. The aerial being the transducer? This makes no sense as all the other previous cowboys claimed to have "fixed" the aerial (and something is receiving good digital signals). Sadly I am not fit enough to go up on the roof myself to see what's what. So now I am confused, puzzled, and not knowing how to sort it out..... (me being the resident "person who knows how to....").

Can anyone make sense of this?  (there is a general wish not to wait til analogue is dropped in 2008).

[beagle]

Not really an expert on this. As far as I know the important factors are (in aproximate importance).

In range of transmitter.

Not being in shadow of hill or other building.

Aerial pointing at transmitter (degree or so off makes big difference).

Not getting bounced signals off other buildings.

Right type of aerial.

Good quality amplifier close to the aerial.

Good quality cable i.e. screened (not the old-fashioned "low loss coax"). I think CT100 is the name of the good stuff, but wouldn't swear to it being appropriate.

Avoid splitting the signal as much as possible.

Avoid running cable past lift motors, fluorescent lights etc.

Don't know what they mean by transducer (but as I said, am no expert).

You can generally find junctions in cable using a device called a Time Domain Reflectometer (like radar down a wire, it tells you the distance from which some signal has been reflected). When I used them they cost tens of thousands and only airline/military technicians tended to have them, but I think they're standard kit for anyone in networking etc these days.
That might localize which floor to start looking at.

[Griffin NoName]

In range of transmitter.  It is. All engineers who have looked at it, except this latest lot who have said nothing except "transducer", say reception at aerial on roof is excellent.

Not being in shadow of hill or other building. It isn't.

Aerial pointing at transmitter (degree or so off makes big difference). Assume it is as reception good (see above)

Not getting bounced signals off other buildings. Assume it isn't. See above.

Right type of aerial. It must be. See above.

Good quality amplifier close to the aerial. There is.

Good quality cable i.e. screened (not the old-fashioned "low loss coax"). I think CT100 is the name of the good stuff, but wouldn't swear to it being appropriate. I bet it's low loss coax. Building is 1970's. Original wiring.

Avoid splitting the signal as much as possible. Been some suggestion it might be. But don't know how to find out how much is too much.

Avoid running cable past lift motors, fluorescent lights etc. The wires all run down cavity next to lift. Original design feature.

Don't know what they mean by transducer (but as I said, am no expert).

The transducer argument is the latest idea and this lot of engineers wont do anything more unless we pay them to find it. That's the problem. Not knowing if it's yet another fancy idea to get paid for old rope. 

You can generally find junctions in cable using a device called a Time Domain Reflectometer (like radar down a wire, it tells you the distance from which some signal has been reflected). When I used them they cost tens of thousands and only airline/military technicians tended to have them, but I think they're standard kit for anyone in networking etc these days.
That might localize which floor to start looking at.

The junction must be on the roof. The cables are all individual by the time they run down the floors. All floors are affected. Another reason why I am wondering why the engineers want to start unravelling each floor.

If it's bad wiring, then wiring to each floor would need replacing. But that's a different thing to finding a transducer and they aren't suggesting that the wiring needs replacing.

Thanks for the breakdown. I just wish I could get up there and look myself. I have a feeling we've hit a dead end as usual. Fobbed off. We've had so many engineers come look over two-three years all with different theories I suspect it will be 2008 and we will still be no wiser.

[beagle]

I doubt you'd be able to deduce much (unless the aerial has been pinched or the cable is obviously decayed and letting in water - very not good). You need someone with the equipment to inject a signal after the amplifier and measure how much survives n floors down, IMHO.
If that's all right then the amplifier on the roof might need kicking hard.

If an injected signal doesn't make it through the building then either the cable needs replacing/re-routeing or there's another amplifier en-route not doing its job.

(All in my non-expert humble opinion).

[Griffin NoName]

You need someone with the equipment to inject a signal after the amplifier and measure how much survives n floors down, IMHO.

We need someone who knows stuff. But I don't know how to find such a person. This latest lot came recommended by John Lewis in Oxford Street which I thought was a brainwave, but seems no better than the yellow pages.

When you call any of the TV aerial companies, what you get is a couple of young lads, never ever the boss or anyone who seems remotely experienced other than in bog standard.

What you say, about the signal makes sense, but how to find anyone equiped and knowledgable enough to do that, because I don't think it's going to be under TV aerial people listings?

Keep wracking my brains through all my old techie contacts but most of them seem to have retired to Spain. Spain may have some of the best wiring in the world.

[Sibling Lambicus the Toluous]

Just to be clear, the problem affects everyone on the antenna equally, right?

For an outdoor antenna, my first suspects for poor performance would be:

- water or corrosion (as beagle mentioned)
- vermin, i.e mice, etc. chewing on the cable
- damaged cable.  Does the cable have any spots where it's flexed often, pinched or subject to friction?
- poor antenna ground
- damaged antenna.  It isn't visibly bent, is it?  No missing parts?

All of these should be in the forefront of the mind of anyone looking at a bad antenna, so if you've had people in, hopefully all this would have been checked out.

One thing I thought of, though: if they've only been checking for continuity with a multimeter, a flaky cable could seem okay.  If nobody's used one before, checking point-by-point with a proper antenna analyser (or a similar idea - what I think of as an "antenna analyser" is for transmitting antennas) might find the problem.

[Griffin NoName]

Thanks Lambi.

My problem is finding any company that actually provides this kind of level of service.

[Sibling Lambicus the Toluous]

How about the "check the antenna itself, then check at each point downstream in order" level of service?   

[Griffin NoName]

That goes back to this lot want to search for a transducer. Until we know why, and whether they should be doing something other than simply searching for a transducer, the Treasurer wont pay for that. Can you explain what they mean by needing to search for a transducer?

[Sibling Lambicus the Toluous]

Not a clue, though I don't have experience splitting an antenna signal between many receivers.

I always thought that a transducer is a device that changes energy from one form to another (usually to electrical energy), so the antenna itself would be a transducer.  Dunno what they're referring to in this case, unless it's a signal amplifier, or the splitter.

[Griffin NoName]

Well that confirms what I think.

It's not the signal amplifier, that's visible on the roof; it's not the splitter either, ditto. And they've been checked a million times.

I checked out what a transducer is and concluded it is actually the aerial.

Now if they can't find the aerial, which everyone else has found, they need to explain why they can't find it. It's on the roof with the amplifier and the splitter and it receives a good signal !!

So what I think is we have yet another lot of cowboys, which is what we have had roughly six times already. Expensively.

No wonder the Treasurer wont pay anyone any more. Especially as this lot were given clear instructions as to what we needed them to do. Having built up a fair amount of knowledge ourselves along the way.

Part of the problem is that I can't get up on the roof myself and these guys run rings round the Treasurer as he has no technical knowledge (I can't even get him to understand that digital TV is different to analogue - he along with millions is going to have tough time in 2008).

All of which leaves me needing to find people who know how to do more than check the obvious and don't need me up on the roof to make them do it. Or crawling in between floors!

And... I can't find anyone. <sigh> or I haven't cracked the correct Google search.

[ivor]

I'll bet it's the wiring.  The wiring would cost a lot to replace and the management company doesn't want to spend it.  The management company just keeps bringing inept people out to make it look like they are doing something.

[Bluenose]

Antennas and cabling are my thing, been an amateur radio operator for 30+ years, although not very active the last few.

Anyway, the only way to sort this out is to start at the antenna and then work your way down.

If you get a good picture directly from the antenna, then the next step is the amplifier.  See if you get a good signal directly from one of the outlets from the distribution amp/splitter.  My bet is its the amp/splitter.  It is unlikely that the distribution cabling is all faulty.  If you are sure that each unit has its own cable running up to the distribution amplifier/splitter then at least some of them, especially those that have the shortest run would have usable signals.  The fact that they all do not says it has to be something in common with them all.

I do not know how many units are fed from this system, but I am highly suspicious of large numbers of outlets being fed from one location unless the people that are doing it really know their onions.  Without physically looking at it, it is hard to say, but if they have a separate distribution amplifier and splitter, or worse yet multiple splitters, then it is probably a design problem and the amp and splitters need to be replaced with a distribution amplifier that is designed to feed the number of outlets in your situation.  If the amplifier is not separate from the splitters, that is it is one designed for the situation, then is the amp receiving power?  These amplifiers have varying ways of receiving power, one way often used for domestic situations is to feed the power up the coax.  I cannot imagine that this has been done in your case, but if it is, maybe the person from whose apartment the power is supposed to be fed simply does not have it switched on, or they threw it away because they did not know hat it was for.  Generally I would expect a distribution amp to be mains fed, has someone switch off the relevant circuit breaker?  Is it unplugged etc?  If it does have power, then I would suspect that the distribution amp may be faulty.

Don't know if this is going to be of any help.  I wish I could just come over and have a look at it, I am sure we could find the problem in a few minutes.  But I suspect that your treasurer may not be too keen on funding a round trip from Melbourne! 

Sibling Bluenose

There is no such thing as a transducer in the manner that your cowboys are talking about.  It sounds like they have learned a nice technical sounding word that they can use to extract a lot of money from innocents abroad.

[goat starer]

Griffin, I would be glad of the excuse to prevent Mrs Goat watching the strem of garbage that comes out of our telly. can I move in?

[Griffin NoName]

I'll bet it's the wiring.  The wiring would cost a lot to replace and the management company doesn't want to spend it.  The management company just keeps bringing inept people out to make it look like they are doing something.

The Treasurer and I are the Management Company

Don't know if this is going to be of any help.  I wish I could just come over and have a look at it, I am sure we could find the problem in a few minutes.  But I suspect that your treasurer may not be too keen on funding a round trip from Melbourne! 
<snip>
There is no such thing as a transducer in the manner that your cowboys are talking about.  It sounds like they have learned a nice technical sounding word that they can use to extract a lot of money from innocents abroad.

Yes it is helpful. Although as yet I am not sure how to apply it. We fix our own service charge and so no, I think we wont be flying you out,,,,,,, shame

Thanks for confirming the transducer is cowboy speak. Good to know I know when to be suspicious..... except I wish one didn't need to be.

Griffin, I would be glad of the excuse to prevent Mrs Goat watching the strem of garbage that comes out of our telly. can I move in?

If Goats are happy with hammocks slung from the ceiling. There's no floor space left.