"Andy Champ" wrote in message
news
Both jobs took longer than expected. The first was because the darling
builders had managed to get both the coax downleads to have whiskers of
braid wrapped round the core in the fitted TV/FM/SAT1+2/Return/Phone
socket in the living room.
Obviously. They always do.


The second time, I was ready for the braid to be all over the place and
sorted that out first. Then I tried every combination going (on my own,
up and loft-ground floor in a 3 storey house loads of times) but
nothing I tried got a good signal. With my dying gasp I suspected whoever
wired it up was even worse than before and tried the 'return' cable, just
on the off chance. That was it.
They do this half the time, because it's a 50/50 chance. You just get used
to it. We work on the assumption that everything will be wrong. This is
usually justified.

Some years ago we did a job where the wallplate was incorporated into a
fancy 'media plate' which incorporated mains, phone, and TV. These plates
were a nightmare to remove and a double nightmare to refit. It was part of
the sparks' job to do the aerial/satellite cables. When I went round testing
the first one was wired the wrong way round, so I took it off the wall,
corrected it, and put it back. This took about 20 minutes! The next one was
OK but the next one wasn't. So I put a piece of black tape on it as a marker
and moved on. Finally I emailed the sparks to tell them to swap round the
cables to about thirty plates. This they agreed to do. But when people
started to move in we got a call from someone saying 'no telly' so I went
out and sure enough the cables were still the wrong way round. So I passed
it back to the sparks, and all further calls to that development were
refused until they had been out and tried swapping the cables round.

On the same job we had strongly advised the fitting of two sat feeds to each
dwelling, but the builder wouldn't pay the extra few quid. Even now we get
calls from there about Sky+.


While looking for possible failure points, I checked out the (new) aerial
closely. The only electrical connections were to two alloy 'horns' near
the back which I guess the signal is focussed onto. Or rather, the
connections were to a small PCB inside the plastic box the horns came out
of. The horns were supposedly attached to the core of the coax by having
the PCB screwed down onto them - however the large contact pads that
would have touched them was still solidly covered in the non-conductive
varnish, and the screws went through the non-plated holes without joining
the two together electrically.

The mention of 'horns' makes me visualise a DIY or European 'high gain'
aerial which will undoubtedly be wideband.


I measured to be sure - yup, no continuity. So I scraped some of the
varnish off and got a 1 ohm connection.

The question (finally) is this: was it designed to pass the energy by RF
coupling?
No, it's just a **** design.

Isn't that a bit lossy on what is a weak signal anyway?
Doubt it really.


And have I ballsed it up by connecting it electrically?
No.

I guess it could
have been some sort of lightning protection, but I can't see it being all
that effective, and it's in a loft now anyway...
No, deffo not lightning protection.


x-posted to uk.tech.digital-tv. Some aerial people there.
The actual real world beating aerial experts live there actually.

Bill