Bloody cowboys !!

1. Your own aerial
(a) the array is obviously the smallest version of some manufacturer's range of
'high gain' aerials. These small 'high gain' arrays generally have gain no
better than a good 18 element array. Sometimes they are significantly worse.
They are generally worse for rejecting off-axis interference, since the polar
response in both planes is 'messy'. The forward lean on the directors is a
gimmick. The one on the front right seems to have suffered a slight accident.
The large full-wave reflector adds little to the performance. The array is
end-mounted. It is heavy and has high windage, so the boom will likely snap
near the mast clamp.
(continued after I've lanced the cat's boil)
Bill







Ahhh . . .

PART 2
The way the cable leaves the array is wrong. It appears to be tangled arround
the reflector support, and there is too much unsecured cable.
There's something deeply odd about the mast. Your picture is of course jpegged
to buggery (by necessity) but can I see the marks made on the mast during a
previous life? It looks like something's been clamped to it about a foot from
the top. Or is it the shadow of the reflectors? The other odd thing about the
mast is the fact that the U bolts at the bottom have made no visible impression
on it. Could it be a very thin gauge steel mast, deliberately left loose
because the installer knows it will crush easily? Certainly the tube wall looks
to be 1mm at most. Steel masts rust very quickly, and aren't to be used unless
galvanised inside and out, and I doubt if this is.
Those12" wall brackets with a lot of stand-off are a liability. In windy
conditions the baseplate can twist, allowing the arms to move sideways. The
twisting motion results in a pull on the wall bolts that is magnified by
leverage. The only proper way to fix to masonry when this amount of overhang is
needed is with a pair of T & K brackets or similar.
The bracket is not upright on the wall. No spirit level then?
The only fixing I can see is bottom left. This is part of the fixing sets used
for little Sky dishes. The bolt is a coach bolt. It screws into a plastic plug.
Definitely inadequate for this installation.
The way the cable comes off the bracket is horrible. The old cable has been
pulled, so will be deformed just above the wall clip. Six year old cable should
never be re-used. From the general standard of the job I'd guess that the cable
joint is just a 'twisted together' job. There won't be a bung in the top of the
mast so it will get just as wet as if it wasn't hidden inside the mast.
(continued when I've changed Grandma's bag)

Bill







Ahhh . . .

PART 3

I forgot to mention that your aerial appears to be wideband -- unneccessary and
detrimental to performance. For SC you need Gp E.

Your neighbours' aerials are at least decently rigged. When I was in Coventry
recently looking at aerials (its a long story) I noticed that some of the local
riggers were obviously frustrated artists. At least that's what I guessed
judging from the amazingly decorative arrangements of tape on the masts. You
must have the same riggers in your area! What pretty patterns!
It looks like the local riggers all all believers in the 'small high gain'
types of array. Most riggers have price lists with standard 18 elements shown
£40 to £60 cheaper than this sort of aerial. It's so easy to point to the
neighbours' aerials and say "That's what you need!"
Bill







Ahhh . . .

"Bill" wrote
[snip expert opinion]

Bill, many thanks for your detailed analysis; you've really picked up on
quite a bit. There's a lot more wrong there than I thought. I think I'm
definitely going to have to ask for the whole thing to be taken down and a
new installation performed. When new

When I think of how much was paid for this work to be done it makes me sick,
and of course the installer was evasive when I phoned him up to complain.

To be honest I've been wondering whether I should "name and shame" the
individual involved.

"Bill" wrote in message
...
PART 3

I forgot to mention that your aerial appears to be wideband --
unneccessary and
detrimental to performance. For SC you need Gp E.

Your neighbours' aerials are at least decently rigged. When I was in
Coventry
recently looking at aerials (its a long story) I noticed that some of the
local
riggers were obviously frustrated artists. At least that's what I guessed
judging from the amazingly decorative arrangements of tape on the masts.
You
must have the same riggers in your area! What pretty patterns!
It looks like the local riggers all all believers in the 'small high gain'
types of array. Most riggers have price lists with standard 18 elements
shown
£40 to £60 cheaper than this sort of aerial. It's so easy to point to the
neighbours' aerials and say "That's what you need!"
Bill


I was in Stratford On Avon today and noticed the same tape arrangements on
masts. It appears to be the "trademark" of one particular company.

Here in Evesham we have a rigger who twists the co-ax around the mast and
tapes it. I always thought that this was a complete no-no at it caused
attenuation of the signals?

Wideband aerials are now the norm around the Sutton Coldfield service area.
Both Lark Stoke and Ridge Hill require wideband aerials for Digital, and
riggers use the same for SC which technically requires an E.

I have recently faced the same dilemma as I couldn't get a quality group E
aerial. Attempts to get a Blake and a TC18E failed, and because I was also
unsure as to whether I would end up using Lark Stoke, Ridge Hill or SC I
bought an XG10EW. It seems okay.


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"British Shorthair" wrote in
:


When I think of how much was paid for this work to be done it makes me
sick, and of course the installer was evasive when I phoned him up to
complain.

To be honest I've been wondering whether I should "name and shame" the
individual involved.

I know the feeling - my first installation here was done by a chap I was
given to understand was ok.

It was rubbish, not strong enough, and soon went off line with a drunk
looking mast, though the antennae seemed adequate. the cable was also
c**p even though I'd asked for proper stuff- at that time I couldn't
recognise the real thing.

I didn't call him back as not only was the installation usleless, he had
no idea about muxes and such; I should have charged him for my short
course in DTT.

I got a "local" certified guy next, only to find that the local phoine
number called a national network, the guy who arrived had no local
knowledge, but he seemed adequate and fixed it, put a new lashing on
etc.

But after he'd gone I noticed that from most angles, the mast wasn't
upright! and that absolutely annoys the hell out of me. EVERY DAY!

I could do so much better myself, but at my time of life, all by myself,
I don't go scampering around on roofs.

The moral is.... just be bloody careful who does the job,

mike

"British Shorthair" wrote in message
...
My parents are suffering impulse interference problems on DTT, after the
local cowboy "upgraded" their aerial. To summarise, he joined two runs of
coaxial cable together to form the downlead - this is on a geographically
low-placed bungalow that is 29 miles from the nearest TX (Sutton
Coldfield)
and by a main road frequented by motorcycles.

Exactly how he's joined the cable together I can't see, as he's stuffed
the
join up the shaky aerial pole. The aerial itself doesn't look that much
different from a £19.99 Labgear from Argos which has about 5/6 elements on
it. A lot of other houses in the area seem to have aerials with more
elements and/or weird-looking orange-coloured aerials that have a
triangular
thing pointing out the front (what are they?).

Now I'm not one for climbing ladders and such so I've only been able to do
what I can on the ground - after doing some reading I've improved things
by
having better RF cables round the back of the TV, and by fitting clip-on
ferrite rings on the cables. This has considerably improved the
situation,
although the problem still remains, but being the perfectionist I am - I
want to see the problem eradicated.

So - here comes my questions then for you lovely people out there.

(a) Ideally ripping the whole thing down and starting again would be best,
but bearing in mind money constraints would a new unbroken downlead made
of
CT100 or even CT125 make the most difference ?

A bigger more sensitive aerial plus the new cable should make a difference.
The distance you mention might mean that your mother is getting only just
enough signal, so it might not take much to upset things. Do not forget to
consider getting the tallest aerial mast you can get away with. If there is
a road that might be causing trouble, the aerial can be pointing slightly
upwards to stop it seeing so much of the road.


(b) I have recently moved back in to my parents' house myself and I
really,
really want another television point in my room. My room is on the same
side of the house as the lounge where the aerial and cable is at the
moment.
What would be the best way of installing the additional TV point ?

If you had bags of signal I would suggest simply using a 'y'-splitter to
give you two outlets. However, if you do not have signal to spare, then
another aerial for you might be required.

Good luck and tell us how it goes.


--
MESSAGE ENDS.
John Porcella

"Ben" wrote in message
...
wrote:
(a) Ideally ripping the whole thing down and starting again would be
best,
but bearing in mind money constraints would a new unbroken downlead made
of
CT100 or even CT125 make the most difference ?


Yes it would make a difference as would making decent connections at
either
end.

Properly screened cable is important in preventing impulse interference,
so something like CT100 should make a big difference. The guy who
installed my aerial said it was best not to break or split the cable at
all, have a different aerial for each TV. I live about the same distance
as you from a main transmitter and there's no way 5/6 elements would be
sufficient here. I've got 10 elements for the upstairs telly (short
cable run) and 14 elements for the downstairs telly because its a long
cable run all the way across the roof and down to ground level.

Sounds sensible.


--
MESSAGE ENDS.
John Porcella

"Bill" wrote in message
...
My parents are suffering impulse interference problems on DTT, after the
local cowboy "upgraded" their aerial. To summarise, he joined two runs
of
coaxial cable together to form the downlead

Depends on how he jointed it, and why.

The aerial itself doesn't look that much
different from a £19.99 Labgear from Argos which has about 5/6 elements
on
it.

He won't have paid more than about £8 for it.

A lot of other houses in the area seem to have aerials with more
elements and/or weird-looking orange-coloured aerials that have a
triangular
thing pointing out the front (what are they?).
A sales enhancing device.


(a) Ideally ripping the whole thing down and starting again would be
best,
but bearing in mind money constraints would a new unbroken downlead made
of
CT100 or even CT125 make the most difference ?
If you're saying that he's re-used the old cable, yes.

My room is on the same
side of the house as the lounge where the aerial and cable is at the
moment.
What would be the best way of installing the additional TV point ?
If the aerial hasn't got an amplifier at the masthead use a little
set-back
amplifier with two or more outputs. Put it behind the living room TV set.

But amplification may not be necessary if your other advice is followed!
Anyway, surely a masthead amp would be preferred over a back of the TV amp
which would simply amplify a signal with a high signal to noise ratio?


--
MESSAGE ENDS.
John Porcella

On 04 Sep 2004 19:22:31 GMT, o (Bill) wrote:

PART 3

I forgot to mention that your aerial appears to be wideband -- unneccessary and
detrimental to performance. For SC you need Gp E.

Your neighbours' aerials are at least decently rigged. When I was in Coventry
recently looking at aerials (its a long story) I noticed that some of the local
riggers were obviously frustrated artists.

What type of artists? **** artists.

Maybe these patterns of tape are the aerial erector's graffiti "tag", enabling
each erector to identify the culprit when they have to put right a **** job.

JPG