How to improve this aerial? Replace or move higher?

In article ,
scribeth thus
Doctor D wrote:

Firstly mount it with the cradle the right way up and without the mast
running through the elements - like the centre cradle mounted aerial here
http://www.wrightsaerials.tv/aerialp...odern/021.html.

Ah, thank you, a picture is worth a thousand words (in this case anyway).


The current method will cause signal attenuation.

Replace the cable with copper on copper double screened co-ax (CT100, PF100
etc) keeping any joints to a minimum and using only F connector joints if
possible.

It already has good cable.


Consider adding a screened masthead amplifier.

There's an amplifier pretty close to it, it's probably only two or
three metres from the aerial.


Consider replacing the aerial with a better quality one. For Sudbury a
quality group E should be better than wideband, sadly they appear to be thin
on the ground these days. Someone may be able to suggest one. Blake are
showing an SR18E on their website
http://www.blake-uk.com/page/aerial_benchmark/Aerial_SR

Thanks, that's the other sort of advice I was after. You're right,
group E is better than wideband (I took a look at the Wolfbane site
after my original post).


Apart from the upside down aerial what's it look like in the direction
its pointing i.e. is it very wooded?..

And..

Have you any neighbours you could check with the see what their
getting?..
--
Tony Sayer

wrote in message
...
Recently our TV reception has deteriorated markedly, we live near
Woodbridge and get our signals from Sudbury so we're getting on for
"fringe area". The Woodbridge relays don't do anything for us. Until
recently reception was pretty good most of the time with the very
occasional drop out and sometimes a 'bad day' with odd atmospheric
conditions.


Obviously the UFO in Rendlesham forest, is absorbing the signals.

Have your council evict them under Section 61 of
the Criminal Justice and Public Order Act 1994 ;-)

Steve Terry

In message , Roger Mills
writes
In an earlier contribution to this discussion,
wrote:

Ivan wrote:
wrote in message
...
So - what to do? The current aerial is a cheap "high gain" one,
here are a couple of pictures ot it:-

http://www.isbd.net/images/DSCF0812.JPG
http://www.isbd.net/images/DSCF0813.JPG

[snip]

Why has the aerial been bolted on upside down?.. you may just as
well have clamped the boom directly to the mast.

I have no idea, maybe there was nothing telling which way was "the
right way up". It's not going to have a significant effect on the
performance anyway is it? (Except the loss of a few inches of height)


It will have *some* but - more importantly - the junction box will be more
likely to become full of water, which is what might have happened.

Unless I'm completely mistaken, the aerial itself (including the
junction box) seems to be the right way up. It's only the mounting
bracket thingy which is on the wrong side of the boom.
--
Ian

wrote in message
...
Recently our TV reception has detriorated markedly, we live near
Woodbridge and get our signals from Sudbury so we're getting on for
"fringe area". The Woodbridge relays don't do anything for us. Until
recently reception was pretty good most of the time with the very
occasional drop out and sometimes a 'bad day' with odd atmospheric
conditions.

I can't see anything obvious that has changed (like failed connectors)
so I suspect that we may be being affected by particularly lush growth
at the tops of some trees which are probably somewhat on our path
towards Sudbury.


Who fitted it! It's upside down. I would stick it on a much longer and
fatter pole - with appropriate fixings. A few feet makes all the
difference.
Maybe a mast head preamp would be just what you need.

wrote in message
...
Ivan wrote:
wrote in message
...
So - what to do? The current aerial is a cheap "high gain" one, here
are a couple of pictures ot it:-

http://www.isbd.net/images/DSCF0812.JPG
http://www.isbd.net/images/DSCF0813.JPG

[snip]

Why has the aerial been bolted on upside down?.. you may just as well
have
clamped the boom directly to the mast.

I have no idea, maybe there was nothing telling which way was "the
right way up". It's not going to have a significant effect on the
performance anyway is it? (Except the loss of a few inches of height)

--
Chris Green

Troll !

Have a look here
http://www.aerialsandtv.com/tvaerial...lyFittedCradle

The site has been mentioned elsewhere in the thread relating to aerial
tests, but it also shows here how a mast running through the element train
can impair aerial performance.

Consider replacing the aerial with a better quality one. For Sudbury a
quality group E should be better than wideband, sadly they appear to be
thin
on the ground these days. Someone may be able to suggest one. Blake are
showing an SR18E on their website
http://www.blake-uk.com/page/aerial_benchmark/Aerial_SR

Thanks, that's the other sort of advice I was after. You're right,
group E is better than wideband (I took a look at the Wolfbane site
after my original post).


See here http://www.aerialsandtv.com/atvschoi...ials.html#XB16 for a
recommended high gain group E at £55.

You would need to upgrade the mast though - and fit it on a T&K bracket at
the very least, with 20% total mast length between the T&K.

You say you have an amplifier fitted. What is it, and how much gain/noise
does it provide?

Bill is the man with the most practical experience here though, and I've no
doubt that his advice on critical location is good stuff.

Bill Wright wrote:


wrote in message
...
Recently our TV reception has detriorated markedly, we live near
Woodbridge and get our signals from Sudbury so we're getting on for
"fringe area". The Woodbridge relays don't do anything for us. Until
recently reception was pretty good most of the time with the very
occasional drop out and sometimes a 'bad day' with odd atmospheric
conditions.

I can't see anything obvious that has changed (like failed connectors)
so I suspect that we may be being affected by particularly lush growth
at the tops of some trees which are probably somewhat on our path
towards Sudbury.

Analogue reception has become pretty ropey too as well so I think it's
aerial (or downlead) rather than anytthing else.

So - what to do? The current aerial is a cheap "high gain" one, here
are a couple of pictures ot it:-

http://www.isbd.net/images/DSCF0812.JPG
http://www.isbd.net/images/DSCF0813.JPG

Leaving aside the obvious deficiencies of the aerial the important thing
-- the biggest factor by far -- when tree screening is the problem, is the
position of the aerial. You need to sweep the the area, trying every
possible aerial location carefully. One metre can make a massive
difference. On innumerable occasions (OK I lie, it's actually 1,345,602
occasions) I have done this and then simply moved the same aerial to a new
location. The difference between one location and another with only a few
feet between them can easily be 15dB. Generally the best spot for one
channel will be the best for all of them.

See my ancient piece on this subject:
http://www.wrightsaerials.tv/resourc...-reception.pdf
It creaks like the trees it talks about, but it's still basically valid.

Bill

I live in the same area as the OP, with similar tree problems. Over 20-odd
years the reception has deteriorated to the point where I now have a large
w/b antenna & masthead LNA on top of 40ft of scaffold pole on the garage
roof!. This gives me about 70dBuV on the 4 main analogue channels, but the
the weakest DTT mux (ITV) is now not even above threshold in the winter
and I lose a couple of others in the summer when the leaves come out.

That is all down to a poor, non line-of-sight path compounded by dense
tree growth over the first couple of hundred metres this end of the path.
Roll on 2011 when the weakest DTT muxes go up about 20dB and I might
even get back to an antenna on the house. Meanwhile it's Freesat (Sky
and non) as the only option.

Considering the OP's question, higher is always better. You can
compensate cable loss with a well-designed system gain profile
(masthead LNA plus possibly a booster amp half way if the cable run
is *really* long)

J

"John Sager" wrote in message
...
Considering the OP's question, higher is always better.
No. Typically the trees will be much higher than any aerial mast you can
install. You will only start to get line-of-sight performance when the
aerial is level with the tops of the trees. The effects of tree screening
are often less lower down, where the canopy is less dense. In extreme cases
ground level is the best performer! Of course, if there is also
topographical screening then height might get you over it.

Bill

Roger Mills wrote:
In an earlier contribution to this discussion,
wrote:

Ivan wrote:
wrote in message
...
So - what to do? The current aerial is a cheap "high gain" one,
here are a couple of pictures ot it:-

http://www.isbd.net/images/DSCF0812.JPG
http://www.isbd.net/images/DSCF0813.JPG

[snip]

Why has the aerial been bolted on upside down?.. you may just as
well have clamped the boom directly to the mast.

I have no idea, maybe there was nothing telling which way was "the
right way up". It's not going to have a significant effect on the
performance anyway is it? (Except the loss of a few inches of height)


It will have *some* but - more importantly - the junction box will be more
likely to become full of water, which is what might have happened.

I've had a long hard look at what I can see of the junction box (via
binoculars and some digital photos) and it looks OK but you could be
right. There's certainly a lot of bird poo up there! I'm by myself
here for the next couple of days so there's no way I'm going climbing
around on ladders, it'll have to wait for the week-end.

Meanwhile I may try an aerial in the alternative (more distant but
higher) position and see if that improves things.

--
Chris Green