On 2006-10-16 18:28:10 +0100, Adrian said:

HI Andy



Basically the dish isn't large enough. Signal strength needs to be
higher, but more
importantly the signal quality.

My thoughts entirely

Why would they fit a 'too small' dish ?
Seems to be asking for trouble

Perhaps this is what the distributor had in stock and told them it was OK.




It may be possible to make *some* improvement with a better quality LNB
on the dish but this is usually a second order thing.





The same 'expert installers' ( it says so on their van !) fitted an
aerial for Terrestrial Irish TV. We are about 5 miles direct line of
sight from the transmitter at Mount Gabriel - and getting a noticeably
snowy picture with some ghosting. The aerial is a 4 dipole + reflector
arrangement, that they've fitted in the loft (where it has to look
through two concrete walls and is about 1ft from an enormous steel
'I-beam' which forms the ridge of the house. To compensate for this,
they've added a high-gain amplifier....

This is pointless. Adding an amplifier when the signal is poor adds
noise as well and
doesn;t improve multipath reception.

Thanks - you're confirming my suspicions g -
wanted to be sure before tackilng them...



To be fair - they did say that if we weren't happy then they'd come
back & fit the aerial outside...

I think you should ask them to do that, to be sure.

g To be sure g



So - what should I expect in terms of satellite 'reliability' and
terrestrial picture quality?? - given that we are somewhat 'out in the
sticks - I don't want to be unreasonable with them, but I also don;'t
want to pay good euro for a 2nd-class job...

It should have gone outside in the first place,

I guess the only thing in their defence was that it was pouring down
at the time - but, working in the Emerald Isle you tend to expect
that!

You would. Also, as you've discovered, satellite signal strength
drops when it's raining.

However, it's really the error rate that counts.


The other thing to do before they come back is to take a look at this site

http://www.lyngsat.com/packages/skyuk.html

For the satellite bands used by Sky, (and many others), there are two
bands (high and low) and vertically and horizontally polarised signals.
When you select the program you want to watch on the receiver, it
sends appropriate control signals up the cable to the LNB at the dish
to select which of the 4 permutations should be used - it as actually
the LNB that does the band and polarisation selection.

What I would recommend is to choose a program at the bottom, middle and
top of each band and of each polarisation (i.e. 12 programs
altogether). Note them down with the Sky channel numbers. Then when
the installers come back, try them all out and make sure they are OK,
ideally when it's raining. If all of this works reliably, then you
can be reasonably confident that all channels will.






Thanks again
Adrian