[mythtvnz] Freeview dish set-up woes

[Neil Bertram]

Matt Poff wrote:
> I swapped the inputs/outputs around on the meter (running out of 
> ideas) and the unit was still powered but didn't squark. However, the 
> channel finder read out in MythTV still showed comparable results to 
> before (signal and signal/noise ratio both around 45%). After a few 
> seconds MythTV crashes.
Hi Matt,

I had huge trouble getting a signal when I installed my dish. In the end 
I bought a 90cm dish with matched LNB off trademe and finally managed to 
get a meaningful signal.

A few things you should probably know:

Firstly, even though Myth is claiming signal etc, if there's no lock, it 
means nothing. It is basically measuring the strength of the LNB noise. 
This confused me for ages, as I was waving the dish around trying to 
make that change, but it is actually pretty random. You may notice you 
get the same result no matter what frequency or polarisation you're trying.

Secondly, satfinders squeal like mad for all sorts of reasons. Mine does 
it just when you connect an LNB, but turning the gain way down usually 
helps. I also found aiming the dish at the apartment building next door 
or at the ground made the meter go nuts, but of course there was no 
signal. I think this is some local oscillation sort of thing, but I'm 
not sure.

Thirdly, most cheap satfinders aren't frequency-specific, so even if 
you're peaking, there's no guarantee that you're aiming at D1. You could 
easily have B3 or some other satellite with pretty good signal on a 75cm 
dish. Make sure you've initially aimed the dish sensibly for your 
location (there's a handy calculator at 
http://www.freeviewshop.co.nz/dish-angle-calculator-i-16.html). A 
compass can be useful, I've got one, but I can aim with just the satfinder.

Lastly, you should make sure you're panning slowly with the correct tone 
set, correct frequency and pol, and the right LNB skew. I had my LNB 
skew way off when I searched the first time, and completely missed the 
signal. If your cable comes out the bottom of the LNB, looking towards 
the satellite from behind the dish, the cable should be sticking out 
about 30 degrees to the right. Have a look at sky dishes in your area to 
see what I mean, although the new double-headed ones make it a bit more 
difficult to see.

If you ask me, your satfinder might be bung if it won't shut up. I don't 
think it's a short or you'd get nothing at all. It could be a faulty 
LNB, or a faulty skystar, or a faulty meter.

It took me 6 months from buying the skystar to get my first signal lock, 
and I tried pretty much everything. For me a new dish and LNB was the 
solution in the end. Let's hope you can be solved a bit easier :)

Where abouts are you in Wellington? I live down in Te Aro, if you're 
lucky I might be able to pop over with another LNB and satfinder and 
help you out, since I really do know how frustrating it can be to get 
this stuff working!


Neil