Skew - affect on signal quality?

scloughley · #1 (**permalink**) 06-20-2005, 08:20 AM

I have installed a dish myself (Globecast), and I get a picture which seems very good (projected onto 76" screen), but I wonder could it look even better since the quality varies between around 45 at the low end, to 60 at the upper end and seems mostly to be around 52-56? Signal strength is always high - around 92.
The mast is not perfectly vertical. But I'm quite sure that I've got the "effective" elev and azimuth right, because moving the dish just a fraction in either elev or azi from where the dish now points sees a huge drop in quality.

The only variable I haven't monkeyed with is the skew, which is set at 114 degrees. Because the mast is slightly off from true plumb, the skew is likely to be a little wrong. But will a few degrees here or there may a difference? The reason I haven't messed with the skew is simple - it's quite a bit of hassle to do this with the Globecast dish. Before attempting, I want to see whether it will be worthwhile, especially since the picture/sound are already pretty good.

bobkat · #2 (**permalink**) 06-20-2005, 09:45 AM

Peaking the skew or dish alignment to achieve maximum signal quality will have no bearing on how clear the picture looks. Since the signals are digital the picture is either there or it isn't. It will however have an effect on rain fade (picture breaking up during a rainstorm). If you notice the picture breaking up into little "tiles" or squares and the audio is breaking up as well then you should tweak the dish for the highest quality. Otherwise leave it alone.

kat

scloughley · #3 (**permalink**) 06-20-2005, 10:24 AM

Interesting. So the fact that the quality is, say 46% on a bad day gives no worse a picture than if it had been 90%?

bobkat · #4 (**permalink**) 06-20-2005, 10:53 AM

Quote:

Originally Posted by scloughley

Interesting. So the fact that the quality is, say 46% on a bad day gives no worse a picture than if it had been 90%?

That's right. Once the picture "locks in" it will have the same overall appearance until the quality drops below a certain level at which point the picture will begin to break up and then it will be gone completely.

kat