[amsat-bb] Re: Loosing the north!!! final conclusion.

Danny Casier Danny.casier at skynet.be
Sat Dec 12 02:10:18 PST 2009

Hi Luc

"I have 24 elements UHF linear yagi and after the switch i got a lot of
small fades with a huge one. "

You have also polarisation. So it's normal you have fading due the spin of
the sat.
24 elements, that's about 30° of opening angle. That's small if your
motorconrol is slow and the time need to reach the good position takes to
long. It is possible, and typical when the sat goes over the 60 degrees
elevation, the sat is moving so quick that your antenna system can't turn
quick enough, so the sat moves out the opening cone of the antenna.

A good way to line up the antenna system is using the sun. (or the moon)
(need blue sky hi hi)
Run a program the gives you the az and el of the sun or (moon) and set the
antenna system to that direction. Then follow the shadow of the antenna if
it lines up with the boom. An outher way is following ISS when it is visible
and see if the antennas moving in the same way as ISS. A couple months ago i
was suppriced. I saw IIS moving more than 45° out (after) of my antenna
system not because it was not good lined up but because i had not updated
the keps within two weeks. My antenna system on 2m is about 45° of opening
angle so i heard ISS loud. But when it was a small sat with tiny output
signal, it was passed without hearing it only due using the wrong keps.

Now, I suggest not to climbing into your tower in a snowstorm to line up our
antenna system. It is not good for bones and brain. Hi hi 

73 Dan ON5UE

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