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RE: Latest AO-40 ALAT/ALON?



Hi Alan,

What MA were you listening, .... I got solid copy from MA3 to MA12 here in
Bermuda, and in Europe got good copy from MA 6 to MA22, ... The US profile
should be about the same as Bermuda. If you are listening outside of that
range then you'll not have much chance.

Yes rain will absorb some of the signal, as will trees & bushes etc, ... so
check the azimuth elev etc.

I use a 60cm dish here and the beamwidth is about 15 degrees, ... in fact I
have found that I have to mis-point my antenna 10 degress up to hit the
bird, i.e. when the tracking program says 0 elevation, I point the antennas
to 10 degrees elevation, ... its a home made dish and has taken a few knocks
over the years, and I guess the focal point is not where it should be....
outside of the 15 degrees beamwidth I can't hear a peep, ... so calibrating
the rotator is very important.

Also Doppler is not consistent between passes you can't rely on computer
calculated Doppler shift, ... you have to use the computer as a start point
of the search, then tune around. This is because most RX converters are not
temperature stablised, and will vary a lot depending on ambient conditions.

So a lot of this to think about, ... but once you've got the system
calibrated it all comes together, ... I got 69 A CRCC OK blocks this morning
(3:30 AM EST), ... and was very happy about it.

Cheers
Paul, VP9MU


-----Original Message-----
From: Alan P. Biddle [mailto:APBIDDLE@ATT.NET]
Sent: Friday, January 19, 2001 3:20 PM
To: paul.willmott@omsl.bm
Subject: RE: [amsat-bb] Latest AO-40 ALAT/ALON?


Paul,

Thanks.  I was trying my very modest mode-S RX system, and got nothing.  As
it is now sleeting, I didn't want to climb the tower with my signal source
to check things out!  However, with my old numbers, and the one's you
provided, it looks as if I am on the wrong end of the squint angle.  I did
apply the AO-13 to AO-40 adjustment.

Alan
WA4SCA


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