[amsat-bb] Re: a cheap LEO tracker for single op

[Robert Bruninga]

I found my old web page with graphics that shows the exact geometry of
passes and elevations.
 See http://aprs.org/LEO-tracking.html  70% of all pass times are below 22
degrees.


After the discussion a few weeks ago, I sat down today to begin building a
web page on the topic and when I went to save it, there was a page already
there that I had made years ago!  So there it is.

Bob, Wb4aPR


-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Rolf Krogstad
Sent: Tuesday, May 28, 2013 4:17 PM
To: Bill (W1PA)
Cc: amsat-bb at amsat.org
Subject: [amsat-bb] Re: a cheap LEO tracker for single op

Bill,

You should find something in the reflector archives from 3 or 4 weeks ago
where there was a discussion of what percentage of passes were overhead.
 It is an extremely low percentage.  If I recall, most are at a an elevation
of 33 degrees or less.

Because of  the wide beam width of my antenna, tilting the antenna at an
angle of 20 to 25 degrees works well for me.  I can copy the satellite
beacons down to the horizon.  And only on the high angle passes do I have a
any drop out

And because of the beam width of the antenna I don't need to keep a hand on
the rotor control all the time.  But it takes some practice to remember to
look at the azimuth reading on the computer and to adjust the rotor
accordingly every couple of minutes.


The problem comes on the more overhead passes.  Because the bird is closest
to my location at that time it seems to accelerate as it gets overhead.  On
those, though, it doesn't seem to be as critical that the rotor be adjusted
anywhere close to the indicated azimuth.  I can hear the signal starting to
fade and it is a reminder to check the azimuth.

I would definitely run a number of passes with the setup before Field Day to
make sure that everything works and that you can remember to do all the
things that your three hands need to do during a pass!

73 from another newbie,

Rolf   NR0T



On Tue, May 28, 2013 at 11:57 AM, Bill (W1PA) <w1pa at hotmail.com> wrote:

> Let me ask this another way...
>
> Assuming minimal setup prior to each pass, can I track a LEO with a
> single rotor well enough for QSO’s?  (single rotor control in one
> hand, VFO/Doppler on my other)
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