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Re: Ant. Alignment and the Moon



At 14:33 15-05-00 -0400, Tony AB2CJ wrote:
>
>After installing a new M^2 antenna, I checked it's alignment using the Moon
>and noticed my antennas were off by 10 degrees or so.  I used Instantrak and
>made sure the computer clock was correct for accurate measurments.  My
>question is, how accurate are the "built-in" keeps in Instantrack and is
>this the best way to align satellite antennas?
>

Tony,

The Moon tracker in InstantTrack doesn't pretend to be very accurate and
could easily be 10 degrees or so out. You will need something more accurate
if you are going to set up by the Moon. There are many good
astronomy/planetarium programs around that will give you an accurate readout
of the Moon's position. I have a copy of MOONKEPS written by P Gerber
HB9BNI. It is a zip file 36k long and it generates a set of kep elements for
each month of a year which can be used in any amateur radio satellite
tracking program. These give accurate results. I could post it if you want.

Why not check your set up using the Sun and the shadow of the beam on the
ground? IT does a good job of tracking the Sun. There was a thread on this
BB several months ago which looked at many different ideas for setting up
antennas. I have 'true-north' marked by pegs in my backyard and I have
always used the shadow method to set up the antennas. The 70cm beam has
heaps of gain and it tracks the digisats perfectly.

Regards, Bill...vk3jt

Milawa Australia

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