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Re: "Precision" Antenna Pointing




>trol systems, has been questioned. My gut feeling is a best of
>about + or  - 2.5 degrees. Anyone ever test this?
Yup, Jeff, I tested my G-5400B's.  I used a 10'pole bolted to each rotor to 
magnify
the slop.  Both of my sets after many years of use show about 1.5° +/- in 
AZ and
about 1° EL.  No problem on EL, just bias it with a little forward weight 
on the
antenna.  Wind at high ELs will of course affect it.

I kludged together a weight and pulleys to bias the AZ, and it worked 
ok.  Wind will do a
job there also, of course.  Some have asked how I measure the angles on a 
10' radius circle.
Well, I have an astro-compass bought at at a surplus store (used one as a Navy
pilot in WWII), and can read an angle to about .25°.

I also use it with the sun to accurately determine and AZ.

I have to refine the AZ bias method, but I'll wait until I have to find out 
just
how accurately I'll have to point any micro antennas,  They worked just fine
on 2.4 gigs on O13 and Dove.  And I measured about 104 kHz of doppler on Dove.

Some have suggested that other errors inherent in our tracking systems will 
also
contribute, but that is an input from someone besides me!

            73, Dave wb6llo@amsat.org
                    Disagree: I learn....
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