[amsat-bb] TVRO Polar mounts for AO-40

[Bob Bruninga <bruninga@xxxxxxxx>]

I am building my AO-40 dish with only a POLAR motor and today got around
to plotting a track of AO-40 against the sky plot of the Geo-Arc.  It
shows a constant 5 degree offset over the 8 hour period.  You can see the
track in this photo:

 http://www.ew.usna.edu/~bruninga/photos/ao40geo.jpg

The photo is of the rectangular AZ/EL sky view of my tracking program.
(It also shows a model of the actual horizon so I can see blockages,
etc...)

This plot shows a constant offset throughtout the pass because
Apogee is near the center.  FOr passes where you have rapid movement down
near perogee, then the declination angle does change as much as about 10
degrees, but usually the satellite is moving so fast then, it is not worth
tracking...

Anyway, just slap any old (non converted or tweeaked) MDS downconverter
about 5 degrees below your edxisting TVRO feed and bingo, armchair
AO-40...  No changes to the mount or drive system required.

 de WB4APR, Bob


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