[amsat-bb] New Rotator X/Y as opposed to Azimuth/Elevation SPX X-Y Rotor

Robert Bruninga bruninga at usna.edu
Mon Oct 13 19:06:25 UTC 2014

> ... it says " the X-Y pedestal has its limitations at low elevation
> (< 2°) around 90° and 270° in azimuth." which ... is West and East

My bad.  Our XY here is N and S.  So I "assumed" that was what they all
were.  But E and W would seem to be worse because you have the problem on
both assending and descending passes that cross east -or- west.  Where as
with N/S, nothing much passes North.

Oops, wrong again.  I am remembering our problems with the SHUTTLE on 28
deg launches so all passes always were to the south, never north.  So we
only had to deal with low southern pass problems.   But with ISS in a 52
degree inclined orbit, then it goes north just as much as south.

Ah, Ha,  Maybe E/W is best, then, since the only time you are down low on
the horizon to the due east or due west, the entire pass is so low it
probably isn’t worth bothering with anway!

So ignore my stream of consciousness.  Looks like they did their  homework
and so they have a good design with E/W axis and it will not be a problem.

On the other hand, as I suggested before, the number of times that an
AZ/EL gets into trouble directly overhead (when the signal is so strong
one doesn’t even need a beam anways)  is so exceedllingly small with
typical LEO passes, it might not be worth changing.

Not saying either is better.  Just filling in some details to think about.
Thakns for the correction about the E/W.  Also I have not read the link,
so you can ignore anything I say too... <wink>


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