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Re: Automatic AMSAT Antenna Rotators

On Sun, 11 May 2003, Eugene H. Marks wrote:

> 1.  Are you saying that most LEO birds are vertically polarized most of the
> time?  This is not intuitively obvious but if so I have to rotate my 2m
> beam.

Yes, definately.  Two years with holding a hand held 4 element beam out
the window of a car convinces me that most of the tiome it is definately
close to vertical.  Also, the satellite dsigns almost guarantee it.

But the 5 satellites I used to receive on my hand held 3 and 4 element
beams are all dead now..

> 2. Why did you put the rotator limit switches in the south?  Are there
> less chances of trying to go through a southern limit switch than a
> northern one?

Because MIR and ISS all pass to the north of me.  Nothing except Shuttle
passes to the south.  And it only does 1200 baud on 2m and doesnt need a

> 3. What angular difference between the calculated azimuth and assumed
> rotator position do you allow before moving the rotator?

6 degrees.  I wait till I see a 6 degreee delta and then hit it for one
second (or whatever is needed)...

I wish more people would suppport these two bits.
Notice 2 bits ONLY, no ground.  This way NO program can cause a
simultaneous RIGHT-LEFT command because the direction is based on the
DIFFERENTIAL between these two bits.  Not relative to ground.

> > Thank
you, >
> Gene Marks    WB2LLP

de WB4APR@amsat.org, Bob

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