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RE: rotator



Message text written by "Greg D."
>
My Az/El setup consists of a pair of index switch-type rotors.  I don't
know 
the brand for the Az rotor, but I am using an Alliance on its side for 
elevation.  The controller is homebrew, based on a Basic Stamp.  A 
discussion of the design and source code are at:  
http://home.jps.net/~gregd/hamsite.htm.<

-----------

Thoughts on using the Alliance rotors (from 10 years with one as an
elevation rotor)
- Arrange it with the side hump down. Drill a 1/8 hole in the lowest part
of the side hump
so that any water that gets in through the antenna mast sleeve drains out.
The water
will get in.
- These things are really sloppy. Mine had at least 10 degrees of slop by
the time I
sent it away. You should have seen the antennas flop in high winds.
- Counterbalance the antennas. This hurts the sloppiness referred to above,
but
keeps the gears alive
- The clicker type position control is worthless at best. And gives 10
degree increments
when it works at all. Forget it. Hose-clamp a 1-turn ball bearing
("precision") pot to the
crossboom and hang a small weight on a few-inch long arm to the rotor. As
the cross-
boom moves the weight hangs down. Use all 3 wires in a bridge indicator
circuit, which
would probably work just fine in a fedback loop. 
Calibrate it. Put a small Tupperware container upside down over it. The
first one lasted
for4-5 years in Midwest winters.
Or use a selsyn. Much better.
- They do work and are useful as long as your antenna beamwidth isn't too
narrow :-)

Good luck,

Ed K9EK
----
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