Re: [amsat-bb] TV aerial rotator question - reply

["Gary \"Joe\" Mayfield" <gary_mayfield@xxxxxxxxxxx>]

Phil,

     Never give up!  I have swapped, traded and bargained my way into a
G-5400.  Along the way I had several configurations, all of which worked for
a while at some point in time.  Here are the ones that actually worked.

1. Timing (just like Bob said) it doesn't do too bad, and after a while you
get a feel for the quirks of your rotor.  I have also used the clicker
rotors with success.  In the U.S. the alliance U-100 and U-110 are popular
as they allow the boom to pass through the rotor.

2.  I have added potentiometers to rotors using rubber bands (I like to call
it belt drive).   This is a high maintenance solution, but it does work.

3.  I have built gear drives.  It is NOT rocket science.  You can make your
own gears with common hand tools, just be patient and take your time.
Remember a little sawing and a lot of filing!  Cut a pattern on poster board
and glue it to some lexan plastic and cut your own gears.  They don't have
to be perfect, and they are not going to be taking a lot of torque, we're
turning a pot not an antenna.  I have also used circuit board material for
this with success as well.

4.  I made my own custom potentiometer once.  In a junk box I had some
enameled wire (I don't know what is was, but if I ever find more I will buy
it!  [maybe tungsten wire?]).  The wire was about 500 Ohms per foot.  I
wrapped this wire around a triple thickness strip of poster board.  I then
encircled the boom in a U-100 with my homebrew resistor.  I used a thin
piece of brass as the wiper on my pot.  This worked well once I got a good
contact established between my home brew resistor and the wiper.

5.  (I haven't done this one)  I have heard of people using some kind of
electronic level that is available commercially.

Good Luck and 73,
Joe
ka0yos@amsat.org



Stuff Clipped.
>
> I had already considered Bob Bruninga's idea where he has mapped time and
> rotation speed to get the desired aerial heading. Bob states that the
> accuracy is adequate, and I'm sure that it is, but I had a more
> engineered solution in mind. I'll think about this a bit more, the idea is
> simple and it may be the only way that I can stay within my strict budget.
>
> Another alternative is to add a multi-turn feed-back pot to my own
somewhat
> bulky home-built rotator as a few people have done with their TV aerial
> rotators. Actually locating a pair of suitable gears has been a real
problem.
> The local appliance repairers don't have anything that is suitable. Maybe
the
> the people who have modified there TV aerial rotators have taken a gear
from
> the controller. Of course, a pot that turns through 360 degrees would be
an
> instant fix.

More Clipped
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