All of the rotor control companies are telling me that the Alliance rotors cannot be controlled because they do not have any position sensing hardware, i.e. a pot or potentiometer.
So now I'm investigating how to add this.
The Alliance U100 rotators were designed in 1950s during the post-WW2 expansion in USA.
It was a mechanical world, and vacuum tubes for electronics. Transistors were emerging from research to first production in mid to late 1950s.
Doug Braun tackled this problem (desire for position feedback) in late 1990s with the "then readily available (and cheap)" Radio Shack TV rotators. They are more $$ today.
This OEM design was sold by ChannelMaster in 1990s.
Adding a Position-Feedback Potentiometer to a TV Antenna Rotatorhttp://www.dougbraun.com/rotor_mod.html
PHOTO GALLERY for workhttp://www.dougbraun.com/pix/rotorpix/
: I used a readily available Radio Shack rotator. The Radio Shack rotator is a Channel-Master OEM mfg. product (Eastern Asia, Carolinas) identical to models sold by other brand-name companies.Gear
: From Small Parts, Inc. (www.smallparts.com
) It is part #GD-4860, cost about $6. It is a 60-tooth 48-pitch plastic gear with a 1/4" hole. Small Parts has a catalog full of cool stuff. Try to order some other stuff with the gear, to offset the shipping charge.Potentiometer
: A Bourns 3540-series 10-turn pot, resistance 2k ohms. (Any standard 10-turn model whould work). Mouser and Digi-Key carry them. The Bourns model is very accurate and well-made. I got it at a hamfest for three bucks. New, they run $12 or so. The actual resistance value depends on the rest of the control circuitry, but you should probably not make it more than 2K or so, to reduce noise pickup.Metal plate
: A bit of scrap aluminum about 1.5" x 3".Nuts and Bolt
: From hardware store (e.g. Home Depot, Ace, Lowe's)Cap over pot
: A 1" PVC pipe cap, also from hardware store (e.g. Home Depot, Ace, Lowe's)
When the rotor turns 360 degrees, the 10-turn pot turns about 9.3 turns.
When putting everything together, make sure that the rotor can travel over its full 360-degree range without jamming the pot at the ends of its rotation.