[amsat-bb] Computer control of Alliance U-100 and similar rotors

Bill Dzurilla billdz.geo at yahoo.com
Tue May 26 15:26:12 PDT 2009

Very cool, my first homebrew project in 20 years appears to be a complete success (knock on wood).  For about $65, I was able to build a modified version of the K8DAV U-100 Rotor controller, and now my Elk antenna turns automatically and follows the satellites during each pass.

My particular rotor is the Alliance HIR, which is electrically the same as the U-83 and the U-98, and which I bought for $25.  The K8DAV controller for these rotors is the same as the one for the U-100, except for the value of the motor start capacitor.  The U-110 takes the same capacitor as the U-100.

This was a fun weekend project and a very useful addition to my satellite setup.  I picked up two of the most expensive parts, the transfomers, for $1 each at the Goodwill store, in the basket of assorted wall-warts in the electronics section (bring a VOM and test the wall-wart before purchasing).  You could also use the transformer and capacitor from the rotor's original controller, but I was afraid to cannibalize it without being sure I could get the new one to work.

Otherwise, the project box was $18, the Basic Stamp board was about $20, and the solid state relays were $7 each on eBay.  All other parts were inexpensive.

Full plans, files, photos, and links for parts at:
http://www.k8dav.com/ and

73, Bill NZ5N


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