Hello Al, you wrote:
The problem is that half way through, when it should read 360 it reads 345. There is a nonlinearity in the readout.
I made and make the same observation with the KR-600X, the AZ rotor of my KR-5600A rotor combination. The KR-600X is completely equal with the AZ rotor of the G-5400B combination regarding control box and wire poti in the rotor (Yaesu took over the Kenpro rotor production and replaced the "KR" by "G").
When I first added rotor control to my tracking software years ago I mounted the KR-600X in the shack over a big 360° linear scale with 1 m diameter and with a pointer that moved around the scale close above it. The rotor ran exactly an 360° turn from the starting position 180° in the south to the end position 180°. In the software I entered 180 for the start positon and 179.9 for the end position. I could adjust the meter so that it also moved exactly into the start and end position, after I had adjusted the rotor interface poti and the "Out Voltage" poti at the control box. .
Then I entered 360° (rsp. 0°) as target position. The rotor moved exactly to that position, the pointer pointed exactly to the opposite direction of the starting position. The meter however pointed to about 342°, so it was wrong by about 15° to 20°. The situation is the same until today. The maximum of the deviation is in the middle of the scale.
So, by my experience and at least in my case the wire poti in the rotor is very linear, but the meter is not.
I agree with Domenico, that the linearity of the poti is important.
73s, Erich, DK1TB
Thanks for the answers. The rotor goes through its 360 just fine. The problem is that half way through, when it should read 360 it reads 345. There is a nonlinearity in the readout.
73, Al W8KHP