More than two years of spare time has been spent on the development, manufacturing details and writing software for a new rotor.
The rotor is designed to rotate the antenna up to 3.7 meters in size and weighing up to 60 kg and tracking with 0.2 deg. precision.
The full rotor system consist:
Step motors SY85STH80-5504 + Dojen Speed reducer M24 225:1 + encoders MAB28 (12-bit) +MC module based on STM32F4 Discovery
+ my software module "X-Y antenna control unit" + modification Gpredict software for predict tracking.
Mechanical draft: 
For continuous tracking, PID loop algorithm is used. For an example graph tracking errors for WORLDVIEW-3 satellite on 615km orbit:
Several other photo:
Future work:
- install X-band downconverter together with L-band;
- check the hardware tracking during wind.
- the need for precise positioning of the antenna. Any positional errors - and the signal may be lost.
Unfortunately, I could not find in the internet methodologies for the X-Y antenna position calibration.
Therefore, I will be very grateful for your help in this matter.
-------------------------------- Added 25 Sept 2016 ---------------------------------