There are some rotors that only use 3 wires between the external motor and their control unit. Those 3 wires are used by the motor (AC) so there is not a potentiometer that could provide a reliable way to know the position. 

If you want to have a relieable rotator that asure the antenna position, you need to add a potentiometer to the system.

For instance most TV rotors doesn’t include a POT, so if you add a POT as I describe at Homebrew rotors (see), it will be able to use your TV rotor via any ARS product. Also a similar method can be applied for TVRO Actuators. In next pictures, you can watch how a POT can be added. It was used in a camera control, using 2 simple a low cost ways:

  • TV rotor for Azimuth control
  • TVRO Actuator for elevation control