ARDUINO BASED ANTENNA ROTATOR – PART3 – Software tracking update

This version is compatible with EASYCOMM2 antenna protocol.
After getting in touch with PstRotator (tracking software) developer, he kindly gave me the solution I was searching for, in order to send back the antenna position to be displayed in the software. He also generously gave me a license for his software, thank you very much.

In the Easycom2 protocol, the software sends the target position to the controller, like
AZxxx.x ELxx.x
There is no fix length for the coordinates.
The software asks for the current antenna position by sending
And the controller should respond with
+xxx.x xx.x
where the first is the azimuth, then the elevation. There is no fix length, but the decimal is mandatory, even if it is 0. Like +23.0 5.0

Note that so far, PstRotator was the only software who could display the antenna position.

This Arduino version is compatible with all tracking software using EasyComm protocol / 9600 bauds.
PstRotator, WXtrack, HRD, MacDoppler… Even WXtoIMG can control the rotator. Orbitron needs the plugin listed below.
It accepts 0-180º elevation, but rotates the antenna accordingly, for max. 90º elevation.

There’s also a variant for AC motors, which offers dry contacts (ON/OFF). It can be easily interfaced with commercial rotators. And one for 180º elevation. Just give me a shout.

If you only want azimuth control, that’s fine. Just don’t install the parts for elevation. Put A1 to GND to always read 0° elevation. This is an example of electric diagram for azimuth only.

The DC motors version has the advantage of using PWM for a softer/smoother antenna movement. It outputs a power response proportional with angle error (Target<->Antenna).
There’s an adjustable Dead Zone, where the antenna doesn’t move for the slightest target offset.
This is the 
plot of Power output corresponding to Angle error.

Once the project is complete and it can move, you must apply the Potentiometer calibration procedure. It ensures correct reading of 0-359deg. / 0-90deg., no matter what kind of potentiometer you’re using.
The motor calibration is only for DC, and tunes the soft stop feature. This is only necessary if you don’t like the default settings.

Check the Arduino code page for the codes, drawings and procedures.

Thank you very much to all who sent me feedback, helping to make this project more reliable.

Orbitron DDE Azimuth Elevation To Serial

Arduino code

PstRotator tracking software




  1. salut.foarte fain proiectul…am facut un rotor de antena folosind un compas electronic dar am ceva probleme cand transmit cu putere peste 20w cam deranjeaza compasul!!!dar acum gasind proiectul tau cred ca o sa incerc si abordarea asta fara compas electronic dar cu potentiomete ca feedback…totusi am cateva intrebari: ceva potentiometre multitura de 20k,crezi ca ar merge in locul celor de 1k din schema?! vazut in unul din video ca aveai ceva dificultati in a avea o citire stabila a valorii de la potentiometru si asta ar fi datorat “zgomotului”produs de celelalte module precum si de PC,cum sar putea elimina aceste interferente astfel incat sa faci rotorul cat mai precis?!

    1. Salut Cristian,
      Potențiometrul de 1K de la azimut produce mult mai mult zgomot (2-3 grade) decât cel de 200 ohm de la elevație (0 – 1 grad).
      Cred ca valoarea ideală e de 100 – 200 ohm. Mi-e teamă că 20K ar fi prea zgomotos.
      Nu mă deranjează o precizie de câteva grade, de vreme ce diagrama de 3dB a antenei are 20-30 de grade.
      Ți-am dat un mail, în caz că vrei să continui cu acest proiect.
      Toate cele bune.

  2. HI
    About EasyComm2 Protocol.What is the correct response to the AZ EL command to query the antenna position?I used HRD software and homemade rotator EasyComm protocol. For “AZ EL” response “+12.3 45.6”, the HRD dashboard did not have any only indicating changes.

  3. Hi,
    It is true, I was not able to get HRD to connect with EasyComm2 Protocol. Perhaps it wants a different response from the controller, which I haven’t figured out yet.
    The only software that displays the antenna position was PstRotator.
    I guess there are different implementations of EasyComm2 and more documentation was impossible to find. If I will find information for a better protocol, I will definitely update his project.
    All the best.

    1. Hey Rodrigues,
      Do you have big enough servos to move the antenna?
      The azimuth servo rotates 360 degrees?
      If so, it’s very possible. The code and construction would be even simpler.
      I’ve sent you an email.

  4. does the code change if I would like to use servos instead of Dc motors ?? and can the azimuth driven by two 180 degree servos??

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