{"id":2482,"date":"2020-12-09T15:48:16","date_gmt":"2020-12-09T13:48:16","guid":{"rendered":"https:\/\/racov.ro\/?p=2482"},"modified":"2026-08-31T17:46:38","modified_gmt":"2026-08-31T14:46:38","slug":"arduino-based-antenna-rotator-part3-software-tracking-update","status":"publish","type":"post","link":"https:\/\/racov.ro\/index.php\/2020\/12\/09\/arduino-based-antenna-rotator-part3-software-tracking-update\/","title":{"rendered":"ARDUINO BASED ANTENNA ROTATOR \u2013 PART3 – Software tracking update"},"content":{"rendered":"
When I worked on this project, I did some research in these communication protocols for antenna rotators.<\/div>\n
There are a lot of protocols, but my first choice was Easycomm, and the second was Yaesu. They are both easy, so I went for Easycomm because it is used by Orbitron (the only “language” Orbitron knows). Yaesu is more popular though.<\/div>\n
Easycomm\u00a0has version 1 and 2. They use identical syntax, but version 2 sends back the antenna position, to be displayed in the tracking software – antenna feedback.<\/div>\n

This version is compatible with EASYCOMM2 antenna protocol.<\/span>
\nAfter 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.<\/span><\/p>\n

In the Easycom2 protocol, the software sends the target position to the controller, like
\nAZxxx.x ELxx.x<\/strong><\/span>
\nThere is no fix length for the coordinates.
\nThe software asks for the current antenna position by sending
\nAZ EL<\/strong><\/span>
\nAnd the controller should respond with
\n+xxx.x xx.x<\/strong><\/span>
\nwhere the first is the azimuth, then the elevation. There is no fix length, but the decimal is mandatory, even if it is 0<\/strong><\/span>. Like +23.0 5.0<\/span><\/strong><\/p>\n

Yaesu (GS232) <\/b>protocol has more commands, but basically it works like that: (<\/span>remember<\/b>, for this protocol, ALL coordinates should have 3 digits, ex. 001 or 012 or 123)<\/span><\/div>\n
\n
Computer initiated\u00a0commands:<\/u><\/div>\n
Move antenna to azimuth xxx (between 000 and 450)<\/div>\n
Mxxx (ex. M123)<\/span><\/b><\/div>\n
There is no command for elevation only, elevation must have azimuth.<\/div>\n
Move antenna to Azimuth And Elevation (aaa Azimuth, eee Elevation)<\/div>\n
Waaa\u00a0eee (ex. W075 032)<\/span><\/b><\/div>\n

Stop azimuth (elevation) movement<\/p>\n

A (E)<\/span><\/b><\/div>\n
Stop all movement<\/div>\n
S<\/span><\/b><\/div>\n
\u00a0<\/b><\/div>\n
Controller initiated responses:<\/u><\/div>\n
What is the Azimuth position? computer sends<\/div>\n
C<\/span><\/b><\/div>\n
Controller responds<\/div>\n
+0xxx (ex. +0123)<\/span><\/b><\/div>\n
\n
What is the Elevation position? computer sends<\/div>\n
B<\/span><\/b><\/div>\n
Controller responds<\/div>\n
+0xxx (ex. +0045)<\/span><\/b><\/div>\n<\/div>\n
\n
What is antenna Azimuth and Elevation? computer sends<\/div>\n
C2<\/span><\/b><\/div>\n
Controller responds<\/div>\n
+0xxx+0xxx (ex. +0123+0045)<\/span>\u00a0<\/b>-No pause-<\/div>\n<\/div>\n<\/div>\n
<\/div>\n
http:\/\/www.radiomanual.info\/schemi\/ACC_rotator\/Yaesu_GS-23_GS-232_user.pdf<\/a><\/span><\/span><\/div>\n

Note that so far, PstRotator was the only software who could display the antenna position.
\n<\/span>This Arduino version is compatible with all tracking software using EasyComm protocol \/ 9600 bauds.<\/span>
\nPstRotator, WXtrack, HRD, MacDoppler… Even WXtoIMG can control the rotator. Orbitron needs the plugin listed below.<\/span><\/p>\n

It accepts 0-180\u00ba elevation, but rotates the antenna accordingly, for max. 90\u00ba elevation.
\n<\/span>There’s also a variant for\u00a0<\/span>AC motors, which offers dry contacts (ON\/OFF). It can be easily interfaced with commercial rotators. <\/span>And one for 180\u00ba elevation, one for 0.1\u00ba precision. <\/span>Just give me a shout.
\n<\/span>Ricardo \/ CT2GQV, made another version for Linux rotctld and gpredict. You’ll find it HERE<\/span><\/a><\/span><\/span><\/span>.
\n<\/span>Jean-Jacques \/ ON7EQ made a modification to the code for a simple controller -azimuth only- and YAESU<\/em>\u00a0communication protocol. Check out his work HERE<\/a><\/span>.<\/span>
\n<\/span><\/p>\n

This is an electric diagram for AC motors.\"\"<\/a>
\n<\/span><\/span><\/p>\n

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\u00b0 elevation. This is an example of electric diagram for azimuth only.
\n\"\"<\/a>
\n<\/span><\/p>\n

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). Therefore, when the antenna starts moving, it accelerates progressively, and, when approaching the desired position, it slows down to full stop. This is known as<\/span> Soft-Start \/ <\/em><\/span>Soft-Stop<\/em>.
\n<\/span>There’s an adjustable Dead Zone, where the antenna doesn’t move for the slightest target offset.
\nThis is the\u00a0<\/span>plot of <\/span>Power output corresponding to Angle error.
\n<\/a><\/span>
\nOnce the project is complete and it can move, you must apply the Potentiometer calibration procedure<\/strong>. It ensures correct reading of 0-359\u00ba<\/span> \/ 0-90\u00ba<\/span>, no matter what kind of potentiometer you are using.
\nThe motor calibration<\/strong> is only for tuning the Soft-Start \/ <\/em><\/span>Soft-Stop<\/em>\u00a0feature. This is necessary if you don’t like the default settings.
\nThe code has been updated several times, and now, for example, you can set the <\/span>antenna<\/span>\u00a0<\/span>update in your tracking software, as fast as you want, 0.5 sec. if you like.<\/span><\/p>\n

Thank you very much to all who sent me feedback, helping to make this project more reliable.
\nAny feedback is highly appreciated.<\/span><\/p>\n

Check the Arduino code<\/span><\/a><\/span><\/span> page for the codes, drawings and procedures.<\/span><\/p>\n