DIY Antenna Tracker

Hi everybody,

I've been developing on an Antenna Tracker based around my Ardupilot Mega V1 for the last few months and am just about to start on Mk 2.
The tracker is  able to rotate continuosuly in azimuth. I wanted this feature so the tracker can be used for close range flying with low power transmitters.

The telemetry on the prototype is acquired from the Ardupilot using Mavlink in exactly the same way as done by Minimosd. Hopefully will also be compatible with PX4 too. The data is then sent down the FrSky telemetry link. I also have in development alternatives to send the data down the video or audio link, and one that attaches direct to a GPS, but am currently concentrating on the hardware side.

The brains on the ground is an STM32F4 Discovery board. Its cheaper than an Arduino and much more powerful. On the airborne side I use an Arduino Pro Mini.

Heres a video of V1  in action. (I am workin on V2 but this time am planning to make it look a bit smarter!)
There is more information about the tracker on my website at


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  • Developer

    Some updates on the tracker.

    Now working using the Video Audio Channel for telemetry as well as FrSky. Good for versatility and redundancy.

    The lower tracker is my original prototype now converted to receive FSK data via the av audio. The one on the tripod is V2 still using FrSky RC telemetry channel. New airborne unit provides both simultaneously

    • That is awesome, Andy. I would very much like functionality like this so I can record flights from the ground while I'm out solo.

      • Developer

        Thanks for the encouragement :)

        I have now tested using the AV audio channel for sending the telemetry data and works well. I got out to around 1 km using my 25 mW 5.8GHz Vtx.  I have now managed to do the demodulation entirely in software (see below for links), using the STM32F4 on the ground side. The modulation (which is easier of course) is done in the STM32F0 in the airborne side.

        The STM32F4 source code with the FSK demod function is available on my Github Repository. I am sure it could be improved, but am very pleased it works as well as it does at the first go.

        fsk modulator source code for STM32F0

        fsk demodulator source code for STM32F4

        The main inspiration for the demodulator was this article by Dennis Sequine

        Simplified FSK Detection

        Also working on incorporating a compass. Here is a vid of the calibration process



    • Developer

      Also spent some time understanding the HMC5883 magnetometer. I hope the video clearly shows why it needs calibrating and also how that is achieved

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