Working amateur radio satellites is fun. What is even more fun though (at least to me)
is building all the automation into a station to make it even more technologically advanced. After all, Amateur Radio is a technical hobby where one is free to experiment and build. In the past I used a TS-2000 (and FT-736R before that) for sat contacts. Gpredict served very well as software for pass prediction and rig control for doppler shift. What I was lacking however was a automatic way to track the antennas so I had to do that manually which often times left me forgetting it during a QSO wondering why the signal was fading given the satellite was still visible.
There are quite a few solutions for Yaesu’s G5500 AZ/EL rotor combo. Which btw. is quite pricey and I never saw the need to spring for it given the limited availability of satellites and operating times. I went with two yagis mounted at fixed 20 degree elevation on a cheap AR-303 rotor and that did the trick as well. What this was lacking though was the ability to remote control the rotor from software. Enter Arduino stage left.
I began by understanding how the rotor controller works on a 3-wire rotor and then built the interface using an Arduino UNO and a relay shield so that I could trigger direction and tuning
Next came the interfacing of all this and adding a LCD display to show status information.
I’m currently trying to fix some last bugs in the code. But more or less it’s working (sometimes) to the point where it’s successfully tracking a satellite.
I will share more about this project in the coming days as I go along fixing the last bugs and making it finally work.