Over a year ago, I blogged that I had assembled a bit of amateur radio gear, the OpenTracker+. This little gadget has a couple of DB-9 ports on it. The first is used to connect to a GPS, and the other to a radio, such as my Kenwood TH-D7A. Together, they form a tracker: the gps provides positioning, which the OT1+ encodes into a packet radio signal and sends via the HT.
Back then, I had it roughly hooked to my Garmin GPS 18 LVC, but I didn’t do a lot of testing with it (I didn’t wire up the proper power supply cabling and the like), but lately I’m trying to get back onto the possibility of doing a high altitude balloon launch, so I dusted it off and decided to get it all working again. Since I built it, Argent Data Systems has begun to sell a nice little compact GPS, the ADS-GM1, which simply plugs into the open tracker, so I went ahead and ordered one, along with the radio/power cable designed to work with my Kenwood HT. I don’t really think that I am going to send this precise hardware into space (it’s rather bulky compared to what can be achieved now) but it will give me experience with the OpenTracker, which has a smaller SMT based version that I could use.
Stay tuned for some smoke testing later.
Addendum: It works! I hooked it up to my TH-D7A, and drove it around for bit. I didn’t bother to calibrate the audio levels very well, but it seems like it works pretty well. Here is a log of the packets received at findu.com for K6HX-9. The voltage varies as I start and stop my car, while the temperature (23C, or about 73F) stays pretty constant (it was a nice day today).