Since I became a Ham in July 2006 I have been intrigued by the utility and general coolness of APRS. I have a radio and a GPS, and all I needed was a TNC or other device. As I searched the internet for items I was pleased to find a subset of TNCs called APRS trackers, which provide an interface between most GPS units and most radios.

I had to decide which one to choose - the choice ended up being between the TinyTrac3 and OpenTracker. I chose OpenTracker for a number of reasons, but mostly because I didn't just want a kit to build, I wanted something to tinker with and (hopefully) improve.

So my plans have gotten bigger. I don't have the kit yet, but I am already dreading the multitude of cables I will need to make this work. Since I bike to work every day, and most of my equipment is portable and removable, attaching and detaching cables can be a real pain. What I really want is an APRS tracker / GPS unit / radio in one convenient package. This is why I chose OpenTracker - I can extend its functionality.

A few days of web searching revealed that I am not the only person who wants a GPS / APRS Tracker / Radio unit, and also that many other people have tried and succeeded at merging two of the three, and sometimes even all three. None of the solutions appealed to me, and since this is a hobby project, I thought I could learn from their experience and hopefully make a cool integrated unit with potential for a kit release. I hope to document this process so it is easily repeatable.

I am not an electrical engineer, nor am I particularly experienced with RF or microcontrollers - I hope to learn these new skills doing this project. I am pretty handy with a soldering iron and have a lot of experience troubleshooting and repairing electronics. Because building a fully integrated device with RF design is well beyond my current capabilities, I have broken the project down into four separate phases. The basic plan is to learn as I go, and get help from more experienced people.

Phase 1 Link

• Get my existing radio, my existing GPS and my OpenTracker kit talking to each other.
• Build or buy a freescale microcontroller programmer.
• Build or but a PIC microcontroller programmer.
• Play with the source code for OpenTracker.

Phase 2 Link
This is where I purchase an OEM GPS smart antenna, connect it to a power source and the OpenTracker and put it in a small enclosure. The “G” stands for GPS. An OEM smart antenna is basically a turnkey GPS solution, and only requires connections to the processor and power.

Phase 3 Link
OpenTracker2 is coming soon, and I would like to take advantage of the cool new features. In addition, I would like to start hacking the OpenTracker code and adding my own enhancements.

Phase 4 Link
Once the GPS integration is tight and mostly bug free and my cool additions to the firmware are taken care of I can add a low power radio chipset to the whole thing.