Gang:

The following one-minute video shows my breadboarded Arduino (ATMega328) tracking two satellites and tuning an FT-817 in response. It also shows the chip periodically announcing the location of the bird in CW, and, as a bonus, you'll see AO-51 being received with a simple dipole directly connected to a low-noise preamp.

http://www.youtube.com/watch?v=XgNcCGXeRyw

This is an application of the Arduino FT-817, Plan 13, CW and Tle EEPROM storage libraries available at: http://code.google.com/p/qrptracker/

One long-term goal is to port this to the Arduino mini-pro, here http://www.arduino.cc/en/Main/ArduinoBoardProMini, add a clip-on real-time-clock and battery, and make a 10 satellite tracking dongle for the FT-817 and TH-D7A that is not much bigger than a USB key, and suitable for portable use. (In that version, the location will be stored in EEPROM, not derived from the GPS unit.) Long, long term, I hope that demoing this technology will inspire ham radio manufacturers to make stand-alone doppler tuning a built-in feature in rigs like the ones above.

Right now, however, the code only tunes the downlink, and I have to spelunk through the code for Instanttune to see how to deal with the FT-817 on transmit :-)

(For the many people new to this list and this wonderful corner of ham radio, I should mention that his project is an experimenter's platform, not a fully-functioning trackbox. For the latter, you want the LVBTracker, available from AMSAT-NA's shop.)

73, Bruce