Saturday, September 20, 2008

APRS

The next topic derived from reactions to the September 2008 issue of QST is APRS. APRS, or Automatic Position Reporting System, is a curious little beast. APRS is, best I can figure, a subset of traditional amateur packet radio, specifically designed for exchanging small bits of information of a local nature. It looks to me to pretty much analogous to broadcast UDP, to put it in terms someone more at home with TCP/IP might understand better.

APRS's most common usage (and the source of its name) is beaconing location information, in conjunction with a GPS receiver. Quite a few hams routinely have an APRS beacon in their cars, constantly announcing their location. I live within a mile of the Tri-State Tollway (I-294), and I routinely pick up APRS bursts on 144.390 with my HT. Unfortunately, my VX-5R isn't APRS-aware, so all it sounds like is modem noise, which I was never very good at interpreting anyway.

Some of Bob's comments in the QST article suggest to me that the repeater coverage work I'm doing (along with K5EHX) could be useful here; it sounds like it wouldn't be too hard to use APRS to do a "what is near me" query against the coverage database and send back a reply. Also, I have a personal weather station, and so putting weather info out onto APRS for the benefit of those traveling through the area seems like a useful thing and shouldn't be too hard to do. So this is on my shortlist of things to do in the not-to-distant future. Since I already have a two-meter mobile that I'm not using (needs a microphone), it would be easy enough to use a RigBlaster or similar device in conjunction with one of my many spare computers and a 2m omni on the roof to get an APRS station up and running.