Exploring APRS

APRS is a digital packet radio system for amateur radio. I have been wanting to play around with it. It  requires a Terminal Node Controller (TNC) and radio to transmit. I have a radio, and I have an iPhone with a GPS. So someone of course figured out you could create all the functions of a TNC.

So those of you that know networking, APRS uses a standard OSI mode AX.25. Sound familiar networking guys? Yep, it basically a X.25 protocol for amateur radio and it’s been around since the 80’s.

Of course with TCP/IP around these days it did not take amateurs too long figure out how to connected the two. So these is also APRS-IS (Internet Systems) which means a radio gateway to TCP/IP for APRS.

So one of the more common uses for APRS is to hook up a GPS to the TNC so that it broadcast your location on a regular basis.

So I tried a IOS application called PocketPacket and simply hooked it up to my Wouxon HT radio with a standard 3/8″ audio cable to my iPhone 5. Since I an located in small geological depression which can make it hard for an HT signal to get out, I also attached the HT to my UHF/VHF roof antenna. It worked!

So I then moved this set up into the Jeep and took a drive over the bridge to the UP area and voila a map of my movements!

There is a lot more you can use APRS for, like messaging, remote weather stations, there is even a ARPS email gateway. I can even use it for SOTA events to announce when I activate a peak!

When looking at the APRS.FI site fellow pacific north westerners may notice all the marine  stations. They are not amateur stations on a boat, they are marine vessels using APRS and APRS-IS. You can track Washington State Ferries along with cargo ships in port on this site.

So I think the next step will be to build an actual TNC and use an old Delorme GPS – or just maybe buy a APRS ready radio for the Jeep.