The Ham Plan – APRS for rally cars

We finally got our call signs: KI6IUC (Kris) and KI6IUE (Christine). It took longer then I expected and other radio folks were telling us that it should be like 5 days not 15 days. :| Nothing to do but wait for it. Now that we have them – let’s have some fun. :)

APRS – Automatic Position Reporting System, is used to transmit the exact location of an object (vehicle) over amateur radio frequencies. A data packet (see: packet radio) can contain a number of additional items, such as direction, speed, altitude, temperature, etc. Short text messages can also be attached. These messages are transmitted on 144.390MHz and re-transmitted by local repeaters called digipeaters.

APRS setup for rally car tracking.

The rally car has a ham radio, a TNC (Terminal Node Connector), and a GPS receiver. A TNC is a little data device that talks to the GPS and sends its information out over the ham radio. Every few minutes the TNC gets the position from the GPS receiver and transmits it over the airwaves with the ham radio. The TNC we’re looking at is the Byonics TinyTrak3.

Service has a scanner and a laptop. The audio from the scanner is hooked to the laptop sound card. The software, AGW Packet Engine + AGW Tracker, receives the data and converts it to a little icon on a map.

Key features: Service knows where we are at all times. There is a ham radio in the car for emergencies. The crew doesn’t have to be ham licensed. Our parents can watch the rally live on findU.com. I’m planning to have a toggle switch on the dash board that can send one of two messages out of the TNC:
1. Rally On!
2. Come get us at this location.

There won’t be much use for it at Rim of the World – as we’ll be 300 yards away in the stadium :| , but I may have it setup to demo and test. The first full scale test will be in Prescott later this year. I would like to thank Anders Green (Lina Racing / Sandblast Rally) for suggesting the idea for use in rally cars and I encourage you drivers and co-drivers out there to spend the week of study time and pick up your amateur radio license.

Class dismissed – KI6IUC clear and monitoring.

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