o build an APRS mobile "Tracker" system, you need a radio, TNC, and GPS. The GPS calculates the Latitude & Longitude coordinates of the mobile station based on data downloaded from satellites. These coordinates are constantly fed to the TNC from the GPS as long as there is voltage sensed on the Ignition Probe wire. (Voltage on the Ignition Probe wire means the vehicle is on.) The TNC converts these GPS coordinates to a data packet and transmits it via the radio.

While the vehicle is turned on, the Tracker system transmits position information every 60 seconds. When the vehicle is off, the Tracker only transmits position information every 60 minutes based upon the last fix from the GPS. (The GPS stops passing data to the TNC when the vehicle is turned off so the TNC must remember its last location.) When APRS data is transmitted, Hams with computers and an APRS Base Station system will be able to observe the movements of the vehicle with the Tracker installed on a computer with APRS and Mapping software.

PRICE: Typical prices are $125 to $134

PRICE: $109 to $125

PRICE: $149 direct from Garmin (Only source.)