APRS Support in Colorado and Oregon

4 June 2009 @ 3:48 PM  / Trail Tech /

Of the digital modes in use by Amateur Radio operators, a popular one on 2m is the Automatic Packet Reporting System (APRS). This unique system allows users to exchange data about what is going on around them, including other users' positions, repeaters, weather stations, ham fests, hospitals, emergency operations centers, search and rescue teams, and more. To participate, most amateurs usually use three pieces of equipment: a radio, a TNC or tracker (a specialized TNC with specific support for APRS), and a GPS receiver with NMEA support. The Colorado and Oregon requireserial data/power cable to communicate with a tracker. For connection details, see the tracker's documentation. The interface mode on the GPS unit should be set to NMEA In/Out and waypoint output should be enabled on the tracker. After connecting the radio to the tracker and tuning it to 144.390MHz (the APRS frequency in North America), waypoints will start to appear on the Garmin handheld.



Seeing waypoints on a map presents a good spatial representation of people and objects relative to the deviceís current position, but Garminís new Additional Waypoint Information NMEA sentence ($PGRMW) allows the tracker to update a waypoint's altitude, symbol and comment. In addition to a more effective visual presentation, waypoints (such as a training session) can now be updated with details that make them more useful (the date and time).


Currently, the Tracker2 from Argent Data Systems supports the $PGRMW sentence but we look forward to more device manufactures and hobbyists taking advantage of this added capability.