APRS

Rick Gilmore W3TM

Agenda

What is APRS?
How does it work?
Gear and software

What is APRS?

Automatic Packet Reporting System

Not the Automatic Position Reporting System
APRS.org

Bob Bruniga WB4APR SK

While best known for APRS, Bruninga was also a retired US Naval Academy (USNA) senior research engineer who had an abiding interest in alternative power sources, such as solar power. In 2018, he authored Energy Choices for the Radio Amateur, published by ARRL.

ARRL Obit

APRS originated in 1982, when Bruninga wrote his first data map program that plotted the positions of US Navy ships for the Apple II platform. A couple of years later, he developed what he called the Connectionless Emergency Traffic System (CETS) on the VIC-20 and C64 platforms for digital packet communications to support an endurance race.

ARRL Obit

The program was ported to the IBM PC platform in 1988, and was renamed APRS in 1992. The recognized North American APRS frequency is 144.39 MHz, and APRS is globally linked via the internet. Bruninga founded the Appalachian Trail Golden Packet (ATPG) event, which fields APRS nodes from Stone Mountain in Georgia to Mount Katahdin in Maine each July.*

ARRL Obit

Bruninga founded the Appalachian Trail Golden Packet (ATPG) event, which fields APRS nodes from Stone Mountain in Georgia to Mount Katahdin in Maine each July.

ARRL Obit

Packet radio

Data mode
Text packets (not images)
Weather station telemetry, text messages, announcements, queries
AND GPS coordinates

How does APRS work?

Packets

Shared frequency (U.S. 144.39 MHz)
Packets sent asychronously
No collision detection, but…
- Receivers at varying distances from the source.
- Packets are either detected or lost.
Most packets are picked up by some station
Overall packet loss is low.

https://web.stanford.edu/class/ee179/labs/Lab8.html