APRS - Automatic Position Reporting System

1. APRS - Automatic Position Reporting System Dennis Kidder WA6NIA 1 June 2001

2. What is APRS? What started out in 1990 as a digital-equivalent of voice networks has evolved into the RF-equivalent of the Internet. Imagine being able to send a short message to anyone, anywhere, anytime. • Automatic Position Reporting System • Developed (and trademarked) by Bob Bruninga WB4APR • Based on AX.25 • Unnumbered Information packets (UI) • UI ‘s are unacknowledged • VHF and HF mobile and fixed operation • Uses GPS (mobile) or fixed coordinates • Other terms: • Mic-E -- Mic Encoder, TNC-less encoding of location, course and speed • MIM - Micro Interface Module -- Telemetry TNC on a chip APRS - Automatic Position Reporting System

3. More about APRS • Can be used to send simple text messages • May be directed to a specific address or “broadcast” • Text messages are acknowledged • Beacon can contain other information: • Weather station • Station status text, e.g., email address, QTH, etc. • Protocol contains encoding for displayed icon • Can filter on “groups” • use special, “designated” messages • limits what is displayed • Applications: • Locating stations in disaster, public service events, etc. • Tracking moving stations • Simple messaging APRS - Automatic Position Reporting System

4. What is needed for APRS? • Simple: just a computer with Internet connection • More complex: • Hardware • VHF -or- HF transceiver • antenna with vertical polarization • APRS-ready TNC -or- • Any APRS software-compatible TNC • Computer if using APRS software • Optional: NMEA-compatible GPS receiver • Software • Depending on radio/TNC, possibly none -or- • WinAPRS -or- MacAPRS • APRS+ • PocketAPRS for Palmtop computers APRS - Automatic Position Reporting System

5. Typical Hardware Garmin GPS units TH-D7G StreetPilot MFJ Data Radio and Kantronics KPC-3 eMap Kenwood GPSmap 162 TM-D700A APRS - Automatic Position Reporting System

6. GPS requirements • What is NMEA? • National Maritime Electronics Association • Defines standardized protocol used by GPS receivers to send coordinates and receive waypoints • TNC or computer receives coordinates from GPS receiver • GPS map displays received stations • Received from TNC or computer as waypoints • Displays callsign of APRS station APRS - Automatic Position Reporting System

7. WinAPRS Screen Shots APRS - Automatic Position Reporting System

8. APRS+SA Screen Shots DeLorme Street Atlas Display Station List APRS - Automatic Position Reporting System

9. How is APRS distributed? • For small groups, just point-to-point • For larger areas, uses digital repeaters and routing protocols • Digital repeaters (digipeaters or digis) are wildcard named “RELAY” and “WIDE” • RELAY can talk to WIDE or to any local • WIDE talks to WIDE • Anyone can run RELAY • WIDEs tend to be fixed and well known. • VHF-HF gateways • Internet gateways • When configuring an APRS station for “packet path” • Use “RELAY,WIDE,WIDE” or, • Specific callsign of RELAY or WIDE station, if known APRS - Automatic Position Reporting System

10. How is APRS distributed? • Listing of raw packets from WA6NIA-14 • Shows position info, repetitive message (email) • Shows two specific WIDE digis ...K7GIL-1 and W6KRW-2 • Also shows the generic wildcard routes: RELAY and WIDE WA6NIA-14>APD214,RELAY*,WIDE,WIDE:=3346.12N/11806.37Wk191/000/Mic-E/M0/Off duty.. ]"42}dennis wa6nia@arrl.net WA6NIA-14>APK101,RELAY,K7GIL-1,W6KRW-2*:@100347z3346.11N/11806.36Wk191/000/Mic-E/M0/Off duty> WA6NIA-14>APD214,RELAY*,WIDE,WIDE:=3346.12N/11806.37Wk191/000/Mic-E/M0/Off duty.. ]"4,} WA6NIA-14>APK101,RELAY,K7GIL-1,W6KRW-2*:@100352z3346.11N/11806.36Wk191/000/Mic-E/M0/Off duty> WA6NIA-14>APD214,RELAY*,WIDE,WIDE:=3346.12N/11806.37Wk191/000/Mic-E/M0/Off duty.. ]"4.}dennis wa6nia@arrl.net WA6NIA-14>APD214,RELAY*,WIDE,WIDE:=3346.11N/11806.38Wk191/000/Mic-E/M0/Off duty.. ]"4(} APRS - Automatic Position Reporting System

11. Where do I find APRS on the air? • HF • Typical operation is on 30 meters - 10.151 MHz (this is actually inside the band limit … uses AFSK on LSB) • VHF • National APRS freq - 144.390 MHz • This is a very active frequency in Southern California • Something new! ARISS - International Space Station • Uplink: 145.990 • Downlink: 145.800 • Route info: NOCALL APRS - Automatic Position Reporting System

12. Internet Resources • Information • http://web.usna.navy.mil/~bruninga/aprs.html • http://www.aprs.net • http://aprs.rutgers.edu • http://aprs.org • APRS servers on the ‘net • www.aprs.net and mirrors • connects with Telnet from WinAPRS or APRS+ • Provides real-time, world-wide display • www.findu.com • Can be accessed by anyone • example: http://map.findu.com/wa6nia-14 • Software sources • TAPR: http://www.tapr.org • WinAPRS • APRS+ • PocketAPRS http://www.pocketaprs.com APRS - Automatic Position Reporting System

13. Demo Configuration • In the conference room • Kenwood TH-D-7G (WA6NIA-1) • Dual-band (VHF/UHF) data radio with built-in APRS-capable TNC • Garmin eMap GPS receiver with interconnecting cable • Notebook with WinAPRS • Palm III with PocketAPRS • In the parking lot: • Kenwood TM-D700A (WA6NIA-14) • Garmin Street Pilot GPS with interconnecting cable • (No waypoint display … NMEA out only) APRS - Automatic Position Reporting System

14. Demo • WA6NIA-14: • beacons on five minute intervals • parked in FU parking lot • WA6NIA-1 • should display WA6NIA-14 and possibly others • stations displayed depends on nearby RELAY or WIDE digi APRS - Automatic Position Reporting System