HFEA Amateur Radio Club - K6QEH

APRS - Automatic Position Reporting System

Dennis Kidder

WA6NIA

1 June 2001

11 April 2001 APRS - Automatic Position Reporting System

What is APRS?

• 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

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.

11 April 2001 APRS - Automatic Position Reporting System

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

11 April 2001 APRS - Automatic Position Reporting System

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

11 April 2001 APRS - Automatic Position Reporting System

Typical Hardware

MFJ Data Radio and

Kantronics KPC-3

TM-D700ATH-D7G

Garmin GPS units

StreetPilot

GPSmap 162

eMap

Kenwood

11 April 2001 APRS - Automatic Position Reporting System

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

11 April 2001 APRS - Automatic Position Reporting System

WinAPRS Screen Shots

11 April 2001 APRS - Automatic Position Reporting System

APRS+SA Screen Shots

DeLorme Street Atlas

Display

Station List

11 April 2001 APRS - Automatic Position Reporting System

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

11 April 2001 APRS - Automatic Position Reporting System

• 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

How is APRS distributed?

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(}

11 April 2001 APRS - Automatic Position Reporting System

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

11 April 2001 APRS - Automatic Position Reporting System

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

11 April 2001 APRS - Automatic Position Reporting System

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)

11 April 2001 APRS - Automatic Position Reporting System

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