APRS Automatic Position Reporting System By Nicolas - M1HOG

Introduction Disclaimer - Nothing in the talk is warranted as accurate, optimal or indeed sensible. Objectives Introduction to APRS and what it can be used for. Introduction to the Club project and what it can do. Practical - High level talk and equipment walkthrough.

APRS Overview Automatic Position Reporting System Exchange information with other APRS equipped stations Call sign GPS Position (Altitude / Speed) Status Messages Comments Show Who / What is nearby – Stations repeaters etc. Send short s via gateways Send Messages and Bulletins via APRS network Receive or send Weather Reports Produce Maps showing stations and messages.

History of APRS Based on Packet Radio, developed in the early 80’s Small packets of data are transported over the AX.25 protocol using 1200 baud Bell 202 audio frequency-shift keying(AFSK) on a 2 meter FM FrequencyAX.25Bell 202audio frequency-shift keying KA9Q - Developed software for an early TNC – Terminal Node controller – Basically a Modem that uses radio instead of a phone line. KA9Q software was later modified to provide a TCP/IP stack and use a phone line modem. This enabled early IBM PC’s to access the Internet and was how I first accessed the Internet.

APRS 2 meter FM Radio – GPS TNC – Radio Modem – PC required Tracker/TNC – No PC required Digipeater IGate

Radio 2 meter FM Radio Ideally with fixed low level audio input and output for easy interfacing to a TNC Most 2 meter FM radios can be easily adapted

GPS Global Positioning System Position, speed and altitude Typically connected to via a serial lead to a Tracker…

Terminal Node Controller Terminal Node Controller - “Radio Modem” Traditional TNC Requires a PC Tiny Track (TNC + Can send position) Open Tracker etc (TNC + Can send position) Radios with built in TNC + Tracker Kenwood D7 Kenwood D700 Yaesu VX-8RA

Tracker TNC vs Tracker Functions as a “Smart” TNC Generates the contents of packets Typically - GPS plot, Call sign, Messages With out requiring a PC and separate TNC Tiny Track Open tracker etc May include a display to show packets received May have various other functions including..

Digipeaters A "digipeater" from "digital repeater", digipeaters receive a packet radio transmission (APRS packet) briefly store it and then retransmit it on the same frequency. Like voice repeaters, digipeaters are used to increase the distance a radio packet can travel Typically digipeaters enable packets to reach…

IGate Sends packets to APRS-IS (Automatic Packet Reporting System-Internet Service) Radio -> TNC -> PC -> Internet connection PC Software - APRS4R many others are available The APRS data is then be plotted on to maps by various internet sites…

APRS.FI - M3NQG IGATE

Recent Tracks

G0LGJ

G0LGJ -> M3NQG

M3NQG - Stations Heard

APRS Review Automatic Position Reporting System Exchange information with other APRS equipped stations Call sign GPS Position (Altitude / Speed) Status Messages Comments Show Who / What is nearby – Stations repeaters etc. Send short s via gateways Send Messages and Bulletins via APRS network Receive or send Weather Reports Produce Maps showing stations and messages.

Club Project – Bluetooth TNC Based on Open Source hardware and software. Draws on Moblinkd, BeRTOS projects Provides Tracker, TNC, GPS and iGate functions APRS Station Comprises 2 meter FM Radio – Android App – APRSDroid Bluetooth TNC – Our Project! Uses Radio to transmit data, not a connection to the Internet!

Radio 2 meter FM Radio Ideally with fixed low level audio input and output for easy interfacing to a TNC Most 2 meter FM radios can be easily adapted

APRSDroid

Mobilinkd ● A better user interface for mobile APRS ● Low cost — much less expensive than existing purpose-built APRS gear. ● Battery powered and Bluetooth connected. ● Excellent performance. ● Ready to go with minimal configuration

Mobilinkd TNC

Club Project – Bluetooth TNC Simplified version of Mobilinkd design and all leaded/plug components Atmel Micro processor, as used in the Arduino, and a few supporting parts Bluetooth board, to link with APRSDroid etc. Can be constructed on Strip/Vero board Firmware based on Mobilinkd project Configuration and software updates from Android app May be possible to add other features – FT857 – Freq change prior to TX, power from the radio.

What Next? Thoughts and feedback from you Complete prototype hardware Test and Demo Kit and build! Have more APRS / Packet Stations on the air.

Links APRS - APRS.FI – aprs.FI BeRTOS - projects/arduino-aprshttp:// projects/arduino-aprs Mobilinkd – APRSDroid – aprsdroid.org

Thank you ! This presentation is available at Nicolas