Transcript Toroids - SADARS

APRS
Automatic Position Reporting System
By Nicolas - M1HOG
www.M1HOG.com
Introduction
• Disclaimer - Nothing in the talk is warranted as accurate,
optimal or indeed sensible.
• Objective – An introduction to APRS and what it can be
used for.
• Practical - High level talk and equipment walkthrough.
What is APRS
• Back a step to 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 Frequency
• 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 first
accessed the Internet.
APRS Overview
• Automatic Position Reporting System
• Invented and trademarked by Bob Bruninga WB4APR
• Developed in the late 1980's for local tactical digital
communications, situational awareness and two way
information exchange. - Phew
• Automatically sends data packets over the air for direct
and indirect reception by other
APRS Overview
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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 Email
Send Messages and Bulletins via APRS network
Receive Weather Reports
Produce Maps showing objects and messages, so
everyone sees the same
APRS
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2 meter FM Radio - 144.800
TNC – Radio Modem – PC required
GPS
Tracker/TNC – No PC required
Digipeater
IGate
Radio
• 2 meter FM Radio - 144.800
• Ideally with fixed low level audio input and output
for easy interfacing to a TNC
• Most 2 meter FM radios can be easily adapted
Terminal Node Controller
• Terminal Node Controller - “Radio Modem”
Traditional TNC
• Tiny Track (TNC)
• Open Tracker etc (TNC)
• Requires a PC
Radios with built in TNC
• Kenwood D7
• Kenwood D700
• Yaesu VX-8RA
GPS
• Global Positioning System
• Position, speed and altitude
• Typically connected to via a serial lead to a
Tracker…
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 (TNC)
• Open tracker etc (TNC)
• 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
M3NQG - Stations Heard
Equipment Walkthrough
• Kenwood HT – Tiny Trak - GPS
• Dave G4ETG – Kenwood 700
Links
• APRS - http://www.aprs.org/
• Tiny Trak - http://www.byonics.com/tinytrak/
• Open Tracker http://www.argentdata.com/products/otplus.html
• Kenwood TH-D7 http://www.kenwood.com/i/products/info/amateur/
thd7ae.html
• Kenwood D700 http://www.kenwood.com/i/products/info/amateur/
tm_d700ae.html
• APRS.FI - http://aprs.fi/
Thank you !
This presentation is
available at
www.SADARS.org
Nicolas
www.M1HOG.com