aprs is a registered trademark of bob bruninga, wb4apr copyright © 2009 – geoff gatward vk2xjg...

APRS is a registered trademark of Bob Bruninga, WB4APRCopyright © 2009 – Geoff Gatward VK2XJG

APRSIntroduction to APRS

Geoff Gatward - VK2XJGFebruary 2009


What is APRS ?• Automatic Packet Reporting System

• Provides situational awareness to all operators of everything that is going on in the local area via packet radio (AX25) protocols.

• Information can be combined with a computer and mapping software to show the transmitted data superimposed on a variety of map displays


• Real-time tracking

– Position report beacons (Posits)– Weather conditions and warnings– Virtual “Objects”

• Message Transmission to other APRS users• VoiceAlert

– 91.5Hz CTCSS – acts as an APRS ‘radar’, or always-on back-channel between APRS operators

• Direction Finding

What can I do with APRS?


• Remote Telemetry– SiteAlert installed at digipeater site to monitor:

• Battery voltage• Ambient Temperature• Mains Fail / Door Alarms

• Posits stored in global online databases– Review track history via the Internet

• Propagation Indication• Home Automation

– APRS Plugin for HA packages

What can I do with APRS? (2)


• Simple PC setup at base station• Tracking of WICEN and other key personnel

– Car rally: Track nominated cars (e.g. 000, Sweep)– Horse events: Track nominated riders – Water events: Track floodboats and nominated

competitors

• Use APRS network as scoring/timing net – Using APRS messaging capabilities– Customised APRS client applications

APRS and WICEN


Local Information

• Information relevant to immediate local area is transmitted by digipeaters– Local repeater frequency, offset and subtone– Local club meeting and net times– Hamfest location & Talk-in details


• Short (40 character) Station to Station Messages• Bulletins & Announcements• EMERGENCY! Beacons

– Equivalent to SOS or MAYDAY transmissions– Sets off alarms in most clients

Messaging Capability


What Equipment Do I Need?

• FIXED (Home)– Transceiver & TNC / Modem– Computer to Run APRS Client Software

• MOBILE:– GPS (with NMEA Serial output)– Transceiver– TNC with GPS capability or APRS Tracker Hardware


Tracker Setups


APRS Clients• Software

– DosAPRS– MacAPRS/WinAPRS– APRS+SA– UI-View– APRSPoint– Xastir– javAPRS– PocketAPRS– APRSce

• Hardware– PacComm TNC’s– TinyTrack– All In One (MicroTrak)– HamHUD– Kantronics KPC 3/3+– Kenwood TH-D7, TM-D700 & TM-D710– OpenTracker– Yaesu Vx8– Avmap


APRS Hardware


UI-View Screenshot Example


APRS Telemetry Example


APRS RF NETWORK


• WIDE Area digipeaters– Each WIDE covers a large area– Coordinated at a state level– Operates with dedicated APRS digipeater firmware

• Fill-In Digipeaters– Set up in areas where access to a WIDE is not possible

• I-Gates– Pass traffic heard via local WIDE digipeaters to Internet– Gate selected traffic from the Internet onto RF

APRS Network Overview


• HF Gates– Inject traffic heard on HF into VHF network

• SatGates – Inject traffic heard via APRS capable Satellites into

VHF network

• Users– As many as possible!

APRS Network Overview (2)


APRS Frequencies• National 2m Frequency – 145.175• National 70cm Frequency – 439.100 • HF

– 30m 10.149 USB (300bps)– 20m 14.098 USB (300bps) – 40m 7.034 LSB (300bps)

• Satellites– ARISS: 145.825– PCSAT (NO44): 435.250 ↑ / 145.825 ↓– GO32: 435.225 (9k6) ↓


• All digipeaters respond to generic aliases• APRS User transmits beacon with fixed path:

– Home Station: APRS via WIDE2-2– Mobile Station: APRS via WIDE1-1,WIDE2-2– HF Station: APRS via GATE,WIDE2-1– Satellite: APRS via ARISS,SGATE,WIDE2-1

• Digipeaters perform smart relaying of beacons

Generic Paths


Beacon Rates

• No need to send beacons too frequently– Beacons ‘expire’ from map after 30 minutes– Conserving air-time for all users

• Recommended rates are:– Home/Fixed station = 30 minutes (1800 seconds)– Mobile station = Smart Beaconing if available,

Otherwise 1 minute minimum (5 minutes on HF)


Path demo - VHF

APRS v WIDE1-1,WIDE2-2

DIGI-ADIGI-E

DIGI-CDIGI-D

DIGI-BDIGI-F

DIGI-G

I-GATE

APRS v DIGI-A*,WIDE2-2

APRS v DIGI-A*,DIGI-B*,WIDE2-1

APRS v DIGI-A*,DIGI-E*,WIDE2-1

APRS v DIGI-A*,DIGI-B*,DIGI-C*,WIDE2*APRS v DIGI-A*,DIGI-E*,DIGI-F*,WIDE2*

APRS v DIGI-A*,DIGI-E*,DIGI-G*,WIDE2*

DIGI-H

All hops used up No further digipeating




Path demo - HF

I-GATE

DIGI-A

HF-GATE

APRS v GATE,WIDE2-1

APRS v GATE*,WIDE2-1

APRS v GATE*,DIGI-A*,WIDE2*

DIGI-B

All hops used up No further digipeatingDIGI-C


Path demo - Satellite

I-GATE

DIGI-A

SATGATE

APRS v ARISS,SGATE,WIDE2-1

APRS v ARISS*,SGATE*,WIDE2-1

APRS v ARISS*,SGATE*,DIGI-A*,WIDE2*

DIGI-B


DIGI-C

APRS v ARISS*,SGATE,WIDE2-1


SSID

• Even though we can tell from a station's ICON the type of station they are, a set of standards have been devised that links the SSID with the ORIGIN of the beacon. These standards apply globally.

– For example, VK3EFG has a TinyTrack setup with the icon as a CAR. When we see this station on the map we know that it is a car, however how did the beacon get into the network? Using the standard SSID table, we could tell this information easily by looking at the callsign.

• VK3EFG-9 would indicate a standard VHF mobile setup.• VK3EFG-6 would indicate that the station is sending APRS via the

ARISS satellites• VK3EFG-15 would indicate that the station is operating HF APRS.• VK3EFG-7 would indicate that the station is using a Kenwood D7

Handheld, and therefore LOW power.


SSID Table

-0 (No SSID) Home Station

-1 Digipeater, or Home Station running a Fill-In Digi,

-2 Digipeater [#2] on 70CM

-3 Digipeater [#3]

-4 HF to VHF Gateway

-5 IGate (Dedicated system, not home station)

-6 Operation via Satellite

-7 Kenwood D7 Handheld

-8 Maritime vessels - Boats, sailboats and ships (VHF / UHF)

-9 Mobiles (VHF / UHF)

-10 Operation via Internet Only (No RF capability)

-11 Aircraft, Helicopters or Balloons

-12 APRStouch-tone users and Portable Units such as Laptops, Camp Sites etc

-13

-14 Interstate Truckers

-15 Operation via HF


Current and Proposed Digipeaters


Further Information…

• APRS Websites:– http://www.aprs.net.au– http://vk2.aprs.net.au– http://wxsvr.aprs.net.au

• OZAPRS Mailing List:– http://aprs.net.au/mailman/listinfo/ozaprs


Q&A

aprs is a registered trademark of bob bruninga, wb4apr copyright © 2009 – geoff gatward vk2xjg...

Documents