1. by: Michael Martens, KB9VBR and
APRS in Wisconsin
The Automated Packet
Reporting System
by: Michael Martens, KB9VBR and
Mark Rasmussen, N9MEA
APRS in North Central Wisconsin Presentation -

2. Overview Introduction Protocol and Implementation Software Hardware
Network
APRS in North Central Wisconsin Presentation -

3. APRS is: A one-to-many, unconnected packet protocol.
A tactical protocol designed for local RF use.
A protocol with many reporting capabilities.
A protocol with SMS capabilities.
A protocol also adapted to the Internet.
A protocol with extensive flexibility built-in.
A protocol still under development.
APRS in North Central Wisconsin Presentation -

4. Introduction
APRS, the Automated Packet Reporting System, is an open system that uses unconnected AX.25 radio packets to transmit and collect data. This data is usually overlaid on a map
APRS in North Central Wisconsin Presentation -

5. Uses of APRS Using GPS data to track vehicle location
Sending short, tactical bulletins and messages between stations
Transmitting data collected by a weather station
APRS in North Central Wisconsin Presentation -

6. The APRS Network Home stations
Mobile and Portable GPS enabled stations (trackers)
Digipeaters (Wide-area and Fill-in)
Internet I-Gates
Automatic Weather Stations
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7. What is needed to begin Computer with APRS software installed
Terminal Node Controller (TNC)
VHF transceiver and antenna
GPS required for mobile stations only
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8. APRS Data Flow
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9. APRS Frequencies VHF 144.39 MHz HF 10.151 MHz LSB
Experimental work is being done on other frequencies.
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10. APRS Raw Packet Originator Path Application
KB9DED>APW251,W9SM-10*,WIDE4-4,qAo,
N9SDL:= N/ W- WinAPRS 2.5.1
-WIMARWAUSAU -251-
Location
Status
APRS in North Central Wisconsin Presentation -

11. APRS Paths WIDEn-N (ex, WIDE3-3)
WIn-N (ex WI2-2, keeps packets within the state of Wisconsin)
Named Path (KC9NW-10, KB9VBR)
Relay and Trace (Obsolete, Do Not Use)
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12. WIDE and WIDEn-N Digipeaters acknowledge WIDE paths
Home stations should not set myalias to Wide
WIDEn-N is not the same as WIDE (WIDE3-3 is not the same as WIDE,WIDE,WIDE)
APRS in North Central Wisconsin Presentation -

13. Named Paths Most efficient form of message propagation
Only the station with the matching Alias will digipeat the message
AB9PJ-4, N9QIP-10, K9ABC-1
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14. WIn-N
Keeps APRS Packets within a geographic location, in this case Wisconsin
Reduces APRS overload as packets won’t propagate beyond their geographic confines
Great for public service event stations (eg walks, parades, races, etc)
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15. Best Path to Use: In the Wausau area: W9SM-1, WIDE2-2
If you are mobile: WIDE1-1, WIDE2-2
If you don’t want your packets to leave the state WI2-2
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16. How APRS Packets Propagate
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17. APRS Real Time Propagation
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18. SSID
Special Station Identifier (SSID) allows multiple stations with the same callsign to coexist on the network.
Home stations have no SSID
Digipeaters may use the ID -1 (W9SM-1)
Mobile Stations may use the ID -9 (KB9VBR-9)
Kenwood APRS radios may use -7 (WA9NBC-7)
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19. SSID Suggestions
No SSID - Home Station, Home Station running I-Gate. -1 Digipeater, Home Station running a Wide1-1 Digi, WX Digipeater -2 Digipeater [#2 or] on 70CM -3 Digipeater [#3] -4 HF to VHF Gateway -5 I-Gate (Not home station)  -6 is for Operations via Satellite -7 Kenwood D7 HH -8 is for boats, sailboats and ships (maybe in the future) -9 is for Mobiles -10 is for operation via the internet only -11 is for APRS touch-tone users  (and the occasional Balloons) -12 Portable Units such as Laptops, Camp Sites etc. -14 is for Truckers -15 is for HF
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20. APRS Software WinAPRS/MacAPRS UI-View APRSDOS APRSpoint
Other platforms include: Palm, Linux, Java
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21. WinAPRS/MacAPRS www.winaprs.org Very easy to use
Uses USGS Tiger maps and integrates with Precision Maps from Undertow Software
Also uses old style APRSDOS vector maps.
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22. UI-View www.uiview.org Lots of features, more complex interface
Handles plug-ins. Vibrant developer network
Uses raster maps. Integrates with Precision maps. Plug-ins for Street Atlas, Mapblast, and Tiger Maps
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23. APRSDos web.usna.navy.mil/~bruninga/aprs.html
The original APRS application. Development going back to 1992
Very rudimentary maps
Has satellite tracking features, network utilization analysis, and direction finding support
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24. APRSpoint www.aprspoint.com
Easy to use, familiar Microsoft style interface
Integrates with Microsoft Streets and Trips exclusively
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25. APRS Software
All APRS software applications are shareware and require a registration fee for continued use. Registration fees range in cost from charity donation to around $100. Some applications may also require you to purchase a map package.
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26. APRS Hardware VHF Transceiver Terminal Node Controller (TNC)
GPS for mobile operation
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27. VHF Transceiver
Any 2 meter radio will work as long as it will work on csq. You will need to make a cable to connect mic audio, RX audio, and PTT to the TNC.
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28. APRS Enabled Radios
Some radios have built in TNCs for direct connection to a computer or APRS interaction right on the display.
Alinco DR-135
Kenwood D-700A
Kenwood TH-D7A
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29. TNC
The TNC, also known as a radio modem converts the digital information from the computer and/or GPS into audio tones.
The APRS network runs at 1200 baud
The TNC communicates with the computer via the serial port.
APRS in North Central Wisconsin Presentation -

30. TNC The most common TNC is the Kantronics KPC-3+
TNCs can be purchased used on EBay for about $ Kantronics TNCs will be higher in price.
Older TNCs work great for home stations, ex: AEA PK-12, MFJ 1270 series, KPC-3
Tiny Trak 3 and 4 - Open Tracker 1+ and 2
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31. Kantronics KPC-3+ About $230 retail
Has a dual port that allows simultaneous computer and GPS connection
Great TNC choice for running an APRS computer in a vehicle
Kantronics KPC-3+
APRS in North Central Wisconsin Presentation -

32. Tiny Trak 4 and Open Tracker 2
About $65-$100 retail
Has a dual port that allows simultaneous computer and GPS connection
Cheaper than a regular TNC but has limitations
Tiny Trak 4
Open Tracker 2
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33. Tiny Trak 3 and Open Tracker 1+
About $32 or $33 (kit) - $42 or $46 (built) retail
Has a single port that only allows connection to a GPS
Cheaper than a regular TNC but it only transmits data
Tiny Trak 3
Open Tracker 1+
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34. Global Positioning System (GPS)
A GPS unit is required for real time mobile tracking
GPSs come in many different forms
Any GPS with NMEA output will work with APRS
Garmin Etrex Legend
Garmin Streetpilot
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35. Home Station Equipment
Watching on RF
Radio
TNC
Computer
Watching on the Internet

36. Tracker Station Equipment
There are two ways to send out your position when mobile.
Dedicated APRS system
Mic-E system

37. Dedicated Tracker Station Equipment
With computer
Radio
TNC (High end unit)
Computer
GPS
Without computer
TNC (simple unit)

38. Dedicated Equipment Pros and Cons
Can watch other units on map and send messages
Position is sent out at predetermined intervals
Separate radio system in the car in case your 2M voice radio dies
Separate radio infrastructure in case your repeater goes down
Could also be used as Winlink or Packet station
Cons
Another radio in the car
More 2M RF to interfere with your local repeater traffic
Higher cost because of more equipment

39. Mic-E Station Equipment
GPS
Cheaper Encode only TNC
Uses your normal voice radio, no extra radio

40. Mic-E Pros and Cons Pros Cons
Don’t have to install another radio in the car
Cheaper than the dedicated equipment way
Can use the cheaper encode only TNC
Cons
Can not track other units on a map
Can not send messages to other units
Position only goes out when you talk on the radio
Position on map could be very old because you didn’t talk on the radio
More expensive for the repeater owners
Won’t work on all repeater systems
No back-up radio if your voice radio fails
If the repeater fails, no one sees your position

41. Putting it all together
Mobile tracking unit with integrated computer.
GPS
Computer running WinAPRS
Transceiver tuned to csq
KPC-3+ TNC
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42. Putting it all together
Portable tracker box
Tracker
GPS
Antenna
Radio
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43. Putting it all together
Who could this be?
Bike Mobile APRS
GPS
Antenna
Radio/Tracker
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44. Putting it all together
APRS Home Station - notice no GPS
TNC
Radio
Computer
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45. Digipeaters
Digipeaters extend the coverage of the portable and mobile units much like a repeater but operating on a simplex frequency. They are usually located at a high location on a tower but can also be located at someone’s home to help fill in a certain area.

46. Digipeaters in the NE District

47. Estimated APRS Coverage to a Mobile

48. APRS Network
I-Gates are internet gateways that expand the reach of APRS worldwide.
An I-Gate listens to the local RF channel and relays the information into an APRS Internet data stream.
I-Gates also relay information from the Internet data stream to a local RF station
APRS in North Central Wisconsin Presentation -

49. Benefits of I-Gates Reduces RF network congestion
Increases the trackability of mobile stations
Allows RF access of weather service bulletins and alerts
Can set up an APRS station without a radio and TNC
Any APRS station can be queried at (map.findu.com/kb9vbr)
APRS in North Central Wisconsin Presentation -

50. Weather Service Messages
The National Weather EMWIN data stream is injected into the APRS data stream.
Alerts and messages can be color coded on the APRS maps.
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51. APRS and the Internet
UI-View radar plug-in superimposes NWS radar data onto the APRS screen.
WinAPRS has a similar feature.
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52. Weather Stations
You can also send out your local weather information if you have the right equipment.
2M radio on
TNC
Weather Station
Possibly a computer

53. Weather Information

54. APRS Satellites PCSAT2 is the second generation APRS satellite
PCSAT1, launched in 2001, is no longer fully operational
PCSAT2 launched August of 2005 has returned to earth with STS-115 in 2006
The ISS is capable of digipeating APRS when the radio is not used for other activities.
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55. APRS Books APRS, Moving hams on Radio and the Internet
A good basic introduction to the mode
OUT OF PRINT
ISBN
APRS in North Central Wisconsin Presentation -

56. APRS Books VHF Digital Handbook Covers APRS, Packet, D-STAR, and more
2008 printing, $19.95
ISBN
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57. For Additional Information
Wisconsin APRS discussion group: groups.yahoo.com/group/wisconsinaprs
web site:
KB9VBR APRS page:
Michael Martens:
Mark Rasmussen:
APRS in North Central Wisconsin Presentation -