NWAPRS serves: Alberta, British Columbia, Northwest Territories,
Washington, Oregon, Idaho, and Montana

 

Automatic Position Reporting System

Included in this file:

  • What is APRS?
  • Useful Applications for APRS
  • Current Version Information
  • APRS Maps
  • Decoding GPS Sentences
  • How to Join the APRS SIG hosted by TAPR
  • APRS Mobile/GPS Operations
  • APRS Weather Station Operations
  • Bringing APRS to the EOC
  • Northwest APRS Digipeaters
  • Northwest APRS Coordinators
  • Northwest APRS SIG List
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  • What is APRS? The Automatic Position Reporting System (APRS) is a packet radio system used for tracking objects, including people, vehicles, boats, aircraft, manned/unmanned balloons, even cows; weather systems, or just about anything, using an Amateur Radio mode called unconnected (UI) packets.

    APRS was developed by Bob Bruninga/WB4APR, and was first introduced to the Amateur Radio Community at the ARRL Computer Networking Conference in New Jersey in 1992. Over the past 12 years APRS usage has grown and expanded across the globe. Many new features and capabilities have been added since its inception. Worldwide, there are over 6000 stations on the map at any one time. APRSdos is available, as are all versions of APRS, via shareware fee off the TAPR web site (http://www.tapr.org) and other web locations.

    In 1994, Keith Sproul/WU2Z, introduced the Macintosh OS version of APRS, appropriately called MacAPRS, at the 1994 Dayton Hamfest, and released it at the 1994 ARRL Digital Communications Conference in Minnesota. About a year later Keith, and twin brother Mark/KB2ICI, released WinAPRS, taking full advantage of the windows interface. Both MacAPRS and WinAPRS are available via shareware fee off the TAPR FTP site. Note, the newest version of WinAPRS will only work with the newer version 5 of Precision Maps. 

    In late 1998, Mike Musick introduced the PocketAPRS software. PocketAPRS operates on a 3Com Palm III or other Palm device upgraded with the Palm OS3 software. With development of APRS for this tiny PDA, miniaturization of a full APRS station is now upon us. 

    A Solaris, Mac OS X, FreeBSD and Linux version of APRS followed in 1999, and is available at http://www.xastir.org, 

    Also in 1999 came the first releases of the long-awaited WindowsCE version of APRS. This version also works with the newer PocketPC devices, such as the Compaq/HP 5400 series, Toshiba, and others, but is no longer in development.

    With WinAPRS development slowed, and lacking an updated set of good quality maps, others have been working hard to keep APRS software development on the front burner. Mike Cai/KF6ZDM/ has developed and released APRSPoint in 2002, which takes advantage of the excellent quality maps in Microsoft Map Point 2002, and includes maps of Canada. You can download APRSPoint at http://www.aprspoint.com. Mike has an arrangement with Microsoft that allows him to sell MS MapPoint software with APRSPoint for around $65. In 2006 Mike further improved APRSPoint and it is now compatible with Microsoft MapPoint 2004 maps only.

    Then along came British ham Roger Barker/G4IDE in 2002 with his open development package of APRS called UI-View16, and it's more robust companion UI-View32. I say "open development" because Roger allows other programmers to create add-on modules that increase the usefulness and potential of UI-View with such features as call-book lookup, weather monitoring and posting of weather alert areas, local area kiosk access, etc. UI-View works great with UnderTow Software Precision Maps versions 5 and 6. The whole look and feel of UI-View is awesome, and is my personal recommendation for someone coming into APRS, or also for use at the EOC. On top of that, the registration fee for UI-View32 (the 16 version is freeware, but has limited use of options) is less than $20USD. Roger takes paypal, which ensures you get your validation number quickly. Note, UI-View does not include Precision Maps. You need to buy that separately. You can find more information on UI-View at Roger's web site: http://www.uiview.org. UI-View now works with Precision Maps v7.0 when you download the updated OCX file.
    ****Note Aug 04: Roger has was diagnosed with cancer and passed away Dec 8th, 2004. Development of UI-View is curtailed, although registration support is now free.********

    An APRS system typcially consists of a computer (PC or Macintosh color system), a TNC (take your pick), and a radio (HT, mobile, desktop) operating on VHF or HF, or both. A mobile APRS system is complemented with a GPS (one with data output). Routine updates in position are transmitted over the air, and show up as moving symbols on a map. This is similar to commercial systems found in rental or high priced cars, yet different because the information is transmitted over the air and displayed on computers running APRS. Fixed APRS stations with internet connectivity can also log onto one of several regional or worldwide APRS databases to see APRS in action around the globe.

    Map development for the various versions of APRS reached a new peak in 1998 with interface between WinAPRS and the Precision Mapping maps by Chicago Software, now UnderTow Software. This new $50 CD is chocked full of U.S. maps down to street level and easily interfaces with several APRS applications, including WinAPRS, Xastir, and UI-View32. While Delorme maps are also compatible with the APRS+SA software, I like Precision maps best of all because they are easier to use. New maps options are coming along nicely. I have seen both select satellite photos and topography maps used well with APRS, but these usually require manual intervention to embed positions with the maps.

    Please note that Chicago Maps has officially discontinued selling the Precision Maps 3.0 and 3.5 version of its software. Version 4 is not compatible with WinAPRS, but the new version 5 is compatible with WinAPRS starting at 2.5.1. Unfortunately there are some development issues with WinAPRS now, and it's not as functional as the older versions that are compatible with PMaps 3.0/3.5. Mark Sproul continues to develop WinAPRS, but other life priorities have slowed development of the program over the past couple of years.

    Digital photo of Idaho Falls APRSdos map, and PocketAPRS on a Palm Pilot III

    This pic doesn't do much justice to the great capability of WinAPRS w/Precision Maps, however the author now recommends using Tiger Maps, which are free.
     

  • Useful Applications for APRS:
    • Routine Mobile Tracking... Probably the key to APRS "addiction". With a GPS providing automated location information, the TNC is routinely updated and keys the transmitter to send the current location to receiving stations. Mobile symbols can be modified to show car, truck, semi, RV, boat, bike, airplane, or any other common mode of transportation. For remote tracking applications no computer is required. If you want to track yourself and bring along a computer, a newer model TNC or HSP (hardware serial port splitter is required (build your own or buy one). Pictured here is the mobile setup in my former vehicle. I can dismount the unit easily and store it in the trunk. From left to right: Agrelo DFjr, KPC-3, DFjr receiver, 2M/440 Voice, VHF/UHF Scanner, Packet 30W Amp, and Garmin GPS. Not seen, just below the DFjr, is an HTX-202 used for packet/APRS.
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    • Weather Reporting... The "second best" feature of APRS, allows you to integrate inexpensive weather stations, like the Davis units, or those from Peet Brothers, and accurately record and report the wind speed and direction, rainfall, barometric pressure, and other criteria. Excellent for supporting weather nets and disaster response. The folks at the National Weather Service are deeply interested in seeing more realtime weather provided by amateur radio, and we may have a NWS-funded remote weather station on the air soon.

    • Boat Tracking... Similar to mobile tracking, a great way to track boats of any size. Trackers have been used for both VHF and HF operations, allowing those near and far to track the vessel as it cruises around the bay or ocean. Our favorite subject, Peter/N7LUS, now has his APRS gear installed aboard his sailboat, and is routinely observed along the east coast or down in the Caribbean. What a life! This followed years of long haul trucking where Pete was easily found on the APRS maps somewhere between LA and Florida.
    • Manned Tracking.... Very similar to what's already been described, just the portable version. Running from internal battery power, a common system might include an HT, miniature TNC (like the Pico Packet or Handi Packet from PacComm, or the new TigerTrak TM-1) or a PIC or MIM, and a TripMate with batteries. The combo can be easily backpack mounted for a hiker or other person on routine trail tracking or hunting for lost persons in the wilderness.
    • Race/Parade Support... APRS is an excellent resource for marathons and parades. Stand-alone trackers can be fixed to key vehicles tracking lead runners or groups, and report exact location back to the start/finish line staff. Emergency resources can be tracked and have their positions routine updated.
    • High Altitude Balloon Tracking... Here's an event that has drawn much interest. HAB events require alot of manpower to launch, track, and recover the balloon and its package that is released upon balloon burst at 90,000+ feet. A stand-alone package consisting of MIM, radio, and telemetry package (GPS, temperature, altimeter, etc) can downlink realtime data and allow tracking the balloon during its descent. Tracking crews manned with mobile APRS stations (computer, TNC, radio, GPS) can drive to the recovery area and quickly get the package back. Consider trying the TigerTrak TM-1 or PacComm Pico Packet for a miniature TNC to keep the weight down.
    • Manned Balloon Tracking... Much like HAB (above), ground crews can easily track the flight with APRS, even predicting potential landing areas downwind.
    • Disaster Response... Display APRS at your EOC. Emergency response teams equipped with APRS stand-alone trackers will indicate their location. Mobiles encountering blocked highways, fires, or other emergency, can plot the exact location. Voice reports from field units can be manually input and keep everyone online informed. The ARRL supports the use of APRS for ARES and RACES call ups.
  • Current Version Information
  • APRS Maps
  • Decoding Global Positioning System Sentences
    • RMC - Recommended minimum specific GPS/Transit data
    • RMC Sentence Format: $GPRMC,123519,A,4807.038,N,01131.324,E,000.0,276.9,150895,000.5,E*73
    • $GPRMC,HHMMSS,A,DDMM.MM,N,DDDMM.MM ,W,XXX.X,XXX.X,DDMMYY,XXX.X,E*XX
    • Decoded 1 2 3 4 5 6 7 8 9 10 11 12
      • 1. Time (UTC) : of fix
      • 2. Position valid (A=valid, V=invalid) :
      • 3. Latitude at UTC time (degrees and minutes)
      • 4. Latitude direction (N=north, S=south)
      • 5. Longitude at UTC time (degrees and minutes)
      • 6. Longitude direction (E=east, W=west)
      • 7. Speed over ground (knots)
      • 8. Course over ground or track (degrees, true)
      • 9. Date (day, month, year) : Date of fix
      • 10. Magnetic variation (degrees)
      • 11. Magnetic variation direction (E=east, W=west)
      • 12. Checksum
    • Garmin-45 RMC: $GPRMC,062428,A,3250.782,N,09645.682,W,000.0,360.0,310595,,*00
    • Tripmate RMC: $GPRMC,020438,A,3300.9990,N,09649.7490,W,53.549,181.3,240397,5.7,E*54
    • APRS processed RMC GPS fix: CS>APRS:@011714z3216.89N/10852.57Wu233/56./APRS/good RMC Fix
    • Points to note:
      • Processed APRS data is 2 decimal places or DDDMM.MM
      • Garmin RMC output is 3 decimal places or DDDMM.MMM
      • Tripmate RMC output is 4 decimal places or DDDMM.MMMM
      • The NMEA format is comma delimited so most software can process the different GPS data strings.
  • APRS Mobile/GPS Operations
    • Remote Tracking... The GPS must have a data output providing RMC, GGA, GGL, or other sentence. This is fed into the TNC and is stored in a buffer until the transmit cycle. On a PacComm TNC, the data pin is 3 and ground is 5. On the Kantronics TNC, data is on pin 2 and ground is 7 for the DB-25. The newest version of the Kantronics firmware (8.3) allows you to input GPS data into the DE-9 radio connector on pins 2 and 6. Check your TNC's manual for correct configuration. Wire the radio to the TNC according to your manual, and configure the TNC to transmit at least once per minute. The newer TNCs support multiple buffers and configurations, which can allow you to program different digi paths or transmit times. Once configured, power up the unit and allow the GPS time to lock on to the satellites. Based on a cold start GPS it may take 10-15 minutes to lock on and provide a current fix.
    • Portable Tracker... I've built several mobile and portable trackers. One of my favorites has been a new configuration of GPS, TNC, and RADIO. This system includes the DeLorme TripMate GPS, PacComm HandiPacket or PicoPacket, and Radio Shack HTX-202. It's completely self-contained, including built-in battery power, or can be powered via a cigarette lighter adaptor and 12vdc. The system is fairly compact, fitting inside a plastic lunch box. With introduction of Kenwood's new TH-D7A, which is an HT with built-in TNC, the tracker is even more compact because the only other accessory needed is a GPS. The new mini-modules including the Tigertronics TigerTrak TM-1 and Byonics TinyTracker II and III are TX modules with RX-desense and further the development of miniature trackers. Couple a small radio and GPS, and head out!
    • Mobile Operating... The setup for mobile ops is slightly different than described above, by adding a laptop computer (OK, you could use your desktop, but why?) and a newer model TNC (KPC-3 Plus), PocketTracker or other modern TNC that has a GPS connected to it, and the TNC connected to a laptop. There's also HamHud and other solutions to bring APRS into your vehicle. With these configurations you can watch your own progress, and update other stations running APRS.
    • Best of the Best Mobile setup: In 1998 Kenwood released their TH-D7A handheld 2m/440 with a mic encoder built in for APRS support. In late 1999 Kenwood introduced a mobile version of the radio called a TM-D700. It too has full APRS support. If you're looking for a King of the Hill setup, this is something to aim for. Add a GPS, and you have a fully functional APRS station and will watch the packets come in on your radio, and display their locations on your select GPS (Garmin serial port GPS not USB, or AvMap G4/G5), thereby eliminating the need for a laptop in the car. You can send messages using the handheld microphone, and watch other APRS stations on the GPS display. If you want the BEST OF THE BEST OF THE BEST APRS/GPS for your mobile, Kenwood upgraded the D700 to the D710 in 2007 and AvMap introduced the GeoSat 5 GPS. For around $1100 USD you too can experience the ultimate APRS mobile solution.
    • Global Positioning System...The GPS system is maintained by the U.S. Department of Defense and consists of about 25 satellites in orbit around the earth. Positioning information is determined by a small receiver which measures the time in micro-seconds that it takes to receives the broadcast from between 1-12 satellites. By receiving the signal from at least four satellites, position information down to about 10 meters can be determined. Also, altitude information can be obtained from the system. In mobile situations, speed and direction are also available. There are a number of commercial GPS devices available, with a number of different features. Garmin used to make a number of neat GPSs with lots of features for a very reasonable price, but production has switched to USB interface which is NOT compatible with APRS. You can still use the out of production Garmin III, III+, V, and Street Pilot Color models, and some others. Make sure the I/O interface is SERIAL. The AvMap G5 is another good choice but will cost you 6 bills. With it's 5" color display and full features, it's clearly to GPS of choice. You can also pick up a serial interface GPS puck which has no display, just outputs data, and still track on APRS.
  • APRS Weather Station Operations
    • A number of low-cost "home" weather stations can be interfaced with APRS to report live and up to date weather information over an APRS network. The display appears as a blue dot. Peet Brothers offers the Ultimeter and Ultimeter II weather stations; Davis has the Wizard weather stations. Radio Shack and others are available as well. Prices start about $375 for a nice station that includes rainfall collecting and reporting. 
    • The LaCrosse 2310 is very reasonably priced and is wireless based, reducing the need for running wires. The base unit connects to your computer via a serial port. You use the Heavy Weather software, which records data continuously. In UI-View you add the UI-Weather add-on, and select the Heavy Weather data file to import weather to UI-View, which then shares it on the internet or via RF with other APRS users. The weather data is also shared with the NWS through the CWOPS programs. Pretty cool stuff. 
    • A separate validation number is required to operate a WX station from APRSdos.
    • Davis Weather Stations also work with APRS, as do others, including those from Oregon Scientific. For about $350, OS will provide complete weather reporting, including statistical recording of data, that interfaces nicely with the APRS applications.
    • The NWS Pendleton OR office purchased and installed a remote weather station to experiment with receiving weather data over RF APRS, and incorporating it to their NWS NWIPS format. The development was successful, and now, in support of Homeland Defense initiatives, many weather stations in operation over APRS are feeding data to the NWS for their modeling and predicting of weather across the region. More cool stuff.
  • Bringing APRS to the EOC
    • WA State EOC, Camp Murray: The WA State EOC at Camp Murray has a full-time APRS station running WinAPRS and Precision Maps. The assigned callsign is W7EMD-3, and the station coordinator is Ralph/WB7VLW. 
    • WA: Mason County EOC, Shelton: Our first county DEM with a fulltime APRS station is Mason County, WA. The station is running WinAPRS with Precision Mapping and is set up to display the locations of all Fire Stations and Emergency Landing Zones in the county. The station call is KB7UVC-3 and Herb is its caretaker. They also have mobile trackers in the communications van (KB7UVC-1), their relay truck (KB7UVC-2) and a portable hand-held tracker on a TH-D7A (KB7UVC-6).
    • WA: Skagit County EOC: I don't have any info on this. Perhaps N7IPB will shed some light. This is the 911 EOC building.
    • WA: Lewis County EOC, Chehalis: An WinAPRS/Precision Maps station is in operation as of September, 2000.
    • WA: Thurston County EOC, Olympia: An APRS station is in operation as of June, 2000.
    • WA: Spokane County EOC: Will become operational soon.
    • MT: Custer County EOC, Miles City. Operated by K7TVE with APRS+SA. Thanks!
  • APRS and the iGate
    • An iGate is an APRS station that is connected to, and is forwarding traffic heard, up to the internet APRServe in Florida. The NWAPRS has several iGates located across the region, and includes home stations gating heard data up to the local servers, and onto the national servers..
    • If you want to see just a NWAPRS picture from the internet, edit the APRServe txt file in your APRS directory and add the following:

      montana.aprs2.net:14579 is the NWAPRS Tier 2 Server (this port feeds just NWAPRS)

      Then re-start APRS and select the NWAPRS link to see only the NWAPRS activity heard on the internet.

  • Northwest APRS WIDE Digipeaters 
    • Typical station setup: Radio, TNC, antenna, power solution. The TNC of choice is the Kantronics KPC-3 with APRS features. Other solutions can employ any TNC-2 compatible TNC and a computer running the DIGI-ned software package.
    • The NWAPRS system is all on one simplex frequency: 144.39 mhz.
  • Northwest APRS Coordinators
  • How to Join the APRS SIG hosted by TAPR
    • Send email to: listproc@tapr.org
    • Leave the subject line blank
    • In message body, type "subscribe aprssig (first name) (last name)
      • e.g. subscribe aprssig david dobbins
    • To unsubscribe, repeat above but change body to "unsubscribe aprssig"
    • WARNING: This list generates 50+ messages a day. As an alternative, you can subscribe to the aprssig digest. This is one email with the contents of all that day's email received.
  • Northwest APRS SIG List (saving the best for last)
    • To join, visit http://www.nwaprs.info/mailman/listinfo/nwaprssig
    • The list manager is pretty robust with features, and you can select if you want to receive each message as it is transmitted, or a daily digest of messages.
    • You can also choose to hold messages when you go on vacation, then start them back up when you return.
    • The list does not generate the enormous amount of traffic as the national SIG
    • We have some real experts in APRS among our group, and it's the best place to ask questions.