Why We Are Here APRS is a powerful tool for emergency management Readiness requires skilled reserve of Hams
What is APRS Automatic Packet Reporting System Packet communication protocol for sharing live data on a network in real time Real time tactical communications and display system for emergencies and public service applications (APRS Spec)
APRS Features Maps Messaging Objects Bulletins and announcements Weather station reporting DX Cluster reporting Internet access Telemetry Voice Alert
History Invented by Bob Bruninga, WB4APR in 1992 The Automatic Packet Reporting Sys- tem was designed to support rapid, reliable exchange of information for local, tactical real-time information, events or nets.
History APRS for DOS was the first program MacAPRS & WinAPRS 1994 by Sproule brothers UI-View—best & most popular Many other APRS apps since – runs on Windows 3.x, NT and XP, Mac, Linux, iPhone, Android and DOS GPS adjunct came afterwards
Uses Passive Fun –Watch the display of many stations –Watch the ISS or PCsat fly by –Watch emergencies in action Tracking –Find your buddies –Track your teenager, wife –Balloons, rockets and public service events –Meet hams spontaneously on the road
Uses Telemetry –Balloons and rockets Post bulletins, event notices and venues Send short messages Send email
More Uses Events –Track the parade Grand Marshal –Track the last marathoner or bike racer Emergencies –Search and rescue –Disaster information –EOC messaging (Single Line) –Track the fire chief
Still More Uses Weather monitoring –See wind speeds and temperatures in the area –Report wind damage –Track tornados
Weather monitoring Users can create and move objects such as hurricanes and funnel clouds. The objects can be transmitted through the APRS network to the NWS Objects could be used to transmit attributes not quantifiable as a number Collection of data Trending Weather Data Weather Alerts from NWS Superimposed RADAR
Theory Assumptions Packet radio Digipeaters APRS Protocol Frequencies GPS
Packet Radio History –AX.25 protocol was approved by ARRL in 1984 –Came from X.25 protocol (the A is for Amateur) –Primary difference from X.25 is allowance for call signs and for unconnected packets
Packet Radio Packets –Strings of data bytes called frames –3 kinds of frames in ordinary packet Information (I frame) Supervisory (S frame) Unnumbered (U frame) –6 kinds of U frames, one is Unnumbered Information frame –UI frames are used for transmitting data in an unconnected mode
Packet Radio In packet radio, qso’s are always between ‘connected’ stations Several qso’s can take place simultaneously on the same frequency Packet qso’s may be digipeated but by specific stations
How is APRS different from Packet Radio? Communication is ‘one to many’ Uses generic digipeating with well- known aliases Supports intelligent digipeating to reduce network flooding Uses UI frames for messaging, bulletins and announcements Provides maps and other features
How APRS uses Packets Uses the same AX.25 protocol but only a part of it Uses Unnumbered Information (UI) frames exclusively Always runs in connectionless mode
How APRS uses Packets Frames are transmitted without expecting any response Reception is not guaranteed Messages work same way but use an ‘ack’ technique
Destination Address The adr ‘SPCL’ is to be used for special events. APRS s/w should provide for only showing stations with this adr (but it doesn’t). Usually just shows the software version. WinAPRS v2.6.1 sets this to APW261
An Intervening Word about Digipeaters Why do we need them? –Increase coverage Digipeater versus repeater –Voice repeaters operate in duplex mode –Digipeaters operate in simplex mode –Digipeaters use store and forward technique
Digipeaters Wide area digipeaters –In this area are usually on a tower –Have good antennas and high power –Operate automatically –Operate all the time –Have Battery Backup
Digipeaters Fill-In digipeater –Usually somebody’s home station –Should be able to communicate with a WIDE station –Purpose is to help low powered stations get to the WIDE
Digipeaters WIDE –Examples: KF7VJO-3 …or not –Examples: W7BOZ
FIX #1: Phase out RELAY and WIDE Paths (also eliminate TRACE, TRACEn-N): The single biggest improvement in the USA was simply getting users to stop using the obsolete RELAY and WIDE paths. The obsolete RELAY and WIDE paths generated multiple dupes in the KPC-3 and PacComm and some other implementations because there is no dupe elimination for dupes heard from other digis.. These obsolete paths generated 3 to 5 times more load on the system than the comparable WIDEn-N path which has perfect dupe elimination algorithms. The fix was easy. Use WIDE1-1 in place of RELAY and WIDEn-N in place of WIDE.
FIX #2: Make WIDEn-N Traceable : The original WIDEn-N system was not traceable, making it impossible to do any network assessment or management.. The New-N Paradigm made WIDEn-N traceable!.. (By eliminating TRACEn-N, Sysops can now move WIDEn-N support from the UIFLOOD parameter to the UITRACE parameter.)
FIX #3: Use WIDEn-N everywhere. The New n-N Paradigm Solution: WIDEn-N is the most efficient APRS path, but it is vulnerable to out- of area QRM from user settings of large values of N.. Fortunately, under the New n-N Paradigm, existing digis now trap large-N abuse and greatly simplify user recommendations to simply one WIDEn-N path.. The New n-N Paradigm simplifies the APRS network to a few distinct digipeater types: WIDEn-N..- The basis of the New n-N Paradigm. They also support SSn-N for state nets (S overlay). WIDE1-1...- Fill-In digis (where required only). Set these fill-in digis MYALIAS to WIDE1-1. One-Hop.. - These digis force big-N packets to 1 hop in extreme density areas. (LA or Dayton for example) PacComm. - These old "T" digi ROMS can still be used locally for up to WIDE2-2 support (with P overlay)
Fix #6, Proportional Pathing for DIGI beacons! One of the biggest loads on the network prior to this New-N Paradigm was simply the flooding in all directions at all distances of the individual DIGI beacons. Many digis were sending out their beacon to 4 and 5 hops in all directions every 10 to 30 minutes. There is no need for this spam.. So part of the New-N paradigm was to come up with the Proportional Pathing algorithm that kept the information update rate at 10 minutes in the immediate direct range of the digi so that passing travelers would be informed, but then the rate was much less for more hops to cut overall load on the network and out-of-area spam.
Back to the UI Packet -- Digipeater Addresses Also known as the ‘unproto path’ Up to 9 addresses Specific or generic aliases Specified in s/w configuration or in the UNPROTO command: APRS V WIDE1-1, WIDE2-1 Represents the route you want your packet to follow
Digipeater Addresses Rules of thumb –Don’t use RELAY –If you can hit a wide, then include it as the first digi in the string –For maximum range, add WIDE2-2 or WIDE3-3 after a specific DIGI Examples: APRS V KF7VJO-3, WIDE2-2 APRS v WIDE1-1, WIDE2-2 APRS V WIDE3-3 Anything MORE than 3 should be avoided!
Digipeater Addresses –You can be really specific about the path Example: APRS V KF7VJO-3, REDSPR, BLKMTN would route you up to Star Valley, nowhere else
Types of Data There are ten main types of APRS Data: –Position –Direction Finding –Objects and Items –Weather –Telemetry –Messages, Bulletins and Announcements –Queries –Responses –Status –Other
Hardware –TNC cables Computer serial port to TNC –Unique to your TNC TNC to radio mike connector –Unique to your TNC and radio
Hardware Consideration for GPS with TNC –2 serial ports are needed (Unless KPC3+) –If only 1 serial port is available, can use a “Port sharing” device
Hardware GPS Receivers –Must have PC interface port –Must output NMEA messages on the PC port –Good to have an external antenna for the GPS –RS-232 or TTL
Software WinAPRS –Pros Everybody knows about it Free maps Can use high quality Precision Maps Unregistered version has full functionality
Software –Cons Help function is bad Not totally stable Not everything works Maps aren’t so good Expensive to register Somewhat limited in scope
Software APRS+SA –Pros Comprehensive functionality High quality Street Atlas maps
Software –Cons No (I said no) help Hard to manipulate maps Confusing Only works with Street Atlas Have to register to use AGWPE Expensive to register
Software UIView –Pros 16 bit version is free, 32 bit version is free too but they request a donation. Quality coding Extensive help files Any GIF or bitmap file can be a map Works with Street Atlas and others Detailed Street level Mapping with Precision Maps
Software –Cons Limited Individual Replay options Author has passed away and sotware no longer supported
Software Xastir –Pros Works on Linux Good map capability –Cons Not a Windows program
Software MacAPRS –Shares same code with WinAPRS
Software APRSICE/32 –Pros Follows WB4APR’s APRS spec very well Maps are available Connects to the internet –Cons Has to be connected to the internet to get maps Hard to configure. Especially to use on RF
Software My recommendation –Use UI-View with Precision Maps 8
Satellites ISS –Excellent signal PCsat –Built by Bruninga’s students at Annapolis Find the satellite’s position –http://liftoff.msfc.nasa.gov/realtime/JT rack/Spacecraft.html
Another way to view APRS Internet APRS.FI –http://aprs.fihttp://aprs.fi –Great online tracking source. –Does dead reckoning FINDU – http://map.findu.comhttp://map.findu.com Struggling to find a free mapsource
Voice Alert Have you ever driven on an all day trip and never found anyone to talk to? Have you passed someone with antennas all over the roof of his car, yet, can't raise him at all? Have you tried to look through the Repeater Guide to help you find a local QSO repeater, but find the listing of 10,000 mostly silent repeaters daunting, especially while moving? Remember, statistically, one out of every 500 cars you pass is another ham! On some interstates, that is one every 10 minutes.
Voice Alert Now, imagine a HAM radio radar that automatically alerts you to other mobiles in simplex range, or a dual band radio with a permanent 3rd full-time nationwide Voice Alert CALL channel that is always on. Driving the interstates with such a radio would guarantee you a new LOCAL contact on average about every 10 minutes or so! Amazingly, such a radio does exist, in fact, two of them. Thousands of HAMs have them and most use them every day. But unfortunately, many of these owners, do not fully use the radio to its full potential on the open road and most of the rest of us are unaware of their amazing functionality. The radios, of course, are the Kenwood TH-D7A(g) Handheld the TM-D700/710 and the Yaesu FTM-350R APRS mobile radios. (And any other APRS radio with the TNC connected directly to the discriminator).
Voice Alert But in the year 2001 or so, we realized that EVERY single APRS mobile operator out there was driving around with a radio guaranteed to be ALWAYS listening on the same North American Continent wide channel, 144.39. The only problem was they all had the volume turned completely off (who wants to listen to a wall-to-wall packet channel while mobile?). Well, it only takes about a second's thought to realize that if we simply turned up the volume to normal level, and set CTCSS-100, then the speaker would still be ALWAYS QUIET, but if someone in simplex range did want to call us, then he could do so with PL-100 and we would always hear the call! Think of it as a 3rd radio in the car. Always on, Always listening for simplex calls, and yet completely silent at all other times. We called this great concept "Voice Alert".
Important Links NEKSUN APRS http://www.k0ham.com/aprshttp://www.k0ham.com/aprs Tucson Amateur Packet Radio (TAPR) – http://www.tapr.orghttp://www.tapr.org NWAPRS – http://www.nwaprs.orghttp://www.nwaprs.org Bob Bruninga WB4APR’s site - http://www.aprs.orghttp://www.aprs.org Tiny Trak - http://www.byonics.com/- http://www.byonics.com/ Web Tracking - http://aprs.fi- http://aprs.fi Another Web Tracking - http://www.findu.com - http://www.findu.com Yet another Web Tracking - http://www.aprs.net- http://www.aprs.net Open APRS Website - http://www.openaprs.nethttp://www.openaprs.net ARPRICE/32 - http://aprsice.wikidot.com- http://aprsice.wikidot.com UI-View Web site - http://www.ui-view.org- http://www.ui-view.org Balloon/Rocket tracker - http://www.bigredbee.com- http://www.bigredbee.com Argent Data Tracker - http://www.argentdata.com/products/aprs.html http://www.argentdata.com/products/aprs.html WA8LMF Website - http://www.wa8lmf.net/ham/index.htmhttp://www.wa8lmf.net/ham/index.htm K9DCI APRS Beginner Guide - http://k9dci.home.comcast.net/APRS%20Beginner%20Guide %20-%20K9DCI%20Ver%205-1.pdf http://k9dci.home.comcast.net/APRS%20Beginner%20Guide %20-%20K9DCI%20Ver%205-1.pdf