Presentation on theme: "Introduction to APRS By Guy Story, KC5GOI "— Presentation transcript:
1 By Guy Story, KC5GOI www.kc5goi.net firstname.lastname@example.org Introduction to APRSBy Guy Story, KC5GOIIntro myself, talk about TDD, winning APRS FD in 1998.
2 Topics to be covered What is APRS? Why do I want APRS? How do I view APRS?OK, now how do I go mobile?Current softwareThe internet piece of the puzzleUpcoming goodies
3 What is APRS Automatic Position Reporting System By Bob Bruninga, WB4APRBrief historytell about how Bob originally used it to track boat races.
4 History of APRSInitial use as we know it in 1990 to track boats during summer cruises. The following flavors followed.MacAPRSWinAPRSAPRS+pocketAPRS just releasedPerlAPRSXAPRS released as beta at 1999 Dayton Hamvention
5 Why do I want APRS? For Starters…. Ok, Joe Ham tells me he has a bike rider down but has no clue were he is.Or, Joe Ham has hail coming down and still has no clue were he is.Joe Ham is part of a disaster evaluation team.elaborate on uses, Skywarn, bike rides, Red Cross assistance, general public service, balloons, DF, messaging
7 Software There are many flavors to APRS DOS APRS WinAPRS and APRS+SA MacAPRSXAPRS for Linux (currently in beta)pocket APRS (Palm Pilot)APRSdigi, digi softwarePerlAPRS
8 OK, now how do I go mobile? TNC route Mic-E route Pic-E route GPS receiverDo I have/want to use a laptop?address laptop configHSP, PCM serial port card or a tnc with software serial port.
9 Mobile Equipment tell about each item starting with mic-e and gong clockwisemic-egps engine for mic-etncpic-etalk about laptop and serial port issues.
10 TNC Verses Mic-E or Pic-E TNC route requires a separate radioMic-E and Pic-E can go in-between radio and mic.Either route can be run on separate radioEither route is referred to as a “TRACKER”
11 Definitions A tracker is a mobile station Posits are position reports UI Frames are frames that do not employ error correction techniques, entirely that is.Digipeaters are stations that act as a simplex repeater except in a digital formatIGATES are stations that feed data to and from the internet
12 DefinitionsGATES are stations that take the HF APRS data and retransmits them on VHF and possible the internet.APRServers are stations that IGATES send data to and redistribute them to the IGATEs
13 How does it work, basically? A tracker or fixed stations sends out a UI frame that has lat/long and possibly other data.If the packet burst passes the checksum, the info is then displayed on the screen.If the checksum fails, the packet is lost. This is not a big deal since the posit will be transmitted again soon.Check sum failure: if the checksum does fail, the fact that the packet will be retransmitted in a relativly short time frame will improve chances of the packet being received.
16 The Next Level IGATES, why would I want to do this? IGATES provide a feed to the net so everyone can see what is going on and allows for messaging on a world levelBalloons, mobile stations, weather events you want to track, using automated watch/warning data to transmit in your area.
17 What else can I do with APRS Connect your weather stationDF abilitestrack vehicles (balloons, trucks, space vehicles, hurricanes)messagesPropagation, PropNet
18 Guy Story:W8XF baloon launch on The X indicates max altitude achieved.
20 Digipeater does and don’ts Don’t use wide, wide wide or relay, wide, wide. This can lead to channel saturation due to uneeded duplicate packets.Use no more than 2 wides or a wide then a relay in a unprotopathUse discrete calls when possible.Alias’ can be used but with restraint.Base stations need to use discrete calls in unprotopaths after a path has been determined.The digis located on this page are all at high altitudes. Unless you are the only station in the area, homes or stations that are at lower altitudes should not use WIDE in the alias list. Relay is prefered. All other stations on this page are home stations or at city facilities.
21 Other station tips What is my tnc deviation? The target is 3 kHz deviationGreatly improves channel throughput.Go to for more data.Open squelch??????Hidden and deaf transmittersDeviation is probably one of the most aspects of packet. If the deviation is not set right then the tones may not get decoded correctly if at all. The end result is increased activity on the channel for the wrong reasons. The retry rate goes up dramatically.Can you run open squelch? Many tnc’s can be modified to do so. This will increase your ability to rx weak signal stations. This helps reduce collisions and reduce the turn around to ptt time. Reduces hidden transmitters.A hidden transmitter is a station that few people can hear. This is why hts are not ideal.Deaf transmitters/trackers. Please avoid if you can. While it is not discouraged to use deaf transmiters it hurts channel througput. A deaf transmitter does not have the abiltiy to hear if the channel is active or not. This will cause a collision.