APRS Implementation Information
for ARES

Latest update: 04/14/07

There are many items to consider as you begin to work with APRS. Not the least of which is what computer you will use. If you are going to run a desktop then you are probably limited to running from your house and probably being a weather station or, if you have no other WIDE coverage area digipeaters within 20 to 50 or so miles, a WIDE Digi. (See digipeaters below before you even consider this). If you are going to run a laptop computer then you have maximum latitude in what you do.

The minimum recommendation is a Pentium I at 200 Mhz. You will find that to be the slowest most people will tolerate for interactive map work. If you have something in the Pentium II or above, it will make your experience much more pleasant. With that said, many people can run a weather station quite well with a smaller computer engine.

TNC - Yes or No

The next main option you will want to think about is if the computer has a full function sound card. Without that you must run a Packet TNC. If you decide to run a TNC, you then need to think about how close to total functionality you want. Many TNCs will work in APRS, but the Kantronics KPC-3+ is the fullest featured (at $160 it durned well should be).

The Second half of the TNC decision involves the ability of the TNC to run in KISS mode. If yours will, then the software you choose can be much more versatile. You say "What does this buy me?". In simple terms, it allows much of the work from the TNC to be done in your computer. Thus if you were to want to run both a weather station and mobile locator on the same TNC, with KISS mode this would be easy. Multiple applications can "share" the TNC when in KISS mode.

Above all, if you buy a new (at least to you) TNC to use for APRS, bring it up under Packet first. This will minimize the confusion and problems you will have. Many bald men started will a full head of hair but decided to do APRS with an untried TNC.

No GPS

While you are thinking about what you will put together, you can actually get a fixed APRS station on the air without a GPS and without standard APRS software. Berry, N0OYM, has a solution.

APRS Software

APRS software takes many forms. Major considerations are:

• No TNC - then you will probably run software like AGWPE.
  • Notes and schematic from KI0IO.
  • AGWPE for multiple PCs or applications
  • AGWPE Configuration PowerPoint presentation. YOU MUST have PowerPoint or the PPT reader to use this presentation (Microsoft has a free download of the reader).

  • Track Only - In Public Service Events (PSEs) there can be times when you need to track a vehicle or individual that is not, does not have a Ham Radio person. A handy device for that is the TinyTrack. This is NOT a TNC but rather a device that gathers GPS information, encodes it and passes it to a transmitter. If you are a good scrounger, you can put together a reasonable locating device for about $200 that can be put on the roof of the vehicle to keep track of the person or vehicle in question.

    Another option is the - just announced - "Pocket Tracker" from BYONICS. This unit requires an outboard GPS and nothing else! It is a low powered (no spec's out yet but it claims 100 hours of operation from a 9V battery) encoder and transmitter that fits in al Altoids can.     GPS, Altoids can with rubber duck - rock and roll!

  • Other sound card options - from Chris, KC0ATC are:
    • The soundcard modem software is called "soundmodem". You want the version that runs in "usermode", not the old kernel package. Soundmodem is not well documented and takes some patience to get it configured. It can be set up to feed packets to multiple downstream programs. http://www.baycom.org/~tom/ham/soundmodem/
    • For digipeating there is aprsdigi from http://www.users.cloud9.net/~alan/ham/aprs/

      Both of these are also available along with lots of other ham software for linux from http://radio.linux.org.au/ (You will probably need the packages ax25-apps, ax25-config, ax-25tools which are available from this site.)

      If you have an older PC with a soundcard then soundmodem, aprsdigi and xastir make a good setup. It takes more effort to get it all going. But it can all be had for free.

• TNC with Windows
  • UI-View - http://www.ui-view.org/
  • APRS
  • WinAPRS - http://aprs.rutgers.edu/WAPRSdoc.htm
  • APRS+SA(Windows version) This is an adaptation of APRS that supports Street Atlas(SA).
    http://www.tapr.org/~kh2z/aprsplus/Download.htm
    • APRS+SA comments from Larry, K0ANI

  • Palm Pilot (or generic)
    • Pocket Packet - - I would start with this one. It has links to Pocket APRS (just below) as well as links for other equipment.
    • Pocket APRS

  • Mac
    • MacAPRS - http://aprs.rutgers.edu/WAPRSdoc.htm

  • DOS (you need a newer computer)
    • APRS DOS
    • APRS+SA(non-Windows version) This is an adaptation of APRS that supports Street Atlas(SA).
      http://www.tapr.org/~kh2z/aprsplus/Download.htm

• TNC with LINUX

  Note: This code works with *MOST* operating systems and is compatable with maps used for UI-View! It also has direct interface with the D700. Thanks to Don, KC0QZR, for the information.

  • XASTIR This is open source code, compatable with USGS maps (that means topo capability) and is *free*. Well almost free. You have to compile the code on your machine.

MAP Software

Map software, like APRS software, has many variations. The most popular seem to be DeLorme, Street Atlas, Rand McNally and Precision Mapping. The cost runs from free with a GPS (Rand McNally) to $50 for either DeLorme or Precision Mapping. Yet another option is the DeLorme topographical version that runs $100.

With the Rand McNally or DeLorme version you will need to generate maps that are specific to where you want to run. These maps will need to have an .INF file to describe to the software the Lat/Lon covered by that map.

The cleanest (and easiest on you) is to run UI-View APRS software with the PmapServ option and Precision Mapping software. This provides coverage of the entire United States with detail down to the one tenth mile resolution (one half the screen shows one tenth mile of land). Total cost of the entire package is about $66 (it varies with the current exchange rate of US Dollar to UK Pound for UI-View).

The GPS

There are at least as many options in GPS as there are in any of the other considerations. They will run from as little as $82 to as much as $600. You DO want a GPS receiver with 12 or more channel receive capability. It takes three satellites to get lat. long. on your position and four if you want altitude. If you only have one channel then the GPS will have to establish contact with them ONE-AT-A-TIME (read that VERY slowly). The twelve channel units can have information from as many as twelve satellites going at once (I have seen units have three satellite lock in under fifteen seconds, where single channel units can easily take ten or twenty minutes).

A critical option is that the GPS output NMEA standard data. Without that you are not able to talk to most software available.
Garmin are top of the line, while Deluo are the least expensive yet seem to work.

Don't forget the interface cable. This comes standard with some units. You will need to look at the computer you will be running. Does your computer have USB connections?

• Yes - You can then run GPS interface cables that get the power from the computer's USB port(s) which saves having batteries in the GPS unit. You can also have a "normal" mouse rather than the "eraser on a stick" or "touch pad" types on laptops.
• No - You will need to run the DB9 Serial Port for this type and will either need batteries in the GPS or you will need to use the PS2 mouse port to power the GPS.

The exception to this is if you are running a Kenwood D700 and are going to connect the GPS directly to the D700. You then get power directly from the D700 via the interface cable and use the internal TNC. In this case there is a DB9 connection on the D700 that goes to the computer (watch out for male/female pins on the cable - this is a more exotic cable than some stores have - I had to make mine from two standard cables - pl).

Software Install

You will install your software per manufacturer / vendor instructions. There will invariably be a few items that will give you heart burn. Since I run UI-View I will share my experiences so that you will understand of what I speak.

Let me preface this with - Roger (UI-View author) did an EXCELLENT job with the software and instructions! But I did find a few little gotchas.

• Initial install and upgrade from 1.8 to 1.93 - very smooth
• Roger was - very - timely in his reply with the "password". Completion of 32 bit install was very easy.
• If you start with the 16 bit version (freeware) you will end up with TWO copies of the software on your machine. The 32 bit version goes in an entirely different portion of the sub-directory tree. I recommend you play with someone else's to decide if you want to do APRS and start with the 32 bit version AND Pmap.- pl
• Registration of the Precision Mapping software and the necessary UI-View to mapping software interface was not as easy.
• When you register with RegisterMyApp.com they tell you to write down specific information that was not displayed on the screen. To their credit, when I retried two more times, there was NO objection from their software. It turned out that they sent the information from the first two tries via E-mail. The third try displayed results on the screen.
• Once the mapping software is registered you can bring the software up. At that point it will ask for you to register it again (or so it seems). This is actually the registration for the mapping interface. You go (again - sigh) to the RegisterMyApp.com and enter the different product code and get a new password.
• You are now complete with most of the install.
• The Precision Mapping software does not install its maps on your hard drive. Once you find out that you do not have street level detail, you will go to their web site to find the FAQs. There you will find that you need to copy the map files (56 of them that take up almost 600 Meg) to the C:\PMAP50\STATES sub-directory. If you do not want the entire US then you can write them to find out which file(s) cover the state(s) you want. (Colorado is number 08 and Wyoming is number 56).
• You then copy in the map(s) you want on to your hard drive and bring up the Precision Mapping software. You then update the configuration option to tell it to look on your hard drive rather than in the CD drive.
• After all of that, operation is seamless. I highly recommend this map option - pl.

Initial Setup

Initial setup of your installation will vary only in the specific commands that you issue and the manner in which you have to enter them (varies with the software you use). The functions you will have to use are:

• Set communication parameters. These will include such things as: Baud rate (9600 works well - Remember this is NOT the transmit baud rate - this IS the rate between your computer and the TNC), Data Bits (many times 8) Stop Bits (many times 0) Com Port number and KISS or other protocol.
• Setup station information. - MYcall with SSID, Lat., Long., Beacon Comment, Frequency of beacon (in minutes), symbol for home operation and symbol for mobile operation.
• Verify status text (mine runs the software version number)
• Set up narrative about your station (name, location, E-mail address - anything [within reason] you are willing to share).
• GPS Setup - If you are running fixed, the Lat/Lon can be picked up from station information. Otherwise you need: Baud rate (mine likes 4800 - again this is NOT the transmit baud rate) Com Port number, "auto enable = yes" (saves you time and hassle) and the type of GPS you are running.
• Load Map - There is a specific way to turn on the UI-View to Precision Mapping interface under the "Load Map" option.
• Tactical Call - Tactical calls are available in UI-View and only take a few minutes to set up. See the UI-View help files for details

Have Fun

You are now at the point where, if you are running UI-View, you hear a very British accent announcing each station as they beacon (this can easily be turned off once everything is running to your satisfaction). This is very comforting as you begin because as you look, once more, at the documentation you hear YOUR machine humming along and doing its thing. Find a friend, or make a new one, that has APRS going. They will be able to answer many questions and save you some frustration.

Advanced Techniques

There are many items that many will not bother with and some will wish they had (once they find out how easy it is). A few of these include
(this section is under development):

• Kenwood TM-D700A: With the D700 setup and running mobile APRS, the GPS connected directly to the D700.
  You can get UI-View to use the D700 as the radio, TNC AND GPS by
  • Running UI-View 1.94, or later
  • Going to the "Setup Comms" menu
    • Set 'host mode' to NONE
    • Set 'Handshake' to NONE
    • Select the TM-D700 command file button
    • Use the "Edit D700 Commands" button to change the default frequency in the D700 commands file to 144.390 -THREE places- make sure you have the same number of digits in the number *after* you edit them as you had to start with.
    • Save the edited file! (Help screen pops up to remind you about saving the file, just before you get to edit the file)
  • Go to TNC setup
    • Set the TNC to the same COM port you have the D700 on.
  This gives you the UI-View map support with almost all of the same options you had before. You will not be able to display the GPS input because the GPS is connected to the D700 rather than the computer for UI-View to see. You will also see a GPS "input" line displayed where the other stations input is displayed. Works great!
  If you wish to go back to mobile APRS without the messaging and map support:
  • Bring down UI-View
  • Turn off the GPS
  • Turn off the D700
  • Turn on the GPS
  • Turn on the D700
    • Look to see if the D700 came back to APRS mode. If not then push "F" then TNC.
  Sha-zam Batman. It works

• Other Input??
• .

DigiPeating

This segment is under development and input and/or corrections are solicited!

Digipeating (name derived from - Digital Repeating) is the process whereby we extend the useful range of VHF/UHF communication within Packet. In APRS digipeating is your entry into the "network" of stations that function together to provide features that would otherwise be unavailable. There are several strong implications in that statement. Since you are going to function as part of an unconnected network (anyone can function within a connected network because the protocols enforce compliance) it is important that you understand the potential impact your station (in the form of your activity on the "channel") will have.

You can minimize your impact on the frequency by remembering just a few pointers. Let's start with how Packet and APRS differ so that we can better understand how to "be a good neighbor".

• Packet
  • You establish a connection (log entry) with another station
  • Your call and the call of the station you are talking to are included in every packet.
  • If you cannot hear them directly, you connect to them VIA another station (that can hear both of you) or via multiple stations, each being able to hear the "previous" and "next" station.
  • All calls (or alias) must be known to establish connection. This is known as the "Path".

• APRS
  • APRS relies on the Unconnected Information (UI) frame (packet).
  • Most information in APRS does not go to a specific station, rather it is broadcast for everyone to hear.
    The exception is when you are using the text messaging and that requires you to know the other stations call (with SSID) and any Digipeating station (with SSID) in the path.
  • Your call and any other information you want (usually Lat./Lon. but sometimes other data) is appended.

Once you look at the descriptions above you say "How do I talk to distant stations?". Easy. APRS uses "generic call" addressing (aliases). There are six aliases used by those doing APRS digipeating but only three are of use to us. They are "Relay", "Wide" and "Trace". Keep in mind that these are your primary "VIA" addresses. Well if there are only three, how can it be complicated? Let's look further:

• Relay - Used by mobile stations to get to the next "Wide" station. This is important! If you are mobile and start your digipeating string with "Wide" and are not heard by a Wide station, your information is lost. Use relay only once.

• Wide - Wide should be run by fixed stations (non-mobil) with good antennas running comparatively high power (25 to 50 watts). The purpose of a "Wide" station is to provide communication over distances of more than twenty five miles (some, like WA0BAG-5, can handle distances up to almost 100 miles, because of the H.A.A.T.)

• Trace - Trace is used by "Smart" digipeaters to track the route a packet took. The digipeater will add its call to the digipeat list as the packet is re-transmitted.

Please NOTE: Both WIDE and TRACE can have an option of "n-n". A digipeater that supports "n-n" will digipeat any "n-n" packet that is "new" (to that digipeater) and will subtract 1 from the number to the right of the dash until that number reaches -0. The digipeater keeps a copy of the packet and will not digipeat that packet again within about the next twenty eight seconds. This considerably reduces the number of superfluous digipeats in high density areas.

You will set up your digipeat aliases as 1) Your call and 2) either Relay or Wide (depending on if you are mobile or fixed). Or worded differently:

• MOBIL = your-call,RELAY
• Fixed poor digipeat location (most of us) = your-call,RELAY
• Fixed excellent digipeat location (like W0AVV) = your-call,WIDE

You then set up your UNPROTO address to something like APRS,RELAY,WIDE or APRS,RELAY,WIDE3-3 (which replaces APRS,RELAY,WIDE,WIDE,WIDE) if you are mobile and reduces the digipeat duplication (see above on n-n). The character string "APRS" in the UNPROTO address is to maintain compatability with those pieces of software that use those characters to convey other information.

What does all this mean? You are probably going to have an UNPROTO of "APRS,RELAY,WIDE2-2" or "APRS,RELAY,WIDE3-3" (without quotes).

Spend some time in APRS and learn your local network before you turn on digipeat.

DigiPeating with a UI-View slant.
http://www.hulleng.karoo.net/g0vrm/content/aprs/digi.htm