VE6MVP's Beginners Guide to APRS

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(Last updated 2013-01-08)

APRS (Automatic Packet Reporting System)

"APRS was developed by Bob Bruninga, WB4APR, as a real-time local tactical communications system for rapidly exchanging digital data of immediate value to operations."  APRS is mostly  known as a system for using radios, GPSs and, optionally, the Internet to transmit position and weather reports as well as messages.    There are quite a number of other uses for the basic concept.  One of the other uses I quite like is the ability to send messages via the APRS network.

One of the greatest needs at emergencies or special events is tracking equipment or people.   Such as the race leader and the tail car or the Salvation Army canteen truck.   These units can be permanently installed in vehicles or carried around in lunch boxes with a HT, GPS, an interface box, a battery and an external rubber duck antenna. 

You can also view the APRS data either from your radio or the Internet by using software.  See the NWAPRS External Links page and WE7U's APRS Client Capabilities Chart    Internet sites to view the positions of hams and objects are APRS.FI, OpenAPRS, APRS World or  Findu.com.

An excellent website with much detail is the Northwest Automatic Position Reporting System (NWAPRS) This loosely knit group is among the trend setters in the APRS world.   I'd strongly urge you to join their mailing list.  A good FAQ page is at http://www.nwaprs.info/faq.htm.

The two most popular mobile APRS systems are the Byonics TinyTrak and the Argent OpenTracker.

VE6MVP's Beginners Guide To Setting Up Your Own APRS Digipeater Unless you know there is a local dead spot for which you feel a digipeater would be useful or there isn't an APRS digipeater for 60 or 80 kms then don't go to the effort.  Duplicate digipeaters with lots of overlapping range just add packet noise to the frequency.

Running an Igate could be a very useful idea.  In an urban environment they will pickup local packets that don't quite make it into the local digipeater.   In the rural areas, even if there is another within a hop or two redundancy is welcomed.   One good program for such is APRSISCE/32.   I do not recommend UIView any more as the author of the software has been dead for a number of years and the source code is not available so the program can't be updated.

Sending messages via APRS

While the position reporting of vehicles and objects is the most used feature of APRS I feel the most valuable feature is the ability to send messages via APRS.   For example using the Garmin Nuvi 350 and the T2-301 mentioned below I can exchange messages via igates with anyone anywhere.  By configuring AB7-7 as a path I can ensure that messages will go further than just two or three hops, even if the Internet is down, and indeed blanket the entire province.  

Note - do not use AB7-7, or your state/province/region paths, unless for testing or in a disaster.   You will congest the network and be considered very annoying if you use this on an everyday basis for position reporting while mobile.   

You can also send, but not receive, emails via APRS.  Rather than putting a recipient call sign at the beginning of the message put in EMAIL <insert email address in @ format> and then your email text.  

I've created a wiki page for interested amateurs in Alberta.  APRS Message Recipients.

Software and hardware I am using as of January 2013.

This list of equipment is, of course, subjective.  There are lots of choices out there.

APRSISCE/32 is the software I'm using to watch for local traffic, igating and sending and receiving messages.

APRSDroid is installed on my Android tablet so I can watch for nearby traffic when I'm not at my computer.   However my current tablet does not have a built in GPS which is a pain when I'm travelling and want to watch the local APRS traffic.  I can enter the local coordinates but sheesh.

Kenwood D710 radio.   Very nice unit and does just about everything I want it to do.   I use the A side for APRS and the B side is either on the repeater I'm talking/listening to or scanning.  One advantage the D710 has over the Yeasu FTM-350 is that you can send data to the radio for it to transmit.  The FTM-350, at this time, can only receive APRS packets to the PC.   I purchased a USB cable on EBay for it.   Note that you don't need the Echolink cable unless you want to use it on Echolink.   I have also used the D710 TNC for VHF email using the Winlink 2000 system.

Argent T2-301 data radio.   Note that it is recently obsolete and you would now want the the T3-301 for the same price.  I also have the Argent serial splitter cable so I can hook up a PC to it at the same time as the Nuvi GPS.  You can also configure this device as a digipeater.   For example I can put this device on a hilltop with a battery, duct tape an antenna to a tree and it will work for days or a week allowing anyone to exchange APRS messages.

Note that the PC MUST be on the red port A of the serial splitter cable to do any configuring.  Thus the Garmin GPS should be on the blue port B.   If you should get those mixed up in the configuration program you can send commands via the Garmin GPS to the OpenTracker device to change the port from Garmin to serial mode.  Yes, I found this out the hard way.  <sigh>

Garmin hockey puck GPS with a serial cable end.  This is used for either the Kenwood, with the appropriate adapter cable, or the Argent T2-301.

Garmin Nuvi 350 GPS.  Yes it's obsolete and can only be purchased on EBay for about $60 or so.   But I really, really like it because I can see what other APRS objects are nearby on either the list display or the map.   I can also send and receive APRS messages on it.  Note that you must use a special Garmin data cable and the cradle to get it into Garmin Fleet Management mode rather than standard consumer GPS mode.      I also purchased the GA 25MCX external antenna on eBay.  This way I can tuck the GPS out of external view and still get a good signal.

You will want the Garmin 010-10813-00 Mini-B Data Cable if using the Nuvi 350 with the T2-301 or, very likely, the T3-301.   If with the Kenwood D710 then, I think, you want the GTRANS Garmin to NMEA Translator Cable (Kenwood Style)

The Nuvi 350 GPS and the $500 or more Avmap Geosat 6 APRS are, to my knowledge, the only GPSs that handle APRS properly.

Hardware I need or really, really want.

I really need a low voltage/timer cutoff device such as the APO3.   I've found the APRS gear appears to use more amps than they really state they do.  (Or maybe I need a new auto battery. )  The shutoff timer is useful to get one last beacon when you are stopped for a while.   And as soon as you start your vehicle it will start up the APRS gear and GPS.  This is particularly useful if your vehicle is stolen.     By having the GPS screen and/or radio display tucked away out of sight the thief will never know that you know where the vehicle is.

Kenwood TH-D72A.   Hand held with built in GPS and APRS and ability to send/receive messages.  Sweet!

Or maybe the Yeasu VX-8DR

Credits

Comments and suggestions from Ray VE6RHS, Curt WE7U, James VE6SRV, Bob WB4APR and David AD6ME

Website copyright 2004-2013 Tony VE6MVP