Automated Packet Reporting System (APRS)

APRS is about exchanging tactical information in real time. This information may be weather reports, Small Messages Service, Repeater advertising, status reporting, telemetry.

The Network

This can be accessed either by radio or the internet, depending on what you want to do We have 2 servers here in ZL, you can connect to either of their address’ which will be in the software you use. If you want to transmit data on to the APRS Internet based network you will need a validation number from Philip at This e-mail address is being protected from spambots. You need JavaScript enabled to view it

To connect via radio you will need a TNC of sorts, the 2 common bits of software needed are KISS (Keep It Simple Stupid) based, and of course a radio. We have a UIDigi repeater on 144.575 simplex, and you will need to be able to receive at least on this frequency. Because APRS is done using un-connected packets, you do not need to be able to transmit back to acknowledge each packet. It is a broadcast system.  We also have an IGate ( ZL2KO-1 ) this is a PC sitting at home here which connects our radio, local and several UIDigis to the internet and provides traffic in both directions. Currently ours is set up to only digipeat traffic from the internet that is within 200km of Palmerston North.

What you need

Software

I will talk about only 2 bits of software. The old UIView, I need to use this as the iGate. This uses local maps which you can either download or make your self, I would not recommend it for anything else other than iGate. Don’t leap in and fire up an iGate, talk to me first please.   My choice of software is AGWTracker. This can be downloaded from http://www.agwtracker.com/. There are a full suite of programmes that support other packet things other than APRS.

For the Internet.

Well you need an internet connection, yes if you go carefully and limit what you ask for you can use a dialup connection for live data, BUT if you ask for all the APRS traffic out of the USA, it is going to take a LONG time to happen.  There are multiple places to go to pick up APRS info on line, but the one at the top of the list at the moment is http://aprs.fi. Follow your nose.  If you want to run a local session rather than a www page, my pick of software is AGWTracker, check the www site referred to above. There are several bits to this:

• AGWTracker – the main application, you need it
• AGWPE – Packet Engine, you will need this if you are running any sort of radio interface
• AGWMonitor – handy in that it allows you to see all traffic
• AGWTerm – Terminal emulator, not much use around here
• UIDigi – for the moment forget about this

OK, to run AGW-Tracker talking to the internet, download it, install it how ever, do the basic configurations under setup and then under actions “connect to APRS server” choose a ZL one. That is it !!!   Over on the monitor window you should see traffic coming in off the internet, the stations tab will start to list these stations, then choose a map tab and open Google Maps and away you go !!! Simple as that.  Once you have connected to the APRS server have a look at the status page of the server http://aprsnz.aprs2.net:14501/, ( if you are connected to “…aprs2….” ) you will see the status of your connection.

For the radio

If you want to use a radio you will need to configure Packet Engine, this is a little program you run before you start AGWTracker and it stays in the tray, you will need to configure it to use your TNC or its own sound card drivers. I could type a few pages on how to configure this, but I am not going to !!! Give it a go, if you get stuck, email me. If you are using a TNC, when you start it, it should flash its LED’s 3 times ( or whatever ) to show it has gone into kiss mode. When actioned, connect the packet engine, and away you go.

A tracker in your car

OK a tracker is made up of a GPS generally (there are other ways) some sort of device acting as a TNC and a radio.

Tiny Tracker 3, this device uses a PIC in a transmit only function, but it will detect a busy channel and not transmit over another station.

Tiny Tracker 4, this uses a bigger PIC and you can load different types of software on to it, like RTTY, CW, PSK31 etc… it does receive as well

Open Tracker. Fits between these 2 and uses a simple PIC and will receive as well as send. These kits are sometimes available in NZ or go and have a hunt on the internet.

A tracker with receive, what does this do? OK it decodes the packets it hears on the radio and formats them and sends them back to your GPS (dependant on type and function) and puts the other station on your GPS display, remember we said this was tactical information, I.E. knowing where other objects are in relationship to you.

What sort of radio

Nothing very flash here, in the most basic, just a transmitter… Other choices might be FT2b, T198, T498 etc, any VHF FM voice transceiver will do fine. It doesn’t take much, as we are only running 1200 baud packet, a mic and speaker connections work fine.

A GPS

So you don’t own a GPS, maybe it is time to buy one. If you are going to buy a handheld unit with a screen, first thing to look for is a serial port, as long as it outputs NMEA sentences you’re away, it would be good if it received them as well. If you are looking at one, it needs to support NZMG (New Zealand Map Grid) and Geodesic Datum 1949, as this is what our CURRENT maps are in, BUT, come September we will have a new grid and datum, so make sure your model can be upgraded, or stay with the old maps, put up with some error or less error and use a different grid which is closer (WGS 84) again, I could type pages on this stuff. Let Google be your friend. The other thing is an external antenna port, this makes a huge difference to coverage.

In my car I have a little “puck” type receiver bought in ZL for $82 delivered overnight, this does just fine and without an external antenna. So that is pretty much it, give it a go and see how you get on. For support, try emailing me or there are a couple of yahoo groups that might help AGWTracker and ZLAPRS. See you there.

If you need any help with getting set up you can contact Max via email at: This e-mail address is being protected from spambots. You need JavaScript enabled to view it