EI7IG's APRS Page

Last updated: 20080222

APRS In Ireland

We have a 'fledgeling' APRS infrastructure here in Ireland, mostly concentrated in the South, South East and East of the country, with a few pockets of activity elsewhere.

Automatic Packet/Position Reporting System was developed by Bob Bruninga, WB4APR, for tracking and digital communications with mobile GPS equipped stations with a two-way radio (check out the APRS Wiki). I am involved in ongoing experiments with APRS in Ireland using a variety of devices including the TinyTrak Pocket Tracker from Byonics, I purchased the pocket trackers for members of TARG for use in AREN activities, and , more recently, the OpenTracker and the prototype OT2 (OpenTracker2).

APRS Snapshots

This is a snapshot of APRS activity in the country. It is automatically generated from an Xastir instance running on my home machine. It updates itself every 5 minutes. Note the Met Eireann supplied weather information (more information below).

Xastir Snapshot

This is a snapshot of APRS activity near my home location. Using the facilities of aprs.fi.

General Irish APRS Information

John, EI8JA, (the SEARG equipment keeper) and I have decided to follow the WIDEn-N Digipeater Paradigm. There are currently(as far as I'm aware), permanent Internet Gateways in Dungarvan, Waterford and Dublin, that service the existing infrastructure. It is currently recommend to use a UI Path of WIDE1-1,WIDE2-2 for all mobile stations, as this should ensure RF Coverage of the entire Country. Drop me an email if you don't agree and we can have a chat about it.

APRS Internet Servers

The APRS-IS is an Internet-based backbone network which interconnects APRS radio networks. The core network consists of three (two now?) first-tier servers and numerous second-tier servers, providing a unified worldwide APRS stream to connected clients.

Purely for practical reasons (aggregation), not political ones, I maintain a Tier 2 server ireland.aprs2.net, which allows Irish APRS Internet Clients a common aggregation point.

Weather Information

Cormac, EI4HQ has spent some time and effort in order to 'process' the Met Eireann supplied weather data into a format suitable for APRS transmission. All the information is freely available from the Met Eireann web site. For the Weather Radar Overlay, I found somewhere (that I don't remember) a Google KML file which had co-ordinates for the Met Eireann Radar Image. After some experimentation I came up with this .geo file for use with

Irish Maps

Here are some maps made available courtsey of Tim, EI8IC. I added the .inf and .geo files in order that Xastir and UI-VIEW can use them.

I have also generated a map of the entire country, with a geo and inf, and the South East with a geo and inf files.

APRS Hardware

The OT2

The OT2 builds on the functionality of the current Opentracker:

The OT2 adds to the above by adding: Industry standard 1-Wire interface (currently not tested). It responds to position queries, both general and directed. It receives incoming position reports and generates waypoints to send to the GPS - either in NMEA mode, like the Kenwood TM-D700/TH-D7, or in Garmin or Magellan protocols. Both of those will select the best match for the symbol, and will include comment text and altitude (in the elevation field.) Some Garmin units will support custom waypoints, so you can upload actual APRS symbols. It currently ACKs text messages. In the future it'll be able to control relay outputs through remote commands, passed in the form of APRS station-to-station messages so that they'll be Igated properly. Strong authentication will be supported. The OT2m board has a space for a 20-amp high-side switch, currently unpopulated (supplier is out of stock), so it can be used on and off a DC load. It has full digipeater support, including WIDEn-n and TRACEn-n style callsign substitution, with optional preemption and hop count limiting. Currently, the KISS TNC feature is working, but has a limited transmit buffer. Basically, it works as long as you don't transmit more than one packet at a time, and it's not more than 256 bytes long. Currently some (possibly all) of the configuration parameters will be remotely changeable.

I really like the OT2, as it is tidy, relatively easy to construct and is very flexible being usable as a tracker and digipeater similtaneously. AREN and TARG, have used APRS as a tactical communications tool on several events. I also have a T2-135 which is an add-on board designed to fit inside the Alinco DR-135T. It makes a portable 'all-in-one' tracker/digipeater/kiss TNC that works quite well with XASTIR for base operations (and is part of my 'go kit'). Mobile, I use a Kenwood TM-D710E along with my venerable Garmin GPS V

An Introduction to APRS

I gave a presentation to the Tipperary Amateur Radio Group on the 3rd of February 2005 as an introduction to APRS, and to the South Eastern Amateur Radio Group the following month and at the Mayo Rally in November. The presentations can be found here (It is 3.8MB zipped).

After reading over the slides a few times, I wrote an article (An Introduction to APRS) in an attempt to make some of the ideas in the slides a bit clearer. A PDF of the article is available here, and a further article on some of the more advanced features is available here