Monday, April 15, 2019

Using APRS During the Connemara Ultra Marathon 2019


Time flies, and it does not seem like a year since the last Connemara Ultra Marathon. Our communications systems are well tried, tested and documented, which means we have a wide choice of reliable facilities at our disposal. Our primary operation, for those in the field and following the Ultra and Full Marathons, was on 3750 KHz using USB which results in a relatively clear channel with little QRM from UK stations. VHF and TM-7 radios were used along the stretch of road from Leenane towards Maam Valley and Maam Cross. This was a busy stretch and catered for Marathon Walkers, Half Marathon Runners and then the Runners from the Ultra and Full Marathons.

A Tetra radio was supplied by the Order of Malta to enable direct access to the Ambulance system should a major problem develop. Fortunately this was not needed on this occasion.

VHF was used to communicate from the Base Location to the medical Centre at Maam Cross. The Order of Malta Ambulances were controlled from Maam Cross.

The course for the event is as depicted below and shows the starting points for each of the Marathons.


This is by no means new technology, but a  new addition to our operation this year. The reason for employing the Automatic Packet Reporting system (APRS) was to save a lot of irrelevant chit chat on the air. Quite often an operator is asked where he is and, unless he knows the area well, his answer would not exactly pinpoint his position unless he gave GPS coordinates. Indeed there is a slight lag before a position appears on the map but this is not "Air Traffic Control" so the the lag is unimportant. This was a great improvement from a Net Controller's point of view.

APRS is, as we all know, and indeed take for granted, a system which will allow the positions to be sent to the APRS server and plotted on Google maps via the Click >> APRS.fi resource. Unfortunately unless one has a major conglomeration of APRS digi-peaters, the only way to make any use of the APRS system is to use the mobile phone App "APRS Droid" which is down-loadable via Google Play.

Two systems were in use during the event; mobile phone data was one and the other was the Android operating system of the TM7 Internet radio. Both systems worked equally well as they used the data system of the cellular network. It was suggested that the APRS facility was switched on as soon as one became mobile and en-route to the activity in Maam Cross to save anyone having to worry about the time operators were going to arrive. Any inquiries from organizers or marshals in the field regarding location of different sections of the marathon could be dealt with immediately or even displayed on a tablet or mobile phone

Here is an example of the screen showing the activity throughout the day.


This satellite view looked better but not as practical from a net controller's point of view. It is obvious why VHF communications are not the system of choice. Ground wave on 80 metres is the ultimate system for use in this terrain.


There are a combination of tracks from all of the operators who took part. As the activity was in progress it was possible to see the individual call signs progressing along the route. Whilst at the individual road junctions, it was possible to show the Gardai where the runners were located and how long it would be before the traffic would need to be halted to let them past.

Two systems were in use during the event so mobile phone data was one and the other was the android operating system of the TM7 Internet radio. Both systems worked equally well as they used the data system of the cellular network. It was suggested that the APRS facility was switched on as soon as one became mobile and en-route to the activity in Maam Cross to save anyone having to worry about the time operators were going to arrive and where they were at the time.

The level of competitor fitness certainly was impressive with the majority of entrants completing the course earlier than previous years. However, there were a few stragglers and these were monitored right to the homeward stretch in the Maam Valley. The numbers were relayed to the finish line before the net was closed. All credit must go to the organizers of the Connemara Ultra Marathon as they have absolutely every angle covered to ensure safety and smooth operation of the event to give the entrants the best of facilities for their efforts.

The map below shows the APRS tracks of operators from leaving home and returning


The trip home provided an opportunity for more relaxed conversation on C4FM and comparison with the TM-7 system.


The Net Control Station with  FTM 100 for VHF, Codan 9780 on HF, Inrico TM-7 on PTT over Cellular and APRS display on the Laptop.

The antenna systems were a vertical co-linear for the VHF Band and an Inverted-Vee for  HF. Easy to deploy and work very well in this area.


In Conclusion, HF is invaluable for full coverage of the Connemara area. VHF gives, at best, a  7.5 Km range with the occasional surprise in places. VHF is fine for dealing with small local problems and not interfering with the main running of the event, The TM-7 is good for the entirety of the region due to the large number of cellular systems in the area. It does not impinge on the main network and can be used to deal with localized problems as well as cover vast distances and into RF black holes.

DMR would have been used on this occasion but, of late, the Irish Brandmeister system had been taken off air for maintenance and updates on a number of occasions at weekends, which meant that this may not have been reliable enough to warrant its use. Perhaps, if a few more weeks had passed, we would have had more confidence in the system although switching our system to another Brandmeister Server may have been a better option.