About Radio Orienteering

Quick Introduction to the ARDF sport – Radio Orienteering

What do you get if you combine a small hand-held radio equipment, running (or walking) in the beautiful Swedish nature, and solving a shortest-route problem? You get radio orienteering and in Gothenburg, the local name is Göteborgs Rävjägare (GRJ). Note that we do not hunt any fox (räv), it is just a name from the dinosaur era (1950s). We simply look for radio transmitters hidden in the landscape on a given map with the help of a compass and more importantly a radio receiver. The location of the transmitters are not provided on the radio-orienteering map, unlike regular-orienteering maps.

Your task is to find radio transmitters hidden in the forest. Usually there are five transmitters where each transmitter takes its turn for transmitting a fabulous Morse code with its identity while the other transmitters remain silent. See https://en.wikipedia.org/wiki/Radio_orienteering and https://pejla.se/ for further information.

All are welcome to reach us and try this sport. See About us / Contact us page for more details.

Resultat natt DM 2020

Fantastic finish for the night radio orienteering. Thanks to banlaggare Erik Sandwall and the nice little cabin.

Probably a new record for the number of participants at 9 people. Thanks to Robert for bringing in folks. Perhaps, we should have additional bonus points for bringing a new person to this sport.

It was again a close finish with the map scale at 1:6000 and without the screens. Robert took the championship by 8 seconds. The second place was equally tight between Tilak and Albin, where Albin dived for the fox and Tilak dived for the plug a fraction later. Albin was a gentleman in saying that Tilak has the plug and let him punch the control. The difference in the recorded time between second  and third is 7 seconds.

Perhaps, the night hunts could be improved with the installation of orienteering screen so that the hunters don’t gather together at the same control,  waiting for the next  transmission. Perhaps some discussion points for the avslutningsfest.

It was good to see the old timers Ingvar and Lars R.

Resultat DM 2020

Some commentary as observed by Tilak and his interactions based on memory after the exhausting run.

I guess this is the closest DM finish with less than a fraction of a second. Although the fox puncher time says 6 seconds.  Perhaps the old timers can correct this guess of mine.

The course was set by Erik Sandwall, the winner of last year’s DM 2019. He was very happy to see so many participants. This time the DM was at the hilly landscape of Kvarnsjön, nicknamed as the Alpine of Alingsås. The landscape reminded me more of NM 2019 in Norway.

Two minutes before the transmission, everyone took off towards the northern side to get bearings while I took off south. Some 400m where there was a path to enter Kvarnsjön. I thought fox3 was close by, only to hear fox4 and fox5 even closer. Climbing up and down and up and down for foxes 4 and 5 was fun. Then, it wasn’t clear if fox3 was on the western side or the northern side of the Kvarnsjön. So, I lost one whole 5mins cycle just waiting for transmission where I met Oscar zipping past for fox5. Next transmission I was close to fox3 but lost the transmission cycle, looking around I was lucky to find it. Then, came fox2 which was well beyond the shooting fences. For some 10 steps I started traveling north instead of southeast when I came across a stream. Managed to catch the fox2 after 2-3 5mins cycles later. This is where I met Robert who was going for fox2 along with Albin who was on his second fox for the day. I got a north bearing on fox1 so traveling along the bearing only to be hit by the shooting fence and some tough terrain where I was bearing for fox1 upon a slope that looked like a 85° dip from the horizon. Good shoes with spikes helped. Getting down on the road only to be hit by more tough looking cliffs. Had to navigate well between the gaps. When reaching closer to fox1, suddenly I noticed Robert! Very surprised to learn that he was there for his last fox. He later told me that he took the road on the eastern side which was a great choice. Darn! Why did I not do that? He was happy to see me there as I was still looking for the fox1. Upon noticing Robert in the valley, I started to move midway between where we stood. A logical choice given two independent bearing when there was barely 10 seconds left for fox1 to start transmission. Robert later said that he was looking for every tree along his way to fox1 while I was doing Rabbit hunt search. I think Robert and I saw the fox1 probably at the same time. Robert was one step away from fox1 while I was two steps away. I dived for the puncher plug that resulted in Robert’s hands over my hands with Robert on one knee while I was lying flat on the forest floor with both hands over the plug. There was a slight giggle between us for holding the plug. Probably, we were unsure if the plug was really in my hands. Then, Robert let go and I think he said “you can take it”. I said “Thanks!” He said “we should maintain Corona distance” and we laughed as we walked back to the car. I think it was barely a fraction of a second as to who got to the puncher plug although the recorded time shows 6 seconds apart. I think with NFC touch based timing could prove to be even more interesting for the future.

My guess is that this is probably the closest fought DM. But Robert thinks there could have been closely fought ones in the past. We laughed as we went back to the start over the beautiful landscape.

Daniel mentioned that he went too far north beyond the map to Vänersborg at the start, the map scale 1:7500 was probably a little magnified compared to the standard scale of 1:10000. He took 3 controls. A good number of foxes to catch, given that this was his third hunt since 1986. It was very nice of Daniel to bring coffee, kex and saft for the entire gang. Tack! It was impressive to see Albin, a new comer for DM, to take all 5 foxes. He said he was going along the bearings. Some regular orienteering experience will bring a tougher competition. While the fastest man on this track was Oscar who unfortunately took a suboptimal path with only took 1hr 21mins. If he gets the optimal path, we would have tougher competition.

While walking back to the car, Robert mentioned that he did not expect me to dive and I still have goosebumps thinking about that dive for the fox1.

Resultat skämtjakten, 17th June 2020

Bifogade bilder visar resultatet i går. Robert vann, grattis!Tre av fyra jägare hittade alla fem rävarna!! Uppenbarligen var de inte tillräckligt svåra..
Så här var rävarna:1 Räven hängde i ett träd, 3 m upp. En tråd uppåt och en neråt, dvs vertikal dipol. Det fanns en stege i närheten, med kodlås. Koden 333 gavs vid start, helt utan förklaringar.2 Vanlig räv, fast den sände i sprint-mode, dvs den sände bara 12 s i varje minut.3 Vanlig antenn, fast påsen var tom! Från antennen gick nämligen en koaxialkabel 5 m bort till omkullfallet träd. Där fanns själva räven och stämplingen!4 Två antenntrådar nedgrävda, dvs en dipol. Räven också nedgrävd! Kolla bilden. Räven är där trädgårdsspaden är.5 Antennsladden var kopplad till en lyktstolpe. Jag trodde det skulle sprida strålningen längs hela gångvägen, men den blev inte så svår som jag trodde.

Resultat cykeljakten /David

Här är resultatet från i går. Eftersom alla återsamlades hemma hos David, vid 2:an, så blir sträckorna det som jägarna cyklade totalt, även om inte alla tog alla rävar. I alla fall som en fågel skulle cyklat i himlen. Jag misstänker att man får lägga på 30-50%. Dvs det blev en bit att cykla, runt 1-1,5 mil!

Tack David för en rolig jakt på en solig kväll! Gott med korv efteråt!


Route Kms Orienteer
4 3 5 1 2 6813 Tilak
1 2 4 3 5 6845
5 3 4 1 2 6986
2 1 5 3 4 7029
1 2 5 3 4 7187
2 1 4 3 5 7220
1 5 3 4 2 7551 Erik, Robert
5 3 4 2 1 7562
2 1 5 4 3 7589
1 2 4 5 3 7680
3 4 5 1 2 7742
1 2 5 4 3 7747
4 3 5 2 1 7922
5 4 3 1 2 7964
5 1 2 4 3 8033
2 1 4 5 3 8054
1 4 3 5 2 8085 Oscar
1 2 3 4 5 8129

Resultat Oscars jakt, Alingsås

Jakten blev mycket lyckad! En varm och solig kväll. Victoria och Albin (nybörjare) var med i junior-sektionen. Lasse R och Robert och Erik S stod för det ordinarie jägarteamet.Alla jägare tog 5 rävar! Och alla tog dom på under en timma! Fantastiskt!
Lite lurigt med vägvalet eftersom det är en del sluttningar, branter och höjder. Rävarna var också rätt så väl gömda och utan skärmar.
Bifogat finns kartan och resultatlistan samt vägvalsbilden.
Vann gjorde Erik S på 36 minTvåa Robert på 40 minTrea Lars R på 46 minFyra Victoria på 46,5 minFemma Albin på 59 min
Tack för jakten, Oscar!