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Attackpoint - performance and training tools for orienteering athletes

Discussion: Interesting analysis

in: fossil; fossil > 2016-03-13

Mar 17, 2016 3:16 AM # 
Always nice to read how someone tackles the course. The SI Air stick is set up just as a receiver, and the box as a transmitter. There is no back and forth dialog like with regular punching. So you should be able to have dozens of people in range at the same time and they would all get the signal and not interfere with each other. That said, I'd like to see it tested...
Mar 17, 2016 3:40 AM # 
Right. And that was my first thought, too, except for the mystery of why a GPS would interfere. Does it transmit anything? I thought they were also "just receivers". Of course most receivers do emit at least a small amount of radiation.

The test I was thinking of for this would be to put 2 air punches on the same wrist and try some high-speed passes by a control that way.

I wonder if there's any significant variation between individual punches. I found mine to be quite flawless all 3 days. As long as I put my arm within maybe 6 or 8 inches of the box it always picked up the punch no matter how fast I was moving. On slow approaches it was more obvious how far it reached out when it would start beeping before I'd quite "arrived". I only ever re-punched one control and that was just because my skis were too loud on the icy snow, I forgot to look for the flashing light until too late, and I figured I probably had it but better to be safe. By Sunday I'd seen enough to be more confident about making high-speed passes.

Oh, also, here's the online trail maps of that place I was telling you about. I've never been there and hadn't actually looked at their map until today, but from this it looks like it has some potential.
Mar 17, 2016 2:37 PM # 
My Garmin 310XT transfers data to the "ant" stick on my laptop as soon as I get them close to each other, so there is some field coming out of the watch.

When the SI Air was first used a couple years ago, the elites wore 2 to make sure the signal was captured. In fact, the first time Greg used it he says he got a third one to put around his ankle. Us peons only got 1, but it worked okay.

I suspect the beeping and flashing may get weaker as the battery wears down. Thus I would suggest using the battery check to make sure you get a strong indication, not just that it works at all. That definitely is worth checking out.
Mar 17, 2016 3:34 PM # 
That's an interesting thought. I wouldn't think the LED flash to be any perceptibly dimmer, but you might detect some variation in the beep volume.

Interesting point about using 2 or more sticks. I was thinking afterwards that it would have been really handy to have one on each wrist. Not for backup purposes but just to be able to punch on either side of the trail without having to deal with high-speed acrobatics when the control is opposite your punch wrist.

Not sure how much of a pain that would create for the download/results computer. The software would need the capability to merge the download data from 2 sticks into a single competitor's results. As long as all punches are time-stamped and clocks are in sync it should be doable, but probably only if the programmer thought of it in advance.

In any case it was really fun to not have to play biathlon trying to get the stick into the hole in the control box. And it definitely had some minor affect on route-choice when there were options to approach a control from different directions and sometimes avoid having to stop altogether.

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