Avalanche beacons and household appliances

Way back in 2001 PisteHors broke the news of a Piste Patroller who had died in an avalanche following a botched rescue operation by colleagues. The rescuers’ beacons had apparently been affected by a mobile phone and the debate as to whether or not mobiles can affect digital avalanche beacons has rumbled on and off ever since.

A police investigation and a couple of court cases found that the search operation had a number of short comings and that the presence of a mobile should not have affected operations. However an investigation by Nic-Impex showed that their first generation digital beacon could be affected by electromagnetic interference.

For a bit of fun we’ve taken a short film of the Ortovox X1 dual antenna beacon. This is a bi-mode beacon. During the primary search phase it functions in analogue mode and it is easy to distinguish between the regular and defined pulse of a real avalanche transceiver and other interference. However at close range it switches to digital mode and has trouble clearly separating signals from devices such as a TV, a laptop, a mobile phone and even a low wattage lamp. Fortunately we don’t find too many of these in avalanche zones.

The old X1, with its dog slow processor, can take a number of seconds to resynchronize with a real signal. Fortunately the move to faster processors (processing speed is severely handicapped by battery life) and three antennas has greatly improved the ability of beacons to separate the wheat from the chaff but if you are getting strange readings, slow down and think of anything that may be affecting your search such as witnesses who still have their beacons in search mode.

Further Information


Posted by davidof on Thursday, 12 February, 2009 at 11:41 AM

Hi David,
Andreas here from HAT and Alpine!
As always I keep an eye on your site and like reading your articles.
Concerning this one, I think we all agree that mobile phones interfears with beepers (especially digital ones) while SEARCHING.
However, the big debate was that some people also said it interfears with the SENDING signal which we don’t think it does and have done many test with.
So the bottom line is, turn of or move your mobile phone while searching but you can keep it on without risk it effecting your sending signal in your beep. (However work might get hold of you while off piste skiing so you should probably turn it off anyway!!!!)
Speak soon

Posted by  on  Thursday, 12 February, 2009  at 10:31 PM

before heading out to france i was practising with my new mammut pusle and an old analogue arva. i tried a few quick tests with a mobile phone and it did seem to confuse searching. both ways round.

so now i just always turn my phone off once heading off piste. like Andreas says, it does also stop work hassling me, especially on a day when i should be working…

why pay for a beeper when you can possibly compromise it effectiveness???

Posted by  on  Friday, 13 February, 2009  at 12:03 AM

i’ve got an iphone that doesn’t turn off. that’s a pain in the ass.

Posted by  on  Sunday, 01 March, 2009  at 05:03 PM

Don’t get caught in an avalanche in the #######....

Posted by  on  Friday, 06 March, 2009  at 10:58 PM
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