It took only six years and a veritable avalanche of evidence, but Europe’s foremost avalanche rescue experts have acknowledged the problem of signal overlap and the shortcomings of multiple-burial “marking” functions.

Manuel Genswein presented, “Transceiver performance when searching for multiple burials,” along with co-authors Juerg Schweizer of the Swiss avalanche institute (SLF) and Fred Jarry and Dominique Létang of the French avalanche institute (ANENA), respectively. They revealed that in tests with novice and “average” beacon users in Davos, Switzerland last season, one-third of the users could not locate one of three buried transmitters within the 12-minute time limit. They traced the problem to “signal overlap,” which happens when the transmit pulse of one transmitter is beeping at the same time as another, thereby concealing it. This often results in lack of “marking” capability, “Stop” or “Stand Still” messages, or the re-emergence of transmit signals that have been previously marked. Sound familiar?

http://www.backcountryaccess.com/2012/10/10/issw-2012-euro-rescue-experts-acknowledge-signal-overlap-problem-encourage-learning-backup-techniques/

People who follow Pistehors will know we’ve been talking about this issue since Lund’s original article, so it is not exactly fair to claim that Europeans are a bunch of ignorant yahoos

http://pistehors.com/news/ski/comments/0805-time-to-retire-the-ortovox-f1/
http://pistehors.com/news/ski/comments/1028-problems-with-multivictim-searches/
http://pistehors.com/news/ski/comments/0831-multiple-burials-revisited/
http://pistehors.com/news/ski/comments/0817-multiple-avalanche-burials-rarer-than-you-think/

In fact, given the very wide readership of this site we’ve maybe done more than anyone to get this problem out into the public domain.

There is no question of ‘acknowledging’ the problems of signal overlap by euro rescue experts! They have always mentioned it and acted upon it. For instance at IKAR they have acted against all influences causing problems with marking. But they’ve stated that for non-professional users there best bet for solving a multiple burial situation is a marking function. This, off course, sounded as bad news for BCA (because de Trackers don’t have a marking function). Hence their ‘happiness’ after ISSW 2012! But all alpine clubs, rescue operations and serious avalanche schools in the EU have taught their participants back-up techniques these last years. Manuel Genswein has developed a back-up system called ‘Micro Search Strips’ and he has pointed out problems with marking functions in every congress or course he has taught that I was part off and no doubt in many others as well (as Bruce Edgerly also mentions in his BCA blog). The German Alpine Club by the way has developed another beack-up system called ‘3 circle method’.

As for the SLF research in question: it is below the standards that we might expect from SLF; certainly the part held in Davos. It’s a shame and suffers from many flows any social scientist would never make. I think they should not expand on it and not mention it anymore. The part they conducted at La Grave with professionals is better, but still below par. Do I therefore think the Tracker2 get’s undeserved credits (as it performed well in these tests)? Hell no! The research was unintentionally biased AGAINST Tracker! And I think the Tracker hasn’t received enough credits for the things it does very well (despite marking is not one of them).

Thanks for the interesting feedback Rolf.