UKH

Does anyone have any experience using this?

https://backcountryaccess.com/product/bca-wireless-beacon-training-park-sys...

I tried it yesterday and all the mammut transceivers failed miserable in multiple (2+) burials. They were terrible, freezing up, confusing directions and distance, just a total fail.

Does anyone know about problems with this kit and mammut transceivers? The mammuts behave fine if I practice by hiding multiple regular transceivers.

No idea for the BCA system but with the Girsberger equivalent (https://www.girsberger-elektronik.ch/rtx457-mobile-en) you can set the pulse length which would give the effect described:

"For standard mode, all transmitters are set up with a pattern that provides a short (70 to 120 ms) pulse duration. This corresponds to most of the devices that are currently on the market.

For expert mode, all transmitters are set up with a pattern that provides a long (240 to 320 ms) pulse duration. This corresponds to older devices. This allows for simulating simple and complex burial scenarios, including multiple burials."

It's in the latter case that one needs to use more advanced techniques like micro-bands and boxes and not follow the arrows on the transceiver. 

On old climbing partner is now IIRC one of their design engineers. I'll point him towards this thread.

you sound like you know what you are talking about! can i have a chat with you sometime?  could you email me? Phil Jardine

any idea how much either of these systems cost?  not obvious on either website

No, I borrowed it from the red cross here in Trondheim, and they have it on temporary loan from somewhere else!

Thanks. I sent BCA an email too. Also, on reflection, it's the first time I've trained exactly where I did, and there's actually a military installation there, so maybe there's interference too

I've tipped Toni off to this thread via Facebook. But don't know if he'll have anything relevant to say - I'm not actually certain what his job is exactly but it does seem to involve going ski touring a lot!

Hi,

Toby A. thanks for pointing me to this, although I am no longer at BCA (at least not full time) snow safety is still close to heart.

I used to run product development, management and sourcing on BCA electronics. WBTP (training park) is one of my products. What happened during development is that we did not know that Mammut is using incoming pulse timing on multiple burial pulse differentiation and delayed pulses 80ms after positive probe hit to send message for control box. There is SW update to change this and all WBTP's can be updated to help Mammut users.

Apart from this, there are beacons out there that change pulse interval for one reason or other and this can happen in "anger". Furthermore all multiple burial technologies currently in the market are unreliable to a point and I strongly recommend learning alternative techniques (such as terrain elimination or micro strips or three circle method) to solve multiple burial situations.

WBTP has random pulse length varying 70-120ms. Nobody should be using anymore analog beacons with 200+ms pulses for myriad of reasons!

Hi, thanks for the reply!

We did some more experiments, and one thing to note is that we did this in the evening, so required headtorches. We found that both our mobile phones and our LED headtorches interfered with the performance of the transceiver. I'm guessing my fancy GPS/bluetooth/wifi watch probably doesn't help either. 

there is a good article about transceiver interference here.  Quite a problem since we all carry so much electronics when we go skiing

https://www.alpine-guides.com/ski/insider-knowledge-ski/transceiver-interfe...

Some watches indeed emit noise that has harmonics of 457kHz, I would think that your LED headlamp also caused some problems.

This is article I wrote couple moons back (I am not very happy about it because i feel like copywriter who corrected my "Finglish" changed some of the content.)

https://backcountryaccess.com/electronic-noise-and-what-it-means-for-your-b...

Good synopsis of Adaxys (Developer and manufacturer of Mammut beacons) paper at ICAR 2014 is here.

http://www.scottishmountainrescue.org/wp-content/uploads/2015/03/IKAR-2014-...

Same paper was also presented at ISSW 2014 but I could not find full paper at the moment.

People have used to "absolute" function of electronics in today's world, unfortunately avalanche beacons does not work that way. They are more like ham radios. To effectively use them one needs constant training with one's personal beacon to understand weaknesses and how to overcome them.  

Good use for retired analog beacon is to use them to check interference caused by your electronics. Put sensitivity to max scan your electronics. You can hear the noise from speaker. General white noise from the speaker will make your range lower and cracks plips and plops will confuse pulse tracking because it is looking for raising edge on RSSI.  

Great stuff, thanks.

I had one of these wireless BCA systems bought from BCA 4 years ago and its installed every season up at Glencoe Mountain where there has been a Beacon park for 10 years now. I also have a portable Ortovox STS system.  The BCA wireless system is very good.  Our one often gets units buried up to 3m and sometimes the ski patrol who install it will put a unit inside a resuscitation dummy to give folks a bit of realism and a scare. Its way better than burying old analog beacons for friends to find, as they give false multiples and in the park you can probe and dig.

As much as anything I have found taking groups into the park with beacons highlights many of the strengths of some beacons, and also the weaknesses. None are good at everything. As has been advised already, folks need a fall back plan to be able to go back to a systematic search when marking fails and also for deep burials when many of the digital beacons fail miserably.  I might be wary of changing the pulse length using the girsberger which although separates the signals for marking can also do the reverse and the processor could see the longer pulse length as two beacons in the same way as frequency drift sometimes does.  I have seen most problems with the Mammut pulse and multiples and the dreaded "stand still"  but not having tried the new one don't know how it performs. The BCA T2 always seemed like the most reliable workhorse and the Ortovox 3+ a good basic beacon with a reliable mark feature up to 3.  The electronics guys on here will no more about that side but as said everyone need to know how to search for multiples using a search strategy for when marking fails and practice deep burial strategy such as pinpointing in a line.  IMHO ......