J2Ski Forum Posts and Replies by ise

Nagrjuna wrote:So we've established mobiles definately can effect the directional search on a digital multi antanna beacon.

We've also established the transmitting beacon can theoretically be effected in specific circumstances (ie. when the phone is searching for a signal) -

You quoted one of the manufacturers explicitly stating that to be untrue.

If this were a problem then we'd be seeing a lot of incidents and we've not seen a single one, the only one ever reported was fond to be spurious. I know from experience searching many, many times this is not an issue.

classic, Chamonix won't ever change :D

Admin wrote:
Given that a lot of modern smart-phones now use Wifi as well as mobile spectrum I find it hard to believe that interference can be eliminated completely. I'm open to being convinced but it does appear that the manufacturers feel they're playing safe with the advice above.

Advice about fields generally has been in transceiver manuals forever, tests show around 30-40 cm separation from metal objects, power sources etc. Even though power cables can be a particular problem but this is not the large effect that has been suggested, a whole variety of terrain factors can alter signal return as can transceiver orientation.

Classically what the novice user does is hold the transceiver rock steady in coarse search modes which is bad and then wave it around erratically in fine search which explains a lot of the oddities people see. An experienced user can fairly quickly correct for most effects and they don't cause a hiccup in searches.

Mobile phone guidance was pretty much entirely based on an incident 5 years ago in Pra-Loup and it's been established in later investigations of that incident that there was no connection with mobile phone interference, the director of piste security resigned later in fact. As a precautionary principle guidance to guides and leaders was altered and information in handbooks updated, you'll see that disappearing over time. It will remain a hard to dispel story in greater public awareness as these things tend to be.

http://www.telegraph.co.uk/news/worldnews/europe/switzerland/4414072/Skiers-enjoy-heavy-snowfall-despite-dire-predictions.html

In Chamonix, in the Chambre Neuf pub, Tom Evans, 36, who works for a London advertising firm, looked like he had had a big day on the mountain.

An avalanche transceiver poked out from under his jacket and he had a climbing harness around his waist.

in the bar :lol: :lol: noooooooooooooooooo..........

Nagrjuna wrote:I did a test down at the beach a few years back with a digital beacon buried alongside a mobile phone that had no coverage and hadn't aquired a signal. It was impossible to pin down the exact location of the beacon buried with the mobile in the final search as accurately as a beacon buried on its own. It simply wasn't producing the same kind of spike pattern you'd normally expect - if you got that effect in a real life situtation it would lead to having to probe a larger area.

A lot of people managed to perform similar tests and get just the same result, it's a classic heuristic trap knowing the result the experiment always proves the hypothesis. I've performed many searches with mobiles on my person or near the sending transceiver and there's simply no effect. The one single time I've seen a signal deflect was from a power line.

As the manufacturers have tried to point out, a phone doesn't effect a victims transceiver. It's a shame people are being confused unnecessarily when others just try to out-knarly each other.

long bits of ribbon that leave a surface trail

leashes are a no-no in avalanche terrain, you need to separate from your kit

got to dash.... snow calling

bandit wrote:

If you want powder traces, these folks sell them...

http://www.snowandrock.com/Department/Gifts+Gadgets/Ski/Powder+Trace+S+R0089.htm

I have some of those but they have "snow and rock" written on them, not a good look :D

If you've been turning your phones off to stop them interfering with the transmit mode that was a misunderstanding, if you wish to carry on doing so as a precaution against a non-existent risk that seems fairly pointless. Precautions taken against risks that don't exist don't add safety while lack of understanding about the equipment we're carrying clearly does diminish group safety.

By all means advise people not to have mobile phones on but if you do then you need to make it clear carrying a phone won't impact them being found in a search.

My background leads me to advise there's no reason to turn off your mobile phone while skiing and a couple of good reasons to leave it on.