 Poster: A snowHead
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Having just returned from Val D'Isere, I did a bit of research on this by speaking to guides and pisteurs. The view is, mobiles can interfere with some digital transceivers but only in one particular circumstance. You need to be talking on it within close range and it is obvious that there is something wrong. That being so, the advice is to ski with you mobile turned ON. In the event of an inccident, you can decide whether to answer it or not, as needed. It seems all the VDI pisteurs work with their phones on.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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I really, really think that's very, very wrong.
It's been extensively tested and documented and the result is just having the mobile on is enough to interfere with the transceiver. It's extraordinarily dangerous advice to leave the phone on and expect the transceiver to work.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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simple phone in top right pocket, transceiver on low left side, as advised by the tech heads at ortovox, i will check with the guys at DTS today
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You need to Login to know who's really who.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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so if all the above are true why do the manufactures not just tell you to keep your phone off when using their products, the information i was given was on a training course on the zugspitz (or whatever the hell it is called) with the head of training for Ortovox, we directly asked the question and his answer was simple keep the phone 30cm from the transceiver. hense top right , low left
i somethinmes think alot of these sites put up info to frighten skiers
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I guess what you want to ask yourself is which do you prefer
In the wrong conditions the cell can interfere with the transceiver.
If I leave on my cell - they will find my body (or within 2 meters of it) and not have to leave it out there until the spring thaws.
If I am injured I want to be found as quickly as possible.
If I am dead I hope they find what is left of me before the cell battery dies if it is still in one piece anyway.
CEM you dont mean that people would put out scare stories about cell phones - shock
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| CEM wrote: |
| so if all the above are true why do the manufactures not just tell you to keep your phone off when using their products, |
err.. they do.
Do bear in mind this problem is more pronounced on digital transceivers.
Anyway, don't take my word for it, grab a transceiver and try it.
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ok so i got the press release from DTS, re this issue, it is a pic embeded in a word doc so can anyone tell me how to get it on here, there advice is that a phone 8 -12 " from the tansceiver will not cause any problems, any closer and it make cause some reduction in range, but it is sporadic and should not affect a search. they say they are less affected than other units because of the way they wrap their antena to minimise any electrical interference. the one other statement that they make is they recomend
to assure OPTIMAL performance you should as the searcher turn off your phone and any other electronic equipment DURING A SEARCH
that to me at least says that having the phone on more than 8" from your transceiver whilst being buried will not affect your chances of being found
the most common problem that i encounter when skiing off piste is the fateful question when did you last do a transceiver practise?......... normal response....do you need to practise!, you just turn them on and they guide you to the victim don't they????
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You'll get to see more forums and be part of the best ski club on the net.
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CEM
Very good info and I totally agree with your comment about practice, practice, practice! I always ski off piste with a guide and almost all the guides I ski with I would consider personal friends. I also usually ski with my brother. Finally, many of the others I ski with I have known for years and are friends.
As such, I would hate to be in the situation where my lack of practice in searching lead to too long a search. Imagine trying to find a brother or friend and the extra pressure. With off piste skiing comes extra dangers and there is a need for an extra response.
Anyway, back to the tranceiver/phone thing! It ios time to put a stop to rumours, myths and scare mungering. It is a simple fact that skiing with your mobile phone on willincrease your chances of being found and decrease the time it takes to get help. There is no noticable downsde. It will not reduce the chances of you being found if you are buried and the effect on a search is insignificant and can be totally erradicated if need be.
However, for peace in the mountains, please put your phobne on silent mode! Skiing perfect powder last week, the beauty was destroyed by some crazy frog ring tone from one of the people in the same group!!!
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SimonN,
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Anyway, back to the tranceiver/phone thing! It ios time to put a stop to rumours, myths and scare mungering. It is a simple fact that skiing with your mobile phone on willincrease your chances of being found and decrease the time it takes to get help. There is no noticable downsde. It will not reduce the chances of you being found if you are buried and the effect on a search is insignificant and can be totally erradicated if need be.
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Are you in either the mobile telephony, or the Avalanche transeiver industries? From what technical standpoint do you base your assertion on?
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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| snowbunny wrote: |
SimonN,
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Anyway, back to the tranceiver/phone thing! It ios time to put a stop to rumours, myths and scare mungering. It is a simple fact that skiing with your mobile phone on willincrease your chances of being found and decrease the time it takes to get help. There is no noticable downsde. It will not reduce the chances of you being found if you are buried and the effect on a search is insignificant and can be totally erradicated if need be.
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Are you in either the mobile telephony, or the Avalanche transeiver industries? From what technical standpoint do you base your assertion on? |
I am in neither industry. However, as you are aware there ahs been a debate on this so while I was in Val D'Isere I thought I would get to the bottom of it. To do this, I spoke to mountain guides, pisteurs, Henry and his team plus a rep from one of the tranceiver companies. Most of these people actually practice searches regularly or in the case of Henry's team, teach people to do searches.
Everybody was in agreement. It is safe to ski with a phone and tranceiver. All the pisteurs in Val D'Isere ski with phones, every mountain guide I know does etc.
And, more importantly, the pisteurs recommended having the phone and having it on. One particular pisteur, that some of you might know, called Fab (speaks at Henry's Avalanche Talks) made a valid point when I questioned him and suggested it might not be safe. He said very firmly that having the phone didn't decrease the chances of being found by tranceiver and increased the chances of being found in the event of tranceiver failure. Those who know Fab will recognise his next comments "Do you think I am stupid? Why would I take any extra risks? If there was a chance that carrying the phone made my job any more dangerous, you think I am the sort of fool who would make it more dangerous". Then he shrugged his shoulders and added "but then, they do pay me to play with dynamite!" (sorry for no French accent, smal shoulder shrug, tilt of the head and grin that makes Fab a very good and amusing speaker!)
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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| SimonN wrote: |
| Anyway, back to the tranceiver/phone thing! It ios time to put a stop to rumours, myths and scare mungering. |
Simon I refer you to this report posted by Ian above:
Digital Avalanche Transceivers affected by Mobile Phones
Made on the 5th of February 2001. This is the first report in English, and one of the first reports published anywhere, that a passive mobile phone can have an effect on certain digital beacons when in SEARCH mode when they are in proximity. I posted this after being contacted by a member of the UIAGM. At that time the UIAGM in France had advised all guided groups to ski/board with mobile phones Off. So I feel some kind of responsibility for this issue, the report was widely circulated and even made it into the UK national press. What I don't feel responsible for are people who have subsequently mis-read or reported what was said.
The original PH report from 25 Dec 2000:
Pisteur Killed in Pra Loop
also refers to the mobile phone issue.
Now as Fab would say do you think I'm an idiot?. Before I wrote that piece I checked for myself. Ortovox and Nic-Impex also performed their own tests and confirmed this information. The expert at Nic-Impex found that distances of within 30-50cm were a problem but exceptionally there could be misreadings with a mobile phone at several meters - we will come back to this point and I will post his findings as a comment to the article above later today. I even found that the ARVA 9000 could give sporadic readings if the searcher had a Sunnto close to the antenna. Petzl have also advised not using certain of their head torches when searching with an avalanche beacon.
That wasn't scare mongering but an impotant bit of safety advice. The delay caused by interference may have been crucial in the rescue of the Pra-Loup pisteur.
The problem particuarly affects single antenna digital beacons - I gave the two model numbers as the ARVA 9000 and Ortovox M2 which were both popular at the time the report was filed and are both still in use. Of course things have moved on, two antenna units are much less severly affected by mobile phone interference but it is something you can easily check for yourself if you have a beacon and a mobile.
I would like to make the point that In the stress of a search having wildly fluctuating distance and direction readings on a beacon is very confusing. Now Fab and Henry are professionals, they are practising all the time. If they are homing in on a victim and suddenly the reading changes they probably have the experience to filter out such readings but what about someone who rarely practises with his beacon? Research shows that recreational skiers are half as likely to find people alive compared to professionals.
Remember we have only been considering passive mobile phones. What is the effect on a search site when a mobile tries to contact its cell or there is an incoming call. Mobile phones adjust their power output depending on the distance to the cell and can put out quite high power transmissions when the cell is some distance away (I know this from some work I was involved with while at British Telecommunications on power output of mobiles when in buildings). As the head of the French avalanche research institute has said "This issue needs further investigatiion - until that happens it is up to each beacon user to draw his own conclusions and make his own tests". Nic-impex found that some beacons they tested were affected by a mobile phone several meters away - was this when it contacted the base station? Imagine you are doing a fine search to locate your buddy 50cm under the snow, this is one of the most stressful points of the search because you have to go very slowly and be very controlled, suddenly the readout on your beacon goes screwy, what affect will this have on you?
I don't agree with Fab's advice on one particular point. I ski with my mobile switched off to preserve battery life in case I need to use it in a real emergency. Getting a mobile phone signal is often marginal away from ski resorts and I don't want the damn thing croaking out on me because the batteries have run dry in the cold and through being left on. On that note mobile phone to be kept on inside jacket pocket. Remember that unlike Fab I'm not spending all day drinking brews in the Val d'Isère pisteurs hut but often spending hours touring so this is a difference of approach.
Fab does have a point. Recco's can detect electronic equipment, it is likely that a mobile phone that is switched on will give a stronger signal to a Recco receiver - that's also why it can affect a beacon. However the Recco detector is designed to pick up electronic equipment that is not powered (such as a Recco reflector). There is also the case of Olivier Buffet
Avoriaz avalanche victim located by mobile phone
who was localized by his mobile operator due to his mobile phone.
Seriously though if anyone can give me a case of where someone has been recovered alive thanks to his mobile phone being switched on I would be interested.
To conclude: The current official advice in France is to turn off your portable phone before beginning a search or to keep mobile phones that are switched on away from the search site. Whether you ski o/p with your phone switched on is something for you to weigh up; the risks are certainly low that it will affect a search.
I also suggest you go back to Fab and Henry (or email them) to ask about the particular point of whether you should keep your mobile phone switched on while you are searching with a digital beacon. I suspect that what they said was that they ski with their mobiles on. They probably both have professional reasons to do that.
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SimonN, Thanks for your insight into what the viewpoint is, of the pros in Val D'Isere. Yesterday, I spoke informally to someone who has worked in the radio signal field, within mobile telephony, for 20 years. Their opinion, was that there is potential for a mobile phone signal to interfere with any other receiver or transmitter, including avalanche transcievers. He also said that the phone would probably be unlikely to stop a transceiver working altogether, but it could cause intermittent signal loss, particularly if the phone was seeking to re-establish contact with a base station, or sending and receiving text or voice, because there are 2 signals involved. He advised switching off a mobile if off piste, until it's needed. The effects of any interference would depend on the MHz frequencies of the phone/transmitters being used.
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You know it makes sense.
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| Seriously though if anyone can give me a case of where someone has been recovered alive thanks to his mobile phone being switched on I would be interested. |
Coming real soon. In America it has been law for the last couple of years that all mobile phones must have location services that allow them to be located to an accuracy of 50 meters. This is to allow the emergency services to find you when you make an emergency call ( Of course the FBI, DEA and CIA have no interest whatsoever in this service being introduced ). So far the first attempt to do this failed because they tried to base it on a technology that used triangulation between the base stations called EOTD, which didn't work satisfactorily! However, soon you will see a raft of mobiles that have GPS incorporated and then you can expect to see a lot of rescue stories...
On the original subject: I would really like to see a proper engineering explanation of how a mobile phone (which is not currently making a call ) can in fact interfere with the operation of an avalanche search device. It seems to me that there must something fundamentally wrong with the design of the beacon if it can get messed up by the mere prescence of one of the most common pieces of electrical equipment on the planet  All I have seen so far has been hearsay. Anyone know of anyone who's actually studied the mechanisms that are at work here?
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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Mike Lawrie,
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On the original subject: I would really like to see a proper engineering explanation of how a mobile phone (which is not currently making a call ) can in fact interfere with the operation of an avalanche search device.
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A mobile phone which is switched on, is an active part of the mobile GSM Network, therefore, it periodically transmits without any action by you. There are regular location and mobility management signals transferred between the two elements, therefore you cannot predict when it will transmit. this is how the network knows where are all the phones are when they are switched on, what condition they are in, how many base stations the phone can see, what power control to apply to communicate with a particular handset. This is how you can be tracked, and this is why you have to switch your phone off on a plane. 3G will make this problem worse, as it is broad spectrum with more power.
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Poster: A snowHead
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| Mike Lawrie wrote: |
On the original subject: I would really like to see a proper engineering explanation of how a mobile phone (which is not currently making a call ) can in fact interfere with the operation of an avalanche search device. |
A mobile phone which is not making a call is still a little digital computer. There are circuits within the phone switching all the time. The copper tracks of the PCB acts as an antenna. Digital signals produce a lot of noise across a wide spectrum and this is picked up by the avalanche beacon in close proximity and can be misinterpreted as signals by the device.
When the telephone is transmitting, although it is on a different and much higher frequency than the beacon there are harmonics which can cause interference.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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snowbunny, I too have spent the best part of 15 years working on mobile phone development. Fact is that on most networks the phone makes contact with the base station about once every half hour (it's configurable but the highest rate would be once every ten minutes). The Location Updating procedure takes about 3 seconds to complete, which means that your beacon would get upset by the the phones transmissions for three seconds once every half hour, if (and only if) the receiver on the beacon was sensitive to transmissions in the 900MHz or 1800MHz bands (which any half decent RF designer should be able to exclude as a possibility).
By the way, the aircraft mith has been debunked and a number of airlines are on the point not only allowing you to leave your mobile switched on during the flight, but in fact will install base stations on the aircraft which will allow you to be reachable even when you are right in the middle of the pacific ocean. Brave new world.
I'm not sure what makes you think that 3G uses more power. It doesn't.
davidof, again, not quite right. The mobile spends about 98% of it's time running on a 32KHz clock and only wakes up about once every 1.2 seconds to do any processing at all. Phones have to go through very strict type approval procedures to prove that they do not produce any spurious emissions
I thought Harmonics were multiples of the fundamental frequency (usually 13 or 26 MHz in a mobile phone's case)?
I don't want to get religious about this. I would just like to know how it can be that a piece of equipment is allowed onto the market which evidently doesn't fulfill some pretty basic requirements in RF design!
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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Mike Lawrie,
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snowbunny, I too have spent the best part of 15 years working on mobile phone development.
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Which is a different technical field.
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You need to Login to know who's really who.
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| Mike Lawrie wrote: |
| I don't want to get religious about this. I would just like to know how it can be that a piece of equipment is allowed onto the market which evidently doesn't fulfill some pretty basic requirements in RF design! |
Are you talking about mobile phones or something else now?
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I thought Harmonics were multiples of the fundamental frequency (usually 13 or 26 MHz in a mobile phone's case)? |
Maybe the 14th harmonic of the 32khz clock and don't forget the intermodulation products of the fundemental and harmonics. Anyway you are the mobile phone engineer, go figure. All I can say is that in the real world the products you are designing will cause my TV screen to shimmer and my radio to buzz.
Anyway it probably won't affect me what safety decisions other people make but people should be aware that some people actually believe what they read on the Internet.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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davidof, It certainly would be interesting to figure out exactly how much energy a 32KHz sine wave as present outside the shielded environment of the GSM chip, does in fact radiate in the 14th harmonic. I suspect that one would have to create a rather sensitive detector in order to detect that signal at a distance of more than 1 cm. Amazing that the Avalanche beacon manufacturers have managed to integrate such a detector into their RF that throws their life saving equipment completely out of kilter at distances of 50cm(?) Not forgetting that one of the specific tests performed on mobile phones is for exactly such emissions at the harmonics of 32KHz and 13MHz!
Like I said, I have no interest in getting religious about it. If it really is true then I'm happy to accept it, but so far all I have seen and heard is conjecture and supposition. A bit of science would be helpful!
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You'll need to Register first of course.
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snowbunny, huh?
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There are many issues of Electro Magnetic Compatibility (EMC) between various electronic products. On every aircraft flight I take we are instructed to turn off mobiles because they may interfere with the aircraft systems. There are many stories of taxis and police cars using radios that prevent the key-fobs of cars from working. Over the years I have had several watches, calculators, and other electronic gadgets that would cause nasty noises on my broadcast radio receivers. I have read accounts of central heating controllers, PIR lamps, burglar alarms and so on that have caused interference to radio receivers. To avoid or reduce such issues all modern electronic equipment needs type approval for EMC. This involves lots of design and testing work by the manufacturers. Even then, cases arise frequently where there is unexpected interactions between devices.
Given the problems found across the range of electronic equipment it is reasonable to expect that there may be some interference between mobile phones and avalanche beacons when they are in close proximity.
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Yesterday The Register reports on a recent study by Carnegie Mellon University, it recommends that the ban on mobile phone use in aircraft should stay.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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Isn't the problem that a mobile phone ramps up its signal if its not connecting to a network? I've been told that's so. So a signal is stronger than in a low signal area like a plane - or buried in an avalanche. So it has more effect on nearby electronic equipment. In an avalanche, that might be your transceiver - especially if you entombment hat pressed the transmit button. In an aircraft, the problem wold be enhanced if the plane had a load of passengers with phones all ramping up their power output. If a base station is fitted to an aircraft, that problem is overcome - at least for non critical stages of flight when highly sensitive equipment is not being used.
I am surprised that modern aircraft do not have electro-magnetic compatibility standard that permit free use of passenger electronic equipment - but it would seem they do not. Hardening equipment to meet, say military, standards of EMC is expensive, though. So I guess that's the reason.
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Adrian, having read that report it seems to indicate that they took a spectrum analyser along with them on a plane, and ( big surprise ) discovered that there were mobile phones switched on and that these quite often wanted to say hello to the network while the plane is coming in to land! So, what the study shows is that in fact just about every flight is subjected to interference from mobile phones. What it does NOT show is that these phones in fact cause any problems, but they only suggest that having a phone transmit during landing might cause interference with GPS ( in fact I'm quite willing to believe that that could be possible ).
Given that just about every flight is in fact subjected to such interference, doesn't that kind of support the theory that that interference is not a big problem I don't see aircraft falling out of the sky due to mobile phone usage.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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I believe that aircraft are designed to have a high immunity to external RF etc, thinking of lightening strikes, radars and other radio transmitters. But many aircraft were designed before mobile phones and the masses of other portable electrical equipment became commonly carried by passengers. EMC involves at least two parties, a transmitter and a receiver. The receiver can be designed and made to very high standards but a rogue transmitter can still break through.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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Mike Lawrie, There was a similar study done by Lufthansa about five years ago, they found even then that there was at least one phone turned on on every flight. The effects of any electronic equipment on the navigation equipment was very noticeable, they just have enough duplicate systems to allow them to deal with the problems when the plane is at cruising altitude.
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You know it makes sense.
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Yet again, we are miles off topic and avoiding the most important questions.
1. If you ski with a mobilephone on and are buried in an avalanche, is the chance of you being found less or more? The answer to this seems, on balance, to be a resounding yes. The potential interference from your phone is only a matter of seconds in the hour and therefore could only momentarily effect the search, although this is extremely unlikely and it would not have a significant effect if it did. The effect, at worst, would be a momentary change in apparent signal strength but this would almost imediately return. In addition, should your tranceiver fail for any reason, the phone could act as a beacon (for RECCO detection, for instance) and help you be found.
2. If you are have a mobile on and you need to make a search, will a mobile effect the search? The real answer is it could, but only if a call was being made on a phone in close proximity to the tranceiever being used for the search. Under those circumstances, it might be advisable to keep any phone that is on away from the search. If no calls are made or received, there might be very occasional and momentary interference but not enough to effect the search.
Overall, it seems to me to be better to have a phone on rather than off. In the event of an accident, searchers should turn their phones off but I think that one should be left on so as to maintain contact with rescue servises etc. So long as there are enough people, it is good practice to have somebody acting as look out / marshal for the avalanche site anyway and they could have the phone.
The biggest down side to having a phone in the mountains is that you never know when it is going to ring. A few years ago I was in a group skiing the Marmaton (sp) Couloirs of Solais in Val D'Isere when one of our team received a call. He was a French Psychiotrist and it was a patient in despair. We had to wait 20 minutes because he felt he could not hang up!!!! Now that is what I call service 
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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SimonN,
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| He was a French Psychiotrist and it was a patient in despair |
I had the same problem with one of our group in Col Pers. Only in his case he was an Austrian tax advisor, and the client was about to be arrested... Somehow the group didn't show the same level of understanding as one would for a psychologist with his potential suicide. Although, I suppose this client could also be a potential suicide?
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Poster: A snowHead
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Reviviing an old controversy, I have stumbled upon a really useful (USA) website about Avalanche Tranceivers , including advice about mobile phones & transceivers, links to handbooks, direct comparisons between models etc.
Very informative.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Novice question.
Ok there will be lots of places in a ski resort with bad mobile reception. But could phones be used in the case of an avalanche to phone the person in the avalanche and use the ring tone as a rough guide.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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Christopher, no, the snow blakets the sound.
I find that our group uses mobiles several times per holiday - eg to find each other when separated in trees or to relay information about danger (eg the guide skis ahead out of sight to see if a route has enough snow or the snow is safe). Sometimes - if the receiver had not had the phone already on, it woiuld have been difficult to contact them.
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You need to Login to know who's really who.
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Christopher, I'd imagine that you'd be extremely lucky to hear it.
rjs, please elaborate. What use are 'duplicate systems' if they all work on the same principle?
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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On the aircraft issue: being a bit of a plane spotter, coming from Toulouse and having a great number of my family and friends working for Airbus or other aerospace/avionics companies, I can confirm that extensive testing by Airbus on mobile phone interference has shown that the phones do not interfere with their aircraft systems. This was tested on aircraft designed as far back as the late 80's I believe, if not further back.
This is official testing by manufacturers and authorities..
This is having the IMV very unidesirable effect that many airlines are now planning/preparing their aircraft for allowing passengers to use their phones in flight...
I have got no expertise in transceiver or phone technology, I was just mentioning this to show previous (mis)beliefs are being shown as erronous by recent studies..
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You'll need to Register first of course.
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Martin Nicholas, Great link for general info, thanks, nice to have my own views and tests (non scientific) confirmed.
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On the subject of mobile phones and interference - if the phone happens to be in a low reception area then it will be much more busy trying to reconnect to the network, running on full clock and transmitting much more often and as Mike Lawrie says earlier these are much more likely to upset something than a phone in idle. So, should the phone be on or off? It seems to make sense to have it on for the purposes of annoying others on the lifts, arranging lunch with the disorganised, and phoning emergency services quickly if something bad does happen but then probably wise to turn it off while doing a search - after all do you really want to lose any accuracy in the search or even take the risk?
Going back to ridiculing easyJet, a favourite pasttime, they used to say that mobile phones should remain off after landing until well inside the terminal building because of .... REFUELLING! A load of crock if ever there was one.
PS. I've also heard a recorded announcement from easyJet saying that when a pilot failed to land a plane and was forced to go around and try again that it's a 'completely normal procedure'. 
Last edited by Then you can post your own questions or snow reports... on Thu 3-01-08 14:16; edited 1 time in total
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it's a 'completely normal procedure'
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I wonder if that is what the ryanair staff said when their captain landed them at the wong airport by mistake last year!
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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Well of course, but it's hardly a 'normal procedure'. It often indicates that something went badly wrong and crashing & killing are not far distant possibilities.
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