UIAA position on avalanche transceivers interference from electronics or other device

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https://acrobat.adobe.com/id/urn:aai...7-67b10546f70c

UIAA position on avalanche transceivers interference from electronics or other devices

Excerpt from section ....when in receive mode

"• Switch off heated socks and boots.
• When using a watch with an electronic screen, or bracelet with electronics for activity or heartbeat monitoring, hold the transceiver in the opposite hand.
• >50cm distance from devices absolutely necessary to conduct the search, for example a head lamp for a search at night.
• >10m distance from a turned on mobile phone, radio or satellite communication device. • >10m distance from a snowmobile with running engine
• Reduce the search strip width to max. 20m if interference cannot be contained by the distance rule.
• Some electric airbag systems may cause interference. When using an affected system, you may need to consider searching without your electric airbag.

Wait, snowmobile engines? What are they putting in snowmobiles now?

The better half was just at instructor training last week at the Silverton Avalanche School and made a quick little video:
https://www.youtube.com/watch?v=A2BchFLWtw0

For those of you who miss the Slide podcast, check out the San Juan Snowcast, he goes into more depth from the same training on his most recent episode. He always has some other good tidbits as well.

I'm not so sure about the 10M thing in the UIAA description. Nor would I take the time to turn off any electronic devices if I was following the 20/50 rule. In my testing, you pretty much have to be touching devices in transmit mode. In search mode, it shouldn't be hard to be 50cm away from all devices, unless you search with your watch hand (most people will naturally use their other), or heated gloves which are easily the scariest device IMO.

FWIW, those of you with BD/Pieps beacons or Avy packs, there was a firmware update to each which supposedly reduces electronic interference. I have no idea to what extent, but it might be worth updating those.

Stuckathunter- think of the digital screen and other electronics in a running snowmobile.

To goldenboys point I do tend to think the UIAA position is very conservative. Perhaps not a bad thing.

To the point of personal testing I did test using receive on a phone that was on, a phone that had airplane mode, and a Garmin GPS/Bluetooth watch. No issues with 1m distance using a Barryvox Element, Barryvox S and even an older SOS beacon

Cell phone, gopro, inreach, analog and digital radios? Does a human body attenuate the interference, like an inreach being in a pack while searching?

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Originally Posted by LeeLau

To goldenboys point I do tend to think the UIAA position is very conservative. Perhaps not a bad thing.

To the point of personal testing I did test using receive on a phone that was on, a phone that had airplane mode, and a Garmin GPS/Bluetooth watch. No issues with 1m distance using a Barryvox Element, Barryvox S and even an older SOS beacon

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Good real experience. Thx.


Did you try the same on transmit?
So many people leave phones on with beacons. Might be separated by a half meter (or less). Does that interfere ?

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Originally Posted by Core Shot

Good real experience. Thx.


Did you try the same on transmit?
So many people leave phones on with beacons. Might be separated by a half meter (or less). Does that interfere ?

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I'm going to try them all with the same transceivers at 0.5m on receive and transmit. Also going to add an Inreach.

It seems like this could change protocol for resort mtn ops as many search staff are carrying and using radios in chest harnesses or jacket breast pockets. Aren’t SAR and guides often using radios?

Seems the video scenario is worse case where the interference device is in a direct line with the transmitter. Rainy day here, I might test and see if interference decreases much if not in a direct line.

To the above point, it would be a strong argument for pants pocket for transceiver if hurried with a radio.

This matches pretty well with what I've been taught and what I teach except that I didn't have a minimum number for a running sled or a device in use for communication. I typically teach the 20/50 rule, warn about heated clothes and anything with bluetooth or GPS and also tell people to practice how they will actually travel so they can learn to troubleshoot their own systems.

In addition to the ignition system newer sleds have buddy-trackers built into them any many sledders are adding them after a couple of major tragedies last year that might have been different if people were keeping closer track of each other. On top of that my understanding is that screens are one of the worst emitters of EFI and the new mountain sleds have huge bright screens on them. My guidance has always been to use the sled for signal acquisition by driving 30-40 meters (strait line as part of a grid pattern), shut the sled down, step a meter away and check for a signal until you find one. Once you have a signal finish the search on foot.

I think the real takeaway here is that bystanders that are not actively part of the rescue should keep clear of the search area which makes a lot of sense in someplace like a ski area. I have a colleague that once set up scenarios under high-voltage power transmission lines (unintentionally) and learned real quick about how that confused students learning to use their transceivers for the first time. This isn't so common for us in the western US in wilderness areas but is more likely around developed infrastructure.

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Originally Posted by cat in january

Seems the video scenario is worse case where the interference device is in a direct line with the transmitter. Rainy day here, I might test and see if interference decreases much if not in a direct line.

To the above point, it would be a strong argument for pants pocket for transceiver if hurried with a radio.

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I meant primarily search team with radios, ie team with transceivers in receive/search mode. If the buried person is wearing a radio, I supposed this could interfere with pin-point searches.

The recommendation about phones off (not even in airplane mode) is interesting. I’d love to see some testing for that. Personally, I tour with phone in airplane mode to save battery but to allow for picture taking.

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Originally Posted by bodywhomper

I meant primarily search team with radios, ie team with transceivers in receive/search mode. If the buried person is wearing a radio, I supposed this could interfere with pin-point searches.

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If you're in search mode and extend your arm while searching, you should easily by more than the recommended 50cm from a radio on your chest.

During fine search, the transmitting transceiver will likely overpower electronic interference once you're that close (still not ideal). It's picking up that beacon from distance that can be problematic. The podcast I referenced above goes into some detail about that.

I agree with cat in january, though. A radio on the chest and a beacon on the chest will likely be less that 20cm apart in transmit. It's one of many reasons I'm a pocket guy.

The GPS watch thing is a new one to me, would have never thought of it. I'm right handed, watch lives on the right wrist, beacon search is conducted with the right hand. Distance is what, 5 cm? Shit. I have wearing a watch on my left hand but I guess that's going to have to change...

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Originally Posted by Boissal

The GPS watch thing is a new one to me, would have never thought of it. I'm right handed, watch lives on the right wrist, beacon search is conducted with the right hand. Distance is what, 5 cm? Shit. I have wearing a watch on my left hand but I guess that's going to have to change...

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Same. Mine was a present from my wife and I just started using it. Bluetooth but apparently no airplane mode

How am I supposed to Strava my meadow skipping without interfering with finding the new touring partner I met on Facebook?

Interesting discussion - thanks for posting Lee

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Originally Posted by goldenboy

If you're in search mode and extend your arm while searching, you should easily by more than the recommended 50cm from a radio on your chest.

During fine search, the transmitting transceiver will likely overpower electronic interference once you're that close (still not ideal). It's picking up that beacon from distance that can be problematic. The podcast I referenced above goes into some detail about that.

I agree with cat in january, though. A radio on the chest and a beacon on the chest will likely be less that 20cm apart in transmit. It's one of many reasons I'm a pocket guy.

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Thanks for the response.

I see most patrol wearing beacon chest harnesses right next to their radios.

Not sure about more general BC users, especially related to use of a radio. I’ve never taken a radio into the BC, the in-reach is in the pack, phone is in a pocket.

The arms-length approach (between transceiver in receive and chest harness radios) makes sense assuming that’s enough distance to mitigate the interference. I have no idea how much interference exists between radios in use and the transceivers in “receive” and if there’s a difference in interference between digital and analog radios. I might have a chance to check analog radios, but not digital. No experience with digital radios.

There are some high transmission lines in one of the areas that I like to make Dawn patrol powder laps. Will take a look at avi exposure in proximity to those lines next time.

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Originally Posted by LeeLau

Same. Mine was a present from my wife and I just started using it. Bluetooth but apparently no airplane mode

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Airplane mode wouldn't matter- any electronic device could cause the interference at that range. Just a regular old Timex would do it if it's digital. But the vast majority of people wear their watch on their non dominant hand and search with their dominant one, which solves the problem, Boissal (and you?) excepted.

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Originally Posted by goldenboy

Airplane mode wouldn't matter- any electronic device could cause the interference at that range. Just a regular old Timex would do it if it's digital. But the vast majority of people wear their watch on their non dominant hand and search with their dominant one, which solves the problem, Boissal (and you?) excepted.

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Unfortunately for every lefty out there, manufacturers only put a beacon attachment on the right-hand side pocket. So if you utilize a pants pocket (which like you I do for similar reasons), and you're a lefty (about 1 in 10), you're likely to run into a watch on your right wrist you need to switch before touring. It's now just a habit for me when doing a beacon check to ensure I switched my watch to the left hand.

Quote:

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Originally Posted by goldenboy

Airplane mode wouldn't matter- any electronic device could cause the interference at that range. Just a regular old Timex would do it if it's digital. But the vast majority of people wear their watch on their non dominant hand and search with their dominant one, which solves the problem, Boissal (and you?) excepted.

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Watch on left hand. Phone in left pocket. Radio also in left pocket or in pack. Transceiver in right pants pocket.

Definitely gonna test though!

They probably used an ortovox for the test. Barryvox is way less sensitive to interference, and it will let the user know if there's interference. I haven't seen it complain about interference on any beacon test.

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Originally Posted by Cocximus

They probably used an ortovox for the test. Barryvox is way less sensitive to interference, and it will let the user know if there's interference. I haven't seen it complain about interference on any beacon test.

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All brands do it. Watch the video I posted, you can see a Mammut beacon lose signals too.

Sent from my SM-G996U1 using Tapatalk

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Originally Posted by Jason4

I have a colleague that once set up scenarios under high-voltage power transmission lines (unintentionally) and learned real quick about how that confused students learning to use their transceivers for the first time.

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Had that happen (back in the analogue transceiver days) in La Rosiere, France. The interference from one of the major France-Italy power lines was really bad. I wouldn't be surprised if some digital transceivers were completely useless close to them.

I have an anecdote about interference and it's something I keep in mind regarding beacon interference...

A couple seasons ago my partner remotely triggered a pretty large avalanche that ran way longer than any slide had gone in that zone in recent memory (took down mature trees, etc.). It obliterated the skin track. It was Sunday afternoon and sunny so there was a good chance someone may have been below us. We switched to search mode and began doing a beacon sweep of the debris. At one point I briefly picked up a signal and my heart began to sink that we had buried someone. The signal was all over the place and very intermittent and it took me a moment to realize it was interference from my phone. I had my beacon in my chest harness (bca tracker 3) and was searching with an out stretched arm with my phone in my pants pocket >50cms away. I turned my phone off and resumed the search without picking up a signal. We cleared the debris and there were no unidentified cars in the parking lot so we were confident no one was left up there. But I'll never forget that brief moment of terror when I picked up that ghost signal. Just wanted to share that beacon interference is a real thing and something to keep in mind in a real situation.

^^Damn dude. Can't imagine how that must have felt. Kudos for being a responsible skier anyway.

Yikes - that’s a frightening story.