New beacon time and electronic interference

[Slim]

Germans normallly use LVS Lawinen verschütteten Gerät. (Spelling?)
Avalanche Buried(people) Aparatus.

DAV is Deutsche Alpen Verein, German Alpine Club

 

[JonathanShefftz]

It was a Beacon & Eggs event with probably 80 people. This wasn't the year I did it, but I would say when I did, there were probably 10 people around me, likely all with their phones on, in addition to everyone else in the area. Go to :33 to get an idea of the crowd. Hopefully I am never backcountry skiing with that many people at the same time.

Huh, I'm familiar with mass starts for skimo races, but not for beacon searches!
With that kind of proximity, perhaps. But even if other searchers are an arm's length away, shouldn't cause a problem.

 

[JonathanShefftz]

@JonathanShefftz ,
View attachment 189594
Of course. We are talking about interface to the searching beacon, not the sending.

The question was, when/why would you have your phone screen turned on when you are doing a search.
This was my answer of a scenario where that might be case:
You take a photo or look at your map on your phone. Put phone back in pocket. Avalanche happens, you turn your beacon to search, and now you are receiving interference with your beacon from your phone screen.

If the beacon is any sort of reasonable distance away from the searcher's torso (i.e., the searcher is not a Tyrannosaurus rex), then the search for the victim should still be fine.
(And if the searcher is a Tyrannosaurus rex, then the victim is facing add'l problems beside the usual avy causes of death.)

 

[JonathanShefftz]

What do you see as the right or preferred use for the Barryvox S analog listening mode?

Personally, my favorite combo for any beacon (although it's not a widespread combo) is digital processing for the distance, direction, and victim count combined with analog sound (i.e., instead of digitized sound) b/c that way little sort of hiccups and irregularities in the sound can indicate signal overlap clues that missed be missed by the digital processing.
(However, I might be deluding myself in thinking that I can outthink the digital processing!)

 

[charlier]

Personally, my favorite combo for any beacon (although it's not a widespread combo) is digital processing for the distance, direction, and victim count combined with analog sound (i.e., instead of digitized sound) b/c that way little sort of hiccups and irregularities in the sound can indicate signal overlap clues that missed be missed by the digital processing.
(However, I might be deluding myself in thinking that I can outthink the digital processing!)

@JonathanShefftz About 5 yrs ago, we tested digital processing and the analog sound combo. I’ve come to realize it’s my confirmation basis - it’s not clear that I can outthink digital signal processing.

 

[JonathanShefftz]

@JonathanShefftz About 5 yrs ago, we tested digital processing and the analog sound combo. I’ve come to realize it’s my confirmation basis - it’s not clear that I can outthink digital signal processing.

That could very well be true!

BTW, the predecessor Barryvox model, the Pulse, had a mode for only analog sound, no digital processing at all, with the display essentially blank.
The only purpose of this was enhanced range. Which was spectacular! I even ran out of room on my test range, since I was backing up against a park fence. Starting a search that far out might not have saved any search time, but it would have been great for a situation where the rescuer is determining whether or not anyone is even buried. (This sounds strange, but even aside from, say, a patroller searching a sidecountry slide, this often happens on Mt Washington, where skiers will trigger a slide and then ski away ... or did they?)

 

[slow-line-fast]

@JonathanShefftz About 5 yrs ago, we tested digital processing and the analog sound combo. I’ve come to realize it’s my confirmation basis - it’s not clear that I can outthink digital signal processing.

Good to know. And if human perception vs digital processing fails or comes to a draw in non-emergency testing, it would surely fail in an emergency.

 

[slow-line-fast]

BTW, the predecessor Barryvox model, the Pulse, had a mode for only analog sound, no digital processing at all, with the display essentially blank.
The only purpose of this was enhanced range. Which was spectacular!

Is there still a tradeoff between range and digital processing, or have they closed that gap?

 

[JonathanShefftz]

Is there still a tradeoff between range and digital processing, or have they closed that gap?

No beacon on the market can come even close to matching the initial signal acquisition range of the old Barryvox Pulse in pure analog mode with the screen turned off.
But plenty (or even all, by some standards) of current models can provide sufficient range for any reasonably anticipated type of search.
So, I'd say the answer to those questions are ... Yes *and* Yes!

 

[jmeb]

No beacon on the market can come even close to matching the initial signal acquisition range of the old Barryvox Pulse in pure analog mode with the screen turned off.

The current Barryvox S in analog mode is pretty impressive but I haven't A/Bd them in the same terrain.

Here's the new standardized guidance infographic from avalanche centers and beacon manufacturers that @charlier mentioned earlier.

Transceiver Interference Guidance | Colorado Avalanche Information Center

avalanche.state.co.us

 

[charlier]

My personal feeling is that most modern beacons (e.g., BCA tracker 4, Mammut Barryvox, Pieps/BD) can identify a buried person relatively fast. Using “probing ahead” method, the rate limiting step is shoveling. Most students in avalanche classes tend to focus on transceiver functions, range,/signal acquisition, and multiple burial flagging until the end of their companion rescue practice. At that point, it’s obvious that digging is the most time consuming part of companion rescue. A fairly recent study by the SLF concluded that burials invoking more than two people have gone from 10% before 2000 to >5% since 2000 and only 1% of accidents are close-proximity burials. My advice is follow the 20/50 cm standard, until we have more data

 

[chris_the_wrench]

Here's the new standardized guidance infographic from avalanche centers and beacon manufacturers that @charlier mentioned earlier.

Shoot, I just bought a lightweight hooded puffy for backcountry descents, but it's got some kind of foil lining. argh, wasn't even thinking about that. At least it came from the outlet store at a cheap price.

 

[Slim]

After our discussions of interference earlier, my thought was to wear my watch on my right wrist, because I am left handed, so that’s where I hold my beacon.

But, a few days ago, I did a multi burial drill, and found out that after the first ‘vicitim’ I switched my beacon to my right hand, becasue I had my shovel and probe in my left hand.

This makes me wonder if I should wear a watch at all. I like having easy access to time, and altimeter, and was considering a GPS watch for quick access navigation, but this makes me reconsider.

In the infographic it says to take your watch off to search. I don’t think I can count on myself to remember that, so I think I will either strap one to a pack, more than 20cm from my beacon, or just not wear one at all.

 

[Slim]

A fairly recent study by the SLF concluded that burials invoking more than two people have gone from 10% before 2000 to >5% since 2000 and only 1% of accidents are close-proximity burials.

Is that a typo? Was it supposed to say: “< 5%”?

Because 10% and “more than 5 %”, are fairly similar.

 

[chris_the_wrench]

After our discussions of interference earlier, my thought was to wear my watch on my right wrist, because I am left handed, so that’s where I hold my beacon.

But, a few days ago, I did a multi burial drill, and found out that after the first ‘vicitim’ I switched my beacon to my right hand, becasue I had my shovel and probe in my left hand.

This makes me wonder if I should wear a watch at all. I like having easy access to time, and altimeter, and was considering a GPS watch for quick access navigation, but this makes me reconsider.

Ive been thinking about this exact scenario for abit. Im right handed but wear my watch on my right hand. But my thinking was pretty similar to what. your describing, once my probe comes out it basically lives in my right hand. I need to train myself to initially grab the beacon with my left hand.

 

[JonathanShefftz]

re watch, set up a searching beacon within range of a transmitting beacon, and now slowly take your GPS watch from outside 50cm to within a couple cm or so of the searching beacon -- report back on whether you see any changes in the searching beacon's display.

 

[Slim]

re watch, set up a searching beacon within range of a transmitting beacon, and now slowly take your GPS watch from outside 50cm to within a couple cm or so of the searching beacon -- report back on whether you see any changes in the searching beacon's display.

I think if you want to test it, you would also want to test with the search beacon turned off, then turning it on, once with the watch near and once without. And near the limit of the range of the searching beacon.
Just in case it was able to maintain a lock on the signal once it had it, but maybe struggle with initial acquisition if there was interference from the watch.

I did get a shorter range than my wife and kids, when testing our beacons range last year. Quite possibly I had more interference from electronics, even though all except the watch were more than 50cm away.

 

[charlier]

Is that a typo? Was it supposed to say: “< 5%”?

Because 10% and “more than 5 %”, are fairly similar.

Typo. Less, than 5%. I usually suggest that my students do not wear a smart watch with the same hand as their transceiver 20-50 guidelines.

 

[JonathanShefftz]

I think if you want to test it, you would also want to test with the search beacon turned off, then turning it on, once with the watch near and once without. And near the limit of the range of the searching beacon.
Just in case it was able to maintain a lock on the signal once it had it, but maybe struggle with initial acquisition if there was interference from the watch.

I did get a shorter range than my wife and kids, when testing our beacons range last year. Quite possibly I had more interference from electronics, even though all except the watch were more than 50cm away.

Many variations are possible.
My main point though was, for people who are so concerned about wearing a GPS watch while searching with an avalanche beacon, first test the combination to see if any interference is actually occurring.
Unlike tests for, say, initial signal acquisition range, spike/null handling, reduced range from signal suppression ... this aspect of avalanche beacon performance is super easy to test.