 Poster: A snowHead
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Is the micro search strategy (multiple burials close together within 10-15 metres) just an analogue transceiver thing or do you need to do this with digital transceivers?
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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bump
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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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Perhaps you could reword the question.
One way of searching is: (stage 1) scan the are looking for a signal, any signal; (stage 2) having got a weak signal move towards it until as strong as possible and hence quite close, perhaps 1 or 2 metres; and, (stage 3) a "micro search" to find the best signal within that small area and hence a good place to start using a probe. With multiple burials separated by 10 metres, as per the question, I would expect stage 2 to hear or detect multiple signals but stage 3 should only find one signal. There are techniques for finding multiple burials with either analogue or digital transceivers.
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You need to Login to know who's really who.
You need to Login to know who's really who.
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Sorry, bit vague.
Let me quote what I was reading:
Example: you hear 3 beeps and the distance reading jumps between 3.5 and 4.8 m. Therefore, 3 buried subjects can be expected within a radius of 5m.
If you have multiple burials within less than 10 to 15 meters, you search using micro strips.
1.Locate and dig out the 1st buried subject.
2.Go back 3 metres and search the area in front of you in parallel search strips.
3.As soon as the distance indication reads 15, you have reached the side of the search strip. Advance 2 to 5 metres and return on the next parallel search strip until this search ends as well (distance > 15)
4.At the point with the lowest distance reading, you leave the micro search strip pattern to "pinpoint" the buried subject through bracketing. Once you locate them you return and continue the micro search pattern.
5. Continue the pattern, until the distance reading in an entire strip never drops below 15.
Now, I think this is only to be used when you encounter problems with multiple burials in the transceivers normal mode and in backup mode you need to use this technique.
This is when a clear distinction is not possible. It sounds like an analog technique with a little bit of digital help on the reading layout.
What I don't understand is why a digital transceiver can't separate the buried people for you in some cases or is it because of the flux lines overlapping?
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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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If you have multiple signals from multiple transceivers then, provided you have enough people, I would hope you try and find them simultaneously. Finding and digging out one person and then moving on to the next and much later onto the third prolongs the agony and reduces the survivability of numbers two and three.
However, to your question. I think the answer is that digital transceivers are not magic. Separating out the multiple signals and locations etc is difficult problem. The transceiver is being waved around in the search area and so tracking a signal is made more complicated than for a stationary device. When we tried searching with a digital transceiver our instructor told us to move slowly to avoid confusing the device. (Then he shouted at us to move even more slowly!) Look at the transceiver itself. It must have a very modest computer to do the analysis, consider the battery size and the battery lifetime. Also look at the number of devices sold and compare that number to MP3 players, mobile phone or digital cameras. The transceiver is the poor relation and can not have much spent on its development and refinement.
Flux lines are misunderstood. They are not distinct lines but they are often (mis)represented as lines. You might consider there to be an infinite number of flux lines around each transmitting transceiver. So I do not believe that "flux lines overlapping" is the issue. The problem is one of complexity, namely tracking two or more signals using a computer that is barely adequate for the task.
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You'll need to Register first of course.
You'll need to Register first of course.
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| Adrian wrote: |
| ......Look at the transceiver itself. It must have a very modest computer to do the analysis, consider the battery size and the battery lifetime. Also look at the number of devices sold and compare that number to MP3 players, mobile phone or digital cameras. The transceiver is the poor relation and can not have much spent on its development and refinement. |
A good point that Adrian, I'd never thought of it in that perspective.
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| Adrian wrote: |
If you have multiple signals from multiple transceivers then, provided you have enough people, I would hope you try and find them simultaneously. Finding and digging out one person and then moving on to the next and much later onto the third prolongs the agony and reduces the survivability of numbers two and three.
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Yeah you would, but I think the instructions are implying that if you can't distinguish singles then your only choice is to get one out, turn thet transceiver off, then move on.
Under normal conditions, and when they can all be distinguished by the search transceiver, you find one, mark with a ski pole or ski or whatever, move on, til you've found them all, then dig and hopefully help arrives to dig as well...
or
find one, others dig, you carry on searching, etc.
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| Adrian wrote: |
| Look at the transceiver itself. It must have a very modest computer to do the analysis, consider the battery size and the battery lifetime. Also look at the number of devices sold and compare that number to MP3 players, mobile phone or digital cameras. The transceiver is the poor relation and can not have much spent on its development and refinement. |
That's not true, modern semiconductor development doesn't work like that, it's pretty low cost to develop specialist applications. Just like MP3 players, mobiles phones and cameras transceiver use a mix of off the shelf components and specialist ones, the pulse for example uses a Nordic nRF905 to do the life signs stuff, that's an off the shelf programable chip. It's a skilled job but you don't need to go out and build a dedicated fab' plant and tool it up to make a transceiver.
Using a transceiver really isn't so very hard, it just takes a bit of practice, I'm not sure how helpful some of these recent threads are, they confuse me and I can't make any sense of some of the posts. I assume they're having the same effect on others and that's a bad thing. It's perfectly clear some of the contributions are based entirely on other material on the internet or in the manual and practical experience is absent.
My suggestion is this stuff is knocked on the head and some of you get together in a park or something and actually try stuff like (I think) a group have been doing already. Go to the seaside, it ought to be fun to try it on the beach or in the dunes 
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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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| GordonFreeman wrote: |
I agree, it was just theory I was asking before I have a chance to try it out! ...as I don't live in the mountains or have a spare transceiver near me to practice with  |
I'd really do the theory after, flux lines make a lot more sense for example after you use a digital transceiver. As for a spare transceiver, I understand, but SH must be an ideal place for you to get some people to practice with. All you need is a few people, a bit of space, some transceivers and a bar for later. Good chance for anyone working out what kit to buy to get some hands on as well.
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