Wearable PLB

[RiverAux]

Here is a link to an article discussing sewing several rescue beacons inside a single life vest.  Though the article talks about them in the context of life jackets for people adrift at sea I don't see why we wouldn't start seeing backpacks with beacons incorporated into them for hikers.

http://www.foxnews.com/scitech/2011/10/27/davy-jones-tracker-space-tech-takes-bat-signal-to-sea/

[Spaceman3750]

A long, long, long, long time ago I remember hearing someone who skiis say that he had a PLB in his jacket and if a certain amount of force is exerted on it (from an avalanche) it automatically activates. At least that's the way I remember it.

[lordmonar]

I would still want to buy a portable....instead of one inside my equipment.  More flexible.

[SARDOC]

I've not heard that a PLB being Shock Activated.  I was under the impression that they were all manually operated.

[Major Lord]

Avalanche alarms are ultrasonic so that rescuers can locate your frosty body with a sensor.  They incorporate shock and manual activation. Radio waves don't go through snow very well at all!

Major Lord

[sardak]

Avalanche alarms are ultrasonic so that rescuers can locate your frosty body with a sensor.  They incorporate shock and manual activation. Radio waves don't go through snow very well at all!

Your misunderstanding of avalanche beacons has kept you away from a market your electronics business could be in. An avy beacon most certainly does transmit radio waves and I'm not familiar with any that incorporate shock activation. They are manually activated, even avalanche airbags require the user to pull a "ripcord" to activate. The transmit/receive range is of course affected by being buried in snow and the average reception range of a beacon is less than 50 meters.

The beacons transmit a radio signal on 457 kHz. When going into an avalanche area, everyone turns their beacon on, which puts it into transmit mode. After an avalanche, the survivors or the rescue team set their beacons to receive. You then DF the signal. Newer beacons use digital signal processing and incorporate multiple antennas to help with problems caused by the transmitter and receiver antennas not being in ideal orientations. Many incorporate digital readouts showing the distance and direction to the transmitter. They also have means of distinguishing between multiple transmitters. One model used to (still does?) have what they called the "God button" which would allow you to remotely turn off an interfering beacon (and therefore dooming whoeverwas attached to it). Now if that could be incorporated into ELTs...

Everything you want to know about avy beacons:  http://beaconreviews.com/transceivers/index.asp

I'm not aware of any PLBs that have any sort of pressure or shock sensor. The technical specs certainly don't allow for such a means of activations.

Having said all that, two years ago in Colorado there was a PLB that activated intermittently for 3 months. After the owner, a backcountry solo skier/snowboarder, was finally found he claimed he was told it was an avalanche beacon. He dutifully turned the PLB on every time he recreated in an avalanche zone and turned it off when he was out, so the beacon was never long enough to DF it, let alone respond to the Sarsat hits. He was located after he forgot to turn it off one day, giving SAR a chance to DF it. He threw his gear in the back of his Subaru wagon (what else) and went to an appointment in town. He came out to find a waiting gaggle of SAR members with DF gear and SWAT members with their gear.

Mike

[Major Lord]

You are absolutely right. Its been a while since I look at avalanche units, and back then, they were at 2275 Hertz, so they were audio frequency- radio frequency! Weirdness.  I like the Ham Radio World. Much less FCC interference, and a world-wide customer base.

Major Lord