[aprssig] tracking avalanche beacons?

[Keith VE7GDH]

Kevin VE7WHK wrote...

> I am curious what can be used to pick up avalanche beacon
> signals other than another beacon? What mode do they use?
> My thought is to use a directional antenna to increase the receive
> range as an aid to SAR teams looking for missing skiers

Curiosity is OK, but when lives are at stake, use the right equipment... 
i.e. a proper avalanche beacon transceiver. They are built to high 
standards, designed to survive in cold and snowy as well as sometimes 
wet conditions.

Early tranceivers (pre 1997 or so) used 2.275 kHz , but modern units 
transmit a pulsed carrier on 457 kHz, with the spec calling for +/- 80 
Hz accuracy. If you do end up building something, make sure it doesn't 
interfere with other tranceivers. There will be exceptions, but in most 
cases, only those right on the scene have a reasonable chance of 
effecting a live recovery. Whatever you build will almost never be at 
the scene, instead being brought in later. If you build something that 
can detect a signal from a long range, it could be helpful when the 
avalanche debris covers an extremely large area, but chances are it will 
still be a conventional tranceiver used to pinpoint the location. If you 
can buy or borrow a couple of conventional avalanche beacons, it would 
probably make your experiments a bit easier.

73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am!"