[aprssig] avalanche beacons

[Keith VE7GDH]

Kevin VE7WHK wrote...

> My purpose is not for finding someone in an avalanche but rather
> for finding skiers who are lost and wearing beacons.. ie flying over
> an area in a helicopter and monitoring the frequency...as a general
> locator system. For someone buried there is no alternative but
> beacons and shovels. Had a snowmobiler loose his life here
> yesterday in a triggered avalanche.

You might want to check out a few helicopters in your area to make sure
none of the electronics equipment onboard is emitting anything on 457
KHz. If  not, it could be a useful tool under some circumstances. We did
some tests a few years ago and our conclusion was that the avalanche
beacon could pick the signal up just as far away as the radio we were
using for testing, but the antenna being used would of course make a
difference. If your results are the same, you could try dangling the
transceiver below the helicopter (some risk of snagging it!) or
mounting it on the skids and extend the audio up to the helicopter,
either by wire or a low powered transmitter. If you end up using
your own receiver, perhaps some kind of ferrite bar / loop antenna
mounted on the skids would do the job. Even though it isn't APRS
related, you might want to ask over on the SAR_APRS list if anyone
has tried what you had in mind.

That's unfortunate about the fatality. Did the deceased or his two
friends all have avalanche beacons / probes / shovels with them?

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