On Sun, 24 Aug 2003 19:35:16 +1200, Barry Lennox wrote:

The 406MHz COSPAS/SARSAT ones are much more accurate, typically about
200-300metres just from a satellite fix, but they are also much more
expensive. Depends on how much you are worth!

It won't be long before the new generation combines a gps fix with the
distress squawk.

With a CD. I just hold my thumb at arms length over the target, then
sight through the CD hole, and get the reflection onto my thumb, hence
the target. Works great, and it seems like they are custom made for
signal mirrors.

The problem with using your thumb is that your hand will obscure more of
the reflection than a stick will.

On Mon, 25 Aug 2003 00:26:46 +0000, "Uncle StoatWarbler"
wrote:

On Sun, 24 Aug 2003 19:35:16 +1200, Barry Lennox wrote:

The 406MHz COSPAS/SARSAT ones are much more accurate, typically about
200-300metres just from a satellite fix, but they are also much more
expensive. Depends on how much you are worth!

It won't be long before the new generation combines a gps fix with the
distress squawk.

They already exist right now, and have done for about 6 years, but
they are expensive, and that won't come down too much. The problem is
the 121.5/243 MHz ones cannot support embeddded data, and
COSPAS/SARSAT plans to stop monitoring these freqs in 2006 (I think,
maybe 2008) because of this limitation and the VERY high rate of false
alarms, over 90% in most countries, inc NZ.

The 406 MHz ones certainly support embedded data, but you pay a lot
for them. The big cost driver is the very stable oscillator required,
plus the many thousands required for certification.