In article ,
"Gary Drescher" wrote:

equipment found in a standard hundred-dollar survival kit. (I myself carry
just a compass, rescue whistle, signal mirror , rope, and . . .


Reading this led me to think back to the discussion some months ago of
laser dazzling incidents involving pilots.

My impression is that even a cheapo ballpoint-pen-sized 5 mW red laser
pointer ($20 variety), while absolutely no threat at any range, could
function as a very effective emergency signal light for a downed pilot
(or lost hiker or skier or . . . ) if they could point it at or close to
a search aircraft, at slant ranges up to ???several miles???, surely at
night, probably even in the daytime.

And one of the more expensive green versions ($100-$200 price range)
would be immensely more effective in the same situation, since the human
eye is much, much more sensitive at its wavelength.

In other words, either one might be essentially as effective as the
search mirror even with the sun out, and immensely more effective on
cloudy days or at night, at about the same weight and not a lot more
cost.

Of course if you really wanted to exploit this technology you'd have
pilots, hikers, etc, carry either type of laser pointer and observers in
the search planes wear special sunglasses that were close to opaque
across the visible, except for a notch-filter passband at the laser
wavelength. Assuming that the individual being searched for was able to
point the pointer at the search plane, or scan its beam across the
search plane, that signal would be near impossible to miss visually.

Anyone know if anything like this is in regular use?