On Nov 13, 3:42 pm, Mxsmanic wrote:
The beam
of a good quality laser (highly collimated, that is) will hardly spread out at
all over a distance of a few thousand feet and thus may still be only a
millimetre or two in diameter.

Complete ********. Just buy a laser pointer and measure the spot size
after 50'. It's already cm wide. The cavity of laser diode is just
too short to produce such high degree of collimation...

Cheers