"Slingsby" wrote in message
om...
Robert John wrote in
message ...
SNIP
A
flat signal mirror has a narrow and therefor much brighter
beam.


You can also buy little stick on convex mirrors for $2.00 or less each
at auto parts stores. Wouldn't the reflected light go out in a cone
shape? After a few hundred feet the cone pattern could be quite
large.

...and therefore (by the law of inverse squares) not nearly as bright.

Vaughn