<< This is all correct. But if the goal of the Setizen is to do a targeted one
star search, then big solid angles of sky coverage is counterproductive. Since
small solid angles are desired, we can use relatively larger aperatures, and
not have the
66 db loss. Instead, lets say the mirror is 10 times smaller. Then the gain
is 100 times less. A lot less than the 100 million times loss! And more than
made up for by the higher EIRP of a powerful laser. Of course, I am lecturing
to the professor again, hehe.
>>
Hi John--
It puzzles me why so many interested in SETI have lost there way. Drake, from
the very first, stressed that SETI was measningless without looking at lots
and lots of stars. There's just nothing intelligent that can be said by
looking at a few stars--and that criticism extends to Phoenix.
A few years ago, some folks at Phoenix tried to be clever by saying "Oh, look
at all the OTHER stars we also see when we look at this target star". But they
stopped. Reason? Because multipath is a killer for all but the nearest stars
and virtually all those other stars in the beam were relatively distant. Of
course, that''s assuming a monochromatic signal...if they had assumed other
modes--and observed for them--they could include all those other stars.
The cosmic haystack is not predominantly a CHANNEL problem--its a TARGET
problem. Looking nearby is, literally, myopic.
73
Chip N1IR