Trakar Shaitanaku wrote:

On Sat, 04 Sep 2004 21:14:17 GMT, Ed <vegased@stripbigfoot.com> wrote:

In other words, would they try to let us know that they exist or would
they simply keep track of us?

Personally, when one considers the risk potentials, broadcasting one's
presence probably is not a good idea, merely from an economics point
of view, if nothing else.

   Depends on your idea of economics.

   Terrestrial broadcasting is done becaise it's more economical than
running communication cables to every possible fixed location, not to
mention recievers in motion.

   Now, at VHF and UHF, pains are taken to concentrate the energy 
toward the horizon, as that's where the intended audience is. Unless one
intentionally creates patterns (frequent at AM broadcast frequencies),
signals are non-directional in horizontal directions, but as little
energyas possible is radiated skyward.

   But there's always the possibility that a civilization at a star
that's near the horizon will happen to be listening in this direction at
the right time, X years later...and there will always be many other such
stations on Earht's limb, in the same part of the spectrum, at any given
moment, from any distant viewpoint...

   And there's always the chance that someone else will be doing
something similar. If not now, then a century or so from now, when we
have Aricebo+ sized dishes in free-fall and/or on the Lunar Farside,
with a better chance to spot such unintentional interstellar signals.

-- 

   You know what to remove, to reply....