[geeks] [rescue] Computerfests (was: first real server hardware) -OT

[Sandwich Maker]

" From: Dan Duncan <dand at pcisys.net>
" 
" On Wed, 28 Apr 2004, Sandwich Maker wrote:
" > " I always picture that or a tracking error looking something like
" > " the beam that took out the White House in Independence Day.
" >
" > would 1GW be enough power?
" 
" Good point.  We should increase it.  It's the only way to be sure.
" 
" > if the beam is roughly as intense as sunlight - that is, ~1kw/m^2 - a
" > 1GW beam would cover 1km^2.  iirc, the sps proposals had -lower-
" > intensities and -larger rectennas.
" > you won't cook much with that.
" 
" Why would you want to maintain a 1km^2 collection area instead of
" something smaller?  Eventually you're going to have to focus it
" into a smaller dot to do anything with it besides grow crops.  I
" suspect your losses to atmospheric resistance are minimized by
" using a smaller beam.  You might as well overlap the focus
" point of several mirrors to get a brighter spot.  If you're using
" solar panels, you can make them to handle light brighter than sunlight.

the size of the sps microwave beam was that big, and you don't gain
anything in efficiency by making the rectenna smaller.  in fact, with
the wavelength they were talking about, the rectenna could be mostly
air which means you could grow crops under it.

unless there's some serious nonlinearity, beam loss is simply a
function of power and wavelength.  intensity cancels size.

" > p.s. if you're already beaming microwaves, why boil water with it?
" 
" If we're distilling ethanol, it would be fine.  If we want electricity,
" we could convert microwaves directly, but we'd probably have to get the
" microwaves from solar panels which aren't that efficient YET.

the sps designs proposed included solar cells or arrays of solar
stirling generators, with a distributed phased-array transmitting
antenna.

" If we
" want electricity from focused sunlight, our best bet is still probably
" to boil water until solar panels become more efficient.  We still boil
" water in coal or nuclear power plants.

it could be focused onto a stirling engine, but that's still a heat
engine.



" From: wa2egp at att.net
" 
" 
" How about synchonous satellites over the equator teathered by carbon nanotube
" cables which carry the "juice". 

the sps designs that i saw were to be in synch orbit iirc.  one of the
reasons for the low intensity beam was safety - little or nothing
would happen if it wandered off the rectenna.
________________________________________________________________________
Andrew Hay                                  the genius nature
internet rambler                            is to see what all have seen
adh at an.bradford.ma.us                       and think what none thought