[linux-elitists] Must have free space lasers!

Ben Woodard ben@valinux.com
Fri May 4 07:40:13 PDT 2001


It is easier than you think. Ham radio people do what is called EME
(Earth Moon Earth) radio contacts all the time. There is significant
signal loss along the way but it is actually quite doable. With a few
hundred watts of RF power and a directional antenna you can do it
reliably. I just read a message a couple of days ago about someone who
did it with only 5W. Of course they had a 12' dish antenna on one end
and a 10' dish antenna and were using experimental DSP based
radios. However 5W for EME is really impressive.

-ben


> Mr . Bad writes:
> 
> > >>>>> "EL" == Eugene Leitl <Eugene.Leitl@lrz.uni-muenchen.de> writes:
> > 
> >     >>  Anyone tried free space lasers yet? And does the
> >     >> lightpointe.com web
> > 
> >     EL> You mean line of sight (LoS) lasers? I've seen a 119 kBps DIY
> >     EL> laser modem from some folks in Oz, but anything else looks
> >     EL> really expensive, like.
> > 
> > Damn, I thought this was about, like, satellite-mounted laser weapons
> > I could use for free (kinda like the zPenguin thingy, but way more
> > destructive).
> > 
> > I'm trying to think of how you'd do laser communication that -wasn't-
> > line-of-sight. I mean, unless you don't count mirrors as
> > line-of-sight. Can you do atmospheric bounce with lasers? Masers?
> 
> You know, I read in a book how there's a retroreflector on the Moon.
> So you can use the Moon to talk to yourself, if you can find the
> retroreflector...
> 
> http://www.lpi.usra.edu/pub/expmoon/Apollo11/A11_Experiments_LRRR.html
> 
> -- 
> Seth David Schoen <schoen@loyalty.org>  | And do not say, I will study when I
> Temp.  http://www.loyalty.org/~schoen/  | have leisure; for perhaps you will
> down:  http://www.loyalty.org/   (CAF)  | not have leisure.  -- Pirke Avot 2:5
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