On Dec 27 2007, 2:52*pm, (Bob Masta) wrote:
On Wed, 26 Dec 2007 09:01:06 -0500, "Ethan Winer" ethanw at
ethanwiner dot com wrote:
Bob,
The output is not "focused" in the same sense as when the dish is used as
a collector
Yes, but the person away from the collector isn't a "large" source either..
So it still seems it would be 100 percent reciprocal, no?
This is like half of a pair of reflectors like you see in parks, where two
people can be hundreds of yards away and talk as if they're next to each
other.
You have given the answer in your example: *If one reflector was all
it took to get 100% reciprocal operation, then they wouldn't use
two reflectors.
Suppose we think of this with light beams instead of sound waves,
and use laser pointers so that we have a planar wave front. * The
guy without a reflector can aim his beam at the distant reflector,
which might have an area of (say) 10 square feet, and anywhere
he aims within that area the beam will be captured and received
more-or-less 100% at the focal point. But the guy at the focal
point can't do the same thing in reverse. *He either needs to aim
his beam *exactly* at the other guy (avoiding the reflector, or
bouncing it on a careful trajectory), or else he needs many, many
beams at slightly different trajectories so that they will cover
the same 10 square-foot area at full intensity at the reflectorless
guy's end. *
Best regards,
Bob Masta
* * * * * * * DAQARTA *v3.50
* *Data AcQuisition And Real-Time Analysis
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Scope, Spectrum, Spectrogram, FREE Signal Generator
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In that connection seems a procedure interesting, restores acoustic
wave fronts according huygens principle:
http:
www.syntheticwave.de
H.