acoustics
On Tue, 25 Dec 2007 11:08:38 -0500, John Popelish
wrote:
Now, if you add another parabola at your location, you will
send almost plane waves (spherical waves as if the center
were far from you), almost the reverse of what you received.
The Sante Fe, NM Childrens Museum has a wonderful outdoor
example of this. Two parabolic dishes, doubtlessly C-band
castoffs, face each other across an open space of maybe
fifty feet, centers at a young person's head height.
In front of each dish is a post-mounted yoke, into which you
place your chin. Back-to-back conversation, outdoors, at
about fifty feet and normal conversational volume - it's
big fun.
Much thanks,
Chris Hornbeck
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