Once again you guys have proved to me that I should keep my day job and
forget about my fascination for theoretical physics. The SciAm article
producing the inspiration was in the May 2007 issue, pg 96. You can read
all about the basic audio technology at www.holosonics.com
Several respondents pointed out that a 432 signal modulated by 2 MHz would
provide a nice 430 and 434 sideband in addition to the 432 carrier. So my
arithmetic was somewhat ill conceived. A better analogy to the audio
version would be to modulate the 432 with a 430 signal, producing a sideband
of 2 MHz and 864 MHz. Once again, the question being does the 2MHz spur
form a wave front analogous to the 432 antenna's pattern or not.
Keith-G3OIT points out that if it worked, why not use laser light to really
form a tight beam? Photons are photons after all. I must retort that
finding a light source stable enough to produce a 1.8MHz difference might be
a bit difficult to construct.
Rick-N6RK and Tom-W8JI (and others) point out that air is
electromagnetically linear. Non-linearity would have to be introduced.
Dan-N3OX suggests that air can be made non-linear by turning up intensities.
At RF you would have to use enough power to create a plasma.
Harold-W0RI suggests that if there were non-linearity in air, then the
spectrum would be filled with mixing products from all sorts of signals
mixing. However, I must retort that naturally occurring signals would all
be arriving on different vectors and would not add or subtract in any
meaningful way.
A decent workshop could easily prove this out. I'd do the experiment myself
but my entire shack was destroyed by a lightning bolt last June. I don't
even own a working radio at the moment. Needless to say I'm RF challenged
at the moment.
How about this? Combine a stable 432 and a 434 signal--even a hybrid
combiner would work. Pump the pair of signals into a 432 yagi and listen to
the 1.8MHz spur at some distance away. Frankly, there is nothing magic
about 432. You could do the same experiment using any yagi--50MHz, 144MHz,
etc, just use 2 signals 1.8MHz apart. Rotate the source antenna while
monitoring the signal strength of the 1.8MHz spur at some distance away.
The pair of signals, separated by 1.8MHz, may possibly combine external to
the antenna since they would be arriving at the detector on the same vector.
Photons do add and cancel each other when they occupy the same space--there
can be no denial of that. The real issue is whether they will add and
subtract in a way so as to produce a 1.8MHz envelope and a related wave
front.
Ford-N0FP
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