The Naval Underwater Systems Center in New London CT had (at least in the
1980s) an antenna range with three semi-spherical arms (ok, call it a 3
legged arch) over a metal "sea" that they used to measure antenna
patterns on scale model ships (at scale model frequencies).
The "arches" supported their probe antennas, and were remotely controlled
(perhaps even automated) and thus they could get fairly nice plots
quickly. The ship model could rotate as well, simplifying the entire
scheme.
Now, in one of my older books, most likely from the ARRL, there was a
discussion about modeling HF beams at VHF/UHF/SHF frequencies, and
measuring the near and far fields (hey, at 2.3 GHz, you don't have to go
all that far to get into the realm of far-field).
For those who absolutely hate the idea of a computer model, and really
dislike range testing at 1:1 scale, here's YOUR way to test any and all
antennas. Build your own artificial world (well, a small part of it,
anyway), and then build scale models of your desired antennas. You can
then test these antennas under ideal, repeatable conditions. I'd imagine
that once you'd started this venture, you'd get scale models of all sorts
of antennas to test, because with the level playing field you'd provide,
everyone would want a chance to play.
Oh yes, you can prove (or disprove) computer modeling, and perhaps
improve the algorithm. My guess is you'll find the computer modeling much
easier than scale testing ... I suspect the Navy found this out as well.
Might make 'em an offer for their surplus scale antenna ranges!
BTW, keep up the great work Steve! Can't wait to see your books in print
(hint, hint, hint). I'll take autographed first editions, please!
73,
Rick, WB3EXR
On Wed, 27 May 1998 20:01:47 -0500 "Steven H. Sawyers n0yvy"
<sawyers@inav.net> writes:
>>Sorry, not having a helicopter available made the full
>three-dimensional
>pattern test somewhat problematic. :-)
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