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Old May 26th 06, 12:13 AM posted to rec.radio.amateur.antenna
 
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Default G..g..g..en....genetic???

OK, I'm a bit worried about bringing up this topic given that my search
of r.r.a.a. archives has turned up the fact that this has been a very
contentious topic in the past... but

GENETIC ANTENNA OPTIMIZATION

There, I got it out.

I'm interested in the possibility of using this kind of search of the
space of possible antennas in those situations that we all end up in,
you've put the antenna too close to the tower, you're shoehorning it
into the attic, or you really really need to mount it on the bumper and
not on the roof.

Has anyone written any software that could do this? I guess what I'm
imagining is that you input the location and extent of fixed
conductors, the tower, the car (yes i know it's hard), the wiring in
the walls, whatever, and then you let the computer chew on what
particular weird zig-zag of metal will give you the pattern you *want*
rather than living with the pattern of an antenna designed without the
additional conductors in place.

For attic antennas, you could have a figure of merit based on some
combination of minimizing loss and minimizing the currents induced in
the fixed conductors. Keep that RF off the house wiring, and the noise
off the antenna, while still radiating most of your power?

I guess there was some prior discussion of use of genetic optimization
processes to design amateur antennas being of dubious legality because
of patents... if this is the case, forget I even posted it.

I could imagine this being of great use to the restricted-space amateur
if the code to do it would be tractable and a sensible interface were
present.

Roy, you wanna write an EZNEC plugin that takes wires #n to #m and
fiddles with them until the far field is within some tolerance of a
desired pattern? I bet it would sell...

It's a thought. I'd be interested in what other people think... the
word "genetic" could even be dropped if it is a sticking point since I
don't really care what particular approach is taken to push the design
toward some goal.

73,
Dan
N3OX
www.n3ox.net