On Wed, 12 Jul 2006 21:16:29 -0500, Tom Ring
wrote:

He got the designs as right as possible, using an EME'rs version of
right. He hit max gain for boomlength within less than 1dB, pattern is
wonderful, SWR BW is astonishing, and pattern and gain are all fairly
constant across the usable SWR BW. Input impedance is not too low, at
about 20-25 ohms, and efficient match can be had with a T-match. And it
handles ice and rain detuning perfectly. Build sensitivity is nice; you
can skew the design by induced errors of +-2mm element length and +-5mm
vertical off the boom and +-2mm element position on the boom with no
significant change. Gain not off by .1dB, pattern not off by 2dB,
normally less. I ran a lot of tests. And I could be misremembering a
bit, but probably by too high rather than too low.

Hi Tom,

This is all pretty significant stuff. Its success probably ties in
with what Reggie had to say about the quality of automated software
being tied to the competence of the user/designer (Reggie may wish to
distance himself from my paraphrase however).

As a negative example, some half decade or more ago we had a fractal
designer who threw as much computational horsepower at this as his
budget would allow in hiring eager, bright faced graduates building
parallel processors. They perhaps knew Genetic Algorithms (the hot
topic in academia whose bloom had long faded in cut-throat industry),
but certainly nothing about the bajillion degrees of freedom in
antenna design. Well, that stack of computers was more a marketing
paper weight than a design producer - I've never seen an independent
headline announcing the dawn of a new age of fractals in Boston. In
fact, it would seem that same NASA program stole their thunder - and
it is still a yawn.

73's
Richard Clark, KB7QHC