KB9MZ (via K3BU):
>And it appears that even the most seasoned of amateurs just focus on GAIN,
>F/B and SWR which is really a very unwise and immature aproach.
I just wanted to give a plug for K6STI's Global Yagi Optimizer
program YO7. An article about it was in the July CQ (page 30). There
was an incorrect figure (Fig. 4) which was corrected in a later issue.
This is one of the most powerful and easy-to-use programs I've
ever seen to do exactly what Art described. It will allow you to weight
Gain, F/B, SWR and Zo over any chosen bandwidth. The program statistically
searches different combinations of element spacings and lengths to optimize
the tradeoff combination you choose. F/B is optimized for a figure of merit
based on the backside pattern rather than a single point measurement at 180
degrees. YO7 also shows you a graphical plot of the patterns at the low,
middle and high ends of the frequency range you choose.
Using YO7, I optimized my KLM 610 3-stack for 35' spacing. Gain
improved by .85 dB, F/B by 7.15 dB, and SWR by 0.2 at the center frequency of
28.4 and improvements were even better at 28.0. It was well worth the $100
cost and I only wish I had used it before I put the antennas up the first
time! After using my stack the first season, I felt the F/B was not what it
should be and YO7 told me how to make everything work better. Brian does
still his software and can be contacted at k6sti@n2.net. I have no interest
in his software except as a VERY satisfied customer.
73, Bill W4ZV
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