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Old June 10th 06, 10:50 PM posted to rec.radio.amateur.antenna
 
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Default Dumb question #433,444,007 - Answer from ARRL Ant Book?


Ken Bessler wrote:
Help? Do I trim or not? I have done some tests with the ant
up and I'm noticing my F/B ratio is not as good as the EZNEC
model predicted (30.62 db predicted, I'm seeing maybe 2-3db)



The Handbook means the self-resonant frequency with no other elements
around. They do NOT mean compared to the size of the driven element.

A driven element can move higher or lower in frequency as you add other
elements, depending on the tuning of the other elements.

I usually do all my F/B tuning first, and then SWR last. By the way, I
HOPE you have a balun at the feedpoint. Without a balun at the
feedpoint, the F/B can be seriously diminished.

73 Tom