I have a copy of the Yardley article. I was trying the concept to work up a
80/30 trap dipole but found that being too close to the third harmonic it
was impossible for me to get both the 80m and 30m sections resonant. I was
designing for 80m then looking at the 30m portion and even though it's a
tiny band I could never bring the impedance into range.
I was using EZNEC+ latest version.
Anyone have any ideas if this will work?
Thanks
jim ab3cv
On Sun, May 26, 2013 at 3:37 PM, James Duffey <jamesduffey@comcast.net>wrote:
>
> Hans - Try:
>
> "Designing Trap Antennas: A New Approach" by Yardley Beers W0JF Ham
> Radio August 1987"
>
> He also had a couple of articles in QEX. A search on the ARRL periodical
> index should lead you to them.
>
> You don't need the article though. The trap should be resonant at the
> geometric mean of the higher and lower frequency, trap = sort(floe*fhigh).
> The antenna length should be what a dipole is at this geometric mean
> frequency and the traps should be in the center of each leg.
>
> There are other variations where the trap is not in the center of each
> leg. I think the QEX articles discuss them. - Duffey KK6MC
> --
> KK6MC
> James Duffey
> Cedar Crest NM
>
> >
>
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