Jim Brown wrote:
> 4) I would NOT try to put dipoles in a fan that are "in between
> harmonics" of others in the fan. That is, I would not put 30M in a fan
> with 40, because it is more likely to interact with the other dipoles.
> On the other hand, my 80/40 fans load quite nicely on 30M, and they
> play very well. They also load and work well on 17M and 12M!
I have dipoles for 80/75, 40, 30, 17, and 12 working on one feedline.
Actually, it is an inverted vee, with the center at 65' and the ends of
the 80M wires at about 30'.
The antenna started out as the "Converted-Vee" design from an article by
W6JKR (now N6ET) in Ham Radio Magazine, December 1969 issue. That design
is two wires separated by about 6", one for 40 and the other for 75. At
the end of the wires for 75 there is a trap resonant at 3750 and a short
extension which makes the antenna also usable on 80. I've been using
this since 1971.
When I got seriously interested in the WARC bands, I added three
additional wires. The total separation is still 6", so near the center
where there are five wires they are only 1.5" apart. There is
substantial interaction, and tuning the added wires was not a trivial
process. It would have been near impossible without an MFJ-259 or
equivalent. I could never get the 12M wire all the way down to 1:1
because there are so many interactions and resonances, but it is good
enough that the tuner in my FT-1000 can handle it.
How well does it work? Well enough to work 240 countries on 30M, 255 on
17M, and 160 on 12M since 2004 running only 200 watts. Since my tower
isn't big enough to add a second yagi to cover the WARC bands, I'm very
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