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Old February 22nd 05, 01:40 PM
Tam/WB2TT
 
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"Larry Gauthier (K8UT)" wrote in message
...
Jim,

I have also tried several horizontal and vertical combinations (everything
you mentioned except a quad loop) on 30 meters. After lots of very
unscientific experimentation and observation, I ended up with: A
multi-band vertical (Hy-gain AV-640) which I use as my 'reference'
antenna, and a horizontal delta loop at about 40 feet. I find the delta
loop quieter than a previous dipole or the AV-640 vertical; it has a
flatter SWR curve (although that doesn't seem to matter much on the narrow
frequency allocation on 30 meters); and gives me better DX signal
reception _almost_ all the time (once in a while the vertical beats the
loop, but it's rare). The delta loop's characteristic impedance is 100
ohms, and I feed it in the corner with a 1/4 wavelength of RG/6 as a
matching balun. Although the calculated length of the loop should be 97.14
feet (frequ/983), I found that the best resonance occurs when the total
wire length is closer to 103 feet (lesson: you can always cut it shorter,
but can't cut it longer).

--
-larry
K8UT


Larry,

You don't apply the dipole fudge factor to full size loops. In fact, some
people claim it should be longer than a free space wavelength. I have seen
various formulas for the length between 1000/f and 1030/f feet. I started
out with 1030/f, but ended up shortening it by about 2 %. I suspect some of
that depends on how close to ground you are; also, I think my wire
stretched.

Tam/WB2TT

"Jim Leder" wrote in message

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