"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
......................

I said in the original post that I didn't always trust what modeling
programs say, but in the case of 'length' I tend to agree with what it is
projecting. I've modeled both the Delta and Quad loop over and over, and
they always come out that the best overall length is closer to 1030/f.
1003/f is always too short, at least at 35-40 feet up. Whatever it is, as
Larry pointed out, it's easier to shorten the elements than add to them.
Larry, I use my vertical as you do: a reference antenna. However there are
times when it works better than the dipole. Depends on propagation effects.
Both have a place, but I can't (too lazy) keep the vertical in the grass
cutting season :+)) .

"Tam/WB2TT" wrote in message
news

"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
.....................

I said in the original post that I didn't always trust what modeling
programs say,

==========================

Very sensible!

Don't risk suffering from delusions of accuracy.

Modelling programs are invariably less acurate than the data stuffed into
them.

And the data stuffed into them nearly always contains nonsensical elements.

Yet results are religiously quoted by old-wives as being of gospel truth and
value, equivalent to misquoted, out-of-context, statements by Terman and
Kraus.

Who believes antenna relative gain figures stated in milli-bels at 14 MHz,
or the take-off angle is 20.7 degrees, when the DC ground conductivity is
average and ground permitivity, just as important, is not even mentioned?

And a 1000 other examples.