In article . com,
"RHF" wrote:

Telamon,

At least according to my reads over the years.
Amateurs have been hooking-up their Dipole
Antennas this way for decades using an ATU.

The Twin (2) feed-in-lines would effective make them
a thicker single conductor.

Assuming that the Twin (2) feed-in-line are mostly Vertical
and the Splight Top Wires (2) are mostly Horizontal

Then what you got is . . . {Marconi}
A Moderate Size Vertical Antenna with a Big Top Hat.
[ Gee isn't that what David Said ? ]


A tuner to fix VSWR antenna problems is not a good way to go. It is OK
to use a shack tuner for small values of VSWR so the transmitter finals
don't have to burn the added reflected power or cause instability. The
tuner in the shack does not cause the antenna to perform better.

Because hams operate on a range of frequencies in a band the strategy
is to have it resonant in the center of the band so the VSWR is about
1:1 there. Then it is about the same at the band ends say for example
1.5:1. Now the tuning unit is not needed at all in the band center and
only has to compensate small values of VSWR at the band edges. This is
an acceptable approach to using a shack tuning unit.

Now before some cleaver but silly person mentions that a certain length
of coax will cause the shack tuning unit antenna side to actually
represent the antenna impedance don't bother. While this is true it
only represents certain operating points and is not usable across a
band or bands on a multi-band antenna.

In order to get better antenna efficiency you need a tuning unit that
actually causes the antennas resonant frequency to change as opposed to
a variable impedance matching unit in the shack. This means the tuner
has to be a part of the antenna and that can't happen in the shack.

Now do you see the problem this presents for SW listening 3 to 30 MHz?

***
Yes, paralleling conductors makes them look like a bigger conductor
because RF current travels on the conductor surface. Generally you want
a better circular symmetry than two wires provide. Three would be better
as a minimum. Generally three to five is a good number. This is of
course diameter and frequency dependent number.

***
I would not know what Dave said. He is in the kill file because he keeps
going off the deep end.

Antennas operate in different modes and they can be classified in that
way. Pay attention to how they operate so you can determine what will
work for you depending on your location and needs.

--
Telamon
Ventura, California