> I think that Harold Beverage also came up with one bi-directional design
> that completely dispensed with a reflection transformer and instead used
> one grounded wire and one floating wire. To make that work, isn't the
> length of the Beverage tied to the desired frequency range?
That works after a fashion, but a reflection transformer works better.
The problem is we ignore the accurate definition of balance and unbalance.
There are very few discussions or articles that mention voltage, they
usually only consider current.
A balanced line has equal and opposite currents AND equal and opposite
voltages to surroundings all along the line length.
One wire is grounded, the other open. The line is never in true balanced
mode as a transmission line, and never perfectly unbalanced as an antenna
mode. This renders the last part of the Beverage ineffective in either mode,
and makes the system sensitive to fractions of a wavelength length changes
as common mode impedance changes.
With some pruning and fussing or enough length, I could get 10-15 dB F/B,
but not over wide frequency ranges. I abandoned that idea around 1972 or so
when I was playing with 500 foot Beverages made from real open wire TV line
out on Wilford Rd. :-) If you remember, I had woods to the south, west, and
north only. So my Beverages were in a V starting from the back of my yard.
Back then, Lifetime and Warren both sold 450 ohm TV ladder line. Real air
insulation with white plastic spreaders.
I changed to ferrite core transformers with 73 mix beads as cores, and never
looked back. While they "worked" grounded on one wire, it was a day and
night difference in F/B ratio at the low end.
73 Tom
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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