[Elecraft] OT: Now Balun effectiveness

[Ron D'Eau Claire]

> As you have stated a doublet with open wire feeders can be built to=20
> have a finite and manageable impedance range over two or three bands,=20
> but getting a manageable impedance range on all 9 bands from 160 to 10 =

> metres is almost impossible to achieve.
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True, 'we pay our money and take our pick' <G>
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Keep in mind that the impedance extremes are less extreme as the length =
of
the antenna goes up, measured in wavelengths. The impedance extremes are
usually found when the antenna is 1/2 wave or less long. As a wire is =
made
longer, the impedance at the current and voltage loops grows less and =
less
extreme.

The point is that if the system using an ATU to resonate a radiator and
match it to a 50 ohm transmitter output can handle the impedances at the =
low
end of the frequency range, it is likely to do FB on frequencies where =
the
radiator length is > 1/2 wavelength - certainly when it is > than 1
wavelength.

Ron AC7AC