Remember (or understand if you did not before) that elevated radials
should be tuned (pruned for length) just like a part of the antenna
(they *are* part of the antenna).
So get out your antenna analyzer and cut one radial a bit on the long
side - attach only that one radial to the vertical and shorten it until
you have the correct readings on the antenna analyzer. Cut the second
radial to the same length - move to the next band and do the same thing
until you are done. Note that the radials can interact on a multiband
setup (just like parallel dipoles), so tune the lowest bands first and
move upward in frequency one band at a time.
The twinlead solution does work, but suffers badly from interaction.
73,
Don W3FPR
Jerry Flanders wrote:
At 04:54 PM 8/19/2008, Vic K2VCO wrote:
Niel Skousen wrote:
I'm installing a used Butternut HF-6v, and the location / elevation
would work with the CPK raised counterpoise. So I'm looking for a
counterpoise kit for a B.Nut HF-6V.. Also, wanting to add 6m, but
that's trivial, unless someone has it sitting around....
You don't need an expensive 'kit'! Just take any old wire and make two
1/4 wavelength radials for each band -- a total of 12 radials. Try to
make them as symmetrical as possible, with the two 40 meter radials
opposite each other, etc.
The ends of the radials must be well-insulated, since even though they
are connected to the coax braid at the center, they will develop
high-ish voltages at the ends.
--
73,
Vic, K2VCO
Details on making a multiband radial from twin-lead are at:
http://www.bencher.com/pdfs/00366IZV.pdf
Jerry W4UK
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