Rick said-
"The fiberglass tubes lower the resonant frequency by an uncontrolled
amount, since they are just fishing poles that do not have any exact
permittivity value. It is analogous to FR-4 PC boards where the impedance
is to some extent an accident of the characteristics of the epoxy glass.
SteppIR has sourced the tubes from various vendors over the years which
further complicates the issue. Any correction factor you would use would be
specific to a particular run of tubes. SteppIR seems to gloss over this
issue. There is a parameter you can set on the controller that scales all
elements by a fudge factor that can be determined experimentally for the
particular copy of the antenna that is being used".
So how do we know that the defaults in our controllers match our tubes? Do
the properties of the tubes change over time as the tubes age? Does the
paint manner?
Thanks,
William Osborne-K5ZQ
<mailto:Wosborne44@gmail.com> Wosborne44@gmail.com
270-205-9565
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