On Sun, 24 May 2009 22:34:09 +0100, Steve Hunt wrote:
>I was shooting for 1.9MHz.
Steve,
One important point. An inductively loaded antenna isn't going to be
very broadband. Less of a problem if your feedline is fat coax and
short as a fraction of a wavelength. You didn't say what your
objective is. Here in NA, virtually all of the CW action is below
1840 kHz except during contests, and even then, CW rarely extends
much above 1900 kHz, and only for a few peak hours.
Another set of thoughts. The smart money says to put your loading as
close to the top as practical, and try to get as much loading as
possible from capacitance (those top wires). Think about how you
might add more than two top wires, even if they must slope, run
irregularly, or even as a fan.
As to the fan -- let's say your supports allow a Tee shape top.
Consider increasing the capacitance of the top by making both sides
of the top of the Tee parallel wires with spacers, the wider the
better! I've not modeled it, but it should work.
73,
Jim Brown K9YC
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