I am trying to find a printed reference to what happens to the
resonant frequency as the antenna height is moved from ground level to
the operating position. (~1/4 wavelength) I've looked in several
references (including the handbook and antenna book, among others). I
know I've seen a plot somewhere, but I cant find it.
The subject came up while our club was putting up an 80m dipole for
the county Emergency Operating Center. We have one end up about 60 feet,
and the other at about 40 feet (it got caught under a Big tree limb).
The lowest SWR we could achieve was at the design frequency of 3.9 MHz.
It was about 1.6 : 1 using an MFJ-259 analyzer and lowering, trimming,
and raising it several times. We fed it with 100 feet of RG-8X to keep
the weight down.
In case someone wants to know, we used (free) #12 insulated stranded
wire for the antenna, but I would have expected a little lower final SWR.
Thanks,
Rod Johnson KA7YOU
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