On May 9, 1:56*pm, wrote:
Tom,

OK, I tried what you suggested. I put my loading coil midway up a 20ft
vertical wire in the EZNEC model. I reduced the number of turns to
lift the resonant frequency to 5.6MHz. EZNEC predicted that the
magnitude of the current at the top of the coil would be 77% of the
magnitude at the bottom.

Then I removed the coil in the model, replaced it with a straight wire
containing an EZNEC lumped load, and adjusted that load for antenna
resonance at 5.6MHz again. I needed +j1630.

Given the dimensions of the coil, the Corum calculator predicted a
lumped circuit equivalent reactance of *+j1573, and it predicted a
current fall-off across the coil of 78%.

Hi Steve,

OK, I'm wondering now exactly what "Corum calulator" you are using
that predices "a current fall-off across the coil of 78%." The
inductance calculator on the HamWaves website that I thought we were
talking about doesn't seem to say anything about "current fall-off" in
coils, though perhaps I'm missing it.

Cheers,
Tom