Current through coils
"Gene Fuller" wrote:
I did not say anything about W8JI's measurements. He had a completely
different setup, and I had nothing to do with it.
Didn't say you did and it's good that the two were unrelated -
just wanted to point out the contradictions between your
EZNEC results and W8JI's 3 nS measurements.
I have uncovered a slight conceptual error in my traveling wave
antenna simulation. I took care to eliminate reflections between
the top of the coil and the load on the traveling wave wire. But
I didn't do anything to eliminate reflections from the bottom of
the coil. So the current phase at the load at the bottom of the
coil is not from a traveling wave. It is instead from a standing
wave or a combination of the two waves.
The bottom section is one foot long. Knowing the frequency,
e.g. 4 MHz, allows us to calculate the delay in that one foot
of wire, i.e. 0.0041 WL = 1.5 degrees. So the current
phase at the bottom of the coil is -1.5 degrees on 4 MHz.
With the current phase at the top of the coil being 10.72
degrees, that gives a phase shift through the coil of
9.22 degrees which is equivalent to 6.4 nS, more than
double W8JI's measured value still posted to his web page.
--
73, Cecil, W5DXP
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