Partly because you used a conductor diameter about 16.5mm and Reg's
was 10mm. (Don't think I'd want to make a self-supporting element
that long and that thin, myself. Maybe 50mm at the base and tapering
to 25 or so?) That probably does not account for the whole
difference. Did you both use the same sort of "ground plane"? Height
above earth has only a slight effect.

Cheers,
Tom


"JLB" wrote in message ...
Kraus (2nd edition, p. 375) gives a different answer.

Interpolating from the diagram on p. 375 (assuming length/diameter = 472) it
is about 90-j250.

Why the difference?

--
Jim
N8EE

to email directly, send to my call sign at arrl dot net
"Reg Edwards" wrote in message
...
For a 5/8-wave vertical above ground at 24 MHz, conductor diameter 10
mm. -

Base feedpoint resistance = 110 ohms
Base feedpoint reactance = -j386 ohms
Base loading coil inductance = 2.6 uH
Coil diameter = 25 mm
Coil length = 33 mm
Number of spaced turns = 13
Wire = 14 awg = 1.64 mm diameter.

For other heights, frequencies and coil dimensions download in a few
seconds
program BOTLOAD for immediate answers.
----
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