Yuri Blanarovich wrote:
In a nutshell, I (and W9UCW, etc.) found that current diminishes accross the
coil. W8JI using Kirchoff and Ohm says it can't.

If you put a loading coil 1/3 of the way up on an end-fed 1/2WL
vertical, the net current will increase across the coil. The
net current can decrease, or increase, or be the same magnitude
for special cases. Think Ifwd+Iref with the coil causing major
phase shifts.

Open-ended antennas like dipoles are standing wave antennas. The
forward current is relatively constant through the coil and the
reflected current is relatively constant through the coil. But
the phasor sum of those two currents can vary wildly from end
to end in the coil because of phase shifts.
--
73, Cecil http://www.qsl.net/w5dxp



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Open-ended antennas like dipoles are standing wave antennas. The
forward current is relatively constant through the coil and the
reflected current is relatively constant through the coil. But
the phasor sum of those two currents can vary wildly from end
to end in the coil because of phase shifts.
--
73, Cecil http://www.qsl.net/w5dxp


Don't we have a case of coil being RF choke to certain extent?
Also I think that behaviour of radiator before and after the coil defines the
magnitude of the current, no?

Yuri, K3BU

Yuri Blanarovich wrote:

Open-ended antennas like dipoles are standing wave antennas. The
forward current is relatively constant through the coil and the
reflected current is relatively constant through the coil. But
the phasor sum of those two currents can vary wildly from end
to end in the coil because of phase shifts.

Don't we have a case of coil being RF choke to certain extent?

RF chokes are usually high enough impedance to drop virtually all
the RF voltage across the choke.

Also I think that behaviour of radiator before and after the coil defines the
magnitude of the current, no?

It can be thought of as a very lossy transmission line where
the loss is radiation. Please see my other posting comparing
a 1/2WL dipole to a loaded dipole.
--
73, Cecil http://www.qsl.net/w5dxp



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