Tom Donaly wrote:
Richard Harrison wrote:

Tom Donaly, KA6RUH wrote:
"There may be a difference in current along the coil, but it isn`t a
current drop."
Call it a decline if you don`t like the word drop.
A wave traveling along an antenna induces current in the wire. This
current causes radiation from the wire. A current traveling from
"a" to "b" in the wire loses energy to
radiation. The energy at "b" is less than the energy at "a" if the
source is at "a".
If the impedance at "a" is the same as the impedance at "b", the
voltage
and the current at "a" are larger than the voltage and current at "b".
We don`t need energy to decline from "a" to "b" to have a current
drop.
We only need current to decline between "a" and "b". Yuri has
demonstrated a "current drop" with r-f ammeters inserted at both ends of
the loading coil. Analysis of the cause is not necessary to demonstrate
a current drop.
As straight wires are usually better radiators than the same wire in
coils, I speculate that the current drop measured by Yuri is mostly due
to the high impedance (High voltage, low current) on the output of the
loading coil.
Best regards, Richard Harrison, KB5WZI


I would urge any young person who reads this and wants to understand
electromagnetics to get a good book on the subject, read what the
authors say, and forget what Richard just posted. He's all wrong.

Well, not entirely, if he follows through the logic of what he says. An
ideal loading inductance does *not* radiate; therefore the current at
its two terminals *must* be the same.

I keep coming back to the same point: until someone correctly
understands what pure unadulterated inductance does in an antenna, he
can never *truly* understand how a real-life loading coil works.



--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek