Cecil Moore wrote:
Jim Kelley wrote:

I'd like to see your Norton analysis of that one.


RF is not DC. Edison questioned how one could measure
100 volts between any two of three terminals. :-)

Are you implying yours is a 3-phase antenna? :-)

ac6xg

Jim Kelley wrote:
Are you implying yours is a 3-phase antenna? :-)

No, just that phasing of RF signals is what is confusing
the DC gurus, just like AC phasing confused Edison.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:

Jim Kelley wrote:

Are you implying yours is a 3-phase antenna? :-)


No, just that phasing of RF signals is what is confusing
the DC gurus, just like AC phasing confused Edison.

What is a DC guru, and why do you address comments to them?

As a suggestion, you might consider increasing the current for the
EZNEC simulation on your webpage. At 20 amps per division it's plus
or minus a pixel at 1024x768.

73, ac6xg

Jim Kelley wrote:
As a suggestion, you might consider increasing the current for the EZNEC
simulation on your webpage. At 20 amps per division it's plus or minus
a pixel at 1024x768.

Excellent suggestion, Jim. I'm sure there is a way to do that
within the EXCEL charting function but, so far, I haven't figured
out how to split the scales. I was going to mow the yard but it's
92 degrees out there and I would rather play with EZNEC anyway.
--
73, Cecil http://www.w5dxp.com

Jim Kelley wrote:
As a suggestion, you might consider increasing the current for the EZNEC
simulation on your webpage.

Done as you suggested by changing the current amplitude scale.
What do you think about the simulation? Stand by for more
additions to that web page.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:

Jim Kelley wrote:

As a suggestion, you might consider increasing the current for the
EZNEC simulation on your webpage.


Done as you suggested by changing the current amplitude scale.
What do you think about the simulation? Stand by for more
additions to that web page.

From what I gathered, the objective of loading the coil with its
characteristic impedance was that there would be no reflection. I was
therefore surprised when you reported something other than a straight
line for the current amplitude along the radiator (let alone an
increase at some point). It is now apparent that what you are
actually plotting is the superposed forward and reflected currents,
and that you have somewhat more than a negligible amount of reflected
current.

The primary utility in looking at the standing wave profile lies in
the fact that it gives an idea of what the superposed field intensity
plot might look like in the near field of the antenna. But it is
obviously the currents associated with waves traveling on the antenna,
both forward and reflected, that actually do the radiating.

I agree with you that it is useful to understand the exact effect the
loading coil has on the traveling wave, and hence the standing wave
profile of the antenna. But I still think it would be prudent to
explore and understand the precise nature of the delay through the
coil more thoroughly before making too many assumptions about this.

73, Jim AC6XG

Jim Kelley wrote:
I was
therefore surprised when you reported something other than a straight
line for the current amplitude along the radiator (let alone an increase
at some point).

Just proves that you are not omniscient. Such is the nature
of a real world inductance especially close to self-resonance.
This is just evidence of another failure of lumped inductance
models. The current through a real-world inductance is NOT
linear if the operating frequency is within 15% of the self-
resonant frequency. For the Nth time, please read and
understand the IEEE white paper at:

http://www.ttr.com/TELSIKS2001-MASTER-1.pdf
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:

Jim Kelley wrote:

I was therefore surprised when you reported something other than a
straight line for the current amplitude along the radiator (let alone
an increase at some point).


Just proves that you are not omniscient.

I doubt that proof of that is actually required. In fact, I think
you'll find that to be true in general for other people as well.


For the Nth time, please read and
understand the IEEE white paper at:

http://www.ttr.com/TELSIKS2001-MASTER-1.pdf

University of Yugoslavia. Yeah, sure thing. Whether it's valid or
not, I'm not convinced that's what you have in your EZNEC printout.
And unless Roy accounts for "current pileup", it's unlikely that it
would show up there.

73, AC6XG

Cecil, W5DXP wrote:
"No, just that phasing of RF signals is what is confusing the DC gurus,
just like AC phasing confused Edison."

In W8JI`s pages I found this on the subject of "Mobile antennas, short
verticals, loading" :
It`s long and Tom warns about taking anything from context, so it should
be searched out and read in its entirety. I have no quarrel with most of
Tom`s pages but find this statement curious:
"When current flows in the transmitter-end of the coil, a magnetic field
is created. The time-varying magnetic field causes charges in the other
turns to instantly move."

Instant movement of charges is instant current, and everyone knows that
current in a coil lags the voltage.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:
"When current flows in the transmitter-end of the coil, a magnetic field
is created. The time-varying magnetic field causes charges in the other
turns to instantly move."

Instant movement of charges is instant current, and everyone knows that
current in a coil lags the voltage.

Instant movement of charges is impossible except in the mind
of someone using the lumped-element model. Apparently, anything
is possible in that kind of mind. As Dr. Corum said: "Lumped
circuit theory fails because it's a *theory* whose presuppositions
are inadequate. Every EE in the world was warned of this in their
first sophomore circuits course. ... Lumped circuit theory isn't
absolute truth, it's only an analytical *theory* - and in those
resonators we have the case where this sophomore *theory* fails
*experimentally. The engineer must either use Maxwell's equations
or distributed elements to model reality."
--
73, Cecil http://www.w5dxp.com