Cecil Moore wrote:


The decrease (drop) in current across a loading coil installed in
a standing-wave antenna does NOT in any way violate Kirchhoff's current
law.

True.

One can imply from Kirchhoff's current law that there is no current
decrease (drop) across a point.

By 'point' I believe you are referring to what is commonly referred to
as a node. Kirchoff's current law stipulates that charge may not
accumulate at nodes. Therefore by definition, any feature of the system
where charge accumulation needs to be considered is not a node. This
makes sense since charge must accumulate on a surface (surface charge
density) (coul / meter squared) or in a dielectric volume (volume charge
density) (coul / meter cubed). Both concepts require some sort of
area or volume which is inconsistant with the notion of a node.

I don't know anyone who disagrees with
that so any argument is just a straw man. Kirchhoff never said the
current at one point in a network had to equal the current at another
point in the network.

The currents through two nodes connected in series, without branches, is
identical. I think that fact was established before Kirchoff but it's
certainly stipulated in circuit theory.

Many patches have been added to the DC circuit model to try to adapt
it to RF networks.

Many? Seems to me that the concept of electric displacement introduced
by Maxwell provides everything needed to extend DC theory all the way
through classical electromagnetics. What am I missing?

Some function after a fashion and some fail utterly.

Like what?

We all need to be able to recognize the difference. For EM waves, the
E-field and H-field are often affected in the same way.

Huh?

Saying that
the E-field voltage drops but the H-field current doesn't drop is
simply nonsense.

Saying the electric field voltage drops is nonsense. Voltage is the
scalar potential defined as the electric potential difference between
two points in space.

The electric field is vector field, characterized as having a field
strength in volts per meter dependant on spatial location, direction,
and perhaps time.

I don't understand what the term 'E-field voltage drop' could mean.
Same with 'H-field current drop'.

Likewise, saying that the H-field current flows and
the E-field voltage doesn't flow is nonsense.

H-field current flows?

The field H (amps per meter), is the so called magnemotive field. It
doesn't flow anymore than voltage flows through a resistor, and is
associated with the generation of magnetic flux. The magnetic flux
density, B, has the units of webers per meter squared and can be
integrated over an arbitrary surface to evaluate the total magnetic flux
passing through that surface. Magnetic flux is somewhat analogous to
current but H is not at all.

The E-field and H-field
are usually inseparable.

In the classical electromagnetic model, E & H are completely separable.
They are coupled via Faraday's law, and Maxwell's so called
displacement current. At steady state (DC) no coupling exists. When
one field quantity _varies_ in time, so will the other in accordance
with the curl equations. The coupling described by the time varying
part of the curl equations only involves the time varying components.

When determining the analysis method used to gather insight into a
physical system, one of the first considerations is to determine if the
time varying field components need to be considered, and if so, which
ones. For example, analysis of a 60 Hz power supply choke, or electric
motor, usually ignores the electric field in the air gap arising from
the time varying magnetic flux density. It's not important in the gap,
but is the driver of undesirable eddy currents in the core laminations.

bart
wb6hqk