Richard Harrison wrote:
Roy Lewallen, W7EL wrote:
"Am I mistaken, but is this not a clear statement that a copper or
aluminum shield will block magnetic flux along with explanation of why
it happens?"

Yes. And now the rest of the story which I`ve already posted several
times.

At the bottom of page 38 in Terman`s 1955 edition;
"It is possible to shield slectrostatic flux WITHOUT simultaneously
affecting the magnetic field by surrounding the space to be shielded
with a conducting cage that is made in such a way as to provide NO
low-resistance path for the flow of eddy currents, while at the same
time offering a metallic terminal upon which electrostatic flux can
terminate."

I invited readers to look at page 43 in the same book whe
"A grid of wires such as shown in the accompanying figure will provide
electrostatic shielding WITHOUT magnetic shielding---."

I also said that similar grids (metal picket fences) were used in AM
broadcast stations I`d worked in to eliminate capacitive coupling to the
antennas which would otherwise favor harmonics of the broadcast
frequency.

W8JI is yet desiring to drive a stake in the heart of the "myth" that
E&H fields are separable if even for an instant. He is dead wrong.

Certainly the E or H field can disappear for part of a cycle. This
happens routinely in a transmission line or in free space, as the energy
is swapped back and forth between the two components. Tom has never said
this is not so. And for whole cycles you can locally change the ratio of
E/H, but you cannot separate them. Maxwell's equations show this. And if
you do change the ratio of E/H, the normal free space ratio is restored
within a small distance.

The magnetic field alone does quite well in transferring all the wave`s
energy through a special transformer which completely bars the electric
field. Of course, current in the transformer`s secondary produces a
voltage and the E-field is immediately restored.

Yes. And does this restored E field not occupy the space between the
winding and the wire grid? If so, how can you tell that the grid has
"stopped" the E field if it exists on both sides of the grid?

This is not witchcraft. In free-space the electric field and the
magnetic field are repeatedly exchanging all the energy back and forth.
It keeps the wave going.

With this I totally agree. That explanation is related to why you can't
simply remove one component or the other.

At a short or open on a transmission line energy is not lost. It is
merely transferred for an instant into the surviving field.

Similarly, all the energy can be transferred through the electric field
with zero magnetic coupling. Imagine two separately shielded coils. Now,
use a coupling capacitor to transfer the energy from one coil to the
other. Voila! E-field transfer with zero magnetic coupling. It`s no
myth. It`s a fact.

It's a myth that there's no magnetic field in the space between a
capacitor's plates.

Roy Lewallen, W7EL