On Apr 9, 3:03*pm, Roy Lewallen wrote:
Keith Dysart wrote:
On Apr 8, 8:51 am, Cecil Moore wrote:
. . .
The
forward wave flows unimpeded through the node as does
the equal magnitude reflected wave. The net energy flow
is zero. The average energy flow is zero.

Anyone who believes there is zero energy at a standing-
wave current node should touch that point on a transmission
line (which just happens to be the same point as the
maximum voltage anti-node).

No one has said there is zero energy. Only that there is
zero energy flow. For energy flow, one needs simultaneous
voltage and current.
. . .

In the interesting case of a current node on an infinite-SWR line, it
appears we do have energy flow without any current, and therefore
without power. Energy flows into the node from both directions in equal
amounts at the same time, and out to both directions in equal amounts at
the same time.

I think I would be tempted to cut the node down the middle creating
two nodes with no current flow or energy flow between them.

What we don't have is *net* energy flow at the node.
Likewise, there's charge flowing into the node from both directions, and
out in both directions, which results in the zero net current. I don't
believe that's the same as saying there's no energy or charge flow at
all, even though the power and current are zero. And it's not necessary
to separately consider forward and reverse waves of current, energy, or
power in order to observe this -- it can be seen from looking only at
the total charge or energy.

One thought experiment I rather like is the infinite SWR ideal line.
Cut the line at all the current zeroes. The voltage, current, and,
I'd suggest, the energy distribution do not change. The line can
be re-assembled, again with no change.

Those who argue that energy is crossing the node, have to explain that
the cut has completely changed the mechanism that keeps the net energy
in its place, but the voltage and current distributions remain the
same. I prefer the basic circuit theory tenet that one can cut a
line carrying no current without impacting the circuit. This leads
to a model with no energy crossing the node.

...Keith