Cecil Moore wrote:
Consider a lossless open-circuit transmission line with reflections.
At one current loop maximum on the line, the instantaneous current
will be positive, i.e. flowing toward the load. At the next current
loop maximum, the instantaneous current will be negative, i.e. flowing
toward the source. 1/2 cycle later, these values reverse sign and
direction.

I think the word you're looking for is *Node*.

Assume the following graphic snapshot of a standing wave
is sinusoidal and includes magnitude and phase.



_
/ \
/ \
_/__________\________________
\ /
\ /
\ _ /

1/2 cycle later the snapshot will look like this. Anyone who doesn't
believe it has never seen it on an o'scope.
_
/ \
/ \
______________/__________\_
\ /
\ /
\ _ /

Right. But the antenna current plots are of the amplitude term of the
standing wave, shown as a function of position. It's not a time plot.
In the equation E*sin(w), E is the amplitude term. The amplitude term
is a contant. It does not vary with time. It varies with position
along the antenna. The solution to E*sin(w) does vary with time because
it is a function of time. You're confusing the two different
functions. Your answer, typically, is that the math is wrong.

73, Jim AC6XG


_
/ \
/ \
______________/__________\_
\ /
\ /
\ /
\ _ /

By the way, here is an I(t) plot where there is a *net* flow of current.

Jim Kelley wrote:
The amplitude term is a contant. It does not vary with time.

Uh Jim, please look at this web page and tell me again
that the amplitude is constant and doesn't vary with time.
The standing wave loop looks like a kid's jump rope. Note
that the amplitude of the standing wave is zero everywhere
two times per cycle. How can the amplitude be constant?
It's RF, for goodness sake.

http://einstein.byu.edu/~masong/HTMs...newave2EX.html
--
73, Cecil, W5DXP

Cecil Moore wrote:

Jim Kelley wrote:
The amplitude term is a contant. It does not vary with time.

Uh Jim, please look at this web page and tell me again
that the amplitude is constant and doesn't vary with time.

The amplitude term of an equation, and the one being plotted on an
antenna current plot, is a constant for any given position in a standing
wave. It's the peak amplitude of the time varying function. It's
really not a matter of opinion.

73, Jim AC6XG

Please don't take me for a fool, Cecil. I've done that demo for the
students for 17 years.

At this point you really need to worry less about producing verbal
output, and worry more about being able to properly absorb and utilize
input information. That part seems to be out of order.

Cecil Moore wrote:

Jim Kelley wrote:
The amplitude term is a contant. It does not vary with time.

Uh Jim, please look at this web page and tell me again
that the amplitude is constant and doesn't vary with time.
The standing wave loop looks like a kid's jump rope. Note
that the amplitude of the standing wave is zero everywhere
two times per cycle. How can the amplitude be constant?
It's RF, for goodness sake.

http://einstein.byu.edu/~masong/HTMs...newave2EX.html
--
73, Cecil, W5DXP