Cecil, W5DXP wrote:
"Neither the instantaneous magnitude nor instantaneous phase is
constant.'

To keep it simple, phase difference between forward and reflected waves
is locked. Velocity and distance to any point (P) on a transmission line
don`t change. So, pick any reference point you like and the phase
difference is simply (beta)(l), where "beta" is the phase shift per unit
length, and "l" is the number of units (length) between the selected
points.

Whether "magnitude" changes depends on definition. Magnitude sometimes
means maximum amplitude of a wave and does not ordinarily change.
However, magnitude used as a synonym for instantaneous amplitude varies
sinusoidally with time.

At complete nulls, volts or amps, depending on the null site we choose,
forward and reverse volts or amps are equal and opposite in both phase
and amplitude at every point in the electrical cycle. Their combination
is always zero.

At node maxima, volts and amps when we have a complete reflection on a
line with negligible loss produce doubles of volts and amps. Maxima of
volts are displaced from maxima of amps by 90-degrees.

Best regards, Richard Harrison, KB5WZI

On Fri, 06 Feb 2004 13:41:13 -0600, Cecil Moore
wrote:
Neither the instantaneous magnitude nor instantaneous phase is constant.
Uh-huh
See for yourself at:
Pathetic
Discovered why you were confused?
even more pathetic

Cecil wrote,

Tdonaly wrote:
You didn't read the rest of my posting. Current is dQ/dt, the rate of
flow of charge with time.

Yes, and at a current loop in a standing wave, dQ is positive
for 1/2 cycle and negative for 1/2 cycle. If the forward and
reflected current are in phase at zero degrees, dQ is moving
toward the load. If the forward and reflected current are in
phase at 180 degrees, dQ is moving toward the source. That's
the convention.

You seem to have lost contact with reality when it comes to AC.
Remember the e^jwt term? The standing wave current at a loop
changes sign, and therefore direction, every 1/2 cycle. Current
cannot stand still because dQ would be zero.
--
73, Cecil, W5DXP


You're not getting it again, Cecil. The instantaneous current is
changing with time, but it isn't moving anywhere. e^jwt doesn't
have any space information in it.
73,
Tom Donaly, KA6RUH

Richard Harrison wrote:
To keep it simple, phase difference between forward and reflected waves
is locked.

Nope, it's not, Richard, as illustrated on this web page:

http://einstein.byu.edu/~masong/HTMs...newave2EX.html

The forward phasor and reflected phasor are rotating in
opposite directions. Sometimes they are in phase (loop)
and sometimes they are 180 degrees out of phase (node).
The variable phase difference between the forward wave
and reflected wave is what causes the standing waves.
--
73, Cecil, W5DXP

Hey Tom,

Did you hear the cops pulled over Janet Jackson last night?

She had a headlight out.

73, Jim AC6XG

Tdonaly wrote:

Cecil wrote,

Tdonaly wrote:
You didn't read the rest of my posting. Current is dQ/dt, the rate of
flow of charge with time.

Yes, and at a current loop in a standing wave, dQ is positive
for 1/2 cycle and negative for 1/2 cycle. If the forward and
reflected current are in phase at zero degrees, dQ is moving
toward the load. If the forward and reflected current are in
phase at 180 degrees, dQ is moving toward the source. That's
the convention.

You seem to have lost contact with reality when it comes to AC.
Remember the e^jwt term? The standing wave current at a loop
changes sign, and therefore direction, every 1/2 cycle. Current
cannot stand still because dQ would be zero.
--
73, Cecil, W5DXP


You're not getting it again, Cecil. The instantaneous current is
changing with time, but it isn't moving anywhere. e^jwt doesn't
have any space information in it.
73,
Tom Donaly, KA6RUH

Tdonaly wrote:
You're not getting it again, Cecil. The instantaneous current is
changing with time, but it isn't moving anywhere. e^jwt doesn't
have any space information in it.

Stick a one ohm resistor at a current loop, Jim, and then look at
the voltage across it. Surprise!!!! It's a sine wave with a positive
part, a zero crossing, a negative part, and another zero crossing.
When the voltage is +, the current is flowing through that resistor
in one direction. When the voltage is -, the current is flowing
through that resistor in the opposite direction. Sorry about that.

To maintain that there's no current flowing through a resistor when
there's an AC voltage across the resistor is ridiculous.
--
73, Cecil http://www.qsl.net/w5dxp



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On Fri, 06 Feb 2004 14:14:46 -0600, Cecil Moore
wrote:
Richard Harrison wrote:
To keep it simple, phase difference between forward and reflected waves
is locked.

Nope, it's not
Uh-huh

On Fri, 06 Feb 2004 14:51:17 -0600, Cecil Moore
wrote:
When the voltage is +, the current is flowing through that resistor
in one direction. When the voltage is -, the current is flowing
through that resistor in the opposite direction.
which makes the resistor capacitive or inductive?

Cecil Moore wrote:

To maintain that there's no current flowing through a resistor when
there's an AC voltage across the resistor is ridiculous.

You're arguing asynchronously. You're arguments bear no relation to the
points being made by your correspondents.

ac6xg

Standing wave is expressed as a ratio, the ratio does not change. The rest
is all bafflegab...

"Cecil Moore" wrote in message
...
Richard Harrison wrote:
To keep it simple, phase difference between forward and reflected waves
is locked.

Nope, it's not, Richard, as illustrated on this web page:

http://einstein.byu.edu/~masong/HTMs...newave2EX.html

The forward phasor and reflected phasor are rotating in
opposite directions. Sometimes they are in phase (loop)
and sometimes they are 180 degrees out of phase (node).
The variable phase difference between the forward wave
and reflected wave is what causes the standing waves.
--
73, Cecil, W5DXP