Jim Kelley wrote:
You have a habit of switching
references without noticing or making note of it. This makes some of
your comments a bit confused sounding, if not blatantly inaccurate.

Jim, it's all your fault for not being telepathic. :-)
I admit that my thought processes are somewhat chaotic
but remember, order often comes out of chaos. I've
experienced an epiphany or two in my time.

I also have a bad habit of declaring something invalid
when it is only irrelevant. It is the conclusions drawn
from irrelevant measurements that are invalid, not the
measurements themselves.

The convention that I try to use is the EZNEC convention.
Everything is referenced to the source signal. When I say
the phase of a standing wave is unchanging, I mean that it
has the same phase as the source signal at the feedpoint
and is the same phase as reported by EZNEC. I apologize for
not being clear about that.

With regard to your comment above, if the maximum amplitude and period
of a sinusoidal wave are both known, then given any instantaneous
amplitude and, knowing whether the slope is positive or negative, the
instantaneous phase can be readily determined.

Take I = K1*cos(x)*cos(wt), a standing-wave equation.
Let t be any fixed value. cos(x) is an amplitude value
and does NOT vary with time. Therefore, the phase of the
standing-wave signal is constant at any particular time
and does NOT depend upon position along the wire or coil.

Now take I = K2*cos(x+wt), a traveling-wave equation.
Let t be any fixed value. The length dimension 'x'
has an effect on phase, i.e. the phase of of the
signal indeed does depend upon BOTH position AND time.

Anyone who understands the math would not dare show
his ignorance by asserting that the delay through a
100T coil is 3 ns on 4 MHz or that the measured phase
shift through a loading coil is somehow proportional
to the delay through the coil in a standing-wave antenna.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:

With regard to your comment above, if the maximum amplitude and period
of a sinusoidal wave are both known, then given any instantaneous
amplitude and, knowing whether the slope is positive or negative, the
instantaneous phase can be readily determined.


Take I = K1*cos(x)*cos(wt), a standing-wave equation.
Let t be any fixed value. cos(x) is an amplitude value
and does NOT vary with time. Therefore, the phase of the
standing-wave signal is constant at any particular time
and does NOT depend upon position along the wire or coil.

The item residing inside the parentheses of a sinusoidal function is
in fact the 'phase' of that function. In the expression above, at any
given time, amplitude is determined by the independent variable,
position. Accordingly, for any given position and time there is a
unique amplitude and phase.

Anyone who understands the math would not dare show
his ignorance by asserting that the delay through a
100T coil is 3 ns on 4 MHz or that the measured phase
shift through a loading coil is somehow proportional
to the delay through the coil in a standing-wave antenna.

In the face of such a redoubtable accusation I'm somewhat reluctant to
admit my view that a phase shift across a coil of this sort would in
fact be directly proportional to any propagation delay through that
coil.

73, ac6xg

Jim Kelley wrote:
In the face of such a redoubtable accusation I'm somewhat reluctant to
admit my view that a phase shift across a coil of this sort would in
fact be directly proportional to any propagation delay through that coil.

That's certainly true for traveling-wave current.
Definitely not true for standing-wave current which
doesn't change phase. I don't know that the comprehension
problem is here - maybe this graph will help.

http://www.w5dxp.com/travstnd.gif
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:

Take I = K1*cos(x)*cos(wt), a standing-wave equation.
Let t be any fixed value. cos(x) is an amplitude value
and does NOT vary with time. Therefore, the phase of the
standing-wave signal is constant at any particular time
and does NOT depend upon position along the wire or coil.

Now take I = K2*cos(x+wt), a traveling-wave equation.
Let t be any fixed value. The length dimension 'x'
has an effect on phase, i.e. the phase of of the
signal indeed does depend upon BOTH position AND time.


Cecil,

I know what you are trying to say, but you got the message screwed up.
If 't' is fixed, then the equations are essentially the same with regard
to 'x'. That is typical; a snapshot in time does not say much about the
wave behavior.

73,
Gene
W4SZ

Gene Fuller wrote:
Cecil Moore wrote:

Take I = K1*cos(x)*cos(wt), a standing-wave equation.
Let t be any fixed value. cos(x) is an amplitude value
and does NOT vary with time. Therefore, the phase of the
standing-wave signal is constant at any particular time
and does NOT depend upon position along the wire or coil.

Now take I = K2*cos(x+wt), a traveling-wave equation.
Let t be any fixed value. The length dimension 'x'
has an effect on phase, i.e. the phase of of the
signal indeed does depend upon BOTH position AND time.


Cecil,

I know what you are trying to say, but you got the message screwed up.
If 't' is fixed, then the equations are essentially the same with regard
to 'x'. That is typical; a snapshot in time does not say much about the
wave behavior.

73,
Gene
W4SZ

It's generally cos(kx), but maybe Cecil is using a wave where k = 1,
that is, the wavelength is 2*Pi.
73,
Tom Donaly, KA6RUH

Tom Donaly wrote:
Gene Fuller wrote:
Cecil Moore wrote:

Take I = K1*cos(x)*cos(wt), a standing-wave equation.
Let t be any fixed value. cos(x) is an amplitude value
and does NOT vary with time. Therefore, the phase of the
standing-wave signal is constant at any particular time
and does NOT depend upon position along the wire or coil.

Now take I = K2*cos(x+wt), a traveling-wave equation.
Let t be any fixed value. The length dimension 'x'
has an effect on phase, i.e. the phase of of the
signal indeed does depend upon BOTH position AND time.


Cecil,

I know what you are trying to say, but you got the message screwed up.
If 't' is fixed, then the equations are essentially the same with
regard to 'x'. That is typical; a snapshot in time does not say much
about the wave behavior.

73,
Gene
W4SZ

It's generally cos(kx), but maybe Cecil is using a wave where k = 1,
that is, the wavelength is 2*Pi.
73,
Tom Donaly, KA6RUH

Tom,

Sure, that too.

I think one of the reasons this subject keeps coming back again, and not
only from Cecil, is that phase is deceptively simple and very easy to
misuse. A year or so ago I counted up at least 5 or 6 different meanings
of "phase" in routine use on RRAA. Lewis Carroll would feel right at
home here.

73,
Gene
W4SZ

Tom Donaly wrote:
It's generally cos(kx), but maybe Cecil is using a wave where k = 1,
that is, the wavelength is 2*Pi.

In the equations I posted, x is in degrees. It is (kx)
in the following graph:

http://www.w5dxp.com/travstnd.gif
--
73, Cecil http://www.w5dxp.com