Jim Kelley wrote:


Cecil Moore wrote:

Jim Kelley wrote:

Honestly, Cecil, it's pretty hard to know what you mean considering
the reckless way you throw around the term 'phase'. I'll grant that
you might know what you mean, but I don't see how you can expect
anyone else to.


Jim, if you have trouble understanding the word "phase",
look it up in a technical dictionary. I don't have time
to waste my time teaching everyone the principles of AC
waves in EE201.

Thanks. Sorry for the unfinished thought. I meant that because of the
reckless way you use the term, I don't know how you expect others to
know what you intend by it when you use it.

FYI: For a signal proportional to cos(x)*cos(wt), the
phase doesn't change with 'x'. That's why standing wave
current cannot be used to measure delay.

Perfect example. The phase of a cosine wave at it's absolute maximum
amplitude is either 0 or 180 degrees. Each point along a sinusoidal
plot represents a different phase angle. Phase varies with time at a
fixed position, or varies with position at a fixed time. For it to have
meaning there must be a reference. 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.

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. FYI: Phase angle (wt) is
found on the x axis of a sinusoidal plot. When period or wavelength and
length are equated, as is the case with a resonant antenna then phase
and position are functionally related.

73, ac6xg

It's hardly surprising that Cecil thinks there's no phase information in
a standing wave, since he leaves it out on purpose. "Cos(x)*Cos(wt)" is
just flat wrong. It's supposed to be "Cos(x + d/2)*e^(i(wt + d/2))." "d"
is the phase difference between a wave traveling in the forward
direction and an equal amplitude wave traveling in the opposite
direction. This is pretty poor shooting for a guy who claims a
degree in symbol slinging.
73,
Tom Donaly, KA6RUH