Cecil Moore wrote:
Owen Duffy wrote:
"AI4QJ" wrote:
not so nicely linear. The antenna is a lossy transmission line just as
Owen's example was a lossy xmission line example with a 25 ohm load at

No, my example stipulated an ideal transmission line, and by that I
mean it to be lossless amongst other things.

What we are saying is that even if the transmission line
is lossless, the *system* is lossy because of the 25 ohm
resistor.

If there were no losses in the *system*, the waves on the
lossless transmission line would be pure standing waves.
Because of the losses in the load, the waves on the lossless
transmission line are not pure standing waves, but a mixture
of standing waves and traveling waves. In your case (#1 below)
the system is primarily a traveling wave system, closer to
flat than to an OC or SC stub because only 11% of the forward
energy is rejected by the load.

You and Cecil are transforming the example to suit yourselves.

I'm not transforming the example. You are the one who put
the lossy resistor in the system. The traveling waves are
the direct result of the installation of the resistor.

Let's look at a few different examples and assume the
measured joules/sec flowing forward toward the load is
100 joules/sec in each case.

1. Your example of 50 ohm lossless coax connected to a 25
ohm load. The forward joules/sec is 100. The reflected
joules/sec is 11.11. The joules/sec consumed by the 25
ohm load is 88.89. 89% of the forward wave is traveling
wave. 11.11% of the forward wave is used by the standing
wave. The system is primarily a traveling wave system.
The energy not delivered to the load is stored in the
standing wave in the LCLCLCLC components of the
transmission line.

2. No load on the lossless coax. The forward joules/sec
and the reflected joules/sec are equal. 100% of the energy
is standing wave energy and all of it is stored in the
LCLCLCLC components of the transmission line. It does not
move from LC to LC. It simply oscillates in place between
L and C. EZNEC confirms that the current phasor does NOT
rotate.

3. 50 ohm load on the lossless coax. The reflected joules/sec
equals zero and the system is flat. 100% of the energy is
traveling wave energy. The only energy in the transmission
line is the energy it took to fill the pipeline, the delay
between power-on and the load dissipating power. The LCLCLCLC
in this case is an energy bucket brigade.

4. 500 ohm load on the lossless coax. Of the forward 100
joules/sec, only 33 joules/sec is accepted by the load.
The other 67 joules/sec are rejected by the load and become
half of the energy in the standing wave. The system is
primarily a standing wave system. The energy not delivered
to the load is stored in the standing wave in the LCLCLCLC
components of the transmission line.
Cecil, I think this is an excellent series of examples, and greatly
helps me understand your thinking. Roy also wrote a great posting,
which I will respond to shortly.

But I wonder if you are thinking of the standing wave as the end of the
reflected wave, or as the envelope described by the reflected waves as
they sequence in time. These choices at first sound nearly identical,
but they are not. A sequence of reflected waves results in sequential
changes that affect the input power. The final standing wave will not
be defined until several sequential waves have occurred. Unless
adjusted, the ongoing stable power flow to the load will be reduced (or
increased) from the initial value by the effects of the standing wave.
So think I.

Thanks for this series of examples.

73, Roger, W7WKB

Jim Kelley wrote:
Cecil Moore wrote:

What I said is the voltage and
current in a standing wave are *always* 90 degrees out of
phase and it is impossible to generate heat when the voltage
and current are 90 degrees out of phase.

So then shouldn't one expect coax to be heated uniformly along its
length at a high SWR?

No, any and all heat is work done by traveling waves, not
standing waves. As long as standing waves exist as standing
waves, they are incapable of doing work or heating anything.

You, of all people, should appreciate that since V*I*cos(90)
equals zero for standing waves, absolutely no work can be
performed by a standing wave. If the energy in a standing
wave is used to provide work, the standing wave ceases to
exist as it does at key-up.

In trying to get any work out of V*I*cos(90)=0, blood out
of a turnip comes to mind.
--
73, Cecil http://www.w5dxp.com

AI4QJ wrote:
This standing wave exists but it does *nothing* to transmit
power from my amp into radiated power.

Just a Nit.

The standing wave does do something to help the process.
It, like the tuner, transforms impedances. Without the
impedance transformation properties of the standing
waves, the system would not work as designed.

With my All-HF-Band notuner dipole (on my web page) the
standing waves are my friends, not my enemies. Without
the standing waves, my ladder-line length selector
method of matching would not work.
--
73, Cecil http://www.w5dxp.com

Roger wrote:
But I wonder if you are thinking of the standing wave as the end of the
reflected wave, or as the envelope described by the reflected waves as
they sequence in time.

I am talking about steady-state and V(t) vs I(t) for
pure standing waves. Standing waves contain no real
active power. At the risk of having Jim Kelley develop
apoplexy :-) standing waves contain only reactive power,
as defined by The IEEE Dictionary.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:

...
In trying to get any work out of V*I*cos(90)=0, blood out
of a turnip comes to mind.

I am not at the point where I would dismiss/cease-to-listen your
argument(s), far from it.

However, I see no reason why standing waves on a string, standing waves
in water, acoustic standing waves in the medium of a tuning fork, etc.
should be expected to behave in any manner inconsistent to em waves in a
medium--which can contain them and whereas standing waves will result ...

While most techs are "rote leaned", I am simply a hobbiest in these
areas, I have no "indoctrinated beliefs."

It is pretty apparent where I would attempt connection with any of these
mechanical waves in an attempt to extract work (power/energy/joules),
and from any "container" capable of containing them.

I have no problem in forming questions about the validity of the math
which drives your argument(s)--in one of my hands lays the
formulas/equations, in the other what my eyes suggest--NO, "what my eyes
tell me" ... close examination of either suggests the other is lie.

You will have patience if this takes a bit--I am sure ...

Regards,
JS

Dave wrote:
or FAQ depending on how you look at it... I should probably repeat this
regularly on here.

This newsgroup should NOT be used as a reference source for concepts or
equations regarding fields, waves, transmission lines, or other physical
phenomena. Please consult published text books and peer reviewed journals
for analysis of technical questions. The regular contributors in this group
have a wide variety of misconceptions and erroneous views which they
frequently throw in as if they were well known facts.

On the lighter side, it can be fun now and then to throw them a simple
problem and watch them swarm around like a kicked hornet nest.



You've got the nerve to spew your complaint about a post like that after
all of the filth in the radio usenet groups? You must be as dense as kb9rqz.

--
Posted via a free Usenet account from http://www.teranews.com

John Smith wrote:

[his same silly chit to get a debate/conversation going, where he may
pick up a clue or two]

You all know I was kidding, right?

I mean, the neighbor(s) would NEVER let me take up their yards with the
MW tank circuit ... it was only meant as an example to compare standing
waves on a string to a EM standing waves in a POSSIBLE circuit.

Warm regards to all,
JS

John Smith wrote:

Oh yeah, and that part about alien metals/technology, I was only
kidding, didn't mean to fool 'ya! :-D

Regards,
JS

AI4QJ wrote:

...
Whatever you.ve been smoking or drinking this week, the one clue I can give
you is that the holiday has passed so it's time to sober up, at least until
next week.


To be quite honest, you got me. As a young man, I had "hippie"
leanings. In all honesty, never out grew 'em ...

However, Marijuana was too slow--avoided opium and its' derivatives like
the plague. Have done barbiturates, alcohol, cross tops, mescaline,
LSD, etc., I can't use my imagination effectively under such
influences--had to give 'em up ... you'll find me much more honest than
clinton ... I inhaled!

Now, I did the above as experiments, maybe I was lucky, I felt I
"learned things", don't do much any more except coffee & cigarettes
(sometimes alcohol--hydrocodone for the broken bone in the neck now and
there will be a day that ends--I count on it.--damn fools want to put a
cadaver bone in my neck!--they ain't foolin' me--that is a dead
mans'/womans' bone!)

I don't like drug addicts, don't find alcoholics much fun either, and
especially if there is a "time element" at play; I do like free
thinkers ...

Sounds to me, you have a problem with my "spirit," more than anything
else, and if you can get that into a "bottle" and "examine" it
closely--I'd be disappointed with myself ... my whole question(s)
is/are, "What have we not examined yet?"; "In detail?"

But then, I came here to argue/debate/explore/learn-about antennas and
everything they touch--and NOT me ... you get this one "freebie" and no
more ...

Regards,
JS

John Smith wrote:

[real chit]

You know, it gripes me, when you attack personalties rather than text,
"words", thoughts, beliefs, ignorance, mis-conceptions?, etc. of others
.... you sure you want to appear as a "few" others do here?

Your expenditure of energy would be much better spent in an argument
constructed to "show the truth." It is concepts we argue here, NOT
personalities. If I like you or not, if you like me or not--it matters
not ...

But then, you already knew that--didn't you?

Some here set (sit?) a bad example, you wish to follow their path(s)? I
think NOT!

Regards,
JS