wrote:
It isn't just "any" -j567 ohm impedance
that can cause resonance with a 43 degree 600 ohm line.

Dan, I believe you will find that any -j567 impedance
in the black box will put the forward and reflected
waves back in phase, i.e. resonant.
--
73, Cecil http://www.w5dxp.com

On Thu, 20 Dec 2007 11:35:39 -0800 (PST), wrote:

Assuming my measurement is correct,

Hi Dan,

Why not prove your measurement is correct?

You already know the reactance. Plot it on a Smith chart for your
line (that is what makes Smith charts useful). Does your 43 degree
rotation lead to resonance?

Contrariwise, put your line at resonance on the Smith chart for your
line and rotate 43 degrees, do you land at the black box's terminal
reactance?

If you are adding more operations than either ONE of these two, then
you are working hard at finding the wrong answer and doing your
measurement incorrectly.

73's
Richard Clark, KB7QHC

Roy Lewallen wrote:
Gene is of course correct. Perhaps the difficulty with basic concepts
such as phase reference is part of the reason why Cecil finds it
necessary to invent and promote his alternative theories.

A moment's thought would reveal one good reason not to reference phase
angles to "the source" -- NEC and EZNEC allow multiple sources, each
having a phase angle chosen by the user.

Roy Lewallen, W7EL

Hello, Roy and all. Every unmoderated science newsgroup I've lurked in
always has one or more individuals that seem to delight in bucking
conventional science wisdom even in those cases where experimental
evidence completely validates the predictions of applied mathematics.
(Gosh, what ever happened to cold fusion?) One guy regularly complains
that respected physics journals won't publish his papers. Of course he
imagines there's someone or some agency out to get him, never
considering other reasons for his rejection. Perhaps on usenet he
acquires some validation.

Hey, people are free to view nature and its processes however they
choose but if they want others to view it that way it takes more than
"Because I say so." Especially to a roomful of skeptics. Of course I'm
also reminded of the hornet's nest that Marilyn vos Savant stirred up a
few years back in academia with the "Monty Hall" problem. (Turned out
she was right after all) The truth always emerges eventually. Theories
often have to be modified as new discoveries occur.

Are you sure I can't interest you in an energy-saving power factor
correction capacitor for your home/ham shack? How about a broadband
dipole with a feedpoint VSWR 1.6 over the contiguous 2-30 MHz band?
Sincerely, and 73s N4GGO,

J.B. Wood wrote:
Roy Lewallen wrote:
Gene is of course correct. Perhaps the difficulty with basic concepts
such as phase reference is part of the reason why Cecil finds it
necessary to invent and promote his alternative theories.

A moment's thought would reveal one good reason not to reference phase
angles to "the source" -- NEC and EZNEC allow multiple sources, each
having a phase angle chosen by the user.

Hello, Roy and all. Every unmoderated science newsgroup I've lurked in
always has one or more individuals that seem to delight in bucking
conventional science wisdom even in those cases where experimental
evidence completely validates the predictions of applied mathematics.

On this newsgroup, John, it's the gurus who are bucking
conventional science with such concepts as:

1. There's no phase shift at a Z01 to Z02 impedance discontinuity
in a transmission line even though the applied mathematics says
there is. Black boxes are quickly introduced to hide the phase
shift from the unwashed masses.

2. There's no difference between
I*cos(kx)*cos(wt) and I*cos(kx+wt)
i.e. between standing waves and traveling waves even though
the applied mathematics graphs are completely different.

3. Standing wave current can be used to measure the delay
through a loading coil even though applied mathematics says
the standing wave current doesn't change its relative phase
anywhere in the 1/4WL antenna from feedpoint to tip.

4. Reflected waves contain zero energy and therefore cannot
deliver energy back to the source even though applied mathematics
says that ExB is the power density of that reflected wave.

5. EM energy can just "slosh around" inside a transmission line.
It doesn't have to travel at the speed of light even though it
is made up of photons which applied mathematics tells us
cannot slow down.

6. The EZNEC graph of traveling-wave current phase contains
a 64% error yet the author says there's nothing wrong.

John, would you care to comment on those six points?
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
6. The EZNEC graph of traveling-wave current phase contains
a 64% error yet the author says there's nothing wrong.

Oops, sorry, should be (100-64) = 36% error.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:

a 64% error yet the author says there's nothing wrong.

John, would you care to comment on those six points?

Hello, Cecil, and I think Roy and others have provided valid comment. I
would like to recommend, in addition to the ARRL publications, the
Schaum's Outline on transmission lines. I don't know if it's still in
print but it was authored by Chipman. Like the other paperback Schaum's
Outlines it is not intended to be an in-depth examination of RF
transmission line theory (if you want that I would recommend King and
Harrison's book). Chipman's book, OTOH delves into the theory at a
level that IMHO doesn't require an EE degree to comprehend. There's
also loads of practical problems worked out (lots of stuff on incident,
reflected and standing waves). I think it would prove timely to pursue
sources besides r.r.a.a for your electromagnetics training. Sincerely,

"Gene Fuller" wrote in message
...
Dave wrote:
"Gene Fuller" wrote in message
...
Cecil Moore wrote:
Gene Fuller wrote:
Cecil Moore wrote:
Gene Fuller wrote:
Cecil Moore wrote:
Gene Fuller wrote:
Cecil Moore wrote:
Gene Fuller wrote:
Cecil Moore wrote:
Gene Fuller wrote:
Cecil Moore wrote:
Gene Fuller wrote:
Cecil Moore wrote:
Gene Fuller wrote:
Cecil Moore wrote:
Gene Fuller wrote:

keep going guys! only 50 more messages to hit 1000 in this thread!
thats got to be a record for r.r.a.a! how many more ways can cecil and
roy go around in circles with phases. can we get roger back in the fray?
that would be good for another dozen or so anyway! jim lux hasn't
contributed recently, where did he drop out? and where, oh where, is
art??????????



And then there is anonymous Dave, who never contributes anything useful.
i gave up trying to be helpful in these endless arguments long ago. i went
through trying to be helpful by pointing out the inconsistencies, then when
i realized that they wouldn't listen i slipped into trolling them just to
watch the fun, and now i'm just jabbing them like a hornet nest.

LESS THAN 20 TO GO TO HIT 1000!!!!

J.B. Wood wrote:
Hello, Cecil, and I think Roy and others have provided valid comment. I
would like to recommend, in addition to the ARRL publications, the
Schaum's Outline on transmission lines. I don't know if it's still in
print but it was authored by Chipman. Like the other paperback Schaum's
Outlines it is not intended to be an in-depth examination of RF
transmission line theory (if you want that I would recommend King and
Harrison's book). Chipman's book, OTOH delves into the theory at a
level that IMHO doesn't require an EE degree to comprehend. There's
also loads of practical problems worked out (lots of stuff on incident,
reflected and standing waves). I think it would prove timely to pursue
sources besides r.r.a.a for your electromagnetics training. Sincerely,

Bob, I've had the book for 30+ years. I'm not kidding about
those six items. Those are the old wives' tales being spread
by about six of the gurus on this newsgroup. I learned this
fields and waves stuff back in the 50s from Ramo, Whinnery,
and Johnson and some good professors at Texas A&M.

In particular, how about taking a look at my math on
the thread titled "Please verify (or disprove)". I would
welcome anyone proving me wrong but so far, there are
zero takers.
--
73, Cecil http://www.w5dxp.com

wrote in message
...
On Dec 20, 4:32 am, Ian White GM3SEK wrote:
Cecil Moore wrote:
But the rules for black boxes do not allow measurements
on the inside. This is how they help clarify the thinking.

So instead of sweeping technical facts under the rug,
you hide them in a black box. In both cases, the only
apparent purpose is to maintain ignorance.

It seems that whatever part of the system you don't
understand, you draw a black box around it so you
don't have to understand it.

No, it is a perfectly normal technique to test a theory or model. The
black box reveals just enough information to solve the problem, and
nothing more.

In this particular case, the impedance at the terminals of the black box
is the only *necessary* information to solve the transmission-line
problem (in the steady state, at one frequency). It is not necessary to
know how that impedance was created.

But Ian,

Suppose the box is labeled -j567 ohms.

Then I ask, "at what frequency is this impedance -j567?".

I find that the impedance for -j567 ohms is 4 Mhz.

Now I take a length of 600 ohm VF = 1 transmission line and vary the
length until I am at resonance with whatever is in the black box at 4
MHz. Resonance would imply 90 degrees total phase shift.

My measurement shows that the length of 600 ohm line to cause this
effect is 43 degrees.

Assuming my measurement is correct, doesn't that tell us a little more
about what is inside the box? It isn't just "any" -j567 ohm impedance
that can cause resonance with a 43 degree 600 ohm line. It is probably
not a discreet capacitor, it would likely be some sort of transmission
line or something that that has 10 deg length, correct?

With a few more measurements, we can determine the Zo of the
transmission line that "appears' to be in the black box, correct and
essentially verify that it a transmission line. We should be able to
both measure and calculate Zo.

If we choose our independent measurements carefully enough, we should
be able to define exactly what is in the black box with only 2
terminals.

I agree you need more than a smith chart (which was where I made my
mistake before).

AI4QJ



No, you can't. if the frequency is fixed, is sinusoidal, and steady state,
then every box that measures -j567 ohms is perfectly equal. that is the
whole idea of a 'black box' not only can't you tell what is inside, it
doesn't matter what you do on the outside, it will always looks the same.
that is the whole purpose of it, you reduce a part of the circuit to a
single component that has well known performance so you remove that part
from the problem.

J.B. Wood wrote:
Cecil Moore wrote:

a 64% error yet the author says there's nothing wrong.

John, would you care to comment on those six points?

Hello, Cecil, and I think Roy and others have provided valid comment.

BTW, the current plotting error in EZNEC is (100-64)
= 36%.

Do you think a 36% plotting error within EZNEC is nothing
to worry about? Do you think when current phase is displayed
as a sine wave instead of a straight line, that is OK?
--
73, Cecil http://www.w5dxp.com