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Old December 8th 07, 02:18 PM posted to rec.radio.amateur.antenna
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Posts: 3,521
Default Standing Wave Phase

Keith Dysart wrote:
On Dec 8, 12:43 am, Cecil Moore wrote:
Keith Dysart wrote:
Cecil Moore wrote:
Keith Dysart wrote:
Of course, if you add 180 degrees you have added 180
degrees to whatever existed before. Do you disagree?
So this meets the criteria you originally proposed and
is an example of 90 degree electical length?

Don't be silly. 180 degrees plus any positive angle
is more than 180 degrees.

The context was mobile loaded antennas shorter than
a physical 1/4WL.


Hmmmm. So you are no longer in agreement with your
original question:
"So are we agreed that a 43.4 degree stub terminated
in 0-j567 ohms impedance is electrically 1/4WL, i.e.
90 degrees long?"


Now I understand your confusion. I was talking about
a -j567 ohm *capacitor*, not a virtual impedance.

I was, of course, using the "impedor" definition of
impedance but since that confused you, let me restate
the question:

"So are we agree that a 43.4 degree stub terminated in
a -j567 ohm impedor is electrically 1/4WL, i.e. 90
degrees long?"

This was the original meaning of the question. I'm sorry
that you took it the wrong way and wasted so many postings
on such a trivial misunderstanding.

It leads
to worthless questions like "where did the missing
degrees go?"


Click on "Load Dat" in the EZNEC model below. There are
*no* missing degrees. All necessary degrees are present
and accounted for. But you will never see them if you
are trying to use standing-wave current to see them.

http://www.w5dxp.com/coil512.ez

This is much like ascribing excessive reality to
"reflected power" which leads to worthless questions
like "where did the reflected power go?".


Since energy must be conserved, the proper question
is: "Where did the reflected wave *energy* go?" Do
you even know the answer? The answer is that there
is exactly the amount of energy existing in a transmission
line to support the forward wave and the reflected wave.
--
73, Cecil http://www.w5dxp.com
 
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