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Old April 17th 09, 09:35 PM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Mar 2007
Posts: 3,521
Default Dish reflector

Jim Kelley wrote:
A standing wave interference pattern is a result of the presence
of traveling waves. One does not replace the other.


Exactly what I have been saying for years against some
stiff opposition - welcome aboard.

You missed the point which is: If one parses all the energy
to the standing wave, it cannot separately be parsed to the
traveling waves. Doing so would violate the conservation
of energy principle.

I you were producing numbers which made sense and were correct, we
wouldn't be having this discussion, Cecil. A wave is at various phases
along it's length. The phase varies from 0 to 360 every complete cycle.
This includes standing waves. Its phase is not "zero" at every point.


You obviously don't understand. Whatever the actual phase
angle is, for a pure standing wave, at any instant of time,
it is constant all up and down the standing wave. NOBODY HAS
EVER SAID IT IS ZERO AT EVERY POINT!!! Such an allegation is
a ridiculous blowing of smoke.

The
EZNEC results you refer to are an archetypal example of the effect.


The EZNEC results are what they are and have been confirmed
by w7el himself. All I can say is: Please correct your mistaken
concepts and then rejoin the discussion. What is it about the
following EZNEC results that you don't understand? Do you need
help in comprehending that a 2.71 degree phase shift in 90 degrees
of antenna is a shortfall of 87.29 degrees?

EZNEC+ ver. 4.0
thin-wire 1/4WL vertical 4/17/2009 2:57:42 PM
--------------- CURRENT DATA ---------------
Frequency = 7.29 MHz
Wire No. 1:
Segment Conn Magnitude (A.) Phase (Deg.)
1 Ground 1 0.00
2 .97651 -0.42
3 .93005 -0.83
4 .86159 -1.19
5 .77258 -1.50
6 .66485 -1.78
7 .54059 -2.04
8 .40213 -2.28
9 .25161 -2.50
10 Open .08883 -2.71

If w7el "measures" the phase shift between segment 3
and segment 7, he will "measure" 1.21 degrees. The actual
delay between segment 3 and segment 7 is about 36 degrees.
When will anyone understand that fact of physics?
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com
 
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