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Old December 9th 07, 08:27 PM posted to rec.radio.amateur.antenna
Cecil Moore[_2_] Cecil Moore[_2_] is offline
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First recorded activity by RadioBanter: Mar 2007
Posts: 3,521
Default Standing Wave Phase

Keith Dysart wrote:
Except that I have offerred a number of examples
which you, the oracle, have declared are not
90 "electrical degrees".


If it is 90 electrical degrees then it is 90
electrical degrees. If it is not 90 electrical
degrees, it is not 90 electrical degrees. I don't
know how to make it any clearer than that.

I, too, can subtract (43.4 + 10) from 90 and get
a number. This does not, by itself, a useful
proposition make.


It does if we know the reflected wave undergoes a
180 degree round-trip phase shift or else the
reflected wave would not be in phase with the
forward wave and therefore the feedpoint impedance
would not be purely resistive.

Please provide your algorithm in sufficient detail
that I can test it against the various examples.


It's the same as determining if an antenna is 0.5WL
or 1.5WL or 2.5WL or 3.5WL or ... Do you also have
a problem with that?

If the phase shift end-to-end is 180 degrees, the
device is 90 electrical degrees long.

If the phase shift end-to-end is not 180 degrees,
the device is not 90 electrical degrees long.

So far, each time you have provided a rule, I
have constructed examples according to the
rule which the oracle has declared are not
90 "electrical degrees".


I have provided no rule. Everything is common sense.
If a dipole is 130 feet, it is 1/2WL on ~3.6 MHz.
If the antenna is 403 feet long, it is 1.5WL on
~3.6 MHz. Why do you have a problem telling the
difference between a 130 foot dipole and a 403
foot dipole?
--
73, Cecil http://www.w5dxp.com