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Old December 9th 07, 06:07 AM posted to rec.radio.amateur.antenna
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Default Loading Coils; was : Vincent antenna

Roy Lewallen wrote:

Please fire up EZNEC and tell us how much current phase
shift is reported for 45 degrees of a 1/2WL dipole.

Can anyone point me to any reference to "standing-wave current" in any
reputable text?


"Transmission Lines", by Chipman, Chapter 8

A periodic waveform with no phase information? Huh?


Yes!!! Here's what Chipman says on page 159: "V(d)=A*cos(Bd).
This expression indicates that in the voltage standing wave
pattern produced on a lossless transmission line by a voltage
reflection coefficient, rho, at the terminal load end, the
*phase is constant over any half wavelength* of the pattern
between successive points of zero voltage magnitude, ..."

The same is true for the current standing wave pattern on
a standing-wave antenna and means that constant phase current
cannot be used for delay measurements.

"PHASE IS CONSTANT OVER ANY HALF WAVELENGTH" including the
part where the coil is located.

Please look at the phase of the current in a 1/2WL dipole
and tell us how to use phase measurements of that current
to determine the delay through the 1/2WL dipole wire.

There's no mystery about traveling or standing waves ...


Roy, please explain the phase shift reported by EZNEC for:

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

Use the "Load Dat" button to view the phase shift.
--
73, Cecil http://www.w5dxp.com
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