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Old January 13th 04, 05:17 AM
Cecil Moore
 
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Roy Lewallen wrote:
The second test, where the
antenna was shortened more than 33 degrees, measured 5% current
reduction and no phase shift. There's no way my data "clearly
illustrates" Cecil's explanation.


Roy, you obviously don't understand what that phase shift is all about.
It is NOT a phase shift in the net current. It is a calculated phase shift
in the forward current and reflected current components through the coil
based on the net current ratios. And your data indeed does "clearly
illustrate" my explanation. Please stop making false statements about what
I said. You did NOT measure the phase angle about which I was talking.
You apparently don't even know what I was talking about.

The forward current into the coil and the reflected current out of the
coil can be assumed to be in phase at resonance. So we have Ifwd at 0 deg
superposed with Iref at 0 deg to obtain the net current into the coil.
The forward current out of the coil lags the forward current into the
coil by some phase angle (PA). The reflected current out of the coil
lags the reflected current into the coil by the same phase angle (PA).
PA is the phase angle I was talking about. You did NOT measure it!

The net current into the coil is Ifwd at 0 deg plus Iref at 0 deg.

The net current out of the coil is Ifwd at -PA plus Iref at +PA

Assuming the net current distribution is a cosine, the phase angle
by which the forward current and reflected current is shifted is
ArcCos(Iout/Iin). For a 5% current reduction that would be ArcCos(0.95)
= ~18 degrees. You did NOT even attempt to measure that phase angle.
There is almost no phase shift in the net current through the coil
which is exactly what you measured.

I feel compelled to respond to these fabrications, and put the record
straight. I'll do it here, since this is where my measurements were
originally posted.


How can you possibly set the record straight when you didn't even
comprehend what I was saying? Here's what I have said:

The net current is the sum of the forward current and reflected current.
Both the forward current and reflected current undergo a phase shift
through the coil. Assuming the forward current and reflected current
are in phase on one side of the coil, that phase shift can be calculated
using ArcCos(Iout/Iin) where those currents are the measured net currents.

A 5% reduction in current is equivalent to an 18 degree phase shift.

A 3% reduction in current is equivalent to a 14 degree phase shift.

Your data matches my explanation exactly! The only data that doesn't
match my explanation is Tom's toroidal coil which he asserts doesn't
have any delay through it at all. I suspect his currents are of equal
magnitude and opposite phase thus indicating a delay but confusing
his magnitude data.
--
73, Cecil http://www.qsl.net/w5dxp



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