Gene Fuller wrote:
Cecil Moore wrote:
I apologize for missing the small detail that S12 was a voltage
measurement rather than a current measurement but I'm sure you can
see how that was an honest mistake and easy to make. You didn't
mention "voltage" at all in your posting and the context was current.
I didn't recall until your objection here today that S12 is a voltage
parameter measurement.

But that leads to a question. Why were you using voltage measurements
to try to disprove Kraus' statement about 180 degree current phase
shifting coils. Quoting from: "Antennas for All Applications", Kraus
and Marhefka, 3rd edition, page 824: "A coil (or trap) can also act
as a 180 deg (current) phase shifter as in the collinear array ...
The coil may also be thought of as a coiled-up 1/2WL element."

The complete quote from Kraus on page 744 in my copy of his 2nd edition is:

"A coil (or trap) can also act as a 180 degree phase shifter as in the
collinear array of 4 in-phase lambda/2 elements in Fig. 16.30b. Here the
elements present a high impedance to the coil which may be resonated
without an external capacitance due to its distributed capacitance. The
coil may also be though of as a coiled-up lambda/2 element."

* It is possible that Kraus edited the comment in the 3rd edition, but I
don't see the word "current" in this quote. It is considered good
editorial form to indicate clearly when you have altered the original
wording, unless you are trying to make a point, I suppose.

Gene, I assume you know it is common practice to insert words in
parentheses in a quotation to make the meaning clear. Such words
are understood not to be part of the quote. Since Kraus illustrated
the current, not the voltage in Figure 23-21 and earlier in figures
14-2, 14-3, and 14-4, it is rather obvious that he was talking about
a 180 degree current shift. Nowhere that I have seen does Kraus
illustrate the voltage on a standing wave antenna or talk much about
that voltage. Do you see the arrows drawn on the antenna in question?
Do you not know that an arrow drawn on a line denotes current? And
note that since all the current arrows are pointing to the right,
there is a 180 degree current phase shift in each of those phase-
shifting coils.

However, I see I should have used brackets because Kraus was already
using parentheses. I promise to do better next time.

Again, there is hardly any technical content in your reply. You have
refused to respond to the questions I listed for you in an earlier
posting. One wonders why you are avoiding the technical issues.

So I'll ask again. At http://www.qsl.net/w5dxp/qrzgif35.gif

is an EZNEC simulation. How do you explain the 0.1+ amp of current
'flowing' into the bottom of the coil and 0.7+ amp of current
'flowing' out of the top of the coil. How, exactly, is the coil
manufacturing extra current? Hint: such a thing happens all the
time in a standing wave environment because standing wave current
doesn't flow. How could it possibly flow with a constant fixed zero
degree phase angle?
--
73, Cecil http://www.qsl.net/w5dxp