RadioBanter - View Single Post

March 13th 06, 03:09 PM posted to rec.radio.amateur.antenna

wrote:

Cecil Moore wrote:
Guess everyone sees the danger in trying to guess what
the results of someone else's measurement will be. Tom
should have measured something around 15.6 degrees. The
fact he didn't sends up a very large red flag.

Tom, I am going to ask you some relatively simple technical
questions. If you continue to refuse to answer those
questions, I and the other readers of r.r.a.a will draw
a logical conclusion about your unwillingness or inability
to answer questions, i.e. a non-technical answer or no
answer at all will cause you to lose credibility.

I was wrong about the radiation resistance equation. See
how readily I admitted my mistake? (When was the last time
you admitted a mistake?)

First question is a short one: Please explain why a century
old method of determining the phase shift through a coil by
measuring its self-resonant frequency is not good enough for
you. Do you really expect us to believe that the phase shift
through a well-designed coil can change by 81% from 16 MHz
to 4 MHz?

Translation of what Cecil actually is saying:

"Whenever multiple measurements by independent sources disagree with me
the measurements others made must be wrong."

I make mistakes but I seem to be on a solid technical
footing here. A number of readers agree. Maybe you can
convince me and them otherwise if you stop refusing to
answer technical questions about your measurements. Your
100 uH coil is the 8+j2500 ohm load in the following
fixed font example. That's at 3.98 MHz with a Q of 313.

Current probes are at X and Y. How is the following
circuit different from your test setup?

+---one wavelength lossless 50 ohm coax-----+
| X
source coil 8+j2500 load
| Y
+-------------------coax braid--------------+

The one wavelength of lossless coax doesn't change any values
in the steady-state situation so the current probes at X and
Y read the same value of currents as yours.

The SWR on the coax is about 16000:1. There is virtually
zero net current flowing through the load because of the
*extreme* mismatch. Virtually all of the current at the coil
is standing-wave current which is known to have unchanging
phase. Roy measured the unchanging phase of standing wave
current and reported close to zero. You measured the
unchanging phase of standing wave current and got close
to zero. It is no wonder you guys get the same value of
current phase delay since you are making exactly the same
error in your measurements spanning a number of years.
I'm surprised that you didn't measure a 0 nS delay.
--
73, Cecil http://www.qsl.net/w5dxp