Cecil Moore wrote:
Gene Fuller wrote:

Why don't you go back and re-read that paper carefully. Pay particular
attention to the part where the author says, with emphasis, that the
magic formula only works when the coil is near or at resonance.


A 75m bugcatcher coil is self resonant at 6.6 MHz. That's
near 4 MHz. Where is all your irrationality coming from?


Cecil,

I guess you can't keep up with your fairy tales.

The exact quote from your message on April 11, at 9:57 am is copied
below. I don't see anything about a bugcatcher coil. Instead there is
some un-described coil stock that requires 37 extra turns in addition to
the starting 32 turns to achieve self-resonance at 4 MHz.

Since the Corum paper highlighted the limitation for applicability of
the magic formula it is possible he thought that the limitation might be
important. However, with your superior intellect it is fully justifiable
to go ahead and accept only those portions of his paper that support
your preconceived notions.

I suppose whatever number you determine will still fall within your 59%
standard of precision.

73,
Gene
W4SZ


[quote]

************************************************** *
Here's a more valid procedure for determining the
delay through a coil. Changing nothing except the
number of turns, add turns until the coil is self-
resonant at the frequency of use. Frequency doesn't
change. Coil diameter doesn't change. Turns per inch
doesn't change. The *ONLY* thing that changes is the
length of the coil. At self-resonance, we *know* the
longer coil is 90 degrees long.
************************************************** *

Take that same 32 turn coil and keeping everything the
same, add turns to the coil until it is self-resonant.
We haven't changed the frequency, the diameter, or the
turns per inch. All we have done is add 37 turns to the
original 32 turn coil to make the self-resonant frequency
equal to 4 MHz with 69 turns. SINCE WE HAVEN'T CHANGED
THE FREQUENCY, WE KNOW THAT THE VELOCITY FACTOR OF THE
COIL HAS NOT CHANGED.

In the velocity factor equation, the only variables are
coil diameter, turns per inch, and wavelength. NONE OF
THOSE VARIABLES ARE CHANGED ABOVE.

So we know that 69 turns makes that coil stock self-resonant
at 4 MHz. That would make the phase shift through 32 turns
equal to 42 degrees, making our above 10 degree assumption
false. 42 degrees is probably fairly close to the actual value.
The velocity factor for that coil stock calculates out to
be 0.023 on 4 MHz.

[end quote]