steveeh131047 wrote:
On Apr 23, 3:21 pm, Cecil Moore wrote:
I have measured the delay through a 75m bugcatcher coil.
It was approximately 25 nS, a magnitude greater than
w8ji's "measurements". It doesn't matter if my measurements
were off by 20%. The magnitude difference between my
measurements and w8ji's "measurements" is too significant
to be ignored.

Cecil: that's a very significant result. If I feed the dimensions of
W8JI's coil into Equation 32 in the Corum Bros. paper it predicts an
axial Velocity Factor of 0.33. That would equate to a delay across the
10" long coil of 24.7nS !!!!!

Of course, you mean *0.033* for the VF of w8ji's coil which
was 10tpi, 100turn, 2" dia.

10"/12/0.033 = 25 feet equivalent to straight wire.

The VF of my Texas Bugcatcher coil is 0.02. It has 4tpi,
26turn, 6" dia.

6"/12/0.02 = 25 feet equivalent to straight wire.

These two coils have essentially equal delays at 4 MHz.
They are each very close to 0.1WL, i.e. 36 degrees.

The delay for one wavelength at 4 MHz is 250.5 nS so
each coil would have a delay of 1/10 that value or
25 nS. Everything fits the model.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com