Jim Kelley wrote:
VF = 0.04 is incredible.

A little knowledge and logic will make it clear.
My 75m Texas Bugcatcher coil is self resonant
at 8.2 MHz which by definition makes it 90 degrees
long. 90 degrees at 8.2 MHz in free space is 30 feet.

The coil is actually 6.5 inches long, i.e. 0.542 feet.

0.542/30 = 0.018 which is the VF of the Texas
Bugcatcher coil at its self-resonant frequency.

The Texas Bugcatcher coil is 4 tpi. The coil with
the VF = 0.04 is 10 tpi. It all makes sense.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com