Richard Clark wrote:

Cecil Moore wrote:
A minimum Tesla coil is 1/4WL. My 75m bugcatcher coil
mounted on my pickup as a base-loaded coil with no
whip is 1/4WL on 6.6 MHz.

An 11.4 meter tall bugcatcher coil - sure.... Such are the rewards of
a Xerox based education.

The physical height of my 75m bugcatcher coil is about 0.167 meters.
Dividing 0.167m by 11.4m gives the velocity factor equal to 0.015.

Your 11.4 meter value assumes a VF of zero. Multiply the 11.4 meters
by the VF of the environment and you will obtain the physical length
for something with an electrical length of 90 degrees.

To obtain an electrical 90 degrees using RG-213:

11.4m * 0.66 = 7.5m

To obtain an electrical 90 degrees using my 75m bugcatcher coil:

11.4m * 0.015 = 0.167m
--
73, Cecil http://www.qsl.net/w5dxp