Walter Maxwell wrote:
IMO, Cecil, you've been hoaxed if you thought a coil self-resonant at 6.6 MHz
was a high-Q coil at 4 MHz.

All I know is that Texas Bugcatcher coils tend to be
near the top of the the 75m mobile shootout results.
Using base loading on a GMC pickup, it is resonant on
3.8 MHz with a six foot stinger. Remove the stinger and
it is self-resonant at 6.6 MHz.

My 75m Texas Bugcatcher coil was a gift from K7JEB.
It is 26.5 turns at 4 tpi on a 6" air core form.
Calculates out to be about 70 uH. I don't know how
to make it higher Q.
--
73, Cecil http://www.qsl.net/w5dxp