Cecil Moore wrote:
I also have a GDO. If I get an open circuit dip, would
that be the parallel resonant frequency? If I get a
short circuit dip, would that be the series resonant
frequency?

I have a 20 turn choke wound on a 5.35" diameter
Quaker Oatmeal box at four turns per inch. I used
my Grid Dip Oscillator to determine the open-circuit
(parallel) self-resonance at 11 MHz. The short-circuit
(series) self-resonance is at 23 MHz.

This is a Knight Kit G-30 GDO with the original
6C4 still working. I built it from a kit in 1959.
--
73, Cecil http://www.w5dxp.com