Reg Edwards wrote:
Can't you see that the first resonance corresponds to the parallel
resonance of the inductance with its stray capacitance, and is what
you call its 1/2-wave resonance?

It may just be semantics. I call the first parallel self-
resonant point the *1/4WL* self-resonant point. At its self-
resonant frequency, a mobile loading coil is 1/4WL long. I
am using that same convention for the coax choke. For instance,
my 75m bugcatcher mobile loading coil is self-resonant at
~6.6 MHz. That's the frequency at which it is 1/4 wavelength
long and presents a high impedance. At some higher frequency,
it is 1/2WL long and presents a low impedance.
--
73, Cecil http://www.qsl.net/w5dxp