Cecil, W5DXP wrote:
"But I can demonstrate a 180 degree phase reversal in a helical coil in
free space so the capacitance to ground is not the complete answer to
what is happening."

Cecil has used the Kraus example of a coil installed as a phase inverter
between 1/2-wave segments of a collinear radiator. Kraus` example uses
self-resonant coils. Self-capacitance resonates with self-inductance in
the Kraus coils.

Inversion is caused by current exchanged between L and C. When the
magnetic field collapses, current flows in a loop through capacitance
and coil whether the resonating capacitance is external or internal to
the coil. The apparent instantaneous current direction is into one end
of the coil and out of the other end of the coil. In the next part of
the cycle, the instantaneous current direction is reversed when the
capacitance is discharging the energy back into the inductance.

Point is, opposite ends of the reactances are 180-degrees out-of-phase
at resonance.

Best regards, Richard Harrison, KB5WZI