Owen Duffy wrote:
I suggest that at resonance (if that is what you meant), impedance is
a maximum, I1 becomes small, |I2||I1|, and the current flowing on
the outside of the coax (I1+I2) is not zero.

Sorry, I got phasing coils and traps confused in
my thought processes. A trap is probably about half
of a 180 degree series resonant phase-shifting coil.

Also please note that points 'A' and 'B' are reversed
between your drawing and N3GO's paper.

The main thing to remember is that the forward wave
on the standing wave antenna is reflected by the
trap. For the voltage and current phasing to be
correct at the feedpoint, the trap must present close
to an open-circuit to the forward wave.
--
73, Cecil http://www.w5dxp.com