Tom Donaly wrote:

Cecil Moore wrote:
Seems the easiest measurement of nonlinearity would be the
harmonics (if any) generated by the antenna that do not
appear in the source signal.

Which wouldn't tell you a single thing about the current
distribution along the length of the dipole.

Yes it would. It would be proof that the current distribution
along the length of the dipole is sinusoidal no matter what
your illusionary perceptions are telling you.

For standing wave antennas, if the source is a pure single
frequency sine wave and if no harmonics are generated
by the antenna system:

1. The forward wave is sinusoidal.

2. The reflected wave is sinusoidal and coherent with the
forward wave.

3. Their superposition results in a sinusoidal standing wave
with the same angular velocity.

Any non-linearity would introduce harmonics.
--
73, Cecil http://www.qsl.net/w5dxp