On antennae that are several half-wavelengths long (beverage, Rhombic, etc)
what does the radiative wavefront look like when close to the antennae, even
though it is presented in the literature as a plane wave further out?

The reason that I ask is the on such longwires, there are parts of the
wire which will be radiating positively, and parts negatively, thereby
suggesting that the outgoing wave, spherical though it might be, has
a +/- modualtion were you to travrse its circumference?