"Ian White said -

Looking edge-on at the line, we have two conductors carrying equal
and
opposite currents, but one is slightly farther away than the other
so
their transverse radiated fields do not quite cancel out.

===========================

Ian, Oh yes they do.

Next to each half wavelength of line there is another half wavelength
of line in which the current is in antiphase with it. And so, in the
far field, the fields from adjacent half-wavelengths of line cancel
each other out.

Now you'll say my logic falls down when the line length is an odd
number of half wavelengths. But you must not consider half
wavelengths of line to be behaving independently of each other.
----
Reg, G4FGQ