JIMMIE wrote:

Concerning a TV station using elliptical polarization is there a
purposeful phase difference between the horizontal and vertical fields
or is it simply just dividing power between horizontal and verical
radiators with no concern as to phase relationship

Jimmie

If equal horizontal and vertical components are in phase, you have
linear polarization. If they're 90 degrees out of phase, you have
circular polarization. If they're at some other relative phase angle,
you have elliptical polarization. (Actually, linear and circular are two
extreme special cases of elliptical polarization.)

This makes a big difference in how the waves behave. The polarization of
a circularly polarized wave rotates 360 degrees each cycle, while the
polarization of a linearly polarized wave is fixed. If you add equal
vertical and horizontal fields in phase, you get a linearly polarized
wave tilted 45 degrees relative to horizontal or vertical. If you rotate
a linearly polarized receiving antenna in that field, you'll get a
maximum when the antenna is aligned with the field, and zero when it's
at right angles to the field, that is, tilted 45 degrees the other way.
If, on the other hand, you add the linearly polarized vertical field to
a linearly polarized horizontal field that's 90 degrees out of phase,
you get a circularly polarized wave. The signal amplitude won't change
at all as you rotate the linearly polarized receiving antenna. It'll
stay at a constant 3 dB below the best response you got from the
linearly polarized field.

If the H and V fields are added with some other phase angle, you'll get
some variation as you rotate the receiving antenna, but no complete null.

Roy Lewallen, W7EL