[BC] Vertical or Horizontal

[wpio fm radio]

Mark, clarify if you want to:

> D. In the presence of shadowing or diffraction effects,
> spots which have very low signal strength when
> horizontal polarization alone is transmitted, tend to
> find a substantial improvement in the horizontally
> polarized component of the field in such shadowed
> areas.

The substantial improvement is an improvement over what....a 
vertical only in the same scenario?  Or a Circular in the 
same scenario.

Thanks
Randy Henry