Topband: Best angle of radiation ?

[Tom W8JI]

> There were numerous technical write ups about stations who wanted the 
> maximum theoretical ground wave signal and spent big bucks to put up 5/8 
> wave verticals.  They were always disappointed in the unexpectedly reduced 
> coverage area that resulted.
>
> Most of the reasoning for this unexpected negative result was attributed 
> to the minor high-angle lobe produced by the 5/8 wave coming back down and 
> interfering with the main lower angle signal.  As a result, those station 
> who had experimented with 5/8 wave towers usually reduced them to 1/2 wave 
> or less.

Somewhere in my textbooks or papers, I have a few places where verticals 
around .55 wavelength are called "non-fading verticals" for that reason.

This shows how low the effective ionosphere height is and how long the 
groundwave is, where the high angle lobe arrives within range of the 
groundwave.