Art Unwin wrote:
Gon`t professionals use the term (take off angle)?"

The FCC publishes vertical radiation patterns for grounded vertical
radiators of several heights between 0.25 and 0.625 wavelengths. These
and selected other curves are made a part of the rules. These curves
must be used to compute the probable skywave intensity in another
station`s service area whenever it appears a questionable interference
may occur. Skywave computations are approximate but give results which
are reliable over a fairly predictable percentage of the time.

The term used by the FCC is "elevation angle" or departure angle. The
FCC governs radiation.

Determining radiation from broadcast stations is a job for professionals
who use the term "elevation angle".

Best regards, Richard Harrison, KB5WZI