On 3/21/2016 1:02 AM, Sal M. O'Nella wrote:
I'm seeking learned opinions.

I think we refer to "beam antennas" that way because they behave like
lamps with reflectors, directing a beam of RF like a beam of light. I
don’t know the historical accuracy of my thinking.

I've built any number of directional antennas, usually yagis but also
quads for HF and VHF and a 20m Moxon. I never asked about the name
before today. How many elements constitute a beam antenna? (ARRL reminds
us that even a single horizontal dipole has some directivity; they seem
to use the word beam only for antennas of two or more elements.)

"Sal"
(KD6VKW)
The present pool of questions from NCVEC for the USA Technician exam
contains:
What is a beam antenna?
A. An antenna built from aluminum I-beams
B. An omnidirectional antenna invented by Clarence Beam
C. An antenna that concentrates signals in one direction
D. An antenna that reverses the phase of received signals
It says the correct answer is C. I suppose the issue is what constitutes
"concentrated" signals. A dipole is directional in any plane that
contains the dipole, but not in perpendicular planes. Maybe that is not
concentrated enough...
Bob Wilson WA9D