On 4/26/2022 12:08 PM, JC wrote:
Actually,
I don't think anyone understands antenna technology.
Those who have taken the time to study it certainly do. The fundamental
concepts have been well understood for a century, and the math for two
more.
Harold Beverage invented the antenna bearing his name in 1921. The
antenna we call a Yagi was invented in 1926 by the Japanese engineer
Shintaro Uda, with a lesser role played by Hidetsugu Yagi. Yagi had the
better press agent. Complex multi-tower directional antennas were in
wide use on the US AM broadcast band in the '30s, and they were not
Yagis -- design variables were (and still are) tower spacing,
orientation, amplitude and phasing of drive currents. As an EE student,
I worked in the office of Pete Johnson, whose consulting practice was
the design of these antennas. He and Carl Smith re-wrote FCC AM
technical regulations after WWII. The turnstile is a relatively new
one, invented by legendary engineer George Brown in 1935.
The oldest engineering textbook in my collection is by Stanford prof
Frederick Terman, published in 1937, and it wasn't the first edition. It
provides all the math needed to design those vertical arrays, as well as
long wires, Vee-beams, and Rhombics. During WWII, Voice of America
shortwave stations had multiple Rhombics beaming to different parts of
Europe and Northern Africa, and the one I toured in my last year of EE,
midway between Dayton and Cincinnati, had two Sterba Curtains, patented
in 1929. The Bruce Array also dates from the '20s.
The Wave Equations, which describe all sorts of vibration, were
developed by French and Swiss scientists in the mid-1750s. They predict
the behavior of sound and radio waves, vibrating strings, musical
instruments, antennas, transmission lines, and light.
73, Jim K9YC
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