[Elecraft] EH Antenna Patent

[Ron D'Eau Claire]

 My favorite patent illustrating this principle is 6,025,810
"Hyper-light-speed Antenna".  This is for an antenna that transmits a
signal faster than the speed of light.

-John
 KI6WX

But John, that antenna had people going on about it for ages! 

Your points are all well made. A "dish" will, indeed, produce a narrow
beam. All it has to do is to be a number of wavelengths across, which is
a darn good thing or every mountain, building and large vehicle would
block HF signals and we'd never be able to communicate. Actually, the
"experts" in Marconi's time were convinced that was true and it took a
number of demonstrations by Marconi before they began to realize that
the "radiations" his equipment was producing somehow did go around
things. 

What most of the experts of the time did not appreciate was the
difference the wavelengths made. The initial evaluation of
"electromagnetic waves" was based on Hertz' experiments which were done
at wavelengths of less than 5 meters using his circular half-wave
"radiators" with the balls at the end where the spark jumped the gap.
Marconi's transmission were at hundreds of meters. That's why waves
diffracted easily around very large objects. 

The rules of the game haven't changed. 

R-F still has a hard time in "real world" conductors at extreme
currents, thanks to the skin effect. That limits the efficiency of small
radiators, which is why Marconi had such a tough time building an
efficient antenna, even when he put wires up hundreds of feet. Let's
see, a quarter wave at 100 kc/s is just a bit over 2300 feet (a bit over
700 meters). 

And, like Marconi's engineer at Glace Bay wrote in his journal back in
1902, evaluating an antenna on the air by comparing how a different
antenna worked yesterday or last week is useless. 

We know a lot more theory behind why things work than they did 100 years
ago, but many of the practical observations are still quite right. 

Ron AC7AC
K2 # 1289