[Elecraft] OT Wullenweber Array

[Ron D'Eau Claire]

While it's an impressive array, it's really just a directive receiving
antenna: a bunch of vertical monopoles more descriptively called a
"circularly disposed antenna array" or CDAA. They are arranged in a circle
with a reflective screen behind them so the direction of an arriving signal
can be determined by the phase difference in the signal as it arrives at two
or more monopoles facing generally in the right direction. 

Since even the US Military can't create a "magic" antenna that defies
physics, the system has a limited bandwidth. To cover a large part of the HF
spectrum, the system is actually three separate antenna arrays covering
three adjacent frequency ranges. Since each system gets smaller as the
frequency goes higher, the three systems "nest" one inside the other, which
makes for a very complicated-looking layout but it's really just a simple
ring of monopoles with a reflector behind each ring (one reflector serves on
two bands so there's only two circular reflector screens). 

Unless you are trying to determine the direction from which a signal is
arriving, it's not much better than most backyard verticals. 

FRD-10 is only a receiving antenna. Even if you used it for transmitting,
it's still just basically a bunch of monopole verticals. 

It probably has a ground system most vertical owners would lust after.

You can read the original US military technical manual here
http://kahuna.sdsu.edu/~mechtron/PremRxPage/ref/wullenweber.pdf

Ron AC7AC