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 _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
