The signal, according to some radio operators who have heard it ratcheting over their headsets, sounds like a buzz saw. Others have compared the racket with the sound of an electric mixer or the continuous firing of machine guns. Since July, short-wave radio operators in Europe, the U.S. and elsewhere have been tormented by a mysterious radio beam that Western intelligence sources say emanates from what is probably the world's most powerful transmitter: a 2 million-watt Soviet military radar station near Kiev.
The behemoth is apparently part of a Soviet effort to develop...