Radio Buffs Lobby to Make Historic 500 kHz a 'Memorial Frequency'For almost a century, 500 kHz was a lifeline for ships worldwide. Better known as 500 kilocycles, it was the spectrum reserved for ships and the shore stations that communicated with them in Morse Code (sometimes referred to as CW, for continuous wave). If you're a real radio old-timer, you might refer to the frequency as 600 meters. "To ensure that SOS calls were always heard, all ship and shore stations were required to monitor 500 kHz at all times," said Richard Dillman, secretary and chief CW operator of the...