TheCodeBreakers
its listening posts at Bainbridge Island in Puget Sound; Winter Harbor,
Maine; Cheltenham, Maryland; Heeia, Oahu; and Corregidor and to a
lesser degree on stations at Guam; Imperial Beach, California;
Amagansett, Long Island and Jupiter, Florida. Each station was assigned
certain frequencies to cover. Bainbridge Island, which was called Station
S, copied solid the schedule of Japanese government messages between
Tokyo and San Francisco. Its two sound recorders guarded the
radiotelephone band of that circuit; presumably it was equipped to
unscramble the relatively simple sound inversion that then provided
privacy from casual eavesdropping. Diplomatic messages were
transmitted almost exclusively by commercial radio using roman letters.
The naval radiograms, however, employed the special Morse code devised
for kata kana, a syllabic script of Japanese. The Navy picked these up
with operators trained in Japanese Morse and recorded them on a
annaabi.ee 
