We have only the vaguest idea where the broadcasts are coming from, and even less idea where they're going. The sounds are strange—the synthesized voices of women and children mixed with snatches of music, Morse code, or high-pitched buzzing. Sometimes the transmissions appear on a fixed schedule, other times in short random bursts. The only thing they have in common is the eerie recitation of numbers, beamed through shortwave radio signals bouncing across the globe.
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