Polish Intelligence 100bd 625Hz FSK
One-way broadcast system, used by one of Polish intelligence agencies for delivery of messages to their operatives abroad on fixed schedules.
This mode has very close ties to the analogue broadcasts from the same agency, known by their ENIGMA codes E11, S11a, and M03. It always sends 15/20 minutes before them, delivering the same message that would later be sent by analogue means, on a nearby frequency. The digital broadcast also repeats 5 minutes after the first one, on the same frequency.
However, not every analogue schedule has a digital equivalent.
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