For decades, shortwave radio has been used to transmit coded
messages to spies or other covert operatives. Stations that are
dedicated to this are usually referred to as "numbers stations".
The station will broadcast a voice, sometimes automated, some-
times live, that will read a sequence of numbers. The voices can
be female, male or even children, and the transmissions are
often capped by a distinctive tune, tone, word(s) or song.
The idea is that the person receiving the broadcast will write down
the numbers, and decode the message using a one-time pad.
These days, one of the few entities still operating numbers stations
is the communist government of Cuba. Their station at 5898 kHz is
usually referred to by listeners and dx'ers as "¡Atención!". I
was recently able to hear it and record it, late on a Saturday night.
Well, more like Sunday morning. It was past 2AM central time.
(July 22nd, 2012)
Click below to listen to a couple of recordings from that night.
Click on the links below to hear or download the mp3 files.