Numbers stations are radio stations dedicated to transmitting sequences of seemingly random and meaningless numbers or letters over the air. Not much is known about them, but it is generally agreed that these are encrypted one-way transmissions, designed to deliver a specific, time-sensitive message to one (and only one) person. However, this has never been confirmed or verified, as far as I know. They’ve been around for decades, dating back to the height of the Cold War, and the mind doesn’t have to stretch far to imagine where this might be used.

Usually a synthesized male or female voice gives out numbers repeatedly, though the stations don’t just transmit numbers and letters. Some intersperse music, tones, or singing, and naturally there are stations in various languages, adding to the mystique. If you’ve ever come across any of these over-the-air, I think you’ll agree they can sound spooky and downright creepy. Especially at night.

Here are a few strange ones, via the Internet Archive:

15728-ready

Since your browser doesn’t support the tag for embedding audio, you can go to the file directly at:<br /> <a href="http://ia301525.us.archive.org/2/items/ird059/tcp_d1_09_ready_ready_15728_irdial.mp3" target="_blank">http://ia301525.us.archive.org/2/items/ird059/tcp_d1_09_ready_ready_15728_irdial.mp3

Swedish rhapsody

Since your browser doesn’t support the tag for embedding audio, you can go to the file directly at:<br /> <a href="http://www.archive.org/download/ird059/tcp_d1_01_the_swedish_rhapsody_irdial.mp3" target="_blank">http://www.archive.org/download/ird059/tcp_d1_01_the_swedish_rhapsody_irdial.mp3

Czech 5-note

Since your browser doesn’t support the tag for embedding audio, you can go to the file directly at:<br /> <a href="http://ia301524.us.archive.org/2/items/ird059/tcp_d1_11_5_note_version_czech_lady_irdial.mp3" target="_blank">http://ia301524.us.archive.org/2/items/ird059/tcp_d1_11_5_note_version_czech_lady_irdial.mp3

6-3-8

Since your browser doesn’t support the tag for embedding audio, you can go to the file directly at:<br /> <a href="http://ia301524.us.archive.org/2/items/ird059/tcp_d1_14_counting_station_spanish_irdial.mp3" target="_blank">http://ia301524.us.archive.org/2/items/ird059/tcp_d1_14_counting_station_spanish_irdial.mp3

dots

Since your browser doesn’t support the tag for embedding audio, you can go to the file directly at:<br /> <a href="http://ia301524.us.archive.org/2/items/ird059/tcp_d3_22_rapid_dots_irdial.mp3" target="_blank">http://ia301524.us.archive.org/2/items/ird059/tcp_d3_22_rapid_dots_irdial.mp3

jamming

Since your browser doesn’t support the tag for embedding audio, you can go to the file directly at:<br /> <a href="hhttp://ia301525.us.archive.org/2/items/ird059/tcp_d3_02_iran_iraq_jamming_efficacy_testting_irdial.mp3" target="_blank">http://ia301525.us.archive.org/2/items/ird059/tcp_d3_02_iran_iraq_jamming_efficacy_testting_irdial.mp3

The Conet Project is a collection of off-air shortwave radio recordings of numbers stations published by the British label Irdial. They’ve collected 150 recordings of transmissions over the past twenty years and published a four-CD set (now out of print and difficult to find).

                  <p>
                    These stations aren’t as rare as one might think. I have no idea how many are active currently, but according to <a href="http://www.archive.org/details/ird059" target="_blank">the article</a> at the Internet archive, there are many, and they have not died away since the end of the Cold War.
                  </p>

                  <p>
                    For more information, check the <a href="http://en.wikipedia.org/wiki/Number_stations" target="_blank">Wikipedia page</a> or try <a href="http://www.spynumbers.com/" target="_blank">http://www.spynumbers.com/</a>.
                  </p>