Stray Signals

Do Shortwave ‘Numbers Stations’ Really Instruct Spies? – Radio World

OTTAWA, Ontario — “6-7-9-2-6. 5-6-9-9-0.” Tune across the shortwave bands (above AM/MW), and chances are you will come across a “numbers station.” There’s no programming to speak of; just a mechanical-sounding voice (male or female) methodically announcing seemingly random groups of single digit numbers for minutes on end.

The site of British intelligence’s numbers station transmitter site, “The Lincolnshire Poacher,” at the RAF base in Akrotiri, Cyprus.
Credit: Lewis Bush, ”Shadows of the State.”

Congratulations! You are now officially a spy-catcher, to the extent that you may have tuned into a spy agency’s “numbers station” transmitting one-way instructions to their minions worldwide.

Numbers stations are unidentified radio broadcasts that consist usually of a mechanical voice “reading out strings of seemingly random numbers,” explained Lewis Bush, author of “Shadows of the State” a new history of numbers stations and the spies who run them. “These are sometimes accompanied by music, tones or other sound effects.” He said. “There are also related stations broadcasting in Morse Code and digital modes.”


Program formats aside, the common purpose of numbers stations is “to broadcast coded messages to spies in distant countries,” said Ryan Schaum. He is co-founder of Numbers Station Research and Information Center (NSRIC), a hobbyist group that reports on these signals at According to Schaum, the “use of shortwave allows complete secrecy and makes it impossible to determine who the recipient is.”

In order to decode the message hidden within the numbers broadcast, “the recipient uses ‘one-time pad’ encryption, which cannot be decoded by anyone without the time pad key,” said Schaum. Printed on paper pads, the one-time pad key allows the recipient to decode the message just once, it is then discarded for a fresh key after every use, thus making the cipher literally

Read the full article at
(Disclaimer: The content of this article is the responsibility of the original author and/or publisher. Stray Signals does not claim ownership of the preceding post).

Comments are closed.