The Dark Art of Listening to the Airwaves: A Report

A number station of undetermined origin was heard 15 June 2011, 0135 UT on 6767 khz. 5 digit cifer was read in multiple languages by what sounded like a computer generated female voice.

It went off air at 0140.

The use of number stations is an ‘old school’ method of communicating with your spies from the home land to the nation where they are doing their surveillance without being detected. The transmission times are short, giving a counterespionage operation little time to determine the location of the transmitting antenna. It is likely that the phasing of the sound of the signal, or a heterodyne that might be heard on top of the signal might offer clues.

The strength of the signal and the use of this reliable but primitive method of messaging suggest that it likely originated in Cuba, Venezuela, or transmitted from sea.