G4NSJ – Number stations time signals & other strange transmissions


What are number stations?

Numbers stations transmit seemingly random sequences of numbers or letters in a repetitive or automated manner. These stations have been around for many decades and may be associated with espionage or covert communications. The exact purpose of numbers stations is a mystery but they have been speculated to be a form of clandestine communication used by intelligence agencies or other covert organisations.

These stations use a mechanical or synthesized voice to transmit coded messages, which are often followed by a series of numbers or letters. These messages are usually broadcast in a repetitive manner. The transmissions occur on specific frequencies or at predetermined times, adding to their secretive nature.

Numbers stations have been reported in various countries around the world, and their transmissions have been heard in several languages. Some numbers stations have distinctive names or call signs, while others are simply known by the sequences of numbers or letters they transmit. Many stations have been known to abruptly cease transmission, only to reappear later with different messages or patterns adding to the mystery surrounding them.

Despite much speculation and interest, the true purpose of numbers stations is unknown. Some theories suggest that they are used for espionage, covert communication with spies in the field, or as a means of relaying instructions to sleeper agents. I doubt that we will ever discover the real purpose of these clandestine transmissions.

Number stations time signals & other strange transmissions are not only interesting but they provide a good benchmark for propagation. RWM is a Russian shortwave time signal station. The station transmits in Morse from Moscow on 4996 kHz, 9996 kHz and 14996 kHz.

The Buzzer

Take a listen on 4625kHz in the evenings and you’ll hear the Buzzer.

Here is an article on the Buzzer by the BBC

Slow Morse on 5345kHz:

There’s a slow Morse transmission, in French, on 5345kHz. I’ve written it down and pasted it into Google Translator. it’s not just groups of letters. it’s well constructed sentences. The transmission is great for CW practice, but it is rather slow for me.

Other frequencies of interest:

3218.5 Katok 65
3243 Goose
3510 Air Horn
4182 T Marker
4224 Katok 65
4310 Goose
4770 Alarm
5292 D Marker

Slow Morse transmissions:

I’ve been listening for some time to a slow CW station on 5345kHz. The transmission is in French. Rather than groups of letters or numbers, there are sentences about various things.  Does anyone know what this might be?