Here you can search the old SpyNubers Logs from BlackCat Systems. These logs go back to 1999.
Spynumbers, also known as Numbers Stations, are generally shortwave radio stations, which broadcasts formatted numbers or letters, and believed to be targeted at intelligence officers or 'spies' in the field. Historically, the numbers/letters where announced via voice or sent via morse code. In more recent decades transmissions include 'digital' modes using phase-shift and frequency-shift keying. Numbers stations probably go back to World War I and reached their height during the cold war.
Just prior to the fall of the Berlin Wall there was significant acitvity across Europe, while other predominant players allegedly included the United States, Cuba, Israel along with East Asian countries, China, Taiwan and the Koreas. Many of these stations still broadcast today although no country has ever publically confirmed they used or use these Spy Numbers Stations.