A series of numbers broadcast in Spanish over open shortwave radio frequencies that can be heard all across the USA nightly between sunset and sunrise on the east coast and it's been going on for decades speculated to be a code to spies in the USA. I never heard of this until this evening until I picked a radom Art Bell show (December 2003) to listen to on my evening walk. Article is from June 2024. https://www.unilad.com/news/world-news/cuba-radio-station-eerie-coded-messages-us-667261-20240609


