According to Lifehacker, numbers stations are for spies and broadcast a series of numbers using shortwave AM stations. No one truly knows what numbers stations are used for, but many who have played around with a radio have found them. Numbers stations might be silent for hours (or days) until short nursery rhymes, morse code, or voices fill the frequency. Talk about bizarre. It’s truly weird and definitely one of the creepier things on the air.
What Are Numbers Stations?
By Brynne Mahafee,