Since 90% of the population doesn't know what shortwave radio is, I feel like I need to start this off with a quick definition:
Shortwave radio is radio communication using the upper MF (medium frequency) and all of the HF (high frequency) portion of the radio spectrum, between 1,800–30,000 kHz (from wikipedia)
...and yes, you need a special radio that can tune into these frequencies. They don't all look like the one in the picture; they come in all shapes and sizes.
Over the years since the last world war, there have been many strange transmissions, some of which are still ocurring today. Some sound like they could have been alerts of some sort. Maybe beacons? And then there are number stations. What are number stations??
A numbers station is a type of shortwave radio station characterized by unusual broadcasts, often created by artificially generated voices reciting streams of numbers, words, letters, tunes or Morse code. They are transmitted in a wide variety of languages and the voices are usually female, although sometimes men's or children's voices are used. (Also from wikipedia)
So the big questions: Who's making these transmissions? Where are they coming from? What are they for? ...and why so creepy?
Below is an NPR segmant on number stations from 2000
