(Source: Top Secret Writers)
Shortwave radios have been a tool of the espionage trade for many years. Radios can transmit information encoded to be picked up by the receiver and then decoded.
This technique was used throughout World War I, World War II, and the Cold War. Like Steganography, radiograms are still being used today.
[…]The techniques were used by the Soviets during the Cold War many years ago, but it seems that they have remained long-lasting fixtures in Russian Espionage.
We actually reported on this back when news broke about the russian agents who used numbers stations for espionage purposes. Yep, shortwave radio is your friend if you don’t want people tracing where you are and what you’re listening to.
Mind you, when you live in a country that suppresses free speach, you also reach for a shortwave radio.