From a purely technical point of view, shortwave radio refers to those frequencies between 3 and 30 MHz. Their main characteristic is their ability to “propagate” for long distances, making possible such worldwide communications as international broadcasting and coordination of long-distance shipping.
From a social point of view, shortwave radio is a method of facilitating worldwide dissemination of information and opinion, and a way to find out what the rest of the world thinks is important. Many countries broadcast to the world in English, making it easy to find out what a given country’s position is on those things it finds important. Shortwave radio can also provide a way to eavesdrop on the everyday workings of international politics and commerce.