Radio is a pervasive media. It reaches out to a wide range of audience almost anywhere in the world. Commercial radio stations are usually broadcast in either FM or AM, and can have a reach of more than a hundred miles from the station’s antenna. That is a long reach, but there are some stations which have a longer reach: shortwave radio. You may be located anywhere in the world and as long as you have a shortwave radio, you can get signals from shortwave radio stations.
However long the reach, it still needs a shortwave radio to pick up the signal. Not all radios are capable of receiving shortwave signals. Additionally, most shortwave radio stations are not commercial but government run or subsidized. One of the best example of a shortwave radio station is the BBC. BBC radio has been broadcasting for a long time, and has become an institution because of this. The signature chimes of Big Ben has reached the farthest corners of the world due to the BBC news service.