Tuning Into The World

So you thought shortwave radio was dead? Think again as Mike Bedford shows you how to listen to and decode distant radio stations…

- Mike Bedford

Living, as we do, in a world of ubiquitous communication, it’s easy to gain a false impression of the radio technology which underpins all this. While this is empowered by Wi-Fi and cellular communications, neither offers anything close to global communication. Wi-Fi achieves a range measured in metres while even mobile phone signals manage only the few kilometres to the closest base station.

Common wireless communication standards are in the UHF or microwave bands where the high bandwidth enables high rates of data transmission at the expense of range. However, at lower frequencies, such as the long- and medium-wave bands, range extends to hundreds of kilometres while the shortwave bands enable global coverage. Of course, the way our mobile phone signals are routed around the world via dozens of point-to-point relays is a modern miracle, as is the undersea fibre-optic network that provides long distance links. Nevertheless, there’s something magical about being able to receive signals from around the world, without the multi-million pound infrastructure that drives our everyday communication.

Here we’re going to learn how to receive global radio signals. We’ll discover how to receive VLF radio signals using nothing more than your PC’s soundcard, learn how to tune into shortwave signals using Web-enabled software defined radios, and see how to convert the unfathomable strings of whistles and bleeps you’ll sometimes find on the shortwave bands into meaningful messages or images.

VLF: how low can you go?