What is Digital Radio?

If you listen to the radio much at all you’ll likely have heard advertisements for Digital Radio. In this article I’ll explain what Digital Radio is all about and what you need to get started.

A Nextwave Digital DAB-390, capable of both Digital and Internet Radio
A Nextwave Digital DAB-390, capable of both Digital and Internet Radio

Digital Radio is a new way of transmitting radio stations, similar to Digital TV. Like Digital TV it allows more stations to be broadcast and provides better quality. In traditional AM or FM radio the radio signal is directly converted to sound out the speaker of the radio. With Digital Radio the sounds are converted to stream of 1s and 0s which is broadcast over radio waves. In addition to the instructions for the sounds to come out the speakers, information such as song titles and station names is also broadcast.

Digital Radio stations in Australia use a format called DAB+. DAB+ has been around since about 2006 and uses an audio format similar to that used on DVDs and Digital TV, called MPEG Surround. The transmission system also uses Forward Error Correction, where multiple copies of the same information are transmitted fractions of seconds apart. This introduces a short delay to the process but enables a Digital Radio to correct any errors caused by radio noise. You will find that a Digital Radio has a delay of about 2 seconds behind the same station being broadcast on AM or FM.

Despite the error correction there has been issues with Digital Radio reception in moving vehicles and there are still not many car stereo head units that support Digital Radio. Handheld digital radios have significantly reduced in cost over the last few years, and are now as cheap as $30. These units work fine in most capital cities. Outside capital cities Digital Radio hasn’t yet been rolled out. If you have good Digital TV reception you’ll likely find Digital Radio will work well too as it’s transmitted from the same towers as TV.

DAB+ Antenna
The vertical loop mounted off the side of the pole is a DAB+ Antenna

If you want to use Digital Radio inside your house in some areas you will need an external antenna. These can be installed on the same pole as your TV antenna and consist of a vertical whip or loop(See picture for one type). You can easily integrate Digital Radio into an existing hifi or home theatre system with a Digital Radio receiver that has an audio output.