veals,
For quite a few years ABC & SBS has added some radio channels to the TV data. The main problem with this system is that it takes data capacity from TV and reception is via fixed usually mains powered receivers.
Digital Radio needs a DAB+ radio to receive it. These are anything from a portable radio, car radio, kitchen radio or HTPC system.
Digital Radio DAB+ & DRM. Please read the links.
AlanH