Digital switch-over: possible propagation based solutions to the lack of spectrum

The move from analogue to digital HF broadcasting using the Digital Radio Mondiale (DRM) standard poses some problems of transition that have not been present for the transition of other digital broadcasting systems most notably that there is little or no additional spectrum available to support the simulcast period when both analogue and digital transmissions will coexist. This paper explores the possibilities of using the in-built capabilities of the DRM standard to offer a propagation based solution to the lack of spectrum.