Radio Mobile is using 2 types of geodata for it's calculations:
Both data types are available in various resolutions. Due to the origine of the source, world wide data is not available for free in all resolutions. The main reason is that high resolution data is only made available for USA en North America and not world wide. Therefore the sources have been tagged World wide and other.
Over time more accurate data becomes available and this data is accessable in Radio Mobile too.
In Radio Mobile for DEM primary SRTM data is used. The usage is automated and can be configured to your needs in 'Options > Internet > SRTM'. In a number of cases it is required to use other sources than the ones that have been pre configured. Reasons for that can be that there are voids in the SRTM data or the data is simply not covered by the SRTM set.
Secondary Radio Mobile can use Land Cover or Clutter. The usage is automated and can be configured to your needs in 'Options > Internet > Landcover'. Corine and Globcover are in the Landcover database for Europe and the world downloadable directly with the Radio Mobile program.
This how to produces a list of sources that provide both DEM and Land Cover data that is useable directly in to Radio Moble or can be used after conversion. Also some tools are mentioned for conversion.
The users of Radio Mobile have joined strength and published 4 sites where SRTM tiles can be downloaded or accessed by Radio Mobile. As a service to the visitors of the Radio Mobile Tutorial these web pages are embedded in to this tutorial.
More information about thes pages at 'Tile Download services'.