DRM/DRM+ Digital Radio Mondiale
There are some good options in order to receive and transmit DRM30 and DRM+ currently available.
Spark free (but not free software) DRM30/DRM+ (also FM/RDS and AM/AMSS) transmitter that supports direct RF output (possible hardware options include the USRP and Diragen). Also supports the use of the royalties-free codec CELT.
Sodira free (but not free software) DRM30/DRM+ receiver. To receive DRM+ one option is to use a VHF to HF downconverver (FMC 108-28 is a good option) together with a receiver like Pappradio (remember to turn off all band-pass filters). Other option for DRM+ reception is the USRP, using GRC - examples here - to grab the I/Q channels and output it to a VAC, then to RateMonkey, and then to Sodira. We believe there is bug (bug confirmed by the author) in the DRM+ decoder of Sodira, that causes a drop of the SNR until a complete loss of sync after some seconds.
Diorama, Matlab implementation of a DRM receiver.
See also DRM_trial_II_in_Sottens reporting a test transmission made with Spark, USRP and an amateur radio amplifier on the decommissioned MW transmitter mast of Sottens