Yesterday i used my HiQSDR frontend for transmitting a shortwave radio signal in digital DRM standard.
I had to use the FPGA firmware version 1.2 which contains enhanced filters that allow modulation of signals with a bandwidth of up to 22kHz in IQ mode (+-11kHz around the tuning frequency).
Stefan, DL2STG, did a great job creating support for the HiQSDR within the Gnuradio project. After noticing a IQ swap the 64QAM DRM signal was decodable. See the constellation diagram below.

HiQSDR DRM TX constellation diagram 64QAM