> So, , what digital modes exist that are in the 12 to 20 kHz range > could I use if I when and bought a SDR today ?
DRM. 9, 10, 18 and 20khz wide. Really good bitrate. and it's free. google DREAM drm receiver. DREAM does transmit too, DV (cd-quality) or data. If this would be legal we would already have wide-digital-sstv with 18 kbit/sec or even streaming video (low quality) on HF.
