I have just configured and got DVB-T2 working with tvheadend, and Im posting here because I thought people might be interested in this.
I have a TurboSight TBS6280 card, and am located near the Crystal Palace transmitter in London.
tvheadend sees the frontends in the system just fine. Obviously, I had to manually add the mux (only one available) as there are no default configurations available.
I set the frequency (554000), the constellation (QAM256) and the bandwidth (8mhz). The rest of the settings I set to auto. tvheadend immediately saw the 4 channels available.
I think this was a bug, but the Map Channels button remained greyed out, as it was not automatically running the initial mux scan. I found that restarting the tvheadend process triggered the mux scan, and then I was able to trigger the "Map DVB services to channels". The next problem was that tvheadend was not seeing any EPG data for the channels. I installed tv_grab and pulled in the channel data, and then all just worked! It records data and xbmc can view the channels just fine.
Im very impressed. This is a great piece of software :)
Steve.