Upload the channels.conf file you created with w_scan.
Add all possible DVB-T2 frequencies (in Germany).
buyzero.de by pi3g
Installation of w_scan on the command line:
sudo apt-get update
sudo apt-get install w-scan
Please note the package name has a minus "-", not an underscore "_".
sudo killall tvheadend; sudo w_scan -ft -cDE >> channels.conf
More information about usage of this tool in this blogpost (German)