So that I remember for next time, and so I can start writing down some of the issues I’ve had to sort out since re-building my servers, here is what you have to do to tune to a DVB-T2 mux in MythTV (0.27 fixes).
This is the frequency for the PSB3 mux on Sandy Heath, I expect the encoding scheme will work pretty much where ever. At the very least it should get you started:
Frequency: 474200000
Bandwidth: 8 MHz
Inversion: Auto
Constellation: QAM 256
LP Coderate: 2/3
HO Coderate: Auto
Trans. Mode: 8K
Guard Interval: 1/32
Hierarchy: None
If that doesn’t work, and you know it should (as in you are on the same transmitter) try setting the tuning timeouts higher. Also, just blindly re-trying because “WHY DOESN’T IT WORK” seemed to help.