You look for the IF from the tuner, almost all tuners are made using the exact same frequency building blocks, and thus the tuner can easily be detected and kno

You look for the IF from the tuner, almost all tuners are made using the exact same frequency building blocks, and thus the tuner can easily be detected and knowing which channel it is tuned to. There's a reason all the BBC channels are on the same DTV mux with ITV & others on different muxes - it means the BBC channels that require a license are all on the same tuner frequency for a local area.