Even the AM21 & all 4 of my HR20s give me some but not all of my subs.
The D* OTA as is gets me: The CW, MyNetwork, MeTV, PBS Create (which I watch a lot), Bounce & some I don't watch (PBS Gov't, Local tourist info & Daystar).
I have a used Tivo series 3 w/lifetime that gets me ALL my subs...