Dish already said that PTA will not support the mythical OTA tuner. (That is, if the OTA tuner is ever released.)
Perhaps ppl don't get the idea of collecting one stream with the big four channels from one [SB] transponder, eg one frequency, ie using ONE tuner.
If they will look at OTA, they will find each of the four station is taking own frequency, so do OTA PTA you'll need FOUR OTA tuners with four GOOD signal ! Adding to that 4x load to drive and much more space will req for that feature. One big plus is OTA MPEG-2 quality is better (in not too many sub-channels there).