I was able to get a timer to work this way too:
Goto 8000 range locals (if you have them), and set a one click timer.
Then edit timer & change channel to OTA channel.
The timer will have correct info unitl recording.
After recording, the info displayed will be "Unknown recording"
I STRONGLY suggest to NOT even attempt to tune to another OTA channel NOR watch the one being recorded during the timer. My 921 did not give a conflict warning & actually tried to tune to a second OTA channel when I tried. Of course the timer screwed up & locked tuner!!!
Also, I get better luck tuning an OTA channel by starting out on a sat channel & via guide or direct number goto an OTA. I then go BACK to a sat channel before attempting to tune to another OTA channel. This way does take a lot longer before it locks up!!!!