I did that right after I got my 722 a few months ago. I picked up some powered rabbit ears from RS. Worked great, but the wife said no way to the ugly looking things. I'm sure I can get away with a small indoor/outdoor type I can mount on my deck.
Both my 211 and 722 rcv the OTA signal at about 20% lower than when I use the SAME CONNECTOR and plug it directly into the back of any HDTV. Stations I get solid with ~lower medium signal strength directly to the HDTV, but pick up only randomly and occassionally... just barely using the SAT OTA tuner.