IIRC, you can get the Sammys to do that, but they still need an access card. You could search the archives here for that answer.
However, you're talking about some relatively old OTA technology. Were I you, I'd look into one of the newer boxes in the sticky.. maybe one that does QAM should you wind up subscribing to cable. My newer ATSC boxes lock on to fringe signals in a way my Sammy just can't.
Walking the fine line between jaw-dropping and a plain ol' yawn.