The 351 is the successor to the 151. For whatever reason, Sammy seems to have dropped the manual from their web site.
As for the 351, be cautious, as there are reams of user reports about audio drop-outs with the 351 when using a digital connection for DD. I have no first hand experience with that, but there are lots of unhappy users out there.
I just retired my 151 in favor of a Sammy 160 (combo OTA and D* HD box).
As for the 151, I had no audio problems at all, and good reception, although I live about 3 miles the way the crow flies from the antennas in my city. I can't comment on fringe area reception. The 160 seems to work just as well as the 151 for OTA Digital.
Back to the 151, I have a PDF copy of the manual, if you want it. Just post your e-mail or shoot me a PM at
bleduc@comcast.net
BGL