I apologize for my late response. I've been in meetings and at iCES and I'm finally catching up. Any followups should be relatively faster.
Page 42 in the manual lists out how to add and delete channels. What you may do is point the antenna at the broadcast tower that is sending the signal and once you get the picture, add the channel in that way.
I'm not sure if a tuner box would do a better job, but it is an option.
Keep me posted.
I have a plasma 2008 Samsung PN50A550. I use an ota antenna with rotator due to several transmitters in my area. Channels are missed when memorizing depending on which transmitter the antenna is pointed at, and the PN50A550 does not allow manually adding channels. I do not want to have to memorize channels every time the antenna is rotated. Any suggestions? I'm new to HDTV but I am trying to learn. Would a stand alone HDTV tuner, allowing the manual addition of channels, placed between tv and antenna solve my problem? And would audio and video be degraded compared to what the tv tuner supplies?