Digital TV Converter Missing Channels?

Well, There Is 1 Channel Im 1/2 Okay With...The CW Or Whatever. Thats An Okay Channel. But I Want Channel 7 (It Used To Be....) KEVN? Fox News? It Was Something Along Those Lines... Anyway...I Tried Moving My Antenna My Highest Signal Has Been 43...Its Normally At 20 Somethin...I Can't Really Make It Much Higher...But I Cant Get That Channel! I Hit "Menu>Serttings>Channel Scan" And It Doesn't Find Anymore Channels Then I Have...Please Help!