I have a Pioneer SD-533HD5 16:9 RPTV operating off of Comcast digital cable with a motorola HD decoder. If I put on one of the networks' digital station with 4:3 programming there are black bars "letterboxing" the sides of the picture. Conversely, when watching analog network 4:3 broadcasts, there are no black bars on the sides, thus in 4:3 mode my TV places gray bars on the sides. My question is, are the networks actually broadcasting the black bars with their 4:3 material? Is the cable company adding them? Is the cable box adding them? The reason I ask is b/c I have stopped watching any 4:3 digital broadcasts b/c it appears that the black bars are "burning" onto my screen (or as the case may be, they are NOT burning that portion of my screen).