Ah, that makes sense. Due to interference, the composite cable setup doesn't work, and that's what forcing you to use the other connection. The VCR solution mentioned above would get the job done (of course, if your plasma TV is hung on a wall, this might not be an attractive option). Not sure kind of composite cable you were using -- it's POSSIBLE a better-shielded cable would be able to reject the interference you were picking up, but if it doesn't, then you might get stuck with an expensive 50' cable and no use for it. Alternative routing of the 50' cable you have MIGHT work, although if the TV is 40' from the receiver/tuner, that doesn't give you much slack for experimenting. Tough dilemma.