There's a similar complaint in the CNET Samsung Forum and the interference vanishes when they have just the recorder and HDTV connected. Only when they connect to the cable box the interference kicks in.

Sadly I think this sort of issue is going to be costly to fix as you bring in the hired guns.
I have a few ideas but in a forum I can't offer much detail but my suspect is that a check of the wiring is needed, both of the power and hook ups. But that's as detailed as I can get here.
Bob