RF interference on TV from upsampler

When operating a television with rabbit-ear antennae, most have probably noted that a weak station becomes more snowy if a cdp is on in the vicinity. Today, I interrupted some music and flipped on the local news for a second. I noted that the TV signal becomes more snowy when I switch on the 96 kHz upsampler...Anyone have any idea why this might be? And is this increased interference from the latest digital sources the real reason that high-end power cords and cables have become the norm?