It is most likely interference. The converter boxes are not shielded.

Thanks maryland irisman.

If your house is relatively new, the lighting circuit for the kitchen should be completely separate from any of the outlets. If you can verify that, then you would be 100% certain that it is just interference with the converter.

The digital cable TV boxes are ridiculously picky about grounding.

They ARE shielded. They're built in sheetmetal cases. Problem is the 'shield' is only grounded to the coax shield, which needs to be very well grounded in and of itself.

The loss of audio/signal is just the box's response to "garbage" on the line, which is, as suggested, interference - and that's only having an effect because of the condition of the cable or the ground.

I went through this in an old house I lived in. Shortcuts and cheats I had "gotten away with" for years with analog cable tv just didn't work with the digital stuff.

She has a digital converter box, not a cable box. The digital converter boxes are not shielded. Those that are, are minimal at best.

Thanks everyone.

You're welcome catherinet.

Pharkus...I'm sure you saw another thread in this forum where the poster was looking for advice on who to get to install home theater and a speaker system. I wonder how many are out there right now with the same scenario you mentioned? I was in a house not long ago for a different reason but I saw their tv antenna wire was telephone station wire and no ground at all from the outdoor antenna!!

maryland_irisman, yes, I saw that thread. I participated in it.

Almost all "between the source and the tv" boxes I've seen are "shielded" to the coax shield, so my advice on this particular thread/problem, despite the exact nature of the device, is to ground the coax properly, assuming the antenna isn't just one sitting on top of the tv - in which case, I'm in agreement that there isn't much that can be done (other than installing a properly-grounded outdoor antenna)