"modern" rf modulator for hd tv

[TechnoQuest]

Does an rf modulator exist that works on newer hd tvs? My Samsung JU6500 does a great job with OTA hd broadcasts and I would like to find a modulator that will go from rca in to coax out with a compatible signal. I tried one I got on ebay but it would not work and I assume it was made before hd came along. The specs (if provided at all) on ebay, amazon, etc. don't mention this and I don't want to keep buying, taking shots in the dark hoping to luckily end up, finally, with one that does the job. Am I wasting my time? Can anyone say one way or the other if what I'm looking for even exists? Thanks to any and all for your input.

 

[kanewolf]

I didn't find anything obvious and not too expensive. The terms to add to your searches are "QAM" and "ATSC" Those are the terms associated with digital TV rather than analog.