ou need to experiment a bit to answer that question.
First off, is there a composite video (yellow jack) output on the HD cable box?
If yes, can you feed this to an auxillary input on your DVD recorder and record a SD program? I doubt a HD program would do too well bt hey, give it a go and see what happens. I'm curious myself.
If you can, in fact, record a SD program in SD, your HD TV should allow an SD input through some composite input. But, it won't be in HD. ...never will.
I can play a VHS through my HDTV so I doubt it'll be a problem for you.