Thank you all for your replies. Lots of good info. Seems more complicated that I thought. I was looking for a unit I could hook-up to the coax out from my digital cable box (my television uses the HDMI out) and manually record. I do not need to record one show while watching another or two shows at the same time. HD would be nice but not necessary. We want to set a timer to record movies when we are not watching TV, using the cable box output, and play them back via HDMI while traveling. We have been using a VCR but it is so old it will not record a digital signal so we need to upgrade.
I did not know that the TiVo's could be programmed manually without a subscription fee. There are lots of them on Ebay so that might be the way to go. I need to do more research.