Looking for a basic DVR to use with my existing SD equipment?

I basically have a standard def system with direct tv. I'm happy with the quality and what I am paying so I dont really want to upgrade anything there but sometimes I want to record some shows. I can make my satellite box change channels on a program, I think it was designed to work with VHS so all I need so some sort of DVR box that I can set to start recording the Svideo and analog audio at a specific time. I bought a capture device for my computer but apparently my computer is not quite fast enough and the quality is much worse than I am used to. Also the software only allows timed or scheduled recording for the tv signals, not the video inputs. I assumed there were DVR boxes that were basically like a vcr where you could just tell them to start recording but it looks like they are all designed for fancy digital sources with fancy program guides and schedules that I dont have. Im open to looking for used equipment but also could spend money on new stuff if the right stuff exists.

Open to hear any thoughts or ideas.