DVR newbie question. We've got the most basic of basic cable services - its maybe 100 channels, no set top box, delivered directly to the TV via a coax cable. Are there some DVR recommendations for use with this - especially looking to not have to add monthly fees or a bunch of other components? Or should most work? We do have a Google Chromecast for streaming as well, but just looking for ways to record programs and/or sports periodically to watch when we're not home.