I worked on some of those XM radios with the DVR/buffering capability, before the merger. Really, it was just limited to the amount of storage you had. I think

I worked on some of those XM radios with the DVR/buffering capability, before the merger. Really, it was just limited to the amount of storage you had. I think the one I did allowed up to 30 minutes but of course you lost it when you switched channels. The music is so insanely compressed (the best channels were 32 kbit AAC+) and RAM/Flash is so much cheaper now, it could really be anything you wanted these days. The satellite signal itself has a bit of time diversity in it (in case one of the birds disappears), like about 1500 mSec worth, as well as terrestrial backup transmitters in most cities (SXM's dirty little secret), so if you really have loss of signal you must be underground for a while.