Even if it could work, that would be a pretty big waste as you could purchase a DVD recorder for a lot less money. The SA8300HD would only be able to record the analogue channels. FYI, Shaw doesn't use SA equipment, but I guess that's what the "PVR" was for.
The real problem though is that the above PVRs need to be connected to the cable service to function, so you couldn't have OTA functionality on its own. The question is therefore moot.