Got this from: Gizmo Lovers Blog TVGOS
The article was from Dec. 2007, but has TVGOS addressed the issue?? 
According to Gemstar, more than 25 million households have TVGOS devices. Many, probably most, of these devices obtain their data from a signal embedded in the local analog PBS station’s broadcast.
What will happen to all of these devices when the analog broadcasts cease on (or before) February 11, 2009? Even if you don’t use antenna, if the local PBS station goes all digital, the feed to your cable provider would be from the digital source.