said by telcodad:
The definition of "Limited Basic" for Comcast is the local OTA broadcast stations along with some local government and education channels: »customer.comcast.com/help-and-su···c-cable/
Unless Comcast had already received a waiver for your area/system, those local broadcast channels should not have been encrypted yet.
In my area, Limited Basic includes more channels than just those you mentioned. For example Discovery, Ion, and TV Guide channel, are advertised as limited basic channels. Ion is not yet encrypted over QAM though yet.