Sean,
I'll check again, but I believe most PBS channels / all the time. 2.2, 44.2, 44.3, and 44.4 2.1 and 44.1 seem to be OK.
I just went to
www.pbs.org and checked what they list for pbshd and compared against what Voom lists online. PBS says 2pm is Evolution, Voom says Becoming American. I'm not home to check what the PG says in the STB but I'm sure the Voom content is hosed. All non-PBS channels are fine. Address is Mendon, MA 01756