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...