Ah yes CBS. This has been a point of frustration for me. I gave up on CBS. I bought an AZbox once, that was a nightmare. That is the only STB that supported some forms of 4:2:2. No recent STB's support 4:2:2 . I can watch them with my PC/Satellite setup, but that is not fluidic, and hence just not worth the trouble most of the time.
The ironic part of the whole thing, i get ABC/NBC/FOX/CW via OTA. But not CBS! So, that just adds insult to injury.
The problem lies in the fact that the STBs only support what is directly supported on the Chipsets. All the STB's out there all use the same small funnel point of Chipsets. (none of which support 4:2:2) STB makers seem to like to dangle that their stb will support it, but never deliver. Oh well....
But, to answer your question, CBS is found on 89w and 97w (Cband) They are Feed channels, and usually come to life in the evenings. You should be able to scan them in and listen to the audio.