I don't consider PBS an National network like the big 4. But if you wanted it you could add two 813 receivers and their corresponding 110 units and be able to record 10 shows at a time= 6 sat 4 ota.
Well that is what many think but you may want to read what I just found. It's an edit from Wikipedia and I was surprised by the statement about PBS.
"Television in the United States has long been dominated by the Big Three television networks, ABC, CBS and NBC, but Fox, launched in 1986, has gained prominence and is now considered as part of the "Big Four". The Big Three provide a significant amount of programming to each of their affiliates, including news, prime-time, daytime and sports programming, but still have periods each day when each affiliate can air local programming, such as local news or syndicated programmes. Since the creation of Fox, the number of American television networks has grown, but the amount of programming they provide is often much less: for example, The CW Television Network only broadcasts for ten hours each week, leaving its affiliates free to broadcast a large amount of syndicated programming. Other networks are dedicated to specialist programmes, such as religious broadcasting or services in languages other than English, especially in Spanish.
The largest television network in the United States, however, is the Public Broadcasting Service, a not-for-profit, publicly owned service. In comparison to the commercial networks, there is no central programming arm or unified schedule, meaning that each PBS affiliate has a significant amount of freedom to schedule programmes as it sees fit."