FWIW, basic cable isn't analog (well, some channels can be delivered in analog), so your points based on that line of thinking don't follow. It's typically not switched-digital because the basic services (such as the major broadcasters) are heavily watched, so there's not much benefit to going to switched-digital.
Ok. But here, basic cable is still analog -- as my nice but rather old Panasonic 27" can attest.
My parents had extended basic. My father's understanding was that Comcast's mandate that they switch to a free, deck-of-cards sized set top box, and/or rent a Comcast DVR, meant in part that the digital signals being delivered are switched. Perhaps that's switched for smaller viewer share, and multicast for those channels with heavy viewership -- that's what I understand you to be saying.
This week's been my week to repeatedly reveal myself for the fool I am. So, I might as well make a thorough job of it in this thread.
P.S. As I recall, his thinking was in part that to keep the "deck of cards" transceiver small, power efficient, and cost effective enough, it must be receiving a single switched signal rather than trying to handle multiple signals. But perhaps it is picking amongst multiple signals, but only handling one of then at a time. (So, e.g. not producing multiple outputs that would enable a old Tivo to keep working.)
Sorry if this subthread is going on too long.
P.S. Thanks again for the explanations/clarifications.
It's generally accurate to say that basic cable isn't _switched_ digital, which isn't the same as saying it's analog.
It's not accurate to say that basic cable is analog - that is, a single channel can fit into a 6 MHz space. Some providers may put their whole basic lineup in analog, but this is decidedly not a technical requirement.
There's a difference between the little Comcast DTA (for receiving clear QAM digital signals that aren't switched) and a tuning adapter (for receiving digital signals that are switched).
For my company, some markets have no analog channels at all - basic cable services are delivered as clear QAM, and customers use a QAM TV, a DTA, or set-top box to receive them.
Other markets have some analog channels and some digital channels as part of basic cable - if you have an analog TV, you can only see the analog ones, unless you have a DTA.
