Kansas Zephyr said:
Yes.
D* will offer local channels in SD, just like they do now.
It remains to be seen if D* will crop a constant 4:3 aspect ratio, or letterbox those using 16:9.
Correct, I think.
This is my understanding, based on my experience working for our local CBS affiliate. Other stations may handle it differently, for example transmitting an SD channel on a sub channel (11.1 would be HD, 11.2 would be SD). But this is one example of how it might work.
Our local CBS station sends one feed to the digital transmitter. After February when the analog feed goes away, this will be the only feed. During HD programming, that feed will be in HD: some network programming and local news are HD. There is still a lot of programming, especially syndicated programs, that are in SD. So the programming will be a mix of HD and SD. As Mr. Zephyr says, it remains to be seen what D* does with the HD programming: crop or letter box.
Think of it this way. Today I have a Zenith digital converter box receiving HD programs off the air and displaying them on an old 4:3 analog TV. I have it set up to crop (display in 4:3). After February, when you choose/get an SD channel on D* the SD programming from the digital transmitter will display normally. But I don't know what will happen to the HD programs. D* may automatically crop them. Or they may display as letter box. I don't think remote controls for SD D* boxes will let you choose between crop and letter box, so you'll get what you get. Letter box? Crop? I don't know.