Today’s Saturday Stumper

Today’s Newsday  Saturday Stumper, by Matthew Sewell, is full of novelty. Not much time to write this morning, so just some clue-and-answer pairs of note:

1-D, three letters, “What was seen on sets in the ’70s.” My first guess was UHF.

14-A, ten letters, “Earnest appeal.” I like the unashamed colloquialism.

10-D, fourteen letters, “Active aspiration.” I guess so.

15-D, fourteen letters, “Vitamin-enriched cereals, for instance.” Don’t tell the kids.

25-D, three letters, “34-wk. period.” Oof.

My favorite in this puzzle: 28-A, eight letters, “Comic relief?”

No spoilers; the answers are in the comments.