There’s nothing subtle about 20d, geeker, in my view. There’s something of the emperor’s new clothes about this. The clue is “Ranges (6)”, and the answer is a double definition. One is range, and the other half is the final letter, in the NATO alphabet.
All well and good, up to a point. But where is the indication to split the clue word? And why there? A good crossword clue should have more than a string of letters in which you make a random break to create two definitions.
A clue for “millimetre” which read “Midsummer’s length (10)” might be acceptable because mid indicates the centre of summer, hence mm, in my view. But with no such indicator “Ranges” doesn’t work for me.