Ordered a surprise attack over a radio (7)

I believe the answer is:

arrayed

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'ordered' is the definition.
(I've seen this before)

I don't understand the rest of the clue.

(Other definitions for arrayed that I've seen before include "Ordered" , "Decoratively assembled" , "Displayed in an arrangement" , "Formed up" , "Marshalled; (finely) dressed" .)

I've seen this clue in The Times.

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