Well, in Tom Clancy's Red Storm Rising, the procedure is making a fast turn watching the sky for planes/helos, then another to the horizon and then lower the scope as fast as they can.
All of this is recorded in a videotape and they look at it after that, to see in slow motion if there was anything.
I don't know if this is the real procedure, but, as said before, in game the masts are not detectable by radar, so is no a risk to take a look
