Noise? Ghosts?
One of the drones maintained a hovering position over the ship's helicopter pad.
Was that "noise" or a "ghost"?

Source: ship's log: USS Rafael Peralta
Ships bridge logs don’t really give very much other than visual sightings passed to the bridge of presumed UAV’s. There’s no indication that radar picked up anything. Rather than confirm the object the destroyers did something interesting... they limited their electronic emissions. Almost like they didn’t want to get additional confirmation as to size, speed & heading of their aerial target. Curious. An actual radar plot would have been useful.