Steve, way back when, they were called radiomen. Now they are called Communications Technician, and there are different categories of them. Radiomen are still a viable asset to the fleet, but they are general service radio operators. The Communications Technicians are affectionately called "spooks."
What we could not talk about many years ago, is now common knowledge and it was called:
Signals Intelligence
It makes you wonder what they are keeping to themselves now-a-days, doesn't it?