I'm showing my age. The chart shows the pre Omni, four course radio range. which began in the late 20's and was replaced in the early 60's. So I would say speedbump is real close.
Four towers set in a square transmitted the letters A and N in Morse code. A pilot flying along one of the four beams toward the square would hear only an A or N in the dashes and dots of the code. The dashes and dots grew louder or more faint as he flew, depending if he was flying toward or away from one of the corners. Turning right or left, he would soon hear a different letter being transmitted, telling him which quadrant he had entered.
The beams flared out, so that at certain points they overlapped. Where the A or N signals overlapped, the Morse code dashes and dots sounded a steady hum, painting an audio roadway for the pilot. When possible, radio-range stations were located near an airport, and situated so that one of the four beams lined up with the principal runway. WAG, the segmented airport symbol represented a segment of the range the range the airport was in. I was the kid on the airport fence when this was the norm so I never flew with this system.
Gene