 B-scope displays were common in airborne radars in the 1950s and 60s, which were mechanically scanned from side to side, and sometimes up and down as well.The spot was swept up the Y-axis in a fashion similar to the A-scope's X-axis, with distances "up" the display indicating greater range.This signal was mixed with a varying voltage being generated by a mechanical device that depended on the current horizontal angle of the antenna.