Which radar scope uses a range step for measuring range?

The A-scope, or Amplitude scope, is designed to display the amplitude of returned radar signals versus time or distance, effectively providing a graphical representation of the range of objects detected. A key feature of the A-scope is its use of range steps, which allows it to measure varying distances to targets by providing visual markers on the screen corresponding to different ranges. Each of these steps represents a specific distance increment, enabling operators to quickly assess how far an object is located based on the intensity of the reflected signal.

The other types of scopes mentioned do not utilize range steps in the same manner. For instance, the B-scope displays both range and azimuth information but does not present data in incremental range steps like the A-scope. The C-scope is more focused on plotting range and bearing in a Cartesian format, while the R-scope is designed to show relative motion and speed. Thus, the specific functionality of the A-scope in utilizing range steps makes it the correct answer in this context.