[in_vino_vomitus]

The radar screens have been tweaked in various mods, so depending on what - if any - mods you're running will depend on the screen you see.

PPI is pretty straighforward, but without [for want of a better term] range rings you need to refer to the A scope.

The scale on the vanilla A scope is logarithmic, so when estimating distance with it, bear that in mind. OTC makes radar far more user friendly, and the 3D tdc mod in TMO includes a precision mode on the A-scope that once again, makes accurate ranging possible. The display you're illustrating looks like OTC.

Anyway - you have multiple scales, one for each range bracket on the range selector switch. You rotate the beam until you have a blip on the PPI and a spike on the A scope, and the position of the spike, on the appropriate scale, gives you the range. In your illustration, the top scale would be 0-60K [yards] the middle would be 0-32K and the bottom would be 0-4K [I suspect the middle scale should have X000 next to it, and the bottom scale doesn't need a multiplier]