I think you might be confusing the Radar Warning Reciever (RWR) with the actual Radar.
There is no rotational wheel for the RWR, it continually sweeps.
If you are using the latest GWX then you can (IIRC) press Shift+R to raise and lower the Radar. When it is raised it will rotate.
The Axis radar technology was always playing catch up with the allies, so it is possible that the allies have improved the technology and therefore you're radar detector will no longer work.
As for the ranges, I don't have those to hand but I bet they're in the GWX manual.
