- Have a large enough base (>10 chunks) with radar and roboport coverage.
- Go to map mode and zoom into the opposite end of your base, enough to be able to place ghost entities
- Select a radar to place and check the coverage shadow in the minimap
The radar shadow is misplaced in the minimap while in map mode.
I suggest moving the minimap for this particular case.
Alternatively we could have a second minimap instead (though my screen isn't too big and that'd be a lot of clutter for me).