One of them is so poorly calibrated, that on most approaches at minimum you will find yourself right overhead a church spire that is about a mile left of centreline.
You might want to revisit your dog and pony show that describes your flight instruction, what next....NDB's are not 'calibrated' in the sense that a VOR might be, however the signal can be distorted by ground objects...or...a poorly functioning receiver/indicator in the airplane.
