Fox Compass
 

GM Fox armored cars had a Pioneer aircraft type compass for determining direction but it was somewhat of a mystery where it was mounted. With some detective work with Les Fisher we were able to determine it went on the armour to the driver's left between the front plate and the vision block. My Fox apparently never had a compass fitted but those that did have a square steel plate welded here for mounting it.

compass calibration
 

In an armored vehicle it is tricky. Aircraft have a painted 'rose' at the airport. orient the vehicle on the 'rose', and correctly calibrate the vehicle compass. make you own 'rose' on the ground. Newc

Good point. I read the installation paper for mounting this compass in the Fox and it says you have to try various locations to avoid the obvious magnetic attraction. It stopped short of offering suggestions where those might be hence the detective work.

Magnetic compasses in armoured vehicles are very inaccurate. Revving up the engine can make the compass rose spin around and on a vehicle with a large turret mounted gun traversing the turret can drag the compass rose around with the barrel.

Now I’m wondering: would that be because it’s an early vehicle from before compasses were fitted, or because it’s a late one from after a decision was made to stop installing magnetic compasses because they didn’t work well enough?