[backhoe]

Can you calibrate the barometer? I have a nasty habit of breaking barometers when I try to calibrate them. Have killed two already.

Yes- recessed in the back plate is an adjustment screw- call your local FAA office ( airport control tower nearest you ) and ask politely for their altimeter reading. It's the local barometric pressure. Set your instrument to match that, and you have it done.

[NautiNurse]

I have broken the little thingy in the back twice. Is it some sort of spring?