Variometer, interior

In a junk box on a rally I found the interior of a variometer. No housing, no knob, so it will never be used again, but maybe for spare parts, one day. Anyway, the photos for those who never saw one inside.

The potentiometer is to calibrate the aerial current meter.

According to information from Jacques, VE2JFE, “we should look into the rear “box” to see if there is a half-wave or a full-wave bridge rectifier” to determine whether it is a MkII or a MkIII unit. So, after torturing it with a small blow torch, here it is:

The round white piece in the middle is the ceramic isolator whre the antenna lead is fed through.

And according to Chris Suslowicz, G8KGS, “The Mk.II Canadian variometer (This will be for the Mk.3 Canadian set) uses: ZA/CAN/BR.14683 Inductance Unit, RF, No.6”.