Continuation of my tests.
I moved the GPS III far away from any electronics or cables in the nose of the plane.
I still have the same problems with both GPS IIIs.
Attached is a data record.
Orange cells = frozen speed data
Red cells = loss of data and bad GPS coordinates.
I have absolutely no confidence in flying with the GPS III.
If the Mercury receives the wrong speed indication, there is a risk that the gyro gain will not be reduced at high speed with my jet.
I will return the GPS IIIs to you for repair or replacement.