Hi J_P.
From what i know, i agree with you about the frequency of the calculator.
You wrote """""And further, the examiner circuit also picks up electronic noise from the air that is added to the calculator signal.
This electronic noise in the air is usually of a similar strength to the signal picked up from the calculator,
and the noise remains even when you remove the calculator""""".
Can you explain me how the noise remains????
Regards
