Which of the following constitutes a spurious emission?
An amateur station transmission made without the proper call sign identification
A signal transmitted to prevent its detection by any station other than the intended recipient
Any transmitted signal that unintentionally interferes with another licensed radio station and whose levels exceed 40 dB below the fundamental power level
An emission outside the signal’s necessary bandwidth that can be reduced or eliminated without affecting the information transmitted✓Bonne réponse
Explication
A spurious emission is defined by two properties together: it lies outside the necessary bandwidth of the transmission, and its level can be reduced without affecting the information being transmitted. Missing identification and deliberately hidden transmissions are separate violations, and the definition contains no 40 dB threshold.