Which of the following might reduce interference by an amateur station to a non-amateur over-the-air radio receiver?
Block the amateur signal with a filter at the antenna input of the affected receiver✓Bonne réponse
Block the interfering signal with a filter on the amateur transmitter
Switch the transmitter from FM to SSB
Switch the transmitter to a narrow-band mode
Explication
The amateur signal is on its own legal frequency, so no filter at the transmitter can remove it; the problem is that the other receiver fails to reject it. A filter at the affected receiver's antenna input keeps the out-of-band amateur signal out of its front end, which is the only choice that addresses the actual mechanism.