Un récepteur est muni de quatre filtres: un de 250 Hz, un de 500 Hz, un de 2,4 kHz et un de 6 kHz. Si vous écoutiez une émission en code Morse et qu'il y avait beaucoup de brouillage, quel filtre utiliseriez-vous?

Why

CW signals, which are Morse code tones, are very narrow in frequency, so a 250 Hz filter blocks the widest range of unwanted noise and interference while letting the signal through. The full explanation — and one for every question — is in Pro.

Practise this section

Station assembly, practice and safety is section B-003 of the Basic exam: Building a station safely: power supplies, grounding, RF exposure, lightning, feedline routing, and what a transmitter, receiver and transceiver actually do.

This question in English · All B-003 questions