Basic Qualification · B-003 Station assembly, practice and safety · B-003-010-006
Un récepteur superhétérodyne a une fréquence intermédiaire de 455 kHz. L'oscillateur local fonctionne au-dessus de la fréquence d'opération. Sur quelle fréquence faut-il régler cet oscillateur pour recevoir un signal à 3,54 MHz?
- A4,450 MHz
- B4,905 MHz
- C13,540 MHz
- D3,995 MHz
Correct answer: D — 3,995 MHz. Question tirée de la banque officielle d'ISDE.
Why
To receive a signal at 3.54 MHz when the local oscillator runs above the incoming frequency, you simply add the intermediate frequency of 455 kHz to the signal frequency. 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.
Drill B-003 — free, no account