Basic Qualification · B-003 Station assembly, practice and safety · B-003-017-011
You have a very loud low-frequency hum appearing on your transmission. In what part of the transmitter would you first look for the trouble?
- A The power amplifier circuit
- B The power supply
- C The variable-frequency oscillator
- D The driver circuit
Correct answer: B — The power supply. From the official ISED question bank, verified word for word.
Why
A loud low-frequency hum usually comes from the power supply because it converts AC mains electricity into the DC power your radio needs. The full explanation — and one for every question — is in Pro.
Practise this section
Building a station safely: power supplies, grounding, RF exposure, lightning, feedline routing, and what a transmitter, receiver and transceiver actually do.