Basic Qualification · B-008 Interference and suppression · B-008-002-007
Your SSB HF transmissions are heard muffled on a sound system in the living room regardless of its volume setting. What causes this?
- A Lack of receiver selectivity
- B Audio rectification of strong signals
- C Harmonics generated at the transmitter
- D Improper filtering in the transmitter
Correct answer: B — Audio rectification of strong signals. From the official ISED question bank, verified word for word.
Why
Your voice sounds muffled because the strong radio waves from your transmitter are being picked up by the audio wires or circuits in the sound system, where they act like a radio receiver and get converted into audible noise. The full explanation — and one for every question — is in Pro.
Practise this section
When things interfere: harmonics, overload, RFI to and from your station, filters, ferrites and how to fix the neighbour's TV.