Basic Qualification · B-008 Interference and suppression · B-008-001-010
A television receiver suffers interference on channel 5 (76 MHz - 82 MHz) only when you transmit on 14 MHz. From your home you see the tower of a commercial FM station known to broadcast on 92.5 MHz. Which of these solutions would you try first?
- AInsert a low-pass filter at the HF transmitter
- BInsert a high-pass filter at the HF transmitter
- CInsert a low-pass filter at the television receiver
- DInsert a high-pass filter at the television receiver
Correct answer: D — Insert a high-pass filter at the television receiver. From the official ISED question bank, verified word for word.
Why
A high-pass filter at the television receiver blocks low-frequency signals like your 14 MHz transmission while letting the desired 92.5 MHz FM and 76 MHz TV signals pass through. The full explanation — and one for every question — is in Pro.
Practise this section
Interference and suppression is section B-008 of the Basic exam: When things interfere: harmonics, overload, RFI to and from your station, filters, ferrites and how to fix the neighbour's TV.
Drill B-008 — free, no account