Basic Qualification · B-008 Interference and suppression · B-008-001-006
The signals from two commercial transmitters combine outside your receiver to produce noise on a desired frequency. What type of interference is this?
- A Harmonic emissions
- B Intermodulation
- C Spurious emissions
- D Receiver overload
Correct answer: B — Intermodulation. From the official ISED question bank, verified word for word.
Why
Intermodulation happens when two strong signals from outside your receiver mix together in a non-linear part of your equipment, creating new unwanted frequencies that sound like noise on your desired channel. 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.