Basic Qualification · B-001 Regulations and policies · B-001-019-006
What is the maximum percentage of modulation permitted for amateur radio voice communications?
- A 50%
- B 100%
- C 90%
- D 75%
Correct answer: B — 100%. From the official ISED question bank, verified word for word.
Why
Voice signals using amplitude modulation are allowed to reach 100% modulation, meaning the carrier wave swings from zero to double its normal strength without distortion. The full explanation — and one for every question — is in Pro.
Practise this section
The rules: who may operate, what the certificate allows, station identification, third-party traffic, what you may and may not transmit, and how ISED regulates the amateur service.