Basic Qualification · B-007 Radio wave propagation · B-007-007-009
Which analog emission mode is the most reliable in auroral propagation?
- ACW, because it resists fading
- BFM, because it is readable even when distorted
- CFM, because it resists fading
- DCW, because it is readable even when distorted
Correct answer: D — CW, because it is readable even when distorted. From the official ISED question bank, verified word for word.
Why
CW, because it is readable even when distorted, is correct because auroral propagation scrambles radio signals, turning voices into garbled noise while leaving simple on-off Morse code dots and dashes understandable. The full explanation — and one for every question — is in Pro.
Practise this section
Radio wave propagation is section B-007 of the Basic exam: How signals travel: the ionosphere and its layers, skip, ground wave, sporadic E, and which bands work when.
Drill B-007 — free, no account