Basic Qualification · B-007 Radio wave propagation · B-007-007-003
Quelle est la cause de la propagation troposphérique guidée (par conduit) des ondes radio?
- AUne inversion de température
- BDes éclairs entre la station émettrice et la station réceptrice
- CUne aurore en direction nord
- DUne zone de très basse pression
Correct answer: A — Une inversion de température. Question tirée de la banque officielle d'ISDE.
Why
A temperature inversion happens when a layer of warm air sits above cooler air near the ground, creating a duct that traps and guides radio waves over long distances instead of letting them escape into space. 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