Basic Qualification · B-007 Radio wave propagation · B-007-001-007
Sur les fréquences basses du spectre HF, qu'est-ce qui rend possible la radiocommunication jusqu'à 200 km de jour?
- AL'onde de saut
- BL'onde d'espace
- CL'onde de sol
- DLa propagation troposphérique guidée (par conduit)
Correct answer: C — L'onde de sol. Question tirée de la banque officielle d'ISDE.
Why
Ground wave allows signals to follow the Earth's surface, hugging the curve to reach distances up to 200 km even when the ionosphere is busy reflecting other frequencies during the day. 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