Basic Qualification · B-006 Feedlines and antenna systems · B-006-001-005
Quelle ligne de transmission, communément en vente sur le marché, peut être enfouie directement dans le sol sur une certaine distance, sans effets défavorables?
- ALa ligne bifilaire ajourée ("window line") de 300 ohms
- BLa ligne ouverte de 600 ohms
- CLa ligne bifilaire de 75 ohms
- DLe câble coaxial
Correct answer: D — Le câble coaxial. Question tirée de la banque officielle d'ISDE.
Why
Coaxial cable is built with a central wire surrounded by insulation and a metal shield that keeps signals inside and blocks outside moisture, making it tough enough to be buried directly in the ground for a while. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and antenna systems is section B-006 of the Basic exam: Getting the signal out: antennas, feedlines, SWR, baluns, matching, and why antenna length depends on frequency.
Drill B-006 — free, no account