Basic Qualification · B-006 Feedlines and antenna systems · B-006-012-007
Quel est l'inconvénient d'une antenne à pièges ("traps")?
- AElle pourrait rayonner des harmoniques plus aisément
- BElle est trop directionnelle aux basses fréquences
- CElle capte plus de bruit que l'antenne dipôle élémentaire
- DElle ne fonctionne que sur une bande
Correct answer: A — Elle pourrait rayonner des harmoniques plus aisément. Question tirée de la banque officielle d'ISDE.
Why
Antenna traps act like filters that isolate sections of the antenna for different frequencies, but they can sometimes fail to block unwanted higher-frequency signals called harmonics, allowing them to escape and cause interference. 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