Basic Qualification · B-006 Feedlines and antenna systems · B-006-008-001
Une antenne dipôle filaire résonne à 3900 kHz. Comment changer sa fréquence de résonance à 3600 kHz?
- AEn la rallongeant
- BEn la raccourcissant
- CEn l'installant comme une antenne demionde inclinée
- DEn utilisant un fil de plus petit diamètre
Correct answer: A — En la rallongeant. Question tirée de la banque officielle d'ISDE.
Why
Lowering a dipole's resonant frequency requires increasing its physical length because a longer wire naturally vibrates at a slower rate, much like a longer guitar string produces a deeper note. 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