Basic Qualification · B-006 Feedlines and antenna systems · B-006-008-002
Une antenne dipôle filaire résonne à 3600 kHz. Comment changer sa fréquence de résonance à 3900 kHz?
- AEn la rallongeant
- BEn l'installant comme une antenne demionde inclinée
- CEn utilisant un fil de plus grand diamètre
- DEn la raccourcissant
Correct answer: D — En la raccourcissant. Question tirée de la banque officielle d'ISDE.
Why
To raise the resonant frequency from 3600 kHz to 3900 kHz, you must make the antenna shorter because a shorter wire vibrates faster, just as a shorter guitar string produces a higher 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