Basic Qualification · B-006 Feedlines and antenna systems · B-006-004-009
Si la longueur d'un câble coaxial qui sert à alimenter une antenne est augmentée de 20 mètres à 40 mètres, quel sera l'effet sur la perte de la ligne?
- ALa perte augmentera de 20 %
- BLa perte augmentera de 100 %
- CLa perte augmentera de 50 %
- DLa perte augmentera de 10 %
Correct answer: B — La perte augmentera de 100 %. Question tirée de la banque officielle d'ISDE.
Why
Doubling the length of a coaxial cable from 20 to 40 metres doubles the total resistance and friction the signal faces, meaning the loss grows by exactly 100%. 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