Basic Qualification · B-006 Feedlines and antenna systems · B-006-012-004
Quelle est l'impédance au point d'alimentation d'un dipôle demi-onde en espace libre ("free space")?
- A52 ohms
- B300 ohms
- C450 ohms
- D73 ohms
Correct answer: D — 73 ohms. Question tirée de la banque officielle d'ISDE.
Why
A half-wave dipole in free space naturally presents a resistance of about 73 ohms at its feed point, which is the specific value your exam expects. 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