Advanced Qualification · A-007 Feedlines and matching · A-007-008-011
Si la résistance ohmique d'une boucle compacte ("miniloop") est de 2 milliohms et que la résistance de rayonnement est de 50 milliohms, quelle est l'efficacité de l'antenne?
- A50 %
- B96,15 %
- C52 %
- D25 %
Correct answer: B — 96,15 %. Question tirée de la banque officielle d'ISDE.
Why
Antenna efficiency measures how much power turns into radio waves instead of heat, calculated by dividing the radiation resistance by the total resistance. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and matching is section A-007 of the Advanced exam: Feedlines and matching at the advanced level: transmission line theory, impedance transformation, stubs and matching networks.
Drill A-007 — free, no account