Basic Qualification · B-006 Feedlines and antenna systems · B-006-004-007
La ligne de transmission ayant les plus faibles pertes en HF est:
- Ala ligne bifilaire de 300 ohms
- Bla ligne ouverte
- Cla ligne bifilaire de 75 ohms
- Dle câble coaxial
Correct answer: B — la ligne ouverte. Question tirée de la banque officielle d'ISDE.
Why
Open-wire line loses the least signal on HF because its conductors are spaced apart by insulators, leaving most of the space around them as air rather than solid plastic. 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