Basic Qualification · B-006 Feedlines and antenna systems · B-006-003-001
A transmission line must be supported for several metres by attaching it to a metal fence. What type of transmission line will NOT be adversely affected by proximity to the fence?
- A Open-wire line
- B Window line
- C Coaxial cable
- D Twin-lead
Correct answer: C — Coaxial cable. From the official ISED question bank, verified word for word.
Why
Coaxial cable works best here because its outer metal shield acts like a protective cage, keeping the radio signal inside and stopping it from interacting with nearby metal objects like a fence. The full explanation — and one for every question — is in Pro.
Practise this section
Getting the signal out: antennas, feedlines, SWR, baluns, matching, and why antenna length depends on frequency.