Basic Qualification · B-006 Feedlines and antenna systems · B-006-001-005
What commonly available transmission line can be buried directly in the ground for some distance without adverse effects?
- A 600-ohm open-wire line
- B 75-ohm twin-lead
- C Coaxial cable
- D 300-ohm window line
Correct answer: C — Coaxial cable. From the official ISED question bank, verified word for word.
Why
Coaxial cable is built with a central wire surrounded by insulation and a metal shield that keeps signals inside and blocks outside moisture, making it tough enough to be buried directly in the ground for a while. 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.