Basic Qualification · B-006 Feedlines and antenna systems · B-006-008-008
Why are insulators used at the ends of a suspended wire antenna?
- A To decrease the effective antenna length
- B To increase the antenna bandwidth
- C To reduce capacitive coupling with the ground
- D To limit the electrical length of the antenna
Correct answer: D — To limit the electrical length of the antenna. From the official ISED question bank, verified word for word.
Why
Insulators stop the high-frequency current from flowing into the support rope or nearby objects, which would otherwise make the antenna behave as if it were longer than it physically is. 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.