Basic Qualification · B-006 Feedlines and antenna systems · B-006-012-009
If you were to cut a half-wave dipole for 3.75 MHz, what would be its approximate length?
- A 40.00 metres
- B 62.40 metres
- C 80.00 metres
- D 38.13 metres
Correct answer: D — 38.13 metres. From the official ISED question bank, verified word for word.
Why
A half-wave dipole for 3.75 MHz is roughly 38.13 metres because radio waves travel slightly slower in wire than in free space, shortening the required length from the theoretical 40 metres. 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.