Basic Qualification · B-006 Feedlines and antenna systems · B-006-011-007
Why are Yagi antennas often used on HF bands from 20 metres to 10 metres?
- ATheir wide bandwidth provides a good match over an entire band
- BTheir high angle of radiation facilitates long-range communications
- CRotatable high-gain antennas become feasible due to shorter element lengths
- DExcellent omnidirectional coverage in the horizontal plane
Correct answer: C — Rotatable high-gain antennas become feasible due to shorter element lengths. From the official ISED question bank, verified word for word.
Why
On the higher HF bands like 20 to 10 metres, the radio waves are shorter, which means the metal rods needed to build a Yagi antenna are physically smaller and lighter. 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