Basic Qualification · B-006 Feedlines and antenna systems · B-006-009-004
If a half-wave dipole is converted to a Yagi by adding a slightly longer element, in what direction(s) does the radiation strength increase?
- A In both directions at right angles to the elements
- B In both directions parallel to the elements
- C From the new element towards the dipole
- D From the dipole towards the new element
Correct answer: C — From the new element towards the dipole. From the official ISED question bank, verified word for word.
Why
Adding a slightly longer element behind the driven dipole creates a reflector that bounces radio waves forward, concentrating the signal from the new element toward the original dipole. 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.