Basic Qualification · B-006 Feedlines and antenna systems · B-006-010-005
If a quarter-wavelength vertical antenna is placed on the roof of a car, in what direction does it send out radio energy?
- A It goes out equally well in all horizontal directions
- B Most of it goes vertically straight-up
- C Most of it goes equally in two opposite directions
- D Most of it goes in one direction
Correct answer: A — It goes out equally well in all horizontal directions. From the official ISED question bank, verified word for word.
Why
A quarter-wavelength vertical antenna mounted on a car roof radiates radio energy in a circle around the mast, meaning the signal strength is the same no matter which compass direction you face. 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.