Basic Qualification · B-006 Feedlines and antenna systems · B-006-010-001
How do you calculate the approximate length in metres of a quarter-wavelength antenna for use on frequencies below 30 MHz?
- A Divide 143 by the operating frequency in MHz
- B Divide 71.3 by the operating frequency in MHz
- C Divide 468 by the operating frequency in MHz
- D Divide 300 by the operating frequency in MHz
Correct answer: B — Divide 71.3 by the operating frequency in MHz. From the official ISED question bank, verified word for word.
Why
To find the length of a quarter-wavelength antenna in metres for frequencies below 30 MHz, you divide 71.3 by the operating frequency in MHz. 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.