Advanced Qualification · A-007 Feedlines and matching · A-007-007-009
The impedance at the centre of a dipole antenna more than 3 wavelengths above ground would be nearest to:
- A 300 ohms
- B 600 ohms
- C 75 ohms
- D 25 ohms
Correct answer: C — 75 ohms. From the official ISED question bank, verified word for word.
Why
When a dipole antenna sits high above the ground, specifically more than three wavelengths up, the earth no longer influences its electrical behaviour. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and matching at the advanced level: transmission line theory, impedance transformation, stubs and matching networks.