Basic Qualification · B-006 Feedlines and antenna systems · B-006-006-003
An end-fed half-wave antenna (EFHW) has a very high feed point impedance. What device could be used to provide a good match to 50-ohm coaxial cable?
- A A quarter-wave stub
- B A counterpoise
- C A good ground on the coax shield
- D A transformer
Correct answer: D — A transformer. From the official ISED question bank, verified word for word.
Why
A transformer changes the electrical resistance at the antenna feed point to match the 50-ohm coaxial cable, allowing power to flow efficiently instead of reflecting back. 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.