Advanced Qualification · A-003 Measurements · A-003-006-011
At what line impedance do most RF wattmeters usually operate?
- A100 ohms
- B300 ohms
- C50 ohms
- D25 ohms
Correct answer: C — 50 ohms. From the official ISED question bank, verified word for word.
Why
Most RF wattmeters are built to work with a standard line impedance of 50 ohms because this value offers a practical balance between power handling and signal loss for typical amateur radio equipment. The full explanation — and one for every question — is in Pro.
Practise this section
Measurements is section A-003 of the Advanced exam: Measurements: meters, oscilloscopes, counters, signal generators, and what a reading actually tells you.
Drill A-003 — free, no account