Basic Qualification · B-003 Station assembly, practice and safety · B-003-001-002
In an HF station that includes an external RF power amplifier, where should a low-pass filter be located?
- A Between the SWR meter and the antenna tuner
- B Between the antenna tuner and the antenna switch
- C As close as possible to the transceiver output
- D As close as possible to the external amplifier output
Correct answer: D — As close as possible to the external amplifier output. From the official ISED question bank, verified word for word.
Why
A low-pass filter belongs right after the external amplifier because that is where strong radio frequency energy leaves the station and heads toward the antenna. The full explanation — and one for every question — is in Pro.
Practise this section
Building a station safely: power supplies, grounding, RF exposure, lightning, feedline routing, and what a transmitter, receiver and transceiver actually do.