Extra exam question E4C12
Subelement E4, AMATEUR PRACTICES· Group E4C
How does a narrow-band roofing filter affect receiver performance?
- A.It improves sensitivity by reducing front-end noise
- B.It improves intelligibility by using low Q circuitry to reduce ringing
- C.It improves blocking dynamic range by attenuating strong signals near the receive frequency (correct answer)
- D.All these choices are correct
WhyA narrow-band roofing filter improves a receiver's blocking dynamic range by attenuating strong signals near the receive frequency. A narrow-band roofing filter, placed early in the IF chain, attenuates strong signals near the receive frequency before they reach later gain stages, which improves the receiver's blocking dynamic range, its ability to keep working properly in the presence of a nearby strong signal, answer C. It doesn't reduce front-end noise to improve sensitivity, and it doesn't use low-Q circuitry to reduce ringing, that's the opposite of how a roofing filter is designed, so "all these choices" is too broad.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2024-2028 NCVEC Element 4 pool (public domain); the explanation above is original writing, see our methodology.
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