Extra exam question E4C06
Subelement E4, AMATEUR PRACTICES· Group E4C
How much does increasing a receiver’s bandwidth from 50 Hz to 1,000 Hz increase the receiver’s noise floor?
- A.3 dB
- B.5 dB
- C.10 dB
- D.13 dB (correct answer)
WhyIncreasing a receiver's bandwidth from 50 Hz to 1,000 Hz raises its noise floor by about 13 dB. Widening a receiver's bandwidth from 50 Hz to 1,000 Hz is a 20-fold increase, and since noise power scales directly with bandwidth, that works out to 10 times the log of 20, about 13 dB more noise floor, answer D. The smaller figures of 3, 5, and 10 dB all correspond to much smaller bandwidth ratios than the 20-fold change described here.
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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