General exam question G4D05
Subelement G4, AMATEUR RADIO PRACTICES· Group G4D
How does a signal that reads 20 dB over S9 compare to one that reads S9 on a receiver, assuming a properly calibrated S meter?
- A.It is 10 times less powerful
- B.It is 20 times less powerful
- C.It is 20 times more powerful
- D.It is 100 times more powerful (correct answer)
WhyA signal reading 20 dB over S9 is about 100 times more powerful than a signal reading S9. The S-meter scale is calibrated so that above S9, each 10 dB of increase corresponds to a 10-times increase in power, so 20 dB over S9 represents 10 times 10, or 100 times more power than an S9 signal, answer D. The signal is stronger, not weaker, ruling out A and B, and it's specifically 100 times, not just 20 times, stronger, so C understates it.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2023-2027 NCVEC Element 3 pool (public domain); the explanation above is original writing, see our methodology.
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