General exam question G8A09
Subelement G8, SIGNALS AND EMISSIONS· Group G8A
G8A09
What type of modulation is used by FT8?
- A.8-tone frequency shift keying (correct answer)
- B.Vestigial sideband
- C.Amplitude compressed AM
- D.8-bit direct sequence spread spectrum
WhyFT8 uses 8-tone frequency shift keying modulation. FT8 encodes its data by shifting among eight discrete audio tones, which is why its modulation is described as 8-tone (8-FSK) frequency shift keying, answer A. It isn't vestigial sideband, isn't a form of amplitude-compressed AM, and it isn't a direct-sequence spread-spectrum scheme, so B, C, and D don't describe FT8's actual modulation.
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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