General exam question G4A11
Subelement G4, AMATEUR RADIO PRACTICES· Group G4A
Why should the ALC system be inactive when transmitting AFSK data signals?
- A.ALC will invert the modulation of the AFSK mode
- B.The ALC action distorts the signal (correct answer)
- C.When using digital modes, too much ALC activity can cause the transmitter to overheat
- D.All these choices are correct
WhyThe ALC system should be inactive when transmitting AFSK data signals because ALC action distorts the signal. AFSK data modes rely on a transmitted signal whose amplitude stays constant so the receiving software can decode the tones cleanly, and ALC's gain-riding action introduces exactly the kind of amplitude variation that distorts that signal, so ALC should stay inactive for AFSK, answer B. ALC doesn't invert modulation, and while overdriving a transmitter can cause heat problems, that's not what ALC itself causes here, so C and the "all of these" option D are wrong.
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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