General exam question G8C13
Subelement G8, SIGNALS AND EMISSIONS· Group G8C
What is indicated on a waterfall display by one or more vertical lines on either side of a data mode or RTTY signal?
- A.Long path propagation
- B.Backscatter propagation
- C.Insufficient modulation
- D.Overmodulation (correct answer)
WhyOne or more vertical lines on either side of a data mode or RTTY signal on a waterfall display indicate overmodulation. Vertical lines appearing on either side of a data or RTTY signal's trace on a waterfall display are a telltale sign of overmodulation, splatter spreading out from the main signal because the transmitter was driven too hard, answer D. They aren't a marker of long-path or backscatter propagation, and insufficient (rather than excessive) modulation wouldn't produce extra spectral energy at all, so A, B, and C 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.
Related questions
- G8C02Which digital mode is used as a low-power beacon for assessing HF propagation?
- G8C03What part of a packet radio frame contains the routing and handling information?
- G8C04Which of the following describes Baudot code?
- G8C05In an ARQ mode, what is meant by a NAK response to a transmitted packet?
- G8C06What action results from a failure to exchange information due to excessive transmission attempts when using an ARQ mode?