Technician exam question T3A06
Subelement T3, RADIO WAVE PROPAGATION· Group T3A
What is the meaning of the term “picket fencing”?
- A.Alternating transmissions during a net operation
- B.Rapid flutter on mobile signals due to multipath propagation (correct answer)
- C.A type of ground system used with vertical antennas
- D.Interference from cable TV in the form of carriers at fixed intervals across the band
WhyPicket fencing means rapid flutter on mobile signals caused by multipath propagation. "Picket fencing" describes the rapid, repetitive flutter heard on a mobile FM signal as multipath propagation causes the signal to alternately reinforce and cancel while the vehicle moves through the interference pattern, sounding like driving past a picket fence, answer B. It has nothing to do with net procedure (A), vertical antenna grounding (C), or evenly spaced interference from cable TV leakage (D), those are unrelated phenomena that happen to also produce regular patterns.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2026-2030 NCVEC Element 2 pool (public domain); the explanation above is original writing, see our methodology.
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