Extra exam question E1A02
Subelement E1, COMMISSION RULES· Group E1A · 47 CFR §97.301, 97.305
When using a transceiver that displays the carrier frequency of phone signals, which of the following displayed frequencies represents the lowest frequency at which a properly adjusted LSB emission will be totally within the band?
- A.The exact lower band edge
- B.300 Hz above the lower band edge
- C.1 kHz above the lower band edge
- D.3 kHz above the lower band edge (correct answer)
WhyThe lowest carrier display that keeps a full LSB voice signal entirely within a band is about 3 kHz above the band's lower edge. LSB places its energy below the carrier frequency, so to keep an entire signal's sidebands inside the band, the displayed carrier has to sit far enough above the lower edge to cover the full occupied bandwidth. A voice-bandwidth LSB signal needs about 3 kHz of room below the carrier, so 3 kHz above the lower band edge is the lowest carrier display that keeps the whole emission in band, answer D. Anything closer to the edge, including the edge itself or a 300 Hz or 1 kHz margin, lets part of the lower sideband spill outside the band.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2024-2028 NCVEC Element 4 pool (public domain); the explanation above is original writing, see our methodology.
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