Question
Which of the following is an advantage of using single sideband, as compared to other analog voice modes on the HF amateur bands?
Answer Options
- A) Very high-fidelity voice modulation
- B) Less subject to interference from atmospheric static crashes
- C) Ease of tuning on receive and immunity to impulse noise
- D) Less bandwidth used and greater power efficiency
Correct Answer: D
Explanation
Single Sideband (SSB) offers two major practical advantages that have made it the dominant voice mode on HF: it uses significantly less bandwidth and is far more power efficient than other analog voice modes like AM or Double Sideband (DSB). By eliminating the carrier and one sideband, SSB reduces the required bandwidth from about 6 \text{kHz} to around 3 \text{kHz}.
Crucially, all of the transmitter’s final amplifier power is directed into the intelligence-carrying sideband, whereas in AM, over half the power is wasted in the carrier, which carries no information. This concentration of power translates directly into a stronger effective signal at the receiving end for the same input power, greatly improving communication reliability over long distances.
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