Which of the following is an advantage of using single sideband, as compared to other analog voice modes on the HF amateur bands?
The correct answer is D: Less bandwidth used and greater power efficiency. An advantage of using single sideband (SSB) compared to other analog voice modes on the HF amateur bands is that it uses less bandwidth and has greater power efficiency. SSB uses about 3 kHz bandwidth (vs 6 kHz for AM) and puts all power into the sideband (no carrier power wasted). For amateur radio operators, this makes SSB more spectrum-efficient and allows more contacts with the same power. Understanding this helps explain why SSB is preferred on HF.
Exam Tip
SSB advantage = less bandwidth and greater power efficiency. Think 'S'SB = 'S'pectrum and 'S'ignal efficient. Uses 3 kHz (vs 6 kHz for AM) and all power in sideband (no carrier wasted). Not about fidelity, static, or ease of tuning.
Memory Aid
"SSB advantage = less bandwidth and greater power efficiency. Think 'S'SB = 'S'pectrum and 'S'ignal efficient. Uses less bandwidth (3 kHz vs 6 kHz) and all power in sideband. Main advantages for HF operation."
Real-World Application
You compare SSB to AM on 20 meters. SSB uses 3 kHz bandwidth while AM uses 6 kHz - you can fit twice as many SSB signals in the same frequency range. Also, SSB puts all 100 watts into the sideband, while AM wastes power on the carrier. This makes SSB more efficient for HF operation.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. SSB doesn't provide very high-fidelity voice - AM actually has better fidelity. SSB's advantage is efficiency, not fidelity.
Option B: Incorrect. SSB isn't less subject to atmospheric static - all modes are affected similarly by static. This isn't an SSB advantage.
Option C: Incorrect. SSB isn't easier to tune or more immune to impulse noise - FM is actually easier to tune and more immune to noise. This isn't an SSB advantage.
题目解析
The correct answer is D: Less bandwidth used and greater power efficiency. An advantage of using single sideband (SSB) compared to other analog voice modes on the HF amateur bands is that it uses less bandwidth and has greater power efficiency. SSB uses about 3 kHz bandwidth (vs 6 kHz for AM) and puts all power into the sideband (no carrier power wasted). For amateur radio operators, this makes SSB more spectrum-efficient and allows more contacts with the same power. Understanding this helps explain why SSB is preferred on HF.
考试技巧
SSB advantage = less bandwidth and greater power efficiency. Think 'S'SB = 'S'pectrum and 'S'ignal efficient. Uses 3 kHz (vs 6 kHz for AM) and all power in sideband (no carrier wasted). Not about fidelity, static, or ease of tuning.
记忆口诀
SSB advantage = less bandwidth and greater power efficiency. Think 'S'SB = 'S'pectrum and 'S'ignal efficient. Uses less bandwidth (3 kHz vs 6 kHz) and all power in sideband. Main advantages for HF operation.
实际应用示例
You compare SSB to AM on 20 meters. SSB uses 3 kHz bandwidth while AM uses 6 kHz - you can fit twice as many SSB signals in the same frequency range. Also, SSB puts all 100 watts into the sideband, while AM wastes power on the carrier. This makes SSB more efficient for HF operation.
错误选项分析
Option A: Incorrect. SSB doesn't provide very high-fidelity voice - AM actually has better fidelity. SSB's advantage is efficiency, not fidelity. Option B: Incorrect. SSB isn't less subject to atmospheric static - all modes are affected similarly by static. This isn't an SSB advantage. Option C: Incorrect. SSB isn't easier to tune or more immune to impulse noise - FM is actually easier to tune and more immune to noise. This isn't an SSB advantage.
知识点
SSB advantages, Bandwidth efficiency, Power efficiency, SSB vs other modes
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.