When selecting a CW transmitting frequency, what minimum separation from other stations should be used to minimize interference to stations on adjacent frequencies?
The correct answer is B: 150 Hz to 500 Hz. When selecting a CW transmitting frequency, a minimum separation of 150 Hz to 500 Hz from other stations should be used to minimize interference to stations on adjacent frequencies. CW signals are narrow (about 150 Hz bandwidth), so this spacing prevents overlap. For amateur radio operators, this spacing ensures clear communications without interfering with adjacent stations. Understanding this helps when finding a clear frequency for CW operation.
Exam Tip
CW frequency spacing = 150-500 Hz. Think 'C'W = 'C'ompact 'W'idth (~150 Hz), so 'C'lose spacing (150-500 Hz) works. Minimum separation of 150-500 Hz prevents interference. Not 5-50 Hz (too close), not 1-6 kHz (too wide).
Memory Aid
"CW frequency spacing = 150-500 Hz. Think 'C'W = 'C'ompact 'W'idth, so 'C'lose spacing. Minimum 150-500 Hz separation prevents interference. CW signals are narrow (~150 Hz), so close spacing works."
Real-World Application
You want to operate CW on 20 meters. You find a station on 14.050 MHz. You select 14.050.3 MHz (300 Hz away) - this 300 Hz separation is within the 150-500 Hz range and prevents interference. CW signals are narrow, so this spacing is sufficient. SSB would need much more spacing (2-3 kHz).
Key Concepts
Why Other Options Are Wrong
Option A (5-50 Hz): Incorrect. 5-50 Hz is too close - CW signals are about 150 Hz wide, so this spacing would cause overlap and interference.
Option C (1-3 kHz): Incorrect. 1-3 kHz is wider than needed for CW - CW signals are narrow, so 150-500 Hz is sufficient.
Option D (3-6 kHz): Incorrect. 3-6 kHz is way too wide for CW - that's more like SSB spacing. CW needs much less separation.
题目解析
The correct answer is B: 150 Hz to 500 Hz. When selecting a CW transmitting frequency, a minimum separation of 150 Hz to 500 Hz from other stations should be used to minimize interference to stations on adjacent frequencies. CW signals are narrow (about 150 Hz bandwidth), so this spacing prevents overlap. For amateur radio operators, this spacing ensures clear communications without interfering with adjacent stations. Understanding this helps when finding a clear frequency for CW operation.
考试技巧
CW frequency spacing = 150-500 Hz. Think 'C'W = 'C'ompact 'W'idth (~150 Hz), so 'C'lose spacing (150-500 Hz) works. Minimum separation of 150-500 Hz prevents interference. Not 5-50 Hz (too close), not 1-6 kHz (too wide).
记忆口诀
CW frequency spacing = 150-500 Hz. Think 'C'W = 'C'ompact 'W'idth, so 'C'lose spacing. Minimum 150-500 Hz separation prevents interference. CW signals are narrow (~150 Hz), so close spacing works.
实际应用示例
You want to operate CW on 20 meters. You find a station on 14.050 MHz. You select 14.050.3 MHz (300 Hz away) - this 300 Hz separation is within the 150-500 Hz range and prevents interference. CW signals are narrow, so this spacing is sufficient. SSB would need much more spacing (2-3 kHz).
错误选项分析
Option A (5-50 Hz): Incorrect. 5-50 Hz is too close - CW signals are about 150 Hz wide, so this spacing would cause overlap and interference. Option C (1-3 kHz): Incorrect. 1-3 kHz is wider than needed for CW - CW signals are narrow, so 150-500 Hz is sufficient. Option D (3-6 kHz): Incorrect. 3-6 kHz is way too wide for CW - that's more like SSB spacing. CW needs much less separation.
知识点
CW frequency spacing, Frequency separation, Interference prevention, CW operation
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.