Why should the ALC system be inactive when transmitting AFSK data signals?
The correct answer is B: The ALC action distorts the signal. Why the ALC system should be inactive when transmitting AFSK data signals is that the ALC action distorts the signal. ALC is designed for voice/SSB and can distort digital signals by trying to level them. For amateur radio operators, this is important for proper digital mode operation. Understanding this helps when operating digital modes.
Exam Tip
ALC inactive for AFSK = ALC action distorts the signal. Think 'A'LC for 'A'FSK = 'A'voids 'L'eveling 'C'auses distortion. ALC is designed for voice/SSB and can distort digital signals. Not inversion, not overheating - just distortion.
Memory Aid
"ALC inactive for AFSK = ALC action distorts the signal. Think 'A'LC for 'A'FSK = 'A'voids 'L'eveling 'C'auses distortion. ALC is designed for voice/SSB and can distort digital signals. Disable ALC for digital modes."
Real-World Application
You transmit AFSK data signals. If ALC is active, it tries to level the signal (designed for voice), which distorts the digital signal. You disable ALC for AFSK operation to prevent distortion. ALC is fine for voice/SSB but distorts digital modes.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. ALC doesn't invert modulation - it levels the signal, not inverts it. Inversion isn't the issue.
Option C: Incorrect. ALC activity doesn't cause transmitter overheating - overheating comes from excessive power, not ALC. Overheating isn't the issue.
Option D: Incorrect. Since A and C are not correct, 'all of the above' cannot be correct. Only signal distortion is the issue.
题目解析
The correct answer is B: The ALC action distorts the signal. Why the ALC system should be inactive when transmitting AFSK data signals is that the ALC action distorts the signal. ALC is designed for voice/SSB and can distort digital signals by trying to level them. For amateur radio operators, this is important for proper digital mode operation. Understanding this helps when operating digital modes.
考试技巧
ALC inactive for AFSK = ALC action distorts the signal. Think 'A'LC for 'A'FSK = 'A'voids 'L'eveling 'C'auses distortion. ALC is designed for voice/SSB and can distort digital signals. Not inversion, not overheating - just distortion.
记忆口诀
ALC inactive for AFSK = ALC action distorts the signal. Think 'A'LC for 'A'FSK = 'A'voids 'L'eveling 'C'auses distortion. ALC is designed for voice/SSB and can distort digital signals. Disable ALC for digital modes.
实际应用示例
You transmit AFSK data signals. If ALC is active, it tries to level the signal (designed for voice), which distorts the digital signal. You disable ALC for AFSK operation to prevent distortion. ALC is fine for voice/SSB but distorts digital modes.
错误选项分析
Option A: Incorrect. ALC doesn't invert modulation - it levels the signal, not inverts it. Inversion isn't the issue. Option C: Incorrect. ALC activity doesn't cause transmitter overheating - overheating comes from excessive power, not ALC. Overheating isn't the issue. Option D: Incorrect. Since A and C are not correct, 'all of the above' cannot be correct. Only signal distortion is the issue.
知识点
ALC, AFSK, Signal distortion, Digital modes
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.