Deep Dive: G4A11
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.
Why Other Answers 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.
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 Example
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.
Source & Coverage
Question Pool: 2023-2027 Question Pool
Subelement: G4A
Reference: 2023-2027 Question Pool · G4 - Amateur Radio Practices
Key Concepts
Verified Content
Question from the official FCC General Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the G4A topic.