*Question G4A11:
Why should the ALC system be inactive when transmitting AFSK data signals?*  

*Correct Answer is  B: The ALC action distorts the signal*  

### AI Response: (may contain errors)  

When transmitting AFSK (Audio Frequency Shift Keying) data signals, it's important to ensure that the signal remains clean and undistorted. Here's why the correct answer is correct and why the other choices are incorrect:

1. **Correct Answer: B - The ALC action distorts the signal**

   - **Explanation**: Automatic Level Control (ALC) is designed to prevent overdriving the transmitter by reducing the gain when the output power exceeds a certain level. However, in digital modes like AFSK, ALC can introduce distortion because it dynamically alters the amplitude of the signal. This can lead to unwanted changes in the signal's characteristics, such as its frequency components, which are crucial for maintaining the integrity of digital data transmission.

2. **Why the other choices are incorrect**:

   - **Choice A: ALC will invert the modulation of the AFSK mode**
     - **Explanation**: ALC does not invert modulation. Its primary function is to control the amplitude, not the phase or frequency, of the signal. Therefore, it does not cause inversion of the modulation.

   - **Choice C: When using digital modes, too much ALC activity can cause the transmitter to overheat**
     - **Explanation**: While excessive ALC activity can lead to inefficiencies and potentially increased heat due to constant gain adjustments, the primary concern with ALC in digital modes is signal distortion, not overheating.

   - **Choice D: All these choices are correct**
     - **Explanation**: Since choices A and C are incorrect, this choice is also incorrect. The main issue with ALC in AFSK transmission is signal distortion, not modulation inversion or overheating.

**Rule of Thumb**: When operating in digital modes, it's best to adjust the transmitter's drive level manually to avoid engaging the ALC, ensuring a clean and undistorted signal.