*Question G4E02:
What is the purpose of a corona ball on an HF mobile antenna?*  

*Correct Answer is  D: To reduce RF voltage discharge from the tip of the antenna while transmitting*  

### AI Response: (may contain errors)  

The correct answer to the question about the purpose of a corona ball on an HF mobile antenna is:

**D: To reduce RF voltage discharge from the tip of the antenna while transmitting.**

### Explanation of the Correct Answer:
- **Corona Ball Function**: A corona ball is a device placed at the tip of an antenna to help manage high voltage discharges. When transmitting, especially at high frequencies, the tip of the antenna can accumulate a significant amount of RF voltage. This can lead to corona discharge, which is an ionization of the air around the antenna tip, potentially causing interference and damage.
- **Purpose**: The corona ball helps to smooth out the electric field at the tip of the antenna, reducing the likelihood of these discharges and ensuring a more efficient and safer operation.

### Why the Other Choices are Incorrect:
- **A: To narrow the operating bandwidth of the antenna**  
  - **Incorrect**: The bandwidth of an antenna is primarily determined by its design and dimensions, not by the presence of a corona ball. A corona ball does not significantly affect the bandwidth.

- **B: To increase the “Q” of the antenna**  
  - **Incorrect**: The "Q" factor of an antenna relates to its selectivity and bandwidth. A corona ball does not increase the "Q" factor; it is more about managing voltage discharge rather than affecting the resonant properties of the antenna.

- **C: To reduce the chance of damage if the antenna should strike an object**  
  - **Incorrect**: While a corona ball may provide some physical protection, its primary function is not to prevent damage from physical impacts. Instead, it is designed to mitigate RF voltage discharge.

### Summary:
- The corona ball is essential for reducing RF voltage discharge at the antenna tip, enhancing safety and performance during transmission. The other options do not accurately describe its function or purpose. 

This understanding is crucial for the Extra Class exam, as it highlights the practical applications of antenna design and safety considerations in amateur radio operations.