*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)  

A corona ball is a small, rounded metal ball placed at the tip of an HF mobile antenna. Its primary purpose is to reduce the RF voltage discharge from the tip of the antenna while transmitting. Here's why the correct answer is correct and why the other choices are incorrect:

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

   - **Explanation**: The sharp tip of an antenna can create high electric field intensities, which may lead to corona discharge, especially at high power levels. A corona ball increases the radius of curvature at the tip, reducing the electric field intensity and thus minimizing the risk of corona discharge. This helps in preventing unwanted RF energy loss and interference.

2. **Incorrect Choices**:

   - **A: To narrow the operating bandwidth of the antenna**
     - **Explanation**: The operating bandwidth of an antenna is primarily determined by its design, such as its length and the materials used. A corona ball does not affect the bandwidth; it is focused on reducing voltage discharge.

   - **B: To increase the “Q” of the antenna**
     - **Explanation**: The "Q" factor, or quality factor, of an antenna relates to its bandwidth and efficiency. It is influenced by the antenna's design and construction, not by the presence of a corona ball. The corona ball does not impact the "Q" factor.

   - **C: To reduce the chance of damage if the antenna should strike an object**
     - **Explanation**: While a corona ball might slightly cushion the impact if the antenna strikes an object, its primary function is not for mechanical protection. Its main role is to manage electrical characteristics, specifically reducing RF voltage discharge.

In summary, the corona ball is an important component for managing electrical properties at the tip of an antenna, specifically to prevent corona discharge, which is why option D is the correct answer.