*Question E9B11:
What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?*  

*Correct Answer is  C: The computed feed point impedance may be incorrect*  

### AI Response: (may contain errors)  

When modeling antennas using software, the antenna is divided into segments to simulate its behavior accurately. The number of segments per half-wavelength is crucial for obtaining reliable results.

### Explanation:

1. **Correct Answer: C: The computed feed point impedance may be incorrect**

   - **Why it's correct:**  
     The feed point impedance is a critical parameter that determines how well the antenna is matched to the transmission line. If the number of wire segments is too low (below 10 segments per half-wavelength), the model may not accurately represent the current distribution along the antenna. This can lead to incorrect calculations of the feed point impedance, which affects the antenna's performance and efficiency.

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

   - **A: Ground conductivity will not be accurately modeled**  
     Ground conductivity is a separate parameter in antenna modeling and is not directly affected by the number of wire segments. It is typically specified independently of the segmentation of the antenna wire.

   - **B: The resulting design will favor radiation of harmonic energy**  
     The radiation of harmonic energy is more related to the design and physical properties of the antenna rather than the segmentation in the model. While segmentation can affect accuracy, it does not inherently cause harmonic radiation.

   - **D: The antenna will become mechanically unstable**  
     Mechanical stability is a physical property of the antenna structure and is not influenced by the number of segments used in a computational model. The segmentation is purely a computational tool and does not affect the physical stability of the antenna.

### Rule of Thumb:

- **Segmentation Rule:**  
  A common rule of thumb in antenna modeling is to use at least 10 segments per half-wavelength to ensure accurate representation of the antenna's electrical characteristics, including the feed point impedance. This helps in capturing the variations in current distribution along the antenna.