*Question G9C01:
Which of the following would increase the bandwidth of a Yagi antenna?*  

*Correct Answer is  A: Larger-diameter elements*  

### AI Response: (may contain errors)  

To increase the bandwidth of a Yagi antenna, you can use larger-diameter elements. Here's why:

1. **Correct Answer: Larger-diameter elements (A)**
   - Larger-diameter elements increase the bandwidth of a Yagi antenna because they reduce the Q factor of the antenna. A lower Q factor means the antenna can operate effectively over a wider range of frequencies. This is due to the fact that larger-diameter elements have a broader range of resonant frequencies.

2. **Why the other choices are incorrect:**
   - **Closer element spacing (B):** Closer spacing between elements generally affects the antenna's gain and pattern rather than its bandwidth. It can lead to increased mutual coupling, which might narrow the bandwidth instead of widening it.
   - **Loading coils in series with the element (C):** Loading coils are typically used to shorten the physical length of an antenna or to make it resonant at a lower frequency. They tend to increase the Q factor, which narrows the bandwidth.
   - **Tapered-diameter elements (D):** Tapering the diameter of elements can help with mechanical stability and weight distribution, but it does not significantly increase bandwidth. The effect on bandwidth is minimal compared to using uniformly larger-diameter elements.

In summary, using larger-diameter elements is a well-known method to increase the bandwidth of a Yagi antenna by reducing the Q factor and allowing the antenna to cover a wider frequency range effectively.