*Question E9E09:
Which of the following is used to shunt feed a grounded tower at its base?*  

*Correct Answer is  C: Gamma match*  

### AI Response: (may contain errors)  

To understand why the correct answer is "Gamma match" for shunt feeding a grounded tower at its base, let's break down each option:

### Correct Answer: Gamma Match
- **Gamma Match**: This is a type of impedance matching network that is commonly used to feed a vertical antenna, such as a grounded tower. It consists of a short length of transmission line connected to the feed point, which allows for tuning the impedance to match the feed line. The gamma match is effective for shunt feeding because it can provide a good match at the base of the tower, allowing for efficient power transfer.

### Why the Other Choices are Incorrect:
- **A: Double-bazooka match**: 
  - This is a type of antenna matching system typically used for dipole antennas. It is not designed for shunt feeding a grounded tower, making it unsuitable for this application.

- **B: Beta or hairpin match**: 
  - A beta match is also used for matching the impedance of antennas, particularly for Yagi antennas. While it can be used in some vertical applications, it is not the standard method for shunt feeding a grounded tower.

- **D: All these choices are correct**: 
  - Since only the gamma match is specifically designed for shunt feeding a grounded tower, this option is incorrect. The other choices do not apply to this specific scenario.

### Summary
- The **gamma match** is the most effective and commonly used method for shunt feeding a grounded tower at its base due to its ability to provide a good impedance match.
- The other options, while they may be useful in other contexts, do not serve the purpose of shunt feeding a grounded tower.

### Useful Rule of Thumb
- When matching antennas, always consider the specific application and the type of antenna being used. For vertical antennas, especially grounded towers, the gamma match is often the preferred choice for effective impedance matching.