Which of the following would increase the bandwidth of a Yagi antenna?
The correct answer is A: Larger-diameter elements. What would increase the bandwidth of a Yagi antenna is larger-diameter elements. Larger-diameter elements have lower Q (quality factor), resulting in wider bandwidth. For amateur radio operators, this is important for multiband operation. Understanding this helps when designing Yagi antennas.
Exam Tip
Increase Yagi bandwidth = larger-diameter elements. Think 'L'arger 'D'iameter = 'L'ower 'D'Q (quality factor) = 'W'ider bandwidth. Larger-diameter elements have lower Q, resulting in wider bandwidth. Not closer spacing, not loading coils, not tapered - just larger diameter.
Memory Aid
"Increase Yagi bandwidth = larger-diameter elements. Think 'L'arger 'D'iameter = 'W'ider bandwidth. Larger-diameter elements have lower Q, resulting in wider bandwidth. Important for multiband operation."
Real-World Application
A Yagi antenna: Using larger-diameter elements (e.g., 1-inch tubing instead of 1/2-inch) reduces the Q (quality factor) of the elements, resulting in wider bandwidth. The antenna will work over a wider frequency range. Larger-diameter elements increase bandwidth - this is why some Yagis use thick elements for wider bandwidth.
Key Concepts
Why Other Options Are Wrong
Option B: Incorrect. Closer element spacing doesn't increase bandwidth - it affects gain and front-to-back ratio, not bandwidth. Closer spacing doesn't help bandwidth.
Option C: Incorrect. Loading coils in series don't increase bandwidth - they reduce bandwidth by increasing Q. Loading coils reduce bandwidth.
Option D: Incorrect. Tapered-diameter elements don't increase bandwidth - they're for mechanical strength, not bandwidth. Tapered elements don't help bandwidth.
题目解析
The correct answer is A: Larger-diameter elements. What would increase the bandwidth of a Yagi antenna is larger-diameter elements. Larger-diameter elements have lower Q (quality factor), resulting in wider bandwidth. For amateur radio operators, this is important for multiband operation. Understanding this helps when designing Yagi antennas.
考试技巧
Increase Yagi bandwidth = larger-diameter elements. Think 'L'arger 'D'iameter = 'L'ower 'D'Q (quality factor) = 'W'ider bandwidth. Larger-diameter elements have lower Q, resulting in wider bandwidth. Not closer spacing, not loading coils, not tapered - just larger diameter.
记忆口诀
Increase Yagi bandwidth = larger-diameter elements. Think 'L'arger 'D'iameter = 'W'ider bandwidth. Larger-diameter elements have lower Q, resulting in wider bandwidth. Important for multiband operation.
实际应用示例
A Yagi antenna: Using larger-diameter elements (e.g., 1-inch tubing instead of 1/2-inch) reduces the Q (quality factor) of the elements, resulting in wider bandwidth. The antenna will work over a wider frequency range. Larger-diameter elements increase bandwidth - this is why some Yagis use thick elements for wider bandwidth.
错误选项分析
Option B: Incorrect. Closer element spacing doesn't increase bandwidth - it affects gain and front-to-back ratio, not bandwidth. Closer spacing doesn't help bandwidth. Option C: Incorrect. Loading coils in series don't increase bandwidth - they reduce bandwidth by increasing Q. Loading coils reduce bandwidth. Option D: Incorrect. Tapered-diameter elements don't increase bandwidth - they're for mechanical strength, not bandwidth. Tapered elements don't help bandwidth.
知识点
Yagi antenna, Bandwidth, Larger-diameter elements, Element diameter
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.