What is a beta or hairpin match?
The correct answer is A: A shorted transmission line stub placed at the feed point of a Yagi antenna to provide impedance matching. What a beta or hairpin match is a shorted transmission line stub placed at the feed point of a Yagi antenna to provide impedance matching. Beta/hairpin matches use a shorted stub to match impedance. For amateur radio operators, this is a common Yagi matching method. Understanding this helps when building Yagi antennas.
Exam Tip
Beta/hairpin match = shorted transmission line stub at feed point. Think 'B'eta 'M'atch = 'B'ent 'M'atching stub (hairpin shape). Beta/hairpin matches use a shorted stub to match impedance. Not 75-ohm coax, not capacitor, not twin-lead - just shorted stub.
Memory Aid
"Beta/hairpin match = shorted transmission line stub at feed point. Think 'B'eta 'M'atch = 'B'ent 'M'atching stub. Beta/hairpin matches use a shorted stub to match impedance. Common Yagi matching method."
Real-World Application
A Yagi antenna: A beta (hairpin) match is a shorted transmission line stub placed at the feed point. The stub is bent in a hairpin shape, providing impedance matching. This is a common Yagi matching method - a shorted stub at the feed point. Beta/hairpin matches are used to match Yagi impedance to feed line.
Key Concepts
Why Other Options Are Wrong
Option B: Incorrect. Beta match isn't a 1/4 wavelength section of 75-ohm coax - it's a shorted stub, not a 75-ohm section. 75-ohm coax isn't beta match.
Option C: Incorrect. Beta match isn't a series capacitor - it's a shorted stub, not a capacitor. Capacitor isn't beta match.
Option D: Incorrect. Beta match isn't a section of 300-ohm twin-lead - it's a shorted stub, not twin-lead. Twin-lead isn't beta match.
题目解析
The correct answer is A: A shorted transmission line stub placed at the feed point of a Yagi antenna to provide impedance matching. What a beta or hairpin match is a shorted transmission line stub placed at the feed point of a Yagi antenna to provide impedance matching. Beta/hairpin matches use a shorted stub to match impedance. For amateur radio operators, this is a common Yagi matching method. Understanding this helps when building Yagi antennas.
考试技巧
Beta/hairpin match = shorted transmission line stub at feed point. Think 'B'eta 'M'atch = 'B'ent 'M'atching stub (hairpin shape). Beta/hairpin matches use a shorted stub to match impedance. Not 75-ohm coax, not capacitor, not twin-lead - just shorted stub.
记忆口诀
Beta/hairpin match = shorted transmission line stub at feed point. Think 'B'eta 'M'atch = 'B'ent 'M'atching stub. Beta/hairpin matches use a shorted stub to match impedance. Common Yagi matching method.
实际应用示例
A Yagi antenna: A beta (hairpin) match is a shorted transmission line stub placed at the feed point. The stub is bent in a hairpin shape, providing impedance matching. This is a common Yagi matching method - a shorted stub at the feed point. Beta/hairpin matches are used to match Yagi impedance to feed line.
错误选项分析
Option B: Incorrect. Beta match isn't a 1/4 wavelength section of 75-ohm coax - it's a shorted stub, not a 75-ohm section. 75-ohm coax isn't beta match. Option C: Incorrect. Beta match isn't a series capacitor - it's a shorted stub, not a capacitor. Capacitor isn't beta match. Option D: Incorrect. Beta match isn't a section of 300-ohm twin-lead - it's a shorted stub, not twin-lead. Twin-lead isn't beta match.
知识点
Beta match, Hairpin match, Shorted transmission line stub, Impedance matching
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.