Deep Dive: G9C11
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.
Why Other Answers 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.
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 Example
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.
Source & Coverage
Question Pool: 2023-2027 Question Pool
Subelement: G9C
Reference: 2023-2027 Question Pool · G9 - Antennas and Feed Lines
Key Concepts
Verified Content
Question from the official FCC General Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the G9C topic.