Deep Dive: G9C05
The correct answer is A: Gain increases. The primary effect of increasing boom length and adding directors to a Yagi antenna is that gain increases. More directors and longer boom create more forward gain. For amateur radio operators, this is why longer Yagis have more gain. Understanding this helps when designing Yagi antennas.
Why Other Answers Are Wrong
Option B: Incorrect. Beamwidth doesn't increase - it decreases (narrows) as gain increases. Beamwidth increase is wrong. Option C: Incorrect. Front-to-back ratio doesn't decrease - it typically increases with more elements. Decrease is wrong. Option D: Incorrect. Resonant frequency doesn't get lower - it stays roughly the same (determined by element lengths). Lower frequency is wrong.
Exam Tip
Longer boom + more directors = gain increases. Think 'L'onger 'B'oom + 'M'ore 'D'irectors = 'L'arger 'G'ain. More directors and longer boom create more forward gain. Not beamwidth increase, not F/B decrease, not lower frequency - just gain increases.
Memory Aid
Longer boom + more directors = gain increases. Think 'L'onger 'B'oom + 'M'ore 'D'irectors = 'L'arger 'G'ain. More directors and longer boom create more forward gain. Primary effect of adding elements.
Real-World Example
A Yagi antenna: Adding more directors and increasing boom length increases the forward gain. A 3-element Yagi might have 7 dBi gain, while a 10-element Yagi might have 15 dBi gain. More elements and longer boom create more gain - this is the primary effect. Gain increases with more directors and longer boom.
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.