Deep Dive: G9A10
The correct answer is D: 5:1. The standing wave ratio that results from connecting a 50-ohm feed line to a 10-ohm resistive load is 5:1. SWR = Zline/Zload (or Zload/Zline, whichever is greater) = 50/10 = 5:1. For amateur radio operators, this is a basic SWR calculation. Understanding this helps when calculating SWR.
Why Other Answers Are Wrong
Option A (2:1): Incorrect. 2:1 is too low - 50/10 = 5:1, not 2:1. Calculation error. Option B (1:2): Incorrect. 1:2 is the inverse and too low - SWR is 5:1, not 1:2. SWR is always ≥ 1:1. Option C (1:5): Incorrect. 1:5 is the inverse - SWR is always ≥ 1:1, so it's 5:1, not 1:5. SWR is the larger ratio.
Exam Tip
50Ω feed line to 10Ω load = 5:1 SWR. Think 'S'WR = 'S'imple ratio = '5'0/'1'0 = '5':1. SWR = Zline/Zload (or larger ratio) = 50/10 = 5:1. Not 2:1, not 1:2, not 1:5 - just 5:1.
Memory Aid
50Ω feed line to 10Ω load = 5:1 SWR. Think 'S'WR = '5'0/'1'0 = '5':1. SWR = Zline/Zload (or larger ratio). Basic SWR calculation.
Real-World Example
A 50-ohm feed line connected to a 10-ohm resistive load. SWR = 50/10 = 5:1. The standing wave ratio is the ratio of the feed line impedance to the load impedance (or the larger ratio). This is a basic SWR calculation - impedance mismatch creates SWR.
Source & Coverage
Question Pool: 2023-2027 Question Pool
Subelement: G9A
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 G9A topic.