What is the relationship between high standing wave ratio (SWR) and transmission line loss?
The correct answer is B: High SWR increases loss in a lossy transmission line. The relationship between high standing wave ratio (SWR) and transmission line loss is that high SWR increases loss in a lossy transmission line. High SWR causes more current to flow (due to standing waves), increasing I²R losses. For amateur radio operators, this is why low SWR is important. Understanding this helps when evaluating feed line performance.
Exam Tip
High SWR and loss = high SWR increases loss in lossy line. Think 'H'igh 'S'WR = 'H'igher 'S'tanding waves = 'H'igher 'L'oss. High SWR causes more current flow, increasing I²R losses. Not no relationship, not measurement difficulty, not loss reduction - just increases loss.
Memory Aid
"High SWR and loss = high SWR increases loss in lossy line. Think 'H'igh 'S'WR = 'H'igher 'L'oss. High SWR causes more current flow, increasing I²R losses. Important reason to maintain low SWR."
Real-World Application
A lossy transmission line with high SWR: Standing waves cause higher current flow in some parts of the line. This increased current causes more I²R losses (power lost as heat). High SWR increases the loss in lossy transmission lines. This is why low SWR is important - it minimizes feed line losses.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. There is a relationship - high SWR increases loss in lossy lines. No relationship is wrong.
Option C: Incorrect. High SWR doesn't make it difficult to measure loss - loss can still be measured. Measurement difficulty isn't the relationship.
Option D: Incorrect. High SWR doesn't reduce the relative effect of loss - it increases loss. Loss reduction isn't the relationship.
题目解析
The correct answer is B: High SWR increases loss in a lossy transmission line. The relationship between high standing wave ratio (SWR) and transmission line loss is that high SWR increases loss in a lossy transmission line. High SWR causes more current to flow (due to standing waves), increasing I²R losses. For amateur radio operators, this is why low SWR is important. Understanding this helps when evaluating feed line performance.
考试技巧
High SWR and loss = high SWR increases loss in lossy line. Think 'H'igh 'S'WR = 'H'igher 'S'tanding waves = 'H'igher 'L'oss. High SWR causes more current flow, increasing I²R losses. Not no relationship, not measurement difficulty, not loss reduction - just increases loss.
记忆口诀
High SWR and loss = high SWR increases loss in lossy line. Think 'H'igh 'S'WR = 'H'igher 'L'oss. High SWR causes more current flow, increasing I²R losses. Important reason to maintain low SWR.
实际应用示例
A lossy transmission line with high SWR: Standing waves cause higher current flow in some parts of the line. This increased current causes more I²R losses (power lost as heat). High SWR increases the loss in lossy transmission lines. This is why low SWR is important - it minimizes feed line losses.
错误选项分析
Option A: Incorrect. There is a relationship - high SWR increases loss in lossy lines. No relationship is wrong. Option C: Incorrect. High SWR doesn't make it difficult to measure loss - loss can still be measured. Measurement difficulty isn't the relationship. Option D: Incorrect. High SWR doesn't reduce the relative effect of loss - it increases loss. Loss reduction isn't the relationship.
知识点
High SWR, Transmission line loss, Increased loss, Lossy transmission line
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.