Which of the following is a source of loss in coaxial feed line?
The correct answer is D: All these choices are correct. Sources of loss in coaxial feed line include water intrusion into connectors, high SWR, and multiple connectors in the line. Water in connectors increases losses and can cause corrosion. High SWR causes reflected power, which increases losses. Each connector adds some loss, and multiple connectors compound this. For amateur radio operators, understanding these loss sources helps maintain feed line performance. Keeping connectors sealed, maintaining low SWR, and minimizing the number of connectors all help reduce losses.
Exam Tip
All three cause feed line loss: water intrusion, high SWR, multiple connectors. When all listed sources are valid causes of loss, 'all of the above' is usually the answer. All contribute to reduced feed line efficiency.
Memory Aid
"All three cause feed line loss: Water intrusion, High SWR, Multiple connectors. Think 'A'll 'L'oss 'S'ources. Keep connectors sealed, maintain low SWR, minimize connectors to reduce losses."
Real-World Application
Your feed line has high losses. Investigation reveals: (1) Water entered through a loose connector, increasing losses and causing corrosion, (2) Your antenna has 3:1 SWR, causing significant reflected power and losses, (3) You have 4 connectors in the line (transceiver, tuner, switch, antenna), each adding loss. All three factors contribute to your feed line losses.
Key Concepts
Why Other Options Are Wrong
Option A: While correct, this is incomplete. High SWR and multiple connectors also cause losses.
Option B: While correct, this is incomplete. Water intrusion and multiple connectors also cause losses.
Option C: While correct, this is incomplete. Water intrusion and high SWR also cause losses.
题目解析
The correct answer is D: All these choices are correct. Sources of loss in coaxial feed line include water intrusion into connectors, high SWR, and multiple connectors in the line. Water in connectors increases losses and can cause corrosion. High SWR causes reflected power, which increases losses. Each connector adds some loss, and multiple connectors compound this. For amateur radio operators, understanding these loss sources helps maintain feed line performance. Keeping connectors sealed, maintaining low SWR, and minimizing the number of connectors all help reduce losses.
考试技巧
All three cause feed line loss: water intrusion, high SWR, multiple connectors. When all listed sources are valid causes of loss, 'all of the above' is usually the answer. All contribute to reduced feed line efficiency.
记忆口诀
All three cause feed line loss: Water intrusion, High SWR, Multiple connectors. Think 'A'll 'L'oss 'S'ources. Keep connectors sealed, maintain low SWR, minimize connectors to reduce losses.
实际应用示例
Your feed line has high losses. Investigation reveals: (1) Water entered through a loose connector, increasing losses and causing corrosion, (2) Your antenna has 3:1 SWR, causing significant reflected power and losses, (3) You have 4 connectors in the line (transceiver, tuner, switch, antenna), each adding loss. All three factors contribute to your feed line losses.
错误选项分析
Option A: While correct, this is incomplete. High SWR and multiple connectors also cause losses. Option B: While correct, this is incomplete. Water intrusion and multiple connectors also cause losses. Option C: While correct, this is incomplete. Water intrusion and high SWR also cause losses.
知识点
Feed line losses, Water intrusion, High SWR, Connector losses
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.