How does the attenuation of coaxial cable change with increasing frequency?
The correct answer is B: Attenuation increases. How the attenuation of coaxial cable changes with increasing frequency is that attenuation increases. Coaxial cable loss increases with frequency due to skin effect and dielectric losses. For amateur radio operators, this is why higher frequencies have more feed line loss. Understanding this helps when selecting feed lines for different bands.
Exam Tip
Coax attenuation vs frequency = increases with frequency. Think 'C'oax 'A'ttenuation = 'C'ontinues 'A'scending with frequency. Coaxial cable loss increases with frequency due to skin effect and dielectric losses. Not independent, not decreases, not Marconi's Law - just increases.
Memory Aid
"Coax attenuation vs frequency = increases with frequency. Think 'C'oax 'A'ttenuation = 'C'ontinues 'A'scending. Coaxial cable loss increases with frequency due to skin effect and dielectric losses. Important for feed line selection."
Real-World Application
Coaxial cable: At 1 MHz, loss might be 0.5 dB per 100 feet. At 100 MHz, loss might be 2 dB per 100 feet. At 1 GHz, loss might be 5 dB per 100 feet. Attenuation increases with frequency due to skin effect (current flows on conductor surface) and dielectric losses. This is why higher frequencies have more feed line loss.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Attenuation isn't independent of frequency - it increases with frequency. Frequency independence is wrong.
Option C: Incorrect. Attenuation doesn't decrease with frequency - it increases. Decrease is wrong.
Option D: Incorrect. Marconi's Law of Attenuation isn't a real thing - attenuation increases with frequency due to skin effect and dielectric losses. Marconi's Law doesn't exist.
题目解析
The correct answer is B: Attenuation increases. How the attenuation of coaxial cable changes with increasing frequency is that attenuation increases. Coaxial cable loss increases with frequency due to skin effect and dielectric losses. For amateur radio operators, this is why higher frequencies have more feed line loss. Understanding this helps when selecting feed lines for different bands.
考试技巧
Coax attenuation vs frequency = increases with frequency. Think 'C'oax 'A'ttenuation = 'C'ontinues 'A'scending with frequency. Coaxial cable loss increases with frequency due to skin effect and dielectric losses. Not independent, not decreases, not Marconi's Law - just increases.
记忆口诀
Coax attenuation vs frequency = increases with frequency. Think 'C'oax 'A'ttenuation = 'C'ontinues 'A'scending. Coaxial cable loss increases with frequency due to skin effect and dielectric losses. Important for feed line selection.
实际应用示例
Coaxial cable: At 1 MHz, loss might be 0.5 dB per 100 feet. At 100 MHz, loss might be 2 dB per 100 feet. At 1 GHz, loss might be 5 dB per 100 feet. Attenuation increases with frequency due to skin effect (current flows on conductor surface) and dielectric losses. This is why higher frequencies have more feed line loss.
错误选项分析
Option A: Incorrect. Attenuation isn't independent of frequency - it increases with frequency. Frequency independence is wrong. Option C: Incorrect. Attenuation doesn't decrease with frequency - it increases. Decrease is wrong. Option D: Incorrect. Marconi's Law of Attenuation isn't a real thing - attenuation increases with frequency due to skin effect and dielectric losses. Marconi's Law doesn't exist.
知识点
Coaxial cable, Attenuation, Increasing frequency, Frequency-dependent loss
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.