In what units is RF feed line loss usually expressed?
The correct answer is D: Decibels per 100 feet. The units in which RF feed line loss is usually expressed are decibels per 100 feet. Feed line loss is typically specified as dB loss per 100 feet at a specific frequency. For amateur radio operators, this is the standard way to specify feed line loss. Understanding this helps when comparing feed lines.
Exam Tip
Feed line loss units = decibels per 100 feet. Think 'F'eed 'L'ine 'L'oss = 'd'B per '1'00 feet. Feed line loss is typically specified as dB loss per 100 feet at a specific frequency. Not ohms, not per 1,000 feet - just dB per 100 feet.
Memory Aid
"Feed line loss units = decibels per 100 feet. Think 'F'eed 'L'ine 'L'oss = 'd'B per '1'00 feet. Feed line loss is typically specified as dB loss per 100 feet. Standard feed line loss unit."
Real-World Application
A coaxial cable specification: Loss = 2.5 dB per 100 feet at 100 MHz. This tells you how much signal is lost in 100 feet of cable at that frequency. Feed line loss is always expressed in decibels per 100 feet - this is the standard unit. This is how feed line loss is specified.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Ohms per 1,000 feet is for resistance, not loss - loss is in decibels, not ohms. Ohms aren't loss units.
Option B: Incorrect. Decibels per 1,000 feet is too long - standard is per 100 feet, not 1,000 feet. 1,000 feet is wrong.
Option C: Incorrect. Ohms per 100 feet is for resistance, not loss - loss is in decibels, not ohms. Ohms aren't loss units.
题目解析
The correct answer is D: Decibels per 100 feet. The units in which RF feed line loss is usually expressed are decibels per 100 feet. Feed line loss is typically specified as dB loss per 100 feet at a specific frequency. For amateur radio operators, this is the standard way to specify feed line loss. Understanding this helps when comparing feed lines.
考试技巧
Feed line loss units = decibels per 100 feet. Think 'F'eed 'L'ine 'L'oss = 'd'B per '1'00 feet. Feed line loss is typically specified as dB loss per 100 feet at a specific frequency. Not ohms, not per 1,000 feet - just dB per 100 feet.
记忆口诀
Feed line loss units = decibels per 100 feet. Think 'F'eed 'L'ine 'L'oss = 'd'B per '1'00 feet. Feed line loss is typically specified as dB loss per 100 feet. Standard feed line loss unit.
实际应用示例
A coaxial cable specification: Loss = 2.5 dB per 100 feet at 100 MHz. This tells you how much signal is lost in 100 feet of cable at that frequency. Feed line loss is always expressed in decibels per 100 feet - this is the standard unit. This is how feed line loss is specified.
错误选项分析
Option A: Incorrect. Ohms per 1,000 feet is for resistance, not loss - loss is in decibels, not ohms. Ohms aren't loss units. Option B: Incorrect. Decibels per 1,000 feet is too long - standard is per 100 feet, not 1,000 feet. 1,000 feet is wrong. Option C: Incorrect. Ohms per 100 feet is for resistance, not loss - loss is in decibels, not ohms. Ohms aren't loss units.
知识点
RF feed line loss, Decibels per 100 feet, Loss units, Feed line specification
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.