On what frequencies are spread spectrum transmissions permitted?
The correct answer is B: Only on amateur frequencies above 222 MHz. On what frequencies are spread spectrum transmissions permitted is only on amateur frequencies above 222 MHz. Spread spectrum is only allowed above 222 MHz. For amateur radio operators, this is important for spread spectrum operation. Understanding this helps ensure legal spread spectrum operation.
Exam Tip
Spread spectrum permitted = only above 222 MHz. Think 'S'pread 'S'pectrum = 'S'tarts at '2'22 MHz. Spread spectrum transmissions are only permitted on amateur frequencies above 222 MHz. Not above 50 MHz, not above 420 MHz, not above 144 MHz - just above 222 MHz.
Memory Aid
"Spread spectrum permitted = only above 222 MHz. Think 'S'pread 'S'pectrum = '2'22 MHz. Spread spectrum transmissions are only permitted on amateur frequencies above 222 MHz. Important for spread spectrum operation."
Real-World Application
Spread spectrum transmissions: They are only permitted on amateur frequencies above 222 MHz (e.g., 222-225 MHz, 420-450 MHz, etc.). Spread spectrum is not allowed on frequencies below 222 MHz (e.g., HF, 6m, 2m). This is the restriction - spread spectrum only above 222 MHz.
FCC Part 97.311Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Above 50 MHz isn't correct - spread spectrum is only allowed above 222 MHz, not 50 MHz. 50 MHz is too low.
Option C: Incorrect. Above 420 MHz isn't correct - spread spectrum is allowed above 222 MHz, not just above 420 MHz. 420 MHz is too restrictive.
Option D: Incorrect. Above 144 MHz isn't correct - spread spectrum is only allowed above 222 MHz, not 144 MHz. 144 MHz is too low.
题目解析
The correct answer is B: Only on amateur frequencies above 222 MHz. On what frequencies are spread spectrum transmissions permitted is only on amateur frequencies above 222 MHz. Spread spectrum is only allowed above 222 MHz. For amateur radio operators, this is important for spread spectrum operation. Understanding this helps ensure legal spread spectrum operation.
考试技巧
Spread spectrum permitted = only above 222 MHz. Think 'S'pread 'S'pectrum = 'S'tarts at '2'22 MHz. Spread spectrum transmissions are only permitted on amateur frequencies above 222 MHz. Not above 50 MHz, not above 420 MHz, not above 144 MHz - just above 222 MHz.
记忆口诀
Spread spectrum permitted = only above 222 MHz. Think 'S'pread 'S'pectrum = '2'22 MHz. Spread spectrum transmissions are only permitted on amateur frequencies above 222 MHz. Important for spread spectrum operation.
实际应用示例
Spread spectrum transmissions: They are only permitted on amateur frequencies above 222 MHz (e.g., 222-225 MHz, 420-450 MHz, etc.). Spread spectrum is not allowed on frequencies below 222 MHz (e.g., HF, 6m, 2m). This is the restriction - spread spectrum only above 222 MHz.
错误选项分析
Option A: Incorrect. Above 50 MHz isn't correct - spread spectrum is only allowed above 222 MHz, not 50 MHz. 50 MHz is too low. Option C: Incorrect. Above 420 MHz isn't correct - spread spectrum is allowed above 222 MHz, not just above 420 MHz. 420 MHz is too restrictive. Option D: Incorrect. Above 144 MHz isn't correct - spread spectrum is only allowed above 222 MHz, not 144 MHz. 144 MHz is too low.
知识点
Spread spectrum transmissions, Above 222 MHz, Frequency restriction, Spread spectrum
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.