Why is duty cycle one of the factors used to determine safe RF radiation exposure levels?
The correct answer is A: It affects the average exposure to radiation. Duty cycle is a factor in determining safe RF radiation exposure levels because it affects the average exposure to radiation. Duty cycle is the percentage of time transmitting. Higher duty cycle means more average exposure over time. Lower duty cycle means less average exposure. For amateur radio operators, this is why SSB (lower duty cycle) allows higher power than CW (higher duty cycle) for the same exposure limit. Understanding this helps optimize power while staying safe.
Exam Tip
Duty cycle = affects average exposure. Think 'D'uty cycle = 'D'etermines 'A'verage exposure. Higher duty cycle = more average exposure. Lower duty cycle = less average exposure. Not about peak exposure, feed line loss, or amplifier heating.
Memory Aid
"Duty cycle = affects average exposure. Think 'D'uty cycle = 'D'etermines 'A'verage. Percentage of time transmitting determines average RF exposure over time. Higher duty cycle = more average exposure."
Real-World Application
You operate CW with 100% duty cycle (continuous transmission) - your average exposure equals your peak exposure. You switch to SSB with 50% duty cycle (talking half the time) - your average exposure is half your peak exposure. The duty cycle determines how much RF energy people are exposed to on average over time.
Key Concepts
Why Other Options Are Wrong
Option B: Incorrect. Duty cycle affects average exposure, not peak exposure. Peak exposure is determined by instantaneous power, not duty cycle.
Option C: Incorrect. Duty cycle doesn't account for feed line loss - that's a separate factor. Feed line loss reduces radiated power but doesn't relate to duty cycle.
Option D: Incorrect. Duty cycle doesn't account for thermal effects of the final amplifier - that's an equipment concern, not an exposure concern. Duty cycle is about transmission time, not amplifier heating.
题目解析
The correct answer is A: It affects the average exposure to radiation. Duty cycle is a factor in determining safe RF radiation exposure levels because it affects the average exposure to radiation. Duty cycle is the percentage of time transmitting. Higher duty cycle means more average exposure over time. Lower duty cycle means less average exposure. For amateur radio operators, this is why SSB (lower duty cycle) allows higher power than CW (higher duty cycle) for the same exposure limit. Understanding this helps optimize power while staying safe.
考试技巧
Duty cycle = affects average exposure. Think 'D'uty cycle = 'D'etermines 'A'verage exposure. Higher duty cycle = more average exposure. Lower duty cycle = less average exposure. Not about peak exposure, feed line loss, or amplifier heating.
记忆口诀
Duty cycle = affects average exposure. Think 'D'uty cycle = 'D'etermines 'A'verage. Percentage of time transmitting determines average RF exposure over time. Higher duty cycle = more average exposure.
实际应用示例
You operate CW with 100% duty cycle (continuous transmission) - your average exposure equals your peak exposure. You switch to SSB with 50% duty cycle (talking half the time) - your average exposure is half your peak exposure. The duty cycle determines how much RF energy people are exposed to on average over time.
错误选项分析
Option B: Incorrect. Duty cycle affects average exposure, not peak exposure. Peak exposure is determined by instantaneous power, not duty cycle. Option C: Incorrect. Duty cycle doesn't account for feed line loss - that's a separate factor. Feed line loss reduces radiated power but doesn't relate to duty cycle. Option D: Incorrect. Duty cycle doesn't account for thermal effects of the final amplifier - that's an equipment concern, not an exposure concern. Duty cycle is about transmission time, not amplifier heating.
知识点
Duty cycle, Average exposure, RF safety, Exposure calculations
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.