What would cause your FM transmission audio to be distorted on voice peaks?
The correct answer is C: You are talking too loudly. FM transmission audio distortion on voice peaks is typically caused by overmodulation - when you speak too loudly into the microphone, your voice signal exceeds the maximum modulation level the transmitter can handle.
FM transmitters have a maximum deviation limit (typically ±5 kHz for amateur radio). When you speak too loudly, the audio signal tries to exceed this limit, causing the transmitter to clip the signal, which results in distortion. The solution is to speak at a normal volume or reduce the microphone gain. Talking louder doesn't help - it makes the problem worse.
Exam Tip
FM distortion on peaks = Talking too loud. Remember: If your FM audio distorts on voice peaks, you're overmodulating - speak at a normal volume or reduce microphone gain.
Memory Aid
"**F**M **D**istortion = **F**orced **M**odulation (think 'FD = FM' = Forced Modulation, too loud)"
Real-World Application
You're transmitting on a 2-meter FM repeater, and other operators tell you your audio is distorted, especially when you get excited and speak louder. The problem is overmodulation - your voice is too loud for the transmitter. You reduce your microphone gain or speak at a more moderate volume, and the distortion disappears.
FCC Part 97.307Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Inverted repeater offset (transmitting on output, receiving on input) would prevent repeater access but wouldn't cause audio distortion on voice peaks.
Option B: Incorrect. Talking louder makes the distortion worse, not better. The problem is already too much audio level.
Option D: Incorrect. High transmit power doesn't cause audio distortion. The issue is audio level, not RF power.
题目解析
The correct answer is C: You are talking too loudly. FM transmission audio distortion on voice peaks is typically caused by overmodulation - when you speak too loudly into the microphone, your voice signal exceeds the maximum modulation level the transmitter can handle. FM transmitters have a maximum deviation limit (typically ±5 kHz for amateur radio). When you speak too loudly, the audio signal tries to exceed this limit, causing the transmitter to clip the signal, which results in distortion. The solution is to speak at a normal volume or reduce the microphone gain. Talking louder doesn't help - it makes the problem worse.
考试技巧
FM distortion on peaks = Talking too loud. Remember: If your FM audio distorts on voice peaks, you're overmodulating - speak at a normal volume or reduce microphone gain.
记忆口诀
**F**M **D**istortion = **F**orced **M**odulation (think 'FD = FM' = Forced Modulation, too loud)
实际应用示例
You're transmitting on a 2-meter FM repeater, and other operators tell you your audio is distorted, especially when you get excited and speak louder. The problem is overmodulation - your voice is too loud for the transmitter. You reduce your microphone gain or speak at a more moderate volume, and the distortion disappears.
错误选项分析
Option A: Incorrect. Inverted repeater offset (transmitting on output, receiving on input) would prevent repeater access but wouldn't cause audio distortion on voice peaks. Option B: Incorrect. Talking louder makes the distortion worse, not better. The problem is already too much audio level. Option D: Incorrect. High transmit power doesn't cause audio distortion. The issue is audio level, not RF power.
知识点
FM modulation, Overmodulation, Audio distortion, Microphone gain
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.