Question T2B05
From subelement T2 - T2B
What would cause your FM transmission audio to be distorted on voice peaks?
Why is this correct?
Over-deviation occurs when you speak too loudly into the microphone, causing the audio amplitude to exceed the FM transmitter's modulation limits. This creates distortion on voice peaks. Options A and D relate to technical settings, not voice levels. Option B suggests the opposite of the solution—talking louder would worsen over-deviation.
Memory tip
Remember the pattern: In FM, audio problems are usually operator technique issues, not equipment failures. When others report distorted audio, first check your speaking habits before adjusting technical settings. The mic is designed for normal conversation volume.
Learn more
Over-deviation is like overdriving any audio system—too much input creates distortion. In FM transmission, your voice directly modulates the carrier frequency. Excessive audio amplitude pushes the frequency deviation beyond the allocated channel bandwidth, violating emission standards in Part 97.221. This interference can affect adjacent frequencies and degrade repeater performance for all users.
Think about it
Why do you think FM systems are more sensitive to loud speaking than AM systems, and what does this tell you about how frequency modulation works?