Question T0C11
From subelement T0 - T0C
What is the definition of duty cycle during the averaging time for RF exposure?
Why is this correct?
Duty cycle is the percentage of time a transmitter is actually transmitting during the RF exposure averaging period. This directly affects average radiation exposure—transmitting 50% of the time means half the average RF output compared to continuous transmission. Options A and B incorrectly describe power differences rather than time percentages, while D defines the opposite (non-transmitting time).
Memory tip
Look for time-based definitions when duty cycle appears in questions. The key pattern: duty cycle always relates to 'time transmitting' divided by 'total time' expressed as a percentage. This concept transfers to power calculations and exposure limits throughout RF safety.
Learn more
Duty cycle determines compliance with Maximum Permissible Exposure limits because FCC regulations consider time-averaged exposure, not instantaneous peaks. In practical operation, modes like CW and SSB have lower duty cycles than continuous carriers like FM or digital modes. Understanding duty cycle helps optimize station power while maintaining emission standards compliance—you can run higher peak power with lower duty cycles.
Think about it
Why do you think the FCC uses time-averaged exposure limits rather than just setting limits based on peak power output?