What is the effect of modulation duty cycle on RF exposure?

RF exposure limits are calculated based on the average amount of RF energy absorbed over a specified time period, rather than instantaneous peak power. The duty cycle represents the percentage of time a transmitter is actively producing RF output during that evaluation period. Because continuous modes like AM or RTTY have a high duty cycle, they result in higher average exposure. Conversely, modes with a lower duty cycle, such as SSB (where power drops between words) or CW (where the carrier is keyed on and off), transmit less average energy. Therefore, if you use a mode with a lower duty cycle, you can transmit at a higher peak power level without exceeding the time-averaged RF exposure safety limits. Distractors suggesting exemptions based on duty cycle are incorrect; all transmitters must adhere to the exposure limits regardless of their operating mode.