ARRL Technician Practice Exam

What factor should be assessed when evaluating RF exposure for compliance?

1. Type of modulation used

2. Duty cycle of transmission

3. Height of the antennas

4. Distance from the operator

The correct answer is: Duty cycle of transmission

When evaluating RF exposure for compliance, considering the duty cycle of transmission is crucial because it influences the average power output over time that a transmitter is operating. The duty cycle refers to the fraction of time that a transmitter is actively transmitting compared to the time it is not. For example, a transmitter that operates at a high duty cycle will expose individuals to RF energy more consistently and potentially at a higher level than one with a lower duty cycle. Assessing the duty cycle allows for a more accurate calculation of the expected RF exposure levels, as it takes into account how long the RF energy is being emitted. This is important for ensuring that the exposure does not exceed the safety limits established by regulatory bodies. If a device has a high duty cycle and transmits continuously, it may require more stringent evaluation and may need additional safety measures than a device with a low duty cycle that transmits intermittently. The other factors—type of modulation, height of the antennas, and distance from the operator—are relevant in various contexts of RF exposure, but they do not directly correlate with the assessment of exposure levels in the same way that duty cycle does. The type of modulation can affect signal characteristics, while the height of antennas and distance from the operator can influence the intensity of