Ham Radio General Class Practice Test 2026 – Complete Exam Prep

Estimating whether an RF signal exceeds the maximum permissible exposure (MPE) involves a comprehensive understanding of various factors that can affect how much exposure a person might receive. Each of the properties mentioned plays a crucial role in this assessment.

The duty cycle is significant because it relates to the amount of time the RF signal is transmitted versus the time it is off. A higher duty cycle means that the signal is on for a more substantial portion of time, which can lead to greater exposure levels over a given period.

The frequency is also important, as different frequencies can have varying biological effects on human tissue. The MPE limits can differ based on frequency ranges since the interaction with body tissues changes. Some frequencies may have higher energy at certain exposure levels than others.

Power density refers to the amount of power per unit area delivered by the RF signal. It is a critical factor in determining the actual energy exposure that a person may encounter when in proximity to an RF source.

Since all three factors—duty cycle, frequency, and power density—are interconnected and necessary to make a comprehensive evaluation of RF exposure levels, the correct choice reflects that understanding by indicating that all of these attributes are essential in the assessment of MPE.