Ham Radio General Class Practice Test

What effect does transmitter duty cycle have when evaluating RF exposure?

1. A lower transmitter duty cycle permits greater short-term exposure levels

2. A higher transmitter duty cycle permits greater short-term exposure levels

3. Low duty cycle transmitters are exempt from RF exposure evaluation requirements

4. High duty cycle transmitters are exempt from RF exposure requirements

The correct answer is: A lower transmitter duty cycle permits greater short-term exposure levels

Transmitter duty cycle is a critical factor when evaluating RF exposure because it reflects the ratio of time a transmitter is active versus the time it is off. When a transmitter has a lower duty cycle, it means it is on for a shorter proportion of time compared to being off. This reduced active time leads to a lower average power output over any given period, which translates to lower potential exposure to RF energy for individuals nearby during those times of operation. As a result, a lower duty cycle allows for greater short-term exposure levels, meaning that individuals can be exposed to higher power levels for short durations without exceeding safety thresholds. This principle is essential in managing RF exposure risk, as it acknowledges that the risk can vary significantly depending on the operational characteristics of the transmitter. Higher duty cycle transmitters, on the other hand, are active for longer periods, which means they can present higher average power levels and potentially increase RF exposure, thereby necessitating more stringent evaluations to ensure safety. Meanwhile, exemptions regarding low and high duty cycle transmitters with respect to RF exposure requirements do not apply, as safety assessments must still be conducted regardless of duty cycle.