*Question E0A10:
When must an RF exposure evaluation be performed on an amateur station operating on 80 meters?*  

*Correct Answer is  A: An evaluation must always be performed*  

### AI Response: (may contain errors)  

To understand when an RF exposure evaluation must be performed on an amateur station operating on 80 meters, let's break down the correct answer and the reasoning behind it.

### Correct Answer: A - An evaluation must always be performed

- **Explanation**: The FCC requires that all amateur radio operators conduct an RF exposure evaluation to ensure that their station complies with the limits set for human exposure to radiofrequency (RF) energy. This evaluation is necessary regardless of the power level or mode of operation. The goal is to protect both the operator and the public from potential RF hazards.

### Why the Other Choices are Incorrect:

- **B: When the ERP of the station is less than 10 watts**  
  - **Explanation**: This is incorrect because the requirement for an RF exposure evaluation is not solely based on the Effective Radiated Power (ERP). Even stations with low power levels may need an evaluation if they are in proximity to people or if they use high-gain antennas.

- **C: When the station’s operating mode is CW**  
  - **Explanation**: This choice is incorrect because the mode of operation (e.g., Continuous Wave (CW), SSB, FM) does not determine the need for an RF exposure evaluation. The evaluation is required for all modes of operation.

- **D: When the output power from the transmitter is less than 100 watts**  
  - **Explanation**: This is also incorrect. While lower power levels may reduce the risk of exposure, the evaluation is still required regardless of whether the output power is above or below 100 watts.

### Summary of RF Exposure Evaluation:

- **Key Points**:
  - An RF exposure evaluation is mandatory for all amateur stations.
  - It ensures compliance with safety standards for RF exposure.
  - The evaluation considers factors such as power levels, antenna gain, and proximity to people.

By understanding these points, you can confidently answer questions related to RF exposure evaluations on the Extra Class exam.