*Question E0A02:
When evaluating RF exposure levels from your station at a neighbor’s home, what must you do?*  

*Correct Answer is  B: Ensure signals from your station are less than the uncontrolled maximum permissible exposure (MPE) limits*  

### AI Response: (may contain errors)  

When evaluating RF exposure levels from your station at a neighbor’s home, the correct answer is:

**B: Ensure signals from your station are less than the uncontrolled maximum permissible exposure (MPE) limits.**

### Explanation of the Correct Answer:
- **Uncontrolled MPE Limits**: These limits apply to areas where the general public may be exposed to RF radiation, such as a neighbor's home. The FCC sets these limits to protect individuals who may not be aware of the potential hazards of RF exposure.
- It is essential to ensure that your station's emissions do not exceed these limits to maintain safety and compliance with regulations.

### Why the Other Choices are Incorrect:
- **A: Ensure signals from your station are less than the controlled maximum permissible exposure (MPE) limits**: 
  - Controlled MPE limits apply to areas where access is restricted to trained personnel who are aware of the risks. Since a neighbor's home is not a controlled environment, this option is not applicable.
  
- **C: Ensure signals from your station are less than the controlled maximum permissible emission (MPE) limits**: 
  - This option incorrectly uses the term "emission" instead of "exposure." MPE refers to exposure limits, not emission limits, making this choice incorrect.
  
- **D: Ensure signals from your station are less than the uncontrolled maximum permissible emission (MPE) limits**: 
  - Similar to choice C, this option incorrectly uses "emission" instead of "exposure." The focus should be on exposure limits, not emission limits.

### Useful Formulas or Rules of Thumb:
- The MPE limits are typically expressed in terms of power density (watts per square meter) or electric field strength (volts per meter). 
- For example, the MPE for general public exposure at frequencies between 30 MHz and 300 MHz is approximately 0.2 mW/cm². 

To ensure compliance, you can calculate the power density using the formula:

$$
S = \frac{P_T \times G_A}{d^2}
$$

where:
- $S$ = power density (mW/cm²)
- $P_T$ = transmitter power (mW)
- $G_A$ = antenna gain (linear)
- $d$ = distance from the antenna (cm)

This formula helps you determine if your station's emissions are within safe limits for the general public.