*Question G0A05:
[97.13(c)(2), 1.1307(b)] What must you do if an evaluation of your station shows that the RF energy radiated by your station exceeds permissible limits for possible human absorption?*  

*Correct Answer is  A: Take action to prevent human exposure to the excessive RF fields*  

### AI Response: (may contain errors)  

To address the question regarding RF energy exposure limits, let's break down the correct answer and the reasoning behind it.

### Correct Answer: A - Take action to prevent human exposure to the excessive RF fields

1. **Why this answer is correct:**
   - The FCC has established Maximum Permissible Exposure (MPE) limits to protect individuals from harmful RF radiation. If your station's RF emissions exceed these limits, it is your responsibility to take corrective action to ensure that no one is exposed to unsafe levels of RF energy. This could involve reducing power, changing antenna placement, or implementing physical barriers.

### Why the other choices are incorrect:

2. **B - File an Environmental Impact Statement (EIS-97) with the FCC:**
   - An Environmental Impact Statement is not required for individual stations unless they are part of a larger project that significantly affects the environment. For most amateur radio operations, simply exceeding RF exposure limits does not necessitate filing an EIS.

3. **C - Secure written permission from your neighbors to operate above the controlled MPE limits:**
   - While it is courteous to inform neighbors about RF emissions, obtaining their permission does not absolve you of the responsibility to comply with FCC regulations. You cannot legally operate above MPE limits just because you have neighbor consent.

4. **D - All these choices are correct:**
   - Since options B and C are incorrect, this choice cannot be correct either.

### Useful Formulas and Rules of Thumb:

- **MPE Limits:** The MPE limits are defined in terms of power density (watts per square meter) and vary based on frequency. For example, the limits for general public exposure are typically lower than those for occupational exposure.
  
- **General Rule of Thumb:**
  - If you are unsure whether your station exceeds MPE limits, you can use the following formula to estimate power density ($S$) at a distance ($d$) from the antenna:
  
  $$
  S = \frac{P_T \times G_A}{4 \pi d^2}
  $$
  
  where:
  - $S$ = power density in watts per square meter (W/m²)
  - $P_T$ = transmitter power in watts
  - $G_A$ = antenna gain (linear)
  - $d$ = distance from the antenna in meters

By understanding these concepts, you can ensure compliance with FCC regulations and protect yourself and others from excessive RF exposure.