*Question E1B03:
[97.13] Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?*  

*Correct Answer is  A: 1 mile*  

### AI Response: (may contain errors)  

To determine the distance within which an amateur station must protect an FCC monitoring facility from harmful interference, we refer to FCC regulations.

1. **Correct Answer Explanation**:  
   The correct answer is **1 mile**. According to FCC rules, amateur stations must ensure that they do not cause harmful interference to FCC monitoring stations within a radius of 1 mile. This is a regulatory requirement to maintain the integrity of the monitoring facilities.

2. **Incorrect Choices Explanation**:  
   - **3 miles**: This distance is not specified in the regulations for protecting FCC monitoring facilities. It exceeds the required 1 mile.
   - **10 miles**: Similar to 3 miles, this distance is also not required and is unnecessarily large for the protection of monitoring facilities.
   - **30 miles**: This is far beyond the necessary distance and is not supported by FCC guidelines for interference protection.

3. **Useful Rules of Thumb**:  
   - Always refer to the latest FCC regulations for specific distances related to interference protection.
   - Remember that the 1-mile rule is specifically for protecting FCC monitoring stations, which is a key point for the Extra Class exam.

In summary, amateur stations must protect FCC monitoring facilities from harmful interference within a distance of **1 mile**.