*Question E1F05:
[97.303] Amateur stations may not transmit in which of the following frequency segments if they are located in the contiguous 48 states and north of Line A?*  

*Correct Answer is  D: 420 MHz - 430 MHz*  

### AI Response: (may contain errors)  

In the context of the Amateur Radio Service, certain frequency segments are restricted based on geographic location and other regulations. 

### Correct Answer: 420 MHz - 430 MHz
- The frequency segment from 420 MHz to 430 MHz is allocated for the Amateur Radio Service, but it is also shared with the Federal Government, particularly for space operations and other critical services. 
- According to the FCC regulations, amateur stations located in the contiguous 48 states and north of Line A are prohibited from transmitting in this segment to avoid interference with these important services.

### Why the Other Choices are Incorrect:
- **A: 440 MHz - 450 MHz**
  - This segment is allocated for amateur use and is commonly used for repeaters and other amateur communications. Therefore, it is permissible for amateur stations to transmit here.

- **B: 53 MHz - 54 MHz**
  - This frequency range is also allocated for amateur use, specifically for the 6-meter band. Amateur stations can transmit in this segment without restrictions.

- **C: 222 MHz - 223 MHz**
  - This segment is part of the 1.25-meter band, which is allocated for amateur use. There are no restrictions on transmitting in this range for amateur operators.

### Summary
- The key takeaway is that the 420 MHz - 430 MHz segment is restricted for amateur use in certain areas to prevent interference with government operations. The other frequency segments listed are open for amateur transmissions.

### Rules of Thumb:
- Always check the latest FCC regulations and band plans for any updates on frequency allocations.
- Be aware of geographic restrictions, especially when operating near government facilities or in shared frequency bands.