*Question G2E05:
What is the standard sideband for JT65, JT9, FT4, or FT8 digital signal when using AFSK?*  

*Correct Answer is  B: USB*  

### AI Response: (may contain errors)  

The correct answer to the question about the standard sideband for JT65, JT9, FT4, or FT8 digital signals when using AFSK is USB (Upper Sideband).

### Explanation of the Correct Answer:
- **USB (Upper Sideband)** is the standard sideband used for these digital modes. This is because these modes are designed to operate in the upper sideband of the frequency spectrum, which allows for better performance in terms of signal clarity and reduced interference.

### Why the Other Choices are Incorrect:
- **A: LSB (Lower Sideband)**: 
  - LSB is typically used for voice communications in the lower frequency bands (like 80m and 40m). Digital modes like JT65 and FT8 do not use LSB.
  
- **C: DSB (Double Sideband)**: 
  - DSB refers to a modulation technique that transmits both the upper and lower sidebands. This is not standard for the mentioned digital modes, which specifically use single sideband (USB).
  
- **D: SSB (Single Sideband)**: 
  - While SSB is a general term that includes both LSB and USB, it does not specify which sideband is used. The question specifically asks for the standard sideband, which is USB for these digital modes.

### Summary:
- The standard sideband for JT65, JT9, FT4, and FT8 is USB because it optimizes the performance of these digital modes.
- LSB, DSB, and the general term SSB do not apply to these specific digital modes in the context of AFSK operation. 

This understanding is crucial for the Extra Class exam, as it highlights the specific operational standards for digital communications in amateur radio.