*Question G2A01:
Which mode is most commonly used for voice communications on frequencies of 14 MHz or higher?*  

*Correct Answer is  A: Upper sideband*  

### AI Response: (may contain errors)  

On frequencies of 14 MHz or higher, the most commonly used mode for voice communications is **Upper Sideband (USB)**. Here's why:

1. **Why the correct answer is correct:**
   - **Upper Sideband (USB)** is the standard mode for voice communications on frequencies above 14 MHz, including the 20-meter band and higher. This is a convention that helps ensure compatibility and consistency among operators.

2. **Why the other choices are incorrect:**
   - **Lower Sideband (LSB)**: This mode is typically used for voice communications on frequencies below 14 MHz, such as the 160, 80, and 40-meter bands. It is not the standard for frequencies of 14 MHz or higher.
   - **Suppressed Sideband**: This term is not a standard mode of operation. It refers to a technique used in single sideband (SSB) transmission where one of the sidebands is suppressed, but it does not specify which sideband is used.
   - **Double Sideband (DSB)**: This mode transmits both sidebands and is not commonly used for amateur voice communications due to its inefficiency compared to SSB, which uses only one sideband.

3. **Useful rules of thumb:**
   - For frequencies **below 14 MHz**, use **Lower Sideband (LSB)**.
   - For frequencies **14 MHz and above**, use **Upper Sideband (USB)**.

Understanding these conventions helps ensure that you are using the correct mode for voice communications on different amateur radio bands.