*Question G2B06:
How can you avoid harmful interference on an apparently clear frequency before calling CQ on CW or phone?*  

*Correct Answer is  A: Send “QRL?” on CW, followed by your call sign; or, if using phone, ask if the frequency is in use, followed by your call sign*  

### AI Response: (may contain errors)  

To avoid harmful interference on a clear frequency before calling CQ, the correct approach is:

**Correct Answer: A**  
Send “QRL?” on CW, followed by your call sign; or, if using phone, ask if the frequency is in use, followed by your call sign.

### Explanation of the Correct Answer:
- **"QRL?"** is a standard Q-code used in amateur radio to inquire if the frequency is in use. By sending this, you are actively checking for any ongoing communications before you start your own transmission.
- Including your call sign ensures that anyone listening knows who is asking, which is important for proper identification and etiquette in amateur radio.

### Why the Other Choices are Incorrect:
- **B: Listen for 2 minutes before calling CQ**  
  While listening is important, simply waiting for 2 minutes does not guarantee that the frequency is clear. Other operators may be using the frequency intermittently, and you might miss them.

- **C: Send the letter “V” in Morse code several times and listen for a response, or say “test” several times and listen for a response**  
  This method is not standard practice and may confuse other operators. It does not effectively communicate your intent to check if the frequency is in use.

- **D: Send “QSY” on CW or if using phone, announce “the frequency is in use,” then give your call sign and listen for a response**  
  "QSY" means to change frequency, which is not appropriate if you are trying to determine if the frequency is clear. This could lead to confusion rather than clarifying the situation.

### Summary:
- Always use established protocols like "QRL?" to check frequency usage.
- Listening is crucial, but active inquiry is more effective.
- Proper etiquette and clear communication help maintain a respectful operating environment.