*Question G2C07:
When sending CW, what does a “C” mean when added to the RST report?*  

*Correct Answer is  A: Chirpy or unstable signal*  

### AI Response: (may contain errors)  

When sending CW (Continuous Wave), the RST report is a way to describe the quality of a received signal. The RST system stands for Readability, Signal strength, and Tone. Sometimes, additional letters are added to the RST report to provide more information about the signal quality.

### Correct Answer: A: Chirpy or unstable signal

1. **Why the correct answer is correct:**
   - The letter "C" added to an RST report indicates that the signal is "chirpy" or unstable. This means that the frequency of the CW signal is not stable and may vary or "chirp" during transmission, which can make it harder to copy accurately.

### Why the other choices are incorrect:

2. **B: Report was read from an S meter rather than estimated**
   - This is incorrect because the letter "C" does not relate to how the report was obtained. An S meter reading is typically used for measuring signal strength, not for indicating chirpiness.

3. **C: 100 percent copy**
   - This is incorrect because "100 percent copy" would mean that the message was received perfectly without errors, but it is not represented by the letter "C" in the RST report.

4. **D: Key clicks**
   - This is incorrect because key clicks are a different type of signal issue, usually caused by poor keying technique or equipment issues, and are not indicated by the letter "C" in the RST report.

### Additional Notes:

- The RST system is a subjective way to report signal quality:
  - **R (Readability):** Scale of 1 to 5
  - **S (Signal strength):** Scale of 1 to 9
  - **T (Tone):** Scale of 1 to 9 (for CW only)

Understanding these additional indicators like "C" for chirpy signals helps operators provide more detailed feedback about signal quality.