*Question T4B05:
What does the scanning function of an FM transceiver do?*  

*Correct Answer is  C: Tunes through a range of frequencies to check for activity*  

### AI Response: (may contain errors)  

The scanning function of an FM transceiver is designed to help operators find active frequencies by automatically tuning through a range of frequencies. 

### Correct Answer: C - Tunes through a range of frequencies to check for activity

- **Explanation**: The scanning function allows the transceiver to move through a set range of frequencies, listening for any active signals. This is particularly useful in finding open channels or monitoring for communications in a specific band.

### Why the Other Choices are Incorrect:

- **A: Checks incoming signal deviation**  
  - This option refers to the measurement of how much the frequency of the signal deviates from its carrier frequency, which is important for demodulation but not specifically related to the scanning function.

- **B: Prevents interference to nearby repeaters**  
  - While FM transceivers may have features to minimize interference, the scanning function itself does not prevent interference; it simply allows the user to find active frequencies.

- **D: Checks for messages left on a digital bulletin board**  
  - This option pertains to digital modes and systems like packet radio or APRS, which are not functions of the scanning feature in an FM transceiver.

### Summary

The scanning function is primarily about finding active frequencies, making option C the correct choice. Understanding the specific functions of your equipment is crucial for effective operation in amateur radio.