*Question T8A09:
What is the approximate bandwidth of a VHF repeater FM voice signal?*  

*Correct Answer is  C: Between 10 and 15 kHz*  

### AI Response: (may contain errors)  

The correct answer to the question about the approximate bandwidth of a VHF repeater FM voice signal is:

**Correct Answer: Between 10 and 15 kHz**

### Explanation:

1. **Why the correct answer is correct:**
   - FM voice signals typically have a modulation index that results in a bandwidth of about 10 to 15 kHz. This is based on Carson's Rule, which states that the bandwidth of an FM signal can be approximated as:
   $$
   BW \approx 2(\Delta f + f_m)
   $$
   where:
   - $\Delta f$ = peak frequency deviation (for VHF FM, this is often around 5 kHz)
   - $f_m$ = maximum modulating frequency (for voice, this is typically around 3 kHz)

   Plugging in these values gives:
   $$
   BW \approx 2(5 \text{ kHz} + 3 \text{ kHz}) = 2(8 \text{ kHz}) = 16 \text{ kHz}
   $$
   This confirms that the bandwidth is indeed around 10 to 15 kHz.

2. **Why the other choices are incorrect:**
   - **A: Less than 500 Hz**: This is too narrow for FM voice signals. Such a bandwidth would be more appropriate for narrowband modes like CW (Morse code).
   - **B: About 150 kHz**: This is excessively wide for a typical VHF FM voice signal. While some wideband signals can occupy this range, standard FM voice does not.
   - **D: Between 50 and 125 kHz**: This range is also too wide for standard VHF FM voice communications. It might apply to some specialized applications but not to typical repeater operations.

### Summary:
- The bandwidth of a VHF repeater FM voice signal is approximately 10 to 15 kHz, which is derived from the characteristics of FM modulation and typical voice frequencies. Understanding Carson's Rule helps in estimating bandwidth for FM signals effectively.