*Question E8C06:
What is the bandwidth of an FT8 signal?*  

*Correct Answer is  B: 50 Hz*  

### AI Response: (may contain errors)  

FT8 is a digital mode used in amateur radio for weak signal communication. It is designed to be efficient in terms of bandwidth and power usage.

1. **Correct Answer: 50 Hz**  
   - FT8 signals have a bandwidth of approximately 50 Hz. This narrow bandwidth is one of the reasons FT8 is effective for weak signal communication, as it allows the signal to be more easily distinguished from noise.

2. **Why the Other Choices are Incorrect:**
   - **10 Hz (Choice A):**  
     This bandwidth is too narrow for FT8. While FT8 is efficient, it still requires more than 10 Hz to transmit its data.
   - **600 Hz (Choice C):**  
     This bandwidth is too wide for FT8. Modes like PSK31 or RTTY might use wider bandwidths, but FT8 is specifically designed to be narrow.
   - **2.4 kHz (Choice D):**  
     This bandwidth is typical for voice modes like SSB (Single Sideband), not for digital modes like FT8. FT8 is much narrower to conserve spectrum and improve weak signal performance.

3. **Useful Information:**
   - FT8 uses 8-tone frequency-shift keying (FSK) with a tone spacing of 6.25 Hz. The total bandwidth is approximately $8 \times 6.25 \, \text{Hz} = 50 \, \text{Hz}$.
   - The narrow bandwidth helps in reducing the impact of noise and allows multiple FT8 signals to fit within a small frequency range, making it ideal for crowded bands.