Question E1C12:
[97.305(c)] In what portion of the 630-meter band are phone emissions permitted?  

Choices:  
A: None  
B: Only the top 3 kHz  
C: Only the bottom 3 kHz  
D: The entire band    

Correct Answer is  D: The entire band  

To answer this, remember the 630-meter band is 472–479 kHz.

Why the correct answer (D) is correct:
- §97.305(c) authorizes phone emissions across the entire 630 m band. There are no sub-band segments on 472–479 kHz for different modes; phone (voice, e.g., SSB/AM), CW, and data are all permitted anywhere within the band, subject to the usual band-edge and power/EIRP limits.

Why the other choices are incorrect:
- A: None — incorrect; phone is explicitly permitted on 630 m.
- B: Only the top 3 kHz — incorrect; there is no “top-only” phone segment.
- C: Only the bottom 3 kHz — incorrect; there is no “bottom-only” phone segment.

Useful rules of thumb:
- Band edges for 630 m:
  - Lower edge: $f_{low} = 472.000$ kHz
  - Upper edge: $f_{high} = 479.000$ kHz
- Keep your occupied bandwidth $B$ inside the band:
  - For USB near the top edge: $f_c \le f_{high} - B$
  - For LSB near the bottom edge: $f_c \ge f_{low} + B$
  - Example: SSB voice with $B \approx 2.8$ kHz → stay about 2.8 kHz away from the relevant band edge.
- Power reminder: the 630 m band is limited by EIRP (typically 5 W EIRP in the U.S.); ensure compliance, though this doesn’t affect where phone is allowed.