Question E1F01:
[97.305] On what frequencies are spread spectrum transmissions permitted?  

Choices:  
A: Only on amateur frequencies above 50 MHz  
B: Only on amateur frequencies above 222 MHz  
C: Only on amateur frequencies above 420 MHz  
D: Only on amateur frequencies above 144 MHz    

Correct Answer is  B: Only on amateur frequencies above 222 MHz  

Correct answer: B — Only on amateur frequencies above 222 MHz.

Why this is correct:
- FCC Part 97 authorizes spread spectrum (SS) only on bands where $f > 222\ \text{MHz}$ (starts at the 1.25 m band and up). See 97.305(c) and 97.311.

Why the other choices are incorrect:
- A (above 50 MHz): This would include 6 meters (50–54 MHz) and 2 meters (144–148 MHz), where SS is not permitted.
- C (above 420 MHz): Too restrictive; it incorrectly excludes the 222–225 MHz band, where SS is permitted.
- D (above 144 MHz): This would include 2 meters (144–148 MHz), where SS is not permitted.

Rules of thumb:
- Frequency rule: $$f > 222\ \text{MHz}$$
- Memory aid: “No SS on 6 m or 2 m; SS starts at 1.25 m and up.”
- Related limit to remember: SS transmissions are limited to 10 W PEP (97.311).