Deep Dive: E2E10
The correct answer is C: FT8. Which of these digital modes has the narrowest bandwidth is FT8. FT8 uses only about 50 Hz bandwidth, making it the narrowest. For amateur radio operators, this is important for weak signal operation. Understanding this helps when selecting digital modes.
Why Other Answers Are Wrong
Option A (MFSK16): Incorrect. MFSK16 has wider bandwidth than FT8 - FT8 is narrower. MFSK16 isn't the narrowest. Option B (170 Hz shift, 45-baud RTTY): Incorrect. 170 Hz shift RTTY has wider bandwidth than FT8 - FT8 is narrower. 170 Hz RTTY isn't the narrowest. Option D (PACTOR IV): Incorrect. PACTOR IV has wider bandwidth than FT8 - FT8 is narrower. PACTOR IV isn't the narrowest.
Exam Tip
Narrowest bandwidth digital mode = FT8. Think 'F'T8 = 'F'ifty Hz (very narrow). FT8 uses only about 50 Hz bandwidth, making it the narrowest. Not MFSK16, not 170 Hz RTTY, not PACTOR IV - just FT8.
Memory Aid
Narrowest bandwidth digital mode = FT8. Think 'F'T8 = 'F'ifty Hz. FT8 uses only about 50 Hz bandwidth, making it the narrowest. Important for weak signal operation.
Real-World Example
Digital mode bandwidth comparison: FT8 uses only about 50 Hz bandwidth, making it the narrowest. MFSK16 uses about 316 Hz, 170 Hz shift RTTY uses about 250 Hz, and PACTOR IV uses several hundred Hz. FT8 is designed for weak signal work with minimal bandwidth. This is the mode - FT8 has the narrowest bandwidth.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E2E
Reference: 2024-2028 Question Pool · E2 - Operating Procedures
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E2E topic.