Question
Which of these digital modes has the narrowest bandwidth?
Answer Options
- A) MFSK16
- B) 170 Hz shift, 45-baud RTTY
- C) FT8
- D) PACTOR IV
Correct Answer: C
Explanation
Bandwidth efficiency is a major focus of modern digital modes, as it allows for more contacts to coexist within a limited frequency segment. The bandwidth of a digital signal is determined by the symbol rate (how fast the data changes) and the frequency shift (for FSK modes).
Of the choices, FT8 has the narrowest bandwidth, occupying approximately 50 Hz. This extremely narrow bandwidth is possible because of the mode’s very low symbol rate, highly structured transmissions, and the use of digital signal processing. By comparison, 45-baud RTTY typically occupies about 250 Hz, and PACTOR IV is even wider, typically 500 Hz or more.
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