Question
To what does the “4” in FT4 refer?
Answer Options
- A) Multiples of 4 bits of user information
- B) Four-tone continuous-phase frequency shift keying
- C) Four transmit/receive cycles per minute
- D) All these choices are correct
Correct Answer: B
Explanation
FT4 is a weak-signal digital mode derived from FT8, designed to be faster for contest operation. The naming convention of many weak-signal modes (like FT8, JT65, Q65) usually denotes a critical technical characteristic of the modulation scheme.
In the FT4 mode, the ‘4’ refers to the modulation scheme used, which is Four-tone continuous-phase frequency shift keying (4-FSK). This means that four different tones are used to encode the data, allowing the mode to transmit information faster than FT8 (which uses 8 tones but in a different timing structure), thus making it more suitable for rapid exchanges required in contests.
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