SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/hamg-ft8-slot

What is good practice when answering an FT8 station calling CQ?

The alternate slot from the calling station, on a clear frequency.

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  1. Always transmit on the caller's exact frequency
  2. Pick a clear frequency in the caller's same time slot
  3. Pick a clear frequency in the alternate time slot ✔

Why: FT8 uses alternating time slots. If you answered in the same slot, you would be talking while the other station is also talking and could not hear its reply.

Huh, didn't know that: FT8 and the related modes JT65, JT9 and FT4 use upper sideband when sent as AFSK.

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You know you're a ham when you wait for the roger beep before speaking in a normal conversation.
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References

Answer: Pick a clear frequency in the alternate time slot. FT8 uses alternating time slots. If you answered in the same slot, you would be talking while the other station is also talking and could not hear its reply.

  1. NCVEC 2023-2027 General Class Pool and Syllabus (6th Errata, Feb 4 2026) ncvec.org/downloads/General%20Class%20Pool%20and%20Syllabus%202023-2027%20Public%20Release%20with%206th%20Errata%20Feb%204%202026.pdf
    Find a clear frequency during the alternate time slot to the calling station
    Checked 2026-10-10.

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