FT4In the HamQSO filter: Digital
FT4: what it is and where to find it on the bands
FT4: a faster sibling of FT8 for contests and quick runs, with 7.5 second cycles.
FT4 works like FT8 at twice the speed, with 7.5 second periods. It trades a little sensitivity for a contact that takes about half the time.
It was designed for contests, and it is useful whenever you want to work many stations quickly.
It has its own dial frequencies, separate from FT8, so the two modes do not step on each other.