What it means on the air: FT4 is a fast, structured weak-signal digital mode from the WSJT-X family, designed for contest-style exchanges with transmission periods much shorter than FT8.
Why operators use it
Its speed trades some sensitivity for faster contacts. Accurate time, standardized messages, clean audio, and quick operator decisions are essential.
Where the contact goes wrong
FT4 is not simply “FT8 at higher power”; overdrive and excessive power create interference across a busy, tightly packed passband.
A cleaner operating method
Synchronize the clock, select FT4 and the published activity frequency, keep transmit audio clean with little or no ALC as instructed, answer in sequence, and log the completed exchange.
Operating boundary
Use current software and radio documentation, published band plans, applicable licensing rules, and the lowest power that closes the path. A decode, map position, or automated exchange does not by itself prove end-to-end communication.
