WSJT-X is a computer program designed to facilitate basic amateur radio communication using very weak signals. The first four letters in the program name stand for “Weak Signal communication by K1JT,” while the suffix “-X” indicates that WSJT-X started as an extended and experimental branch of the program WSJT.
The WSJT project was started in 2001. Since 2005 it has been an Open Source project. All code is licensed under the GNU Public License (GPL). Many users, too numerous to mention here individually, have contributed suggestions and advice that have greatly aided the development of WSJT and its sister programs.
For WSJT-X in particular, we acknowledge contributions from AC6SL, AE4JY, DJ0OT, G3WDG, G4KLA, G4WJS, IV3NWV, IW3RAB, K3WYC, K9AN, KA6MAL, KA9Q, KB1ZMX, KD6EKQ, KI7MT, KK1D, ND0B, PY2SDR, VE1SKY, VK3ACF, VK4BDJ, VK7MO, W4TI, W4TV, and W9MDB. Each of these amateurs has helped to bring the program’s design, code, testing, and/or documentation to its present state.
Most of the color palettes for the WSJT-X waterfall were copied from the excellent, well documented, open-source program fldigi, by W1HKJ and friends.
We use development tools and libraries from many sources. We particularly wish to acknowledge importance of the GNU Compiler Collection from the Free Software Foundation, the "clang" compiler from LLVM at the University of Illinois, and the Qt Project from Digia PLC. Other important resources include the FFTW library by Matteo Frigo and Steven G. Johnson; SLALIB, the Positional Astronomy Library by P. T. Wallace; and a high-precision planetary ephemeris and associated software from NASA’s Jet Propulsion Laboratory.