WSJT-X implements communication protocols or "modes" called FST4, FST4W, FT4, FT8, JT4, JT9, JT65, Q65, MSK144, and WSPR, as well as one called Echo for detecting and measuring your own radio signals reflected from the Moon. These modes were designed for making reliable, confirmed QSOs under extreme weak-signal conditions.
JT4, JT9, and JT65 use nearly identical message structure and source encoding (the efficient compression of standard messages used for minimal QSOs). They use timed 60-second T/R sequences synchronized with UTC. JT4 and JT65 were designed for EME ("moonbounce") on the VHF/UHF/microwave bands. JT9 is optimized for the MF and HF bands. It is about 2 dB more sensitive than JT65 while using less than 10% of the bandwidth. Q65 offers submodes with a wide range of T/R sequence lengths and tone spacings; it is highly recommended for EME, ionospheric scatter, and other weak signal work on VHF, UHF, and microwave bands.
FT4 and FT8 are operationally similar but use T/R cycles only 7.5 and 15 s long, respectively. MSK144 is designed for Meteor Scatter on the VHF bands. These modes offer enhanced message formats with support for nonstandard callsigns and some popular contests.
FST4 and FST4W are designed particularly for the LF and MF bands. On these bands their fundamental sensitivities are better than other WSJT-X modes with the same sequence lengths, approaching the theoretical limits for their rates of information throughput. FST4 is optimized for two-way QSOs, while FST4W is for quasi-beacon transmissions of WSPR-style messages. FST4 and FST4W do not require the strict, independent time synchronization and phase locking of modes like EbNaut.
As described more fully on its own page, WSPR mode implements a protocol designed for probing potential propagation paths with low-power transmissions. WSPR is fully implemented within WSJT-X, including programmable "band-hopping".
Latest General Availability (GA) release: WSJT-X 2.5.1
WSJT-X 2.5 provides features and capabilities new since version 2.3, including the Q65 mode and improved rig control. New features are described in the WSJT-X User Guide here and in the Release Notes. If you will use the new Q65 mode, please read the Quick-Start Guide to Q65.
On Windows platforms, WSJT-X 2.5 also includes MAP65 3.0.0, a wideband polarization-matching tool intended for EME. If you will use MAP65, be sure to read the Quick-Start Guide to WSJT-X 2.5.0 and MAP65 3.0.
Documentation: The WSJT-X 2.5 User Guide is available online. This document should always be your first source for help. Use your browser's search facility to find a keyword or topic.
Versions of WSJT-X labeled with a "-rcx" suffix, for example WSJT-X v2.2.0-rc6, are Release Candidates sometimes offered temporarily for beta testing purposes. You should upgrade to the GA release when it becomes available. The -rc# program versions are not suitable for long-term general use.
Installation packages for WSJT-X 2.5.1
Installation instructions for Linux can be found here in the User Guide. Download the package file appropriate for your system, from the list below. (Versions installable with "apt-get" and "yum" will be made available as soon as our package maintainers create the packages.)
Installation instructions for version 2.5.1 can be found here in the User Guide.
WSJT-X is licensed under the terms of Version 3 of the GNU General Public License (GPL). Development of this software is a cooperative project to which many amateur radio operators have contributed. If you use our code, please have the courtesy to let us know about it. If you find bugs or make improvements to the code, please report them to us in a timely fashion.
Build and installation instructions are in the INSTALL file inside the tarball.
©2001-2021 by Joe Taylor, K1JT