Program Development


WSJT-X implements communication protocols or "modes" called FT4, FT8, JT4, JT9, JT65, QRA64, ISCAT, MSK144, and WSPR, as well as one called Echo for detecting and measuring your own radio signals reflected from the Moon.  These modes were all designed for making reliable, confirmed QSOs under extreme weak-signal conditions. 

JT4, JT9, JT65, and QRA64 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.  JT65 and QRA64 were designed for EME ("moonbounce") on the VHF/UHF bands; JT65 has also proved popular and effective for worldwide QRP communication at HF.  JT9 is optimized for the LF, MF, and HF bands.  It  is about 2 dB more sensitive than JT65 while using less than 10% of the bandwidth.  With either JT9 or JT65, world-wide QSOs are possible with power levels of a few watts and compromise antennas.  JT4 and QRA64 are optimized for EME on the VHF and higher bands, and especially the microwave bands from 2.3 to 24 GHz. 

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.

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 2.1.2

WSJT-X 2.1.1 was a bug-fix release to address several regressions in version
WSJT-X 2.1.2 is an emergency bug-fix release to correct errors that crept into the latest hamlib and affected control of certain Icom radios in v2.1.1.   See the first two sections at the top of of Release Notes for a list of all program changes since WSJT-X 2.1.0.
Upgrading from a previous version will be straightforward.  There is no need to uninstall or move any files.  If you upgrade from version 2.0.1 or earlier, on first startup you should reset the default frequencies table to include suggested FT4 frequencies.  Go to File | Settings | Frequencies, right-click in the Working Frequencies list, and select Reset.

The WSJT-X 2.1 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.
German translations of two associated documents by Enrico Schürrer, OE1EQW:
If you plan to use FT8 DXpedition Mode, be sure to read the FT8 DXpedition Mode User Guide.

Versions of WSJT-X labeled with a "-rcx" suffix, for example WSJT-X v2.1.0-rc3, 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 2.1.2


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.)
Note: these packages are unlikely to install properly on Linux distributions with required dependencies at lower versions than those on the named distributions.  In such cases building from source is the correct way to install WSJT-X 2.0.

Macintosh macOS: 
Installation instructions for version 2.1.2 can be found here in the User Guide.  
Source Code:

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.
©2001-2020  by Joe Taylor, K1JT