WSJT-X User Guide

1. Introduction

WSJT-X is an open source 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 branch of an earlier program, WSJT, which was first released by Joe Taylor, K1JT, in 2001. Bill Somerville, G4WJS, Steve Franke, K9AN, and Nico Palermo, IV3NWV, have been major contributors to development of WSJT-X since 2013, 2015, and 2016, respectively. Bill Somerville died unexpectedly in December 2021; Uwe Risse, DG2YCB, joined the core development team soon afterward and worked with us until February 2026. Brian Moran, N9ADG, joined the team in 2022; John Nelson, G4KLA and Charlie Suckling, DL3WDG in 2024; Roger Rehr, W3SZ, in 2025; and Terrell Deppe, KJ5HST, and David Christle, KD0BTO, in 2026. Over the years many other hams have contributed to WSJT-X development in more limited ways. We are extremely grateful for all of these contributions.

WSJT-X provides flexible rig control for nearly all modern radios used by amateurs and a wide variety of special aids such as automatic Doppler tracking for Earth-Moon-Earth (EME) QSOs and lunar-Echo testing. The program analyzes received passbands up to 5 kHz wide and runs equally well on Windows, Macintosh, and Linux systems.

Version Numbers for our programs have major, minor, and patch numbers separated by periods: for example, WSJT-X 3.0.0. Temporary release candidates are sometimes made in advance of a new general-availability (GA) release, in order to obtain user feedback. Release candidates are given version labels such as 3.0.0-rc1, 3.0.0-rc2, etc., leading up to the general availability (GA) release of version 3.0.0. Release candidates should be used only during a defined testing period, and they carry an implicit obligation to provide feedback to the program developers. Release candidates should not be used on the air after a GA release with the same number.

MAP65 and QMAP are companion programs originally written by K1JT to facilitate Earth-Moon-Earth (EME, or "Moonbounce") communication with digital protocols developed for WSJT and WSJT-X. When used with radio-frequency hardware providing coherent signal channels for two orthogonal polarizations, MAP65 can yield automatic polarization-matched reception for every JT65 or Q65 signal in a 90 kHz sub-band. QMAP uses a single polarization channel and only the Q65 mode, also covering a 90 kHz sub-band. It works cooperatively with WSJT-X to provide automatic Doppler compensation and other features important for EME, especially on 1296 MHz and higher amateur bands. These programs are installed automatically along with WSJT-X (but MAP65 only on the Windows platform).

Hamlib is an independent, open-source software library that provides a consistent Application Programming Interface (API) for computer control of radios used by hams. Hamlib is essential to all features of WSJT-X that control your radio, and the latest stable version is included with all of our program releases. Like WSJT-X, Hamlib is under constant development by a group of volunteers. When necessary — perhaps when you acquire a very new radio — you can update your active Hamlib version from within WSJT-X.

1.1. New in Version 3.0

WSJT-X 3.0 incorporates all developments successfully tested in experimental versions and a number of new items. The list below summarizes important new features. For more details you should carefully read the sections in this guide linked in the following notes.

Band Buttons can be enabled and displayed from the View menu. Two sets of buttons are available: an HF-oriented set for 160 m through 70 cm bands, and a VHF-and-up set for 8 m through 24 GHz. See the Band Buttons section for more details.
FT8 Decoding includes an option for parallel processing with up to a dozen concurrent threads, yielding improved performance.
Filters can be used to suppress display of certain categories of decodes. For example, you can hide, ignore, or highlight stations worked before on the current band, or worked today or yesterday. Categories are defined on the File | Settings | Filters tab, and options to turn categories on or off are found on the Filters menu.
Wait and Reply, Wait and Call, and Wait and Pounce are options to help you make QSOs under difficult propagation conditions while minimizing useless transmissions. See Wait Features for details.
Audible Alerts can play an audio sound to alert you to reception of a message with specified content. Activating this feature requires access to at least two audio output devices. See Audible Alerts for details.
Auto-Sequencing, Filters, Reply-to-CQ, and Wait features are now available for all WSJT-X QSO modes: the 72-bit modes JT4, JT9, and JT65, as well as the 77-bit modes FST4, FT4, FT8, MSK144, and Q65.
Full Duplex Mode allows WSJT-X to transmit and receive at the same time. This feature can be useful for satellite operation, where the audio source is normally set to the transponder downlink, and for monitoring your own transmitted signal by using a webSDR as the audio input source.
Transceiver Control Interface (TCI), a software layer allowing control, data transfer, and synchronization between a wide variety of hardware devices and software applications, is supported by WSJT-X for both rig control and audio input/output.
SuperHound operators can activate Wait and Call for a SuperFox callsign, even if SuperFox has not yet been decoded. However, blind calling of SuperFox is prevented. Fox operators receive a warning message if another Fox appears to be on the same frequency, and WSJT-X will prevent inadvertent Fox transmissions from falling within a conventional WSPR sub-band.
Transmitted Power and SWR can be displayed (as reported by the radio) in a Status Bar label. Transmission can be stopped automatically if SWR exceeds 2.5 — for example, if you accidentally select the wrong antenna. These features work with most modern radios controlled via Hamlib or FLRig.
Right-click of Tune Button can be used to initiate ATU tuning in some rig models. This feature requires the radio to be equipped with an internal ATU and controlled via Hamlib.
Band Hopping checkboxes for FT8, FT4 and MSK144 can activate sequential reception intervals on the main sub-bands, or on up to eight specified dial frequencies. The latter can be useful for contests and other situations with frequencies of special interest.
Saved Audio Files can be scheduled for automatic deletion after 30 days. This feature can be used to keep disk usage for saved files within reasonable limits, while still preserving important information that might prove useful for later analysis.
CALL3.TXT files for either terrestrial or EME use can be downloaded by clicking a button on the File | Settings | Colors tab.
New EME Features include easier ways to select dial frequencies within an EME sub-band and to offset your Tx frequency by an integer number of MHz from the Rx frequency, to accommodate different regulatory frequency allocations. New buttons are provided for quick access to Echo mode and six popular Q65 sub-modes. For experimental purposes, the sub-modes 15A, 15B and 15C can be decoded with EME delay.
QSO Logging supports the ADIF field type for satellite QSOs, and the Log automatically option is available when not in contest mode. New checkboxes on the File | Settings | Reporting tab provide new support for certain contests.
OpenSSL runtime DLLs are now installed automatically with WSJT-X on Windows.
High Resolution Monitors are supported with better scaling of fonts and widget sizes.

1.2. Documentation Conventions

This guide includes many screen shots to illustrate user settings and program features. Keep in mind that WSJT-X is a multi-platform application; the detailed appearance of windows and user controls will be different in Windows, Linux, or macOS environments. The underlying functionality is the same on all operating systems, however. Where desirable we call special attention to important platform differences.

Most people access the WSJT-X User Guide primarily through a browser. Use the browser’s search function, generally invoked from the keyboard with the keys CTRL+F, to search the guide for help on a particular topic or keyword.

The names of WSJT-X windows, menus, and on-screen controls are displayed in this manual in boldface type, as in Wide Graph. File names and information entered via keyboard is shown in a monospace font, for example all.txt.

In this manual the following icons call attention to particular types of information:

Tips on program features or capabilities that might otherwise be overlooked.

Notes containing information that may be of interest to particular classes of users.

Warnings about usage that could lead to undesired consequences.

1.3. User Interface in Other Languages

The WSJT-X user interface (UI) is now available in many languages. When a translated UI is available for the computer’s default System Language, it will appear automatically on program startup. The UI language may be overridden if desired by starting WSJT-X with a command line option. For example, to start WSJT-X with its user interface in Spanish or Japanese, start a command-prompt window and enter one of these the commands:

wsjtx --language es

wsjtx --language ja

The top portion of the main window will then look like one of the following examples:

1.4. How You Can Contribute

WSJT-X is part of an open-source project released under the GNU General Public License (GPLv3). If you have programming or documentation skills or would like to contribute to the project in other ways, please make your interests known to the development team. The project’s public source-code repository can be found at GitHub, and you can open Issues and submit explicit pull requests there. We encourage those with translation skills to volunteer their help by translating this User Guide or the program’s user interface.

Bug reports and suggestions for new features or improvements to the User Guide may be submitted at the GitHub site or sent to one of the email lists listed in the Support section. You must join the group in order to post messages there.

1.5. License

Before using WSJT-X, please read our licensing terms here.

2. Modes

WSJT-X offers eleven different protocols or modes: FST4, FT4, FT8, JT4, JT9, JT65, Q65, MSK144, WSPR, FST4W, and Echo. The first eight are designed for making reliable QSOs under weak-signal conditions. They use nearly identical message structure and source encoding. JT65 was designed for EME (“moonbounce”) on VHF and higher bands and is mostly used for that purpose today. Q65 is particularly effective for tropospheric scatter, rain scatter, ionospheric scatter, TEP, and EME on VHF and higher bands, as well as other types of fast-fading signals. JT9 was designed for the HF and lower bands. Its submode JT9A is 1 dB more sensitive than JT65 while using less than 10% of the bandwidth. JT4 offers a wide variety of tone spacings and has proven highly effective for EME on microwave bands up to 24 GHz. The “slow” modes use timed sequences of alternating transmission and reception. JT4, JT9, and JT65 use one-minute sequences, so a minimal QSO takes four to six minutes — two or three transmissions by each station, one sending in odd UTC minutes and the other even. FT8 is four times faster (15-second T/R sequences) and less sensitive by a few dB. FT4 is faster still (7.5 s T/R sequences) and especially well-suited for radio contesting. FST4 is designed especially for the LF and MF bands. Both FST4 and Q65 offer a wide variety of timed sequence lengths, and Q65 a range of tone spacings for different propagation conditions. On the HF bands, world-wide QSOs are possible with any of these modes using power levels of a few watts (or even milliwatts) and compromise antennas. On VHF bands and higher, QSOs are possible (by EME, scatter, and other propagation types) at signal levels 10 to 15 dB below those required for CW.

MSK144, and optionally submodes JT9E-H are “fast” protocols designed to take advantage of brief signal enhancements from ionized meteor trails, aircraft scatter, and other types of scatter propagation. These modes use timed sequences of 5, 10, 15, or 30 s duration. User messages are transmitted repeatedly at high rate (up to 250 characters per second for MSK144) to make good use of the shortest meteor-trail reflections or “pings”. MSK144 uses the same structured messages as the slow modes and optionally an abbreviated format with hashed callsigns.

Note that some of the modes classified as slow can have T/R sequence lengths as short the fast modes. “Slow” in this sense implies message frames being sent only once per transmission. The fast modes in WSJT-X send their message frames repeatedly, as many times as will fit into the Tx sequence length.

WSPR (pronounced “whisper”) stands for Weak Signal Propagation Reporter. The WSPR protocol was designed for probing potential propagation paths using low-power transmissions. WSPR messages normally carry the transmitting station’s callsign, grid locator, and transmitter power in dBm, and with two-minute sequences they can be decoded at signal-to-noise ratios as low as -31 dB in a 2500 Hz bandwidth. FST4W is designed for similar purposes, but especially for use on LF and MF bands. It includes optional sequence lengths as long as 30 minutes and reaches sensitivity thresholds as low as -45 dB. Users with internet access can automatically upload WSPR and FST4W reception reports to a central database called WSPRnet that provides a mapping facility, archival storage, and many other features.

Echo mode allows you to detect and measure your own station’s echoes from the moon and to make other measurements useful for optimizing your EME station’s performance.

3. System Requirements

SSB transceiver and antenna
Computer running Windows 7 or later, macOS 10.15 or later, or Linux
1.5 GHz or faster CPU and 200 MB of available memory; faster machines are better
Monitor with at least 1024 x 780 resolution
Computer-to-radio interface using a serial port or equivalent USB device for T/R switching, or CAT control, or VOX, as required for your radio-to-computer connections
Audio input and output devices supported by the operating system and configured for sample rate 48000 Hz, 16 bits
Audio or equivalent USB connections between transceiver and computer
A means for synchronizing the computer clock to UTC within ±1 second

4. Installation

Installation packages for Windows, Linux, and macOS are found on the WSJT Downloads Page.

4.1. Windows

For 64-bit Windows 10 and later: Download and execute the package file wsjtx-3.0.2-devel-win64.exe. Install WSJT-X into its own directory, for example C:\WSJTX or C:\WSJT\WSJTX, rather than the conventional location
C:\Program Files …\WSJTX. All program files relating to WSJT-X will be stored in the chosen installation directory and its subdirectories. Logs and other writeable files are normally found in the directory
C:\Users\<username>\AppData\Local\WSJT-X.

Your computer may be configured so that this directory is “invisible”. It’s there, however, and accessible. An alternative (shortcut) directory name is "%LocalAppData%\WSJT-X\".

The built-in Windows facility for time synchronization may not be adequate. We recommend the program Meinberg NTP Client: see Network Time Protocol Setup for downloading and installation instructions. Recent versions of Windows are now shipped with a more capable Internet time synchronization service that is suitable if configured appropriately. We do not recommend SNTP time setting tools or others that make periodic correction steps; WSJT-X requires that the PC clock be monotonically increasing and smoothly continuous.

Having a PC clock that appears to be synchronized to UTC is not sufficient. “Monotonically increasing” means that the clock must not be stepped backwards. “Smoothly continuous” means that time must increase at a nearly constant rate, without steps. Any necessary clock corrections must be applied by adjusting the rate of increase, thereby correcting synchronization errors gradually.

WSJT-X uses the OpenSSL libraries for TLS network connections. Current WSJT-X Windows installers include the required OpenSSL runtime DLLs. If they are missing or cannot be loaded, you may see the following error message when using features such as SuperFox verification, Update Hamlib, LoTW downloads, or eQSL uploads.

If you installed WSJT-X from the official Windows installer, first try updating to the latest installer package. Reinstalling the same package may help if files in the local installation were removed or damaged. The OpenSSL DLLs must match the Qt libraries used to build the program and are normally installed with WSJT-X, so installing unrelated system-wide OpenSSL DLLs is not the recommended fix.

If you cannot update or reinstall WSJT-X, or do not have an Internet connection on the computer used to run WSJT-X 3.0, you can download the LoTW file manually. Go to https://lotw.arrl.org/lotw-user-activity.csv in a web browser, download the file, then move it to the WSJT-X log files directory. This directory can be opened by selecting File|Open log directory from the main menu.

WSJT-X expects your sound card to do its raw sampling at 48000 Hz. To ensure that this will be so when running under recent versions of Windows, open the system’s Sound control panel and select in turn the Recording and Playback tabs. Click Properties, then Advanced, and select 16 bit, 48000 Hz (DVD Quality). Switch off all audio enhancement features for these devices.
You can uninstall WSJT-X by clicking its Uninstall link in the Windows Start menu, or by using Uninstall a Program on the Windows Control Panel | Programs and Features option or in File | Settings | Apps.

4.2. Linux

You can use WSJT-X on any 64-bit Linux system by downloading and executing the appropriate "AppImage" file from the WSJT Downloads Page. These packages contain all required dependencies for use of WSJT-X, but they do not provide access to MAP65, QMAP, or any of the related utility programs.

Complete installation packages are provided on the WSJT Downloads Page for 64-bit Debian-based and RedHat-based Linux systems. Be sure to fetch the package built for your machine’s architecture: it will have x86_64 in the file name for Intel/AMD machines, aarch64 for ARM.

To install on Debian-based Linux, for example Ubuntu 22.x or later, execute the following command in a terminal:

sudo dpkg -i <package-name>
To uninstall:

sudo dpkg -P wsjtx

You may also need to execute the following command in a terminal:

sudo apt install libgfortran5 libqt5widgets5 libqt5network5 \
     libqt5printsupport5 libqt5multimedia5-plugins libqt5serialport5 \
     libqt5sql5-sqlite libfftw3-single3 libgomp1 libboost-all-dev \
     libusb-1.0-0 libportaudio2

To install on Fedora, CentOS, Red Hat, and other rpm-based systems:

sudo rpm -i <package-name>
To uninstall:

sudo rpm -e wsjtx

You may also need to execute the following command in a terminal:

sudo dnf install libgfortran fftw-libs-single qt5-qtbase \
     qt5-qtmultimedia qt5-qtserialport qt5-qtsvg \
     qt5-qtserialport libgomp boost libusbx portaudio

4.3. MacOS

For macOS installers are provided for x86_64 (Intel) systems and for ARM64 (Apple silicon) systems. Download the correct package for your system from the WSJT Downloads Page, double-click on the file name, and follow the on-screen prompts in the Installer app.

If you have already installed a previous version, you can retain it by changing its name in the Applications folder (such as from WSJT-X to WSJT-X_2.7.0). You can then proceed to the installation phase.

Take note also of the following:

Use the Mac’s Audio MIDI Setup utility to configure your sound card for 48000 Hz, two-channel, 16-bit format.

If you are using macOS with an external audio device and find that Tx audio spontaneously switches to the motherboard sound device after a few transmissions, try setting the sample rate to 44100 Hz rather than the otherwise recommended 48000 Hz.

Use System Preferences to select an external time source to keep your system clock synchronized to UTC.
To uninstall simply drag the WSJT-X application from Applications to the Trash Can.

5. Menus

Menus at top of the main window offer many options for configuration and operation. Some are self-explanatory; additional details for others are provided below. Keyboard shortcuts for some frequently used menu items are listed at the right edge of the menu.

5.1. WSJT-X menu

This menu appears on the Macintosh only. Settings appears here, labeled as Preferences, rather than on the File menu. About WSJT-X appears here rather than on the Help menu.

5.2. File menu

5.3. Configuration Menu

Some users prefer to create and use entries on the Configurations menu for switching between modes. Simply Clone the Default entry, Rename it as desired, and then make all desired settings for that configuration. All settings will be restored whenever you select that configuration.

As well as switching between configurations while running WSJT-X, you can also start the application from the command line in any desired configuration. Use the command-line option --config <configuration-name>, or -c for short, as in these examples for configurations named FT8 and Echo:

wsjtx --config FT8
wsjtx -c Echo

5.4. View Menu

Most items on the View menu can be clicked to display a specified window. Some are self-explanatory or described in detail elsewhere in this guide; additional details for others are included below.

Active Stations

Active Stations is a window with two distinct purposes. The first can help you work the most distant stations, in particular for the distance-scored ARRL International Digital Contest. You can set the maximum length of the list and the maximum “Age” of displayed decodes, measured in Rx sequences. You can request display of only ready-to-be-called stations: those whose most recent transmission is a CQ, RR73, or 73 message. For the ARRL International Digital Contest the window displays scoring Rate (points in the most recent hour), your total accumulated Score, and the number of Band Changes in the past hour.

When WSJT-X is used together with sister program QMAP, the Active Stations window displays the frequencies, SNRs, Q65 sub-modes, and Maidenhead locators for stations recently decoded by QMAP over its full 90 kHz bandwidth. Stations using a 30-second sub-mode of Q65 are highlighted in yellow. You can limit the displayed list by checking the Wanted only and/or CQ only boxes. The total number of QSOs found in wsjtx.log is shown, for example to follow your progress in an EME contest.

SWL Mode

SWL Mode reduces the main window to show just the menus, decodes windows, and status bar. You may find this useful when running multiple instances of the application. The size and location of the main window are saved and recalled independently for this view.

Message Creator, QSY Monitor, and Enable Message Popups

A special messaging system can be used to invite your QSO partner to move to another band or mode (for example, during a contest), or to convey some short canned messages. There are two main parts, the Message Creator and the QSY Monitor. Received messages are displayed in popup windows.

Use the Message Creator to create and send these special messages with just a few clicks. When using this feature for the first time, make sure that your IARU Region has been set (upper right on the File | Settings | General tab). Activate the Message Creator window by checking its name on the View menu. Four tabs are available: HF, VHF, EME and General: