1. Introduction

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 branch of an earlier program, WSJT, first released 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.

WSJT-X Version 2.5 offers eleven different protocols or modes: FST4, FT4, FT8, JT4, JT9, JT65, Q65, MSK144, WSPR, FST4W, and Echo. The first seven 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 tresholds 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, even if they are far below the audible threshold.

WSJT-X provides spectral displays for receiver passbands as wide as 5 kHz, flexible rig control for nearly all modern radios used by amateurs, and a wide variety of special aids such as automatic Doppler tracking for EME QSOs and Echo testing. The program runs equally well on Windows, Macintosh, and Linux systems, and installation packages are available for all three platforms.

Version Numbers: WSJT-X release numbers have major, minor, and patch numbers separated by periods: for example, WSJT-X Version 2.1.0. Temporary beta release candidates are sometimes made in advance of a new general-availability release, in order to obtain user feedback. For example, version 2.1.0-rc1, 2.1.0-rc2, etc., would be beta releases leading up to the final release of v2.1.0. Release candidates should be used only during a short testing period. They carry an implied obligation to provide feedback to the program development group. Candidate releases should not be used on the air after a full release with the same number is made.

1.1. New in Version 2.5.0-rc1

WSJT-X 2.5.0 introduces an enhanced Q65 decoder that measures and compensates for linear frequency drifts of Q65 signals. Activate this feature by setting a spinner control Max Drift on the WSJT-X main window to a number greater than 0. We suggest a setting of 10 for submode Q65-60A, the recommended submode for EME on 50 and 144 MHz, which will accommodate drift rates up to 20 Hz/minute. Similarly, we suggest Max Drift = 40 for submode Q65-15C, used for for 10 GHz QSOs (up to 900 km) via aircraft scatter and drift rates up to about 20 Hz/s.

On the Windows platform only, WSJT-X 2.5.0 installations now include an early version of MAP65 3.0. This program works together with suitable hardware that converts RF to baseband. The hardware/software combination implements a wideband, highly optimized receiver for the Q65 and JT65 protocols, with matching transmitting features that require a standard SSB transceiver. MAP65 is effective in both single-polarization and dual-polarization systems. If two polarization channels are available, MAP65 determines and matches the linear polarization angle of each decodable signal. This capability provides a major advantage for efficient EME communication on bands up to 432 MHz. A single-channel MAP65 system works extremely well for EME on 1296 MHz and higher bands, displaying all signals in a 90 kHz sub-band and decoding all the Q65 and JT65 signals.

1.2. Documentation Conventions

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

Notes containing information that may be of interest to particular classes of users.
Tips on program features or capabilities that might otherwise be overlooked.
Warnings about usage that could lead to undesired consequences.

1.3. User Interface in Other Languages

The WSJT-X user interface is now available in many languages. When a translated user interface is available for the computer’s default System Language, it will appear automatically on program startup.

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. We especially encourage those with translation skills to volunteer their help, either for this User Guide or for the program’s user interface.

The project’s source-code repository can be found at SourceForge, and communication among the developers takes place on the email reflector wsjt-devel@lists.sourceforge.net. Bug reports and suggestions for new features, improvements to the WSJT-X User Guide, etc., may be sent there as well. You must join the group before posting to the email list.

1.5. License

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

2. System Requirements

  • SSB transceiver and antenna

  • Computer running Windows 7 or later, macOS 10.13 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

3. Installation

Installation packages for released versions on Windows, Linux, and OS X are found on the WSJT Home Page. Click on the WSJT-X link at the left margin and select the appropriate package for your operating system.

3.1. Windows

Download and execute the package file wsjtx-2.5.0-rc1-win32.exe (Win 7, Win 8, Win10, 32-bit) or wsjtx-2.5.0-rc1-win64.exe (Win 7, Win 8, Win10, 64-bit) following these instructions:

  • 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 are stored in the chosen installation directory and its subdirectories.

  • Logs and other writeable files are normally found in the directory


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 is usually not adequate. We recommend the program Meinberg NTP Client: see Network Time Protocol Setup for downloading and installation instructions. Recent versions of Windows 10 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.

<em>WSJT-X</em> LoTW download TLS error

  • WSJT-X requires installation of the OpenSSL libraries. Suitable libraries may already be installed on your system. If they are not, you will see this error shortly after requesting a fetch of the latest LoTW users database. To fix this, install the OpenSSL libraries.

    • You can download a suitable OpenSSL package for Windows from Windows OpenSSL Packages; you need the latest Windows Light version. For the 32-bit WSJT-X build, use the latest Win32 v1.1.1 version of the OpenSSL libraries, for the 64-bit WSJT-X use the latest Win64 v1.1.1 version of the OpenSSL libraries (Note: it is OK to install both versions on a 64-bit system) which, at the time of writing, were Win32 OpenSSL Light Package and Win64 OpenSSL Light Package respectively.

    • Install the package and accept the default options, including the option to copy the OpenSSL DLLs to the Windows system directory. There is no obligation to donate to the OpenSSL project. Un-check all the donation options if desired.

If you still get the same network error after installing the OpenSSL libraries then you also need to install the Microsoft VC++ 2013 Redistributable component. From the download page select vcredist_x86.exe for use with the 32-bit WSJT-X build or vcredist_x64.exe with the 64-bit build, then run it to install.
If you cannot install the OpenSSL libraries or do not have an Internet connection on the computer used to run WSJT-X 2.5, 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 Settings|Apps on Windows 10.

3.2. Linux

Debian, Ubuntu, and other Debian-based systems including Raspberry Pi OS:

The project team release binary installer packages targeted for one contemporary version of a Linux distribution. Although these may work on newer Linux versions or even different distributions, it is unlikely that they work on older versions. Check the notes provided with the release for details of the targeted Linux distributions and versions. If the binary package is not compatible with your Linux distribution or version, you must build the application from sources.

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 \

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

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

3.3. OS X and macOS

macOS10.13 and later: Download the file wsjtx-2.5.0-rc1-Darwin.dmg to your desktop, double-click it and consult its ReadMe file for important installation notes.

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_2.2). 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.

4. Settings

Select Settings from the File menu or by typing F2. (On Macintosh select Preferences from the WSJT-X menu, or use the keyboard shortcut Cmd+,). The following sections describe setup options available on eight tabs selectable near the top of the window.

4.1. General

Select the General tab on the Settings window. Under Station Details enter your callsign, grid locator (preferably the 6-character locator) and IARU Region number. Region 1 is Europe, Africa, the Middle East, and Northern Asia; Region 2 the Americas; and Region 3 Southern Asia and the Pacific. This information will be sufficient for initial tests.

Settings Window

Meanings of remaining options on the General tab should be self-explanatory after you have made some QSOs using WSJT-X. You may return to set these options to your preferences later.

If you are using a callsign with an add-on prefix or suffix, or wish to work a station using such a call, be sure to read the section Nonstandard Callsigns.
Checking Enable VHF/UHF/Microwave features necessarily disables the wideband multi-decode capability of JT65. In most circumstances you should turn this feature off when operating at HF.

4.2. Radio

WSJT-X offers CAT (Computer Aided Transceiver) control of relevant features of most modern transceivers. To configure the program for your radio, select the Radio tab.

Radio Tab
  • Select your radio type from the drop-down list labeled Rig, or None if you do not wish to use CAT control.

    • Alternatively, if you have configured your station for control by DX Lab Suite Commander, Flrig, Ham Radio Deluxe, Hamlib NET rigctl, or Omni-Rig, you may select one of those program names from the Rig list. In these cases the entry field immediately under CAT Control will be relabeled as Network Server. Leave this field blank to access the default instance of your control program, running on the same computer. If the control program runs on a different computer and/or port, specify it here. Hover the mouse pointer over the entry field to see the required formatting details.

    • Select Omni-Rig Rig 1 or Omni-Rig Rig 2 to connect to an Omni-Rig server installed on the same computer. Omni-Rig will be started automatically by WSJT-X.

  • Set Poll Interval to the desired interval for WSJT-X to query your radio. For most radios a small number (say, 1 – 3 s) is suitable.

  • CAT Control: To have WSJT-X control the radio directly rather than though another program, make the following settings:

    • Select the Serial Port or Network Server including the service port number used to communicate with your radio.

      A special value of USB is available for custom USB devices like those used by some SDR kits. This is not the same a virtual serial port provided by USB connected transceivers and CAT interfaces, for those use the COM or serial port name that refers to them.
    • Serial Port Parameters: Set values for Baud Rate, Data Bits, Stop Bits, and Handshake method. Consult your radio’s user *guide for the proper parameter values.

    CAT interfaces that require handshaking will be non-responsive until the correct Handshake setting is applied.
    • Force Control Lines: A few station setups require the CAT serial port’s RTS and/or DTR control lines to be forced high or low. Check these boxes only if you are sure they are needed (for example, to power the radio serial interface).

  • PTT Method: select VOX, CAT, DTR, or RTS as the desired method for T/R switching. If your choice is DTR or RTS, select the desired serial port (which may be the same one as used for CAT control).

    When using a proxy application for rig control, CAT is usually the correct option for PTT Method assuming the proxy application is capable of keying your transceiver independently.
  • Transmit Audio Source: some radios permit you to choose the connector that will accept Tx audio. If this choice is enabled, select Rear/Data or Front/Mic.

  • Mode: WSJT-X uses upper sideband mode for both transmitting and receiving. Select USB, or choose Data/Pkt if your radio offers such an option and uses it to enable the rear-panel audio line input. Some radios also offer wider and/or flatter passbands when set to Data/Pkt mode. Select None if you do not want WSJT-X to change the radio’s Mode setting.

  • Split Operation: Significant advantages result from using Split mode (separate VFOs for Rx and Tx) if your radio supports it. If it does not, WSJT-X can emulate such behavior. Either method will result in a cleaner transmitted signal, by keeping the Tx audio always in the range 1500 to 2000 Hz so that audio harmonics cannot pass through the Tx sideband filter. Select Rig to use the radio’s Split mode, or Fake It to have WSJT-X adjust the VFO frequency as needed, when T/R switching occurs. Choose None if you do not wish to use split operation.

When all required settings have been made, click Test CAT to test communication between WSJT-X and your radio. The button should turn green to indicate that proper communication has been established. Failure of the CAT-control test turns the button red and displays an error message. After a successful CAT test, toggle the Test PTT button to confirm that your selected method of T/R control is working properly, the button turns red if the rig has been successfully keyed. (If you selected VOX for PTT Method, you can test T/R switching later by using the Tune button on the main window.)

4.3. Audio

Select the Audio tab to configure your sound system.

_WSJT-X_ Audio Configuration Screen
  • Soundcard: Select the audio devices to be used for Input and Output. Usually the Mono settings will suffice, but in special cases you can choose Left, Right, or Both stereo channels.

    • Be sure that your audio device is configured to sample at 48000 Hz, 16 bits.

      If you select the audio output device that is also your computer’s default audio device, be sure to turn off all system sounds to prevent inadvertently transmitting them over the air.
      Windows 7 and later may configure audio devices using the Texas Instruments PCM2900 series CODEC for microphone input rather line input. (This chip is used in many radios with built-in USB CODECs, as well as various other audio interfaces.) If you are using such a device, be sure to set the mic level in the Recording Device Properties to 0 dB.
  • Save Directory: WSJT-X can save its received audio sequences as .wav files. A default directory for these files is provided; you can select another location if desired.

  • AzEl Directory: A file named azel.dat will appear in the specified directory. The file contains information usable by another program for automatic tracking of the Sun or Moon, as well as calculated Doppler shift for the specified EME path. The file is updated once per second whenever the Astronomical Data window is displayed.

  • Remember power settings by band: Checking either of these will cause WSJT-X to remember the Pwr slider setting for that operation on a band-by-band basis. For example, when Tune is checked here and you click the Tune button on the main window, the power slider will change to the most recent setting used for Tune on the band in use.

4.4. Tx Macros

Tx Macros are an aid for sending brief, frequently used free-text messages such as the examples shown below.

Tx Macros Screen
  • To add a new message to the list, enter the desired text (up to 13 characters) in the entry field at top, then click Add.

  • To remove an unwanted message, click on the message and then on Delete.

  • You can reorder your macro messages by using drag-and-drop. The new order will be preserved when WSJT-X is restarted.

  • Messages can also be added from the main window’s Tx5 field. Simply hit [Enter] after the message has been entered.

4.5. Reporting

Reporting Screen
  • Logging: Choose any desired options from this group. Operators in a multi-operator station may wish to enter their home callsign as Op Call.

  • Network Services: Check Enable PSK Reporter Spotting to send reception reports to the PSK Reporter mapping facility.

  • UDP Server: This group of options controls the network name or address and port number used to exchange information with a third party application that interoperates with WSJT-X. Exchanged information includes decoded messages, general program status, QSOs logged, highlighting of callsigns in the WSJT-X band activity window, and limited facilities to initiate QSOs in response to CQ or QRZ messages. Full details of the protocol can be found in comments at the top of this file in our source code repository: https://sourceforge.net/p/wsjt/wsjtx/ci/master/tree/Network/NetworkMessage.hpp

The Outgoing interfaces and Multicast TTL fields are only present when a multicast group IP address has been entered in the UDP Server field.

Programs like JTAlert use the UDP Server feature to obtain information about running WSJT-X instances. If you are using JTAlert to control WSJT-X, be sure to check the Accept UDP requests box.

4.6. Frequencies

By default, the Working Frequencies table contains a list of frequencies conventionally used for modes FT8, JT4, JT9, JT65, MSK144, WSPR, and Echo. Conventions may change with time or by user preference; you can modify the frequency table as desired.

Frequency Screen
  • To change an existing entry, double-click to edit it, type a desired frequency in MHz or select from the drop down list of options, then hit Enter on the keyboard. The program will format your changed entry appropriately.

  • To add a new entry, right-click anywhere on the frequency table and select Insert. Enter a frequency in MHz in the pop-up box and select the desired mode (or leave the Mode selection as All). Then click OK. The table may include more than one frequency for a given band.

  • To delete an entry, right-click it and select Delete, multiple entries can be deleted in a single operation by selecting them before right-clicking.

  • Right-click anywhere within the table body and click Reset button to return the table to its default configuration.

Other more advanced maintenance operations are available on the right-click context popup menu that should be self-explanatory.

Frequency Calibration: If you have calibrated your radio using WWV or other reliable frequency references, or perhaps with the technique described in Accurate Frequency Measurements with your WSPR Setup, enter the measured values for Intercept A and Slope B in the equation

Dial error = A + B*f

where “Dial error” and A are in Hz, f is frequency in MHz, and B is in parts per million (ppm). Frequency values sent to the radio and received from it will then be adjusted so that frequencies displayed by WSJT-X are accurate.

Station Information: You can save Band, Offset and Antenna Description information for your station. The antenna information will be included in reception reports sent to PSK Reporter. By default the frequency offset for each band is zero. Nonzero offsets may be added if (for example) a transverter is in use.

  • To simplify things you might want to delete any unwanted bands — for example, bands where you have no equipment. Then click on a Frequency entry and type Ctrl+A to “select all,” and drag-and-drop the entries onto the Station Information table. You can then add any transverter offsets and antenna details.

  • To avoid typing the same information many times, you can drag-and-drop entries between the lines of the Station Information table.

  • When all settings have been configured to your liking, click OK to dismiss the Settings window.

4.7. Colors

Colors Screen
Decode Highlighting
  • WSJT-X uses colors to highlight decoded CQ messages of particular interest. Check the box Show DXCC, grid, and worked-before status on the Settings | General tab, and any boxes of interest to you on the Colors tab. You can drag any line up or down to raise or lower its logical priority. Right-click any line to set a new foreground or background color. Foreground and background colors are applied separately, and careful choices of foreground, background, and priority can provide two indications of worked-before status.

  • Press the Reset Highlighting button to reset all of the color settings to default values.

  • Check Highlight by Mode if you wish worked before status to be per mode.

  • Check Only grid Fields sought if you are only interested in the leading two character grid locator Fields rather than teh four character grid locator Squares.

  • Check Include extra WAE entities if you are interested in the extra entities defined for DARC WAE and CQ Marathon awards.

  • Worked before status is calculated from your WSJT-X ADIF Logging file, you may replace ADIF log file with one exported from your station logging application, Rescan ADIF Log rebuilds the WSJT-X worked before indexes using the current ADIF log file.

    The WSJT-X ADIF file records must contain the "CALL" field. The "BAND", and "MODE", and "GRIDSQUARE" fields are optional depending on your DXing objectives. DXCC entity, continent, CQ, and ITU Zone data for call prefixes and certain well known overrides are derived from the cty.dat database which is bundled with WSJT-X (See Logging for details).
Logbook of The World User Validation

Stations who are known to have uploaded their logs to the ARRL LoTW QSL matching service can be highlighted. The data used to determine this is available online.

  • Fetch Now will download a fresh dataset from the Users CSV file URL. The LoTW team normally update this data weekly.

  • Adjust Age of last upload less than to set the period within which a station must have uploaded their log to LoTW to trigger highlighting.

4.8. Advanced

Settings Advanced

JT65 VHF/UHF/Microwave decoding parameters

  • Random erasure patterns logarithmically scales the number of pseudo-random trials used by the Franke-Taylor JT65 decoder. Larger numbers give slightly better sensitivity but take longer. For most purposes a good setting is 6 or 7.

  • Aggressive decoding level sets the threshold for acceptable decodes using Deep Search. Higher numbers will display results with lower confidence levels.

  • Check Two-pass decoding to enable a second decoding pass after signals producing first-pass decodes have been subtracted from the received data stream.


  • Set a positive number in Degrade S/N of .wav file to add known amounts of pseudo-random noise to data read from a .wav file. To ensure that the resulting S/N degradation is close to the requested number of dB, set Receiver bandwidth to your best estimate of the receiver’s effective noise bandwidth.

  • Set Tx delay to a number larger than the default 0.2 s to create a larger delay between execution of a command to enable PTT and onset of Tx audio.

    For the health of your T/R relays and external preamplifier, we strongly recommend using a hardware sequencer and testing to make sure that sequencing is correct.
  • Check x 2 Tone spacing or x 4 Tone spacing to generate Tx audio with twice or four times the normal tone spacing. This feature is intended for use with specialized LF/MF transmitters that divide generated frequencies by 2 or 4 as part of the transmission process.

Special Operating Activity: Generation of FT4, FT8, and MSK144 messages

  • Check this box and select the type of activity to enable auto-generation of special message formats for contesting and DXpeditions. For ARRL Field Day, enter your operating Class and ARRL/RAC section; for ARRL RTTY Roundup, enter your state or province. Use “DX” for section or state if you are not in the US or Canada. In the RTTY Roundup, Stations in Alaska and Hawaii should enter “DX”.

  • Check Fox if you are a DXpedition station operating in FT8 DXpedition Mode. Check Hound if you wish to make QSOs with such a Fox. Be sure to read the operating instructions for FT8 DXpedition Mode.

4.9. Dark Style

An optional Dark style is available. To make it effective you will probably want to redefine your color settings. In Windows or Linux, start the program from a command-prompt window using the following command, or modify the WSJT-X desktop shortcut accordingly:

wsjtx --stylesheet :/qdarkstyle/style.qss

In macOS, enter the following command from a terminal:

open /Applications/wsjtx.app --args -stylesheet :/qdarkstyle/style.qss

In Linux using the Unity or GNOME GUI the following commands will update the WSJT-X start up:

sed '/Exec=wsjtx/ s/$/ -stylesheet :\/qdarkstyle\/style.qss/' \
  /usr/share/applications/wsjtx.desktop >~/.local/share/applications/wsjtx.desktop
update-desktop-database ~/.local/share/applications/

Depending on your operating system, the main WSJT-X window will look something like this:

Windows Dark

5. Transceiver Setup

Receiver Noise Level
  • If it is not already highlighted in green, click the Monitor button to start normal receive operation.

  • Be sure your transceiver is set to USB (or USB Data) mode.

  • Use the receiver gain controls and/or the computer’s audio mixer controls to set the background noise level (scale at lower left of main window) to around 30 dB when no signals are present. It is usually best to turn AGC off or reduce the RF gain control to minimize AGC action.

    The PC audio mixer normally has two sliders, one for each application attached which should be set to maximum (0dB FS) as it cannot help with distortion from overly high or low input levels from your receiver and another Master level which is analogue attenuator on the sound card before the Analogue to Digital Converter (ADC). The Master level can be used to adjust the signal level received by WSJT-X.
Bandwidth and Frequency Setting
  • If your transceiver offers more than one bandwidth setting in USB mode, it may be advantageous to choose the widest one possible, up to about 5 kHz.

  • If you have only a standard SSB filter you won’t be able to display more than about 2.7 kHz bandwidth. Depending on the exact dial frequency setting, on HF bands you can display the full sub-band generally used for one mode.

Transmitter Audio Level
  • Click the Tune button on the main screen to switch the radio into transmit mode and generate a steady audio tone.

  • Listen to the generated audio tone using your radio’s Monitor facility. The transmitted tone should be perfectly smooth, with no clicks or glitches. Make sure that this is true even when you simultaneously use the computer to do other tasks such as email, web browsing, etc..

  • Adjust the Pwr slider (at right edge of main window) downward from its maximum until the RF output from your transmitter falls slightly. This is generally a good level for audio drive.

  • Toggle the Tune button once more or click Halt Tx to stop your test transmission.

6. Basic Operating Tutorial

This section introduces the basic user controls and program behavior of WSJT-X, with particular emphasis on the JT9, JT65, and FT8 modes. We suggest that new users should go through the full HF-oriented tutorial, preferably while at your radio. Note that as of late 2018, digital usage on the HF bands has mostly moved from JT65 and JT9 to FT8. So you may wish to pay particular attention to FT8, in Section 6.6.

Subsequent sections cover additional details on Making QSOs, WSPR mode and VHF+ Features.

6.1. Main Window Settings

  • Click the Stop button on the main window to halt any data acquisition.

  • Select JT9 from the Mode menu and Deep from the Decode menu.

  • Set the audio frequencies to Tx 1224 Hz and Rx 1224 Hz.

    Sliders and spinner controls respond to Arrow key presses and Page Up/Down key presses, with the Page keys moving the controls in larger steps. You can also type numbers directly into the spinner controls or use the mouse wheel.

6.2. Download Samples

  • Select Download samples…​ from the Help menu.

  • Download some or all of the available sample files using checkboxes on the screen shown below. For this tutorial you will need at least the JT9 and JT9+JT65 files.

Downlod Samples

6.3. Wide Graph Settings

  • Bins/Pixel = 4

  • Start = 200 Hz

  • N Avg = 5

  • Palette = Digipan

  • Flatten = checked

  • Select Cumulative for data display

  • Gain and Zero sliders for waterfall and spectrum set near midscale

  • Spec = 25%

  • Use the mouse to grab the left or right edge of the Wide Graph, and adjust its width so that the upper frequency limit is about 2400 Hz.

6.4. JT9

For this step and the next, you may want to pretend you are K1JT by entering that callsign temporarily as My Call on the Settings | General tab. Your results should then be identical to those shown in the screen shot below.

Open a Wave File:
  • Select File | Open and select the file ...\save\samples\JT9\130418_1742.wav. When the file opens you should see something similar to the following screen shot:

Main UI and Wide Graph
Decoding Overview

Decoding takes place at the end of a receive sequence and proceeds in two steps. The first decode is done at the selected Rx frequency, indicated by the U-shaped green marker on the waterfall frequency scale. Results appear in both the left (Band Activity) and right (Rx Frequency) text windows on the main screen. The program then finds and decodes all signals in the selected mode over the displayed frequency range. The red marker on the waterfall scale indicates your Tx frequency.

Seven JT9 signals are present in the example file, all decodable. When this file was recorded KF4RWA was finishing a QSO with K1JT. Since the green marker was placed at his audio frequency, 1224 Hz, his message K1JT KF4RWA 73 is decoded first and appears in the Rx Frequency window. The Band Activity window shows this message plus all decodes at other frequencies. By default, lines containing CQ are highlighted in green, and lines with My Call (in this case K1JT) in red.

Decoding Controls

To gain some feeling for controls frequently used when making QSOs, try clicking with the mouse on the decoded text lines and on the waterfall spectral display. You should be able to confirm the following behavior:

  • Click or double-click on either of the decoded lines highlighted in green. These actions produce the following results:

    • Callsign and locator of a station calling CQ are copied to the DX Call and DX Grid entry fields.

    • Messages are generated for a standard minimal QSO.

    • The Tx even box is checked or cleared appropriately, so that you will transmit in the proper (odd or even) minutes.

    • The Rx frequency marker is moved to the frequency of the CQing station.

    • The Gen Msg (“generated message”) radio button at bottom right of the main window is selected.

    • Double-click does all of the above and also activates Enable Tx so that a transmission will start automatically at the proper time.

    • You can modify the double-click behavior by holding down the Shift key to move only the Tx frequency or the Ctrl key to move both Rx and Tx frequencies.

    You can prevent your Tx frequency from being changed by checking the box Hold Tx Freq.
  • Double-click on the decoded message K1JT N5KDV EM41, highlighted in red. Results will be similar to those in the previous step. The Tx frequency (red marker) is not moved unless Shift or Ctrl is held down. Messages highlighted in red are usually in response to your own CQ or from a tail-ender, and you probably want your Tx frequency to stay where it was.

  • Click somewhere on the waterfall to set Rx frequency (green marker on waterfall scale).

  • Shift-click on the waterfall to set Tx frequency (red marker).

  • Ctrl-click on the waterfall to set both Rx and Tx frequencies.

  • Double-click on a signal in the waterfall to set Rx frequency and start a narrow-band decode there. Decoded text will appear in the right window only.

  • Ctrl-double-click on a signal to set both Rx and Tx frequencies and decode at the new frequency.

  • Click Erase to clear the right window.

  • Double-click Erase to clear both text windows.

6.5. JT9+JT65

Main Window:
  • Select JT9+JT65 on the Mode menu.

  • Toggle the Tx mode button to read Tx JT65 #, and set the Tx and Rx frequencies to 1718 Hz.

  • Double-click on Erase to clear both text windows.

Wide Graph Settings:
  • Bins/Pixel = 7

  • JT65 …​. JT9 = 2500

  • Adjust the width of the Wide Graph window so that the upper frequency limit is approximately 4000 Hz.

Open a Wave File:
  • Select File | Open and navigate to ...\save\samples\JT9+JT65\130610_2343.wav. The waterfall should look something like this:

Wide Graph Decode 130610_2343

The position of the blue marker on the waterfall scale is set by the spinner control JT65 nnnn JT9, where nnnn is an audio frequency in Hz. In JT9+JT65 mode the program will automatically decode JT9 signals only above this frequency. JT65 signals will be decoded over the full displayed frequency range.

JT9 signals appear in the Cumulative spectrum as nearly rectangular shapes about 16 Hz wide. They have no clearly visible sync tone like the one at the low-frequency edge of all JT65 signals. By convention the nominal frequency of both JT9 and JT65 signals is taken to be that of the lowest tone, at the left edge of its spectrum.

This sample file contains 17 decodable signals — nine in JT65 mode (flagged with the character # in the decoded text windows), and eight in JT9 mode (flagged with @). On multi-core computers the decoders for JT9 and JT65 modes run simultaneously, so their results will be interspersed. The Band Activity window contains all decodes (you might need to scroll back in the window to see some of them). A signal at the frequency specified by the green marker is given decoding priority, and its message is displayed also in the Rx Frequency window.

  • Confirm that mouse-click behavior is similar to that described earlier, in Example 1. WSJT-X automatically determines the mode of each JT9 or JT65 message.

    When you double-click on a signal in the waterfall it will be properly decoded even if on the “wrong” side of the JT65 nnnn JT9 marker. The Tx mode automatically switches to that of the decoded signal and the Rx and Tx frequency markers on the waterfall scale resize themselves accordingly. When selecting a JT65 signal, click on the sync tone at its left edge.
  • Double-click on the waterfall near 815 Hz: a JT65 message originating from W7VP will be decoded and appear in the Rx Frequency window. Between the UTC and Freq columns on the decoded text line you will find dB, the measured signal-to-noise ratio, and DT, the signal’s time offset in seconds relative to your computer clock.

UTC dB DT Freq Mode Message







  • Double-click on the waterfall at 3196 Hz. The program will decode a JT9 message from IZ0MIT:

UTC dB DT Freq Mode Message







  • Scroll back in the Band Activity window and double-click on the message CQ DL7ACA JO40. The program will set Tx mode to JT65 and the Rx frequency to that of DL7ACA, 975 Hz. If you hold down the Ctrl key, both Rx and Tx frequencies will be moved. If you had checked Double-click on call sets Tx Enable on the Setup menu, the program would configure itself to begin a transmission and start a QSO with DL7ACA.

  • Hold Ctrl down and double-click on the decoded JT65 message CQ TA4A KM37. The program will set Tx mode to JT9 and the Rx and Tx frequencies to 3567 Hz. The program is now configured properly for a JT9 QSO with TA4A.

Reopen the First Sample File:
  • Select File | Open and navigate to …​\save\samples\130418_1742.wav.

Taking full advantage of the wide-band, dual-mode capability of WSJT-X requires a receiver bandwidth of at least 4 kHz. These data were recorded with a much narrower Rx bandwidth, roughly 200 to 2400 Hz. If you have no Rx filter wider than about 2.7 kHz, you will be using data like this. For best viewing, adjust Bins/Pixel and the width of the Wide Graph so that only the active part of the spectrum shows, say 200 to 2400 Hz. Re-open the example file after any change of Bins/Pixel or Wide Graph width, to refresh the waterfall.

The signals in this file are all JT9 signals. To decode them automatically in JT9+JT65 mode you’ll need to move the JT65 nnnn JT9 delimiter down to 1000 Hz or less.

Waterfall Controls

Now is a good time to experiment with the Start control and the sliders controlling gain and zero-point of the waterfall and spectrum plots. Start determines the frequency displayed at the left side of the waterfall scale. Sliders set the baseline level and gain for the waterfall and the several types of spectra. Good starting values should be close to mid-scale. You might want to uncheck Flatten when adjusting the sliders. Re-open the wave file after each change, to see the new results.

6.6. FT8

Main Window:
  • Select FT8 on the Mode menu.

  • Double-click on Erase to clear both text windows.

Wide Graph Settings:
  • Bins/Pixel = 5, Start = 100 Hz, N Avg = 2

  • Adjust the width of the Wide Graph window so that the upper frequency limit is approximately 3300 Hz.

Open a Wave File:
  • Select File | Open and navigate to ...\save\samples\FT8\181201_180245.wav. The waterfall and Band Activity window should look something like the following screen shots. (This recording was made during the "FT8 Roundup" contest, so most transmissions happen to be using RTTY Roundup message formats.)

Wide Graph Decode 170709_135615
ft8 decodes
  • Click with the mouse anywhere on the waterfall display. The green Rx frequency marker will jump to your selected frequency, and the Rx frequency control on the main window will be updated accordingly.

  • Do the same thing with the Shift key held down. Now the red Tx frequency marker and its associated control on the main window will follow your frequency selections.

  • Do the same thing with the Ctrl key held down. Now both colored markers and both spinner controls will follow your selections.

  • Double-clicking at any frequency on the waterfall does all the things just described and also invokes the decoder in a small range around the Rx frequency. To decode a particular signal, double-click near the left edge of its waterfall trace.

  • Now double-click on any of the lines of decoded text in the Band Activity window. Any line will show the same behavior, setting Rx frequency to that of the selected message and leaving Tx frequency unchanged. To change both Rx and Tx frequencies, hold Ctrl down when double-clicking.

To avoid QRM from competing callers, it is usually best to answer a CQ on a different frequency from that of the CQing station. The same is true when you tail-end another QSO. Choose a Tx frequency that appears to be not in use. You might want to check the box Hold Tx Freq.
Keyboard shortcuts Shift+F11 and Shift+F12 provide an easy way to move your Tx frequency down or up in 60 Hz steps.
An online FT8 Operating Guide by ZL2IFB offers many additional tips on operating procedures.
FT8 DXpedition Mode:

This special operating mode enables DXpeditions to make FT8 QSOs at very high rates. Both stations must use WSJT-X Version 1.9 or later. Detailed operating instructions for FT8 DXpedition Mode are available online. Do not try to use DXpedition mode without reading these instructions carefully!

FT8 DXpedition mode is intended for use by rare-entity DXpeditions and other unusual circumstances in which sustained QSO rates well above 100/hour are expected. Do not use the multi-signal capability unless you satisfy this requirement, and do not use DXpedition Mode in the conventional FT8 sub-bands. If you are contemplating operation as Fox using DXpedition Mode, find a suitable dial frequency consistent with regional band plans and publicize it for the operators you hope to work. Remember that on-the-air signal frequencies will be higher than the dial frequency by up to 4 kHz.
When finished with this Tutorial, don’t forget to re-enter your own callsign as My Call on the Settings | General tab.

6.7. FT4

FT4 is designed for contesting, particularly on the HF bands and 6 meters. Compared with FT8 it is 3.5 dB less sensitive and requires 1.6 times the bandwidth, but it offers the potential for twice the QSO rate.

Main Window:
  • Select FT4 on the Mode menu.

  • Double-click on Erase to clear both text windows.

Wide Graph Settings:
  • Bins/Pixel = 5, Start = 100 Hz, N Avg = 1

  • Adjust the width of the Wide Graph window so that the upper frequency limit is approximately 3300 Hz.

Open a Wave File:
  • Select File | Open and navigate to ...\save\samples\FT4\200514_182053.wav. The waterfall and Band Activity window should look something like the following screen shots. This sample file was recorded during a practice contest test session, so most of the decoded messages use the RTTY Roundup message formats.

Wide Graph Decode FT4
ft4 decodes
  • Click with the mouse anywhere on the waterfall display. The green Rx frequency marker will jump to your selected frequency, and the Rx frequency control on the main window will be updated accordingly.

  • Do the same thing with the Shift key held down. Now the red Tx frequency marker and its associated control on the main window will follow your frequency selections.

  • Do the same thing with the Ctrl key held down. Now the both colored markers and both spinner controls will follow your selections.

  • Now double-click on any of the lines of decoded text in the Band Activity window. Any line will show similar behavior, setting Rx frequency to that of the selected message and leaving Tx frequency unchanged. To change both Rx and Tx frequencies, hold Ctrl down when double-clicking.

Best S+P Button

The FT4 user interface includes a button labeled Best S+P.

Best S+P

Clicking Best S+P during an Rx cycle arms the program to examine all CQ messages decoded at the end of the Rx sequence. The program will select the best potential QSO partner (from a contesting perspective), and treat it as if you had double-clicked on that line of decoded text. Here "best potential QSO partner" means "New Multiplier" (1st priority) or "New Call on Band" (2nd priority). "New Multiplier" is currently interpreted to mean "New DXCC"; a more broadly defined multiplier category (for the ARRL RTTY Roundup rules) will be implemented in due course. We may provide additional priority rankings, for example “New Grid on Band” (useful for North American VHF contests), sorting by signal strength, etc.

Best S+P is a useful feature only if you have defined what "best" is supposed to mean. This is done by configuring suitable options on the Settings | Colors tab. Selection and ordering of color-highlighting options determines what potential QSO partners will be chosen by the "Best S+P" feature. Optimum choices will be different for different contests. In a contest using RTTY Roundup rules we recommend activating My Call in message, New DXCC, New Call on Band, CQ in message and Transmitted message, reading from top to bottom.

Keyboard shortcuts Shift+F11 and Shift+F12 provide an easy way to move your FT4 Tx frequency down or up in 90 Hz steps.
For easy keyboard control of transmitted messages, check Alternate F1–F6 bindings on the Settings | General tab. In contest-style operation you can then hit F1 to solicit a QSO by sending CQ. Similarly, keys F2 to F5 will send the messages in entry fields Tx2 to Tx5. More details on contest-style operation can be found in The FT4 Protocol for Digital Contesting.
When finished with this Tutorial, don’t forget to re-enter your own callsign as My Call on the Settings | General tab.

6.8. FST4

Do not confuse FST4 with FT4, which has a very different purpose! FST4 is designed primarily for making weak-signal 2-way QSOs on the LF and MF bands. T/R periods from 15 s up to 1800 s are available. Longer T/R periods provide better sensitivity only if Tx and Rx frequency instability and channel Doppler spread are small enough so that received signals remain phase coherent over periods spanning several transmitted symbols. Generally speaking, Rx and Tx frequency changes during the transmission and channel Doppler spread should each be small compared to the symbol keying rate shown for each T/R duration in Table 7 within section Protocol Specifications. For example, the keying rate for the 1800 s T/R period is 0.089 Baud, so successful operation using this T/R length requires Tx and Rx frequency stability better than 0.089 Hz over the duration of the 1800 s transmission in addition to channel Doppler spread smaller than 0.089 Hz.

Operation with FST4 is similar to that with other WSJT-X modes: most on-screen controls, auto-sequencing, and other features behave in familiar ways. However, operating conventions on the 2200 and 630 m bands have made some additional user controls desirable. Spin boxes labeled F Low and F High set lower and upper frequency limits used by the FST4 decoder, and these limits are marked by dark green angle-bracket symbols < > on the Wide Graph frequency scale:

FST4 Decoding Limits

FST4 center

It’s best to keep the decoding range fairly small, since QRM and transmissions in other modes or sequence lengths will slow down the decoding process (and of course will be undecodable). By checking Single decode on the the File | Settings | General tab, you can further limit the decoding range to the setting of F Tol on either side of Rx Freq.

A noise blanker can be enabled by setting the NB percentage to a non-zero value. This setting determines how many of the largest-amplitude samples will be blanked (zeroed) before the data is submitted to the decoder. Most users find that settings between 0% (no blanking) and 10% work best. If the noise blanker percentage is set to -1%, then the decoder will try 0, 5, 10, 15, and 20 % in succession. Similarly, a setting of -2% causes the decoder to loop over blanking percentages 0, 2, 4, …​ 20 %. To save time, the multiple blanking percentages triggered by negative NB settings are tried only for signal candidates located near (within +/- 20 Hz) of the Rx frequency setting.

Open a sample Wave File:
  • Select FST4 on the Mode menu. Set T/R to 60 s and Decode | Deep.

  • Set NB (noise blanker) to 0%.

  • Set up the Wide Graph display with settings appropriate for the FST4-60 mode. For example, try Bins/Pixel 2 and N Avg 4. Set the Start frequency and the width of the Wide Graph to include the frequency range that you want to decode. For this example, make sure that Start is less than 1000 Hz and that the Wide Graph extends to above 1400 Hz.

  • Set F Low 1000, F High 1400. These settings define the decoder’s frequency search range.

  • Open a sample Wave file using File | Open and select the file …​\save\samples\FST4+FST4W\210115_0058.wav. After WSJT-X has processed the file you should see something similar to the following screen shot: