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 and experimental branch of the program WSJT.

WSJT-X Version 2.0 offers nine different protocols or modes: FT8, JT4, JT9, JT65, QRA64, ISCAT, MSK144, WSPR, and Echo. The first five are designed for making reliable QSOs under extreme weak-signal conditions. They use nearly identical message structure and source encoding. JT65 and QRA64 were designed for EME (“moonbounce”) on the VHF/UHF bands and have also proven very effective for worldwide QRP communication on the HF bands. QRA64 has a number of advantages over JT65, including better performance on the very weakest signals. We imagine that over time it may replace JT65 for EME use. JT9 was originally designed for the LF, MF, and lower HF bands. Its submode JT9A is 2 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. These four “slow” modes use one-minute timed sequences of alternating transmission and reception, 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 operationally similar but four times faster (15-second T/R sequences) and less sensitive by a few dB. 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 and other propagation types) at signal levels 10 to 15 dB below those required for CW.

ISCAT, 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”. ISCAT uses free-form messages up to 28 characters long, while MSK144 uses the same structured messages as the slow modes and optionally an abbreviated format with hashed callsigns.

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 they can be decoded at signal-to-noise ratios as low as -31 dB in a 2500 Hz bandwidth. WSPR users with internet access can automatically upload 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 1.9.0. Temporary “beta” release candidates are sometimes made in advance of a new general-availability release, in order to obtain user feedback. For example, version 1.9.0-rc1, 1.9.0-rc2, etc., would be beta releases leading up to the final release of v1.9.0. 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 has been made.

1.1. New in Version 2.0.1

For quick reference, here’s a short list of features and capabilities added to WSJT-X since Version 1.9.1:

  • New FT8 and MSK144 protocols with 77-bit payloads permit these enhancements:

    • Optimized contest messages for NA VHF, EU VHF, Field Day, RTTY Roundup

    • Full support for "/R" and "/P" calls in relevant contests

    • New logging features for contesting

    • Integration with N1MM Logger+ and Writelog for contesting

    • Improved support for compound and nonstandard callsigns

    • Nearly equal (or better) sensitivity compared to old protocols

    • Lower false decode rates

  • Improved color highlighting of received messages

  • Improved WSPR sensitivity

  • Expanded and improved UDP messages sent to companion programs

  • Bug fixes and other minor tweaks to user interface

Note that for FT8 and MSK144 there is no backward compatibility with WSJT-X 1.9.1 and earlier. Everyone using these modes should upgrade to WSJT-X 2.0 by January 1, 2019.
WSJT-X Version 2.0 drops support for Apple Mac OS X 10.9 (Mavericks). It is possible to build from source for this operating system version but the DMG installer package requires 10.10 or later.

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 particuar 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. 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 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 also be sent to the WSJT Group email reflector. You must join the relevant group before posting to either email list.

2. System Requirements

  • SSB transceiver and antenna

  • Computer running Windows (XP or later), Linux, or OS X

  • 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-2.0.1-win32.exe, 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 (x86)\WSJTX.

  • All program files relating to WSJT-X will be stored in the chosen installation directory and its subdirectories.

  • Logs and other writeable files will normally be 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 (see Network Time Protocol Setup for downloading and installation instructions) or Dimension 4 from Thinking Man Software. Recent versions of Windows 10 are now shipped with a more capable Internet time synchronization service that is suitable if configured appropriately.

  • <em>WSJT-X</em> LoTW download TLS error From this version onward WSJT-X requires the OpenSSL libraries to be installed. Suitable libraries may already be installed on your system, if they are not you will see this error shortly after startup. To fix this you need to install the OpenSSL libraries.

    • You can download a suitable OpenSSL package for from Windows OpenSSL Packages, you need the latest Win32 v1.0.2 Lite version (Note it is the Win32 package even if you are using a 64-bit Windows operating system) which at the time of writing was Win32 OpenSSL Lite Package.

    • Install the package and accept the default options, including the option to copy the OpenSSL DLLs to the Windows system directory (this is important).

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 and 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 2.0, 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.
  • 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 on Properties, then Advanced, and select 16 bit, 48000 Hz (DVD Quality). Switch of 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 Raspbian:

The project team release binary installer packages for Linux when a new WSJT-X release is announced, note that these are built to target one contemporary version of a Linux distribution. Although these may work on newer Linux versions or even different distributions, it is unlikely that they will 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 libqt5multimedia5-plugins libqt5serialport5 libqt5sql5-sqlite libfftw3-single3

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

  • 32-bit: wsjtx-2.0.1-i686.rpm

    • To install:

      sudo rpm -i wsjtx-2.0.1-i686.rpm
    • Uninstall:

      sudo rpm -e wsjtx
  • 64-bit: wsjtx-2.0.1-x86_64.rpm

    • To install:

      sudo rpm -i wsjtx-2.0.1-x86_64.rpm
    • Uninstall:

      sudo rpm -e wsjtx

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

sudo dnf install fftw-libs-single qt5-qtmultimedia qt5-qtserialport

3.3. OS X and macOS

OS X 10.10 and later: Download the file wsjtx-2.0.1-Darwin.dmg to your desktop, double-click on 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 (say, from WSJT-X to WSJT-X_1.9). 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 each of eight tabs selectable near the top of the window.

4.1. General

Settings Window

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.

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 Compound 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

Radio Tab

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.

  • 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.

    Omni-Rig is available only under Windows.
  • 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 transcivers 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 idependently.
  • 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. (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

_WSJT-X_ Audio Configuration Screen

Select the Audio tab to configure your sound system.

  • 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 Vista 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 Screen

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

  • 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 on Tab 1 or the Free msg field on Tab 2. 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 by a program that will receive status updates from WSJT-X. Cooperating applications like JTAlert use this feature to obtain information about a running WSJT-X instance. If you are using JTAlert, be sure to check the three boxes at lower right.

  • N1MM Logger+ Broadcasts: To send information on logged QSOs directly to N1MM Logger+, check the box and enter the IP address and port number for N1MM.

4.6. Frequencies

Frequency Screen

Working 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.

  • 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 any entry and click Reset button to return the table to its default configuration.

Other more advanced maintenance operations are available on the right-click context 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.

  • 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 on line.

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

  • Adjust Age of 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 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 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.

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. This choice has the desirable effect of allowing the Wide Graph (waterfall and 2D spectrum) to display the conventional JT65 and JT9 sub-bands simultaneously on most HF bands. Further details are provided in the Basic Operating Tutorial. A wider displayed bandwidth may also be helpful at VHF and above, where FT8, JT4, JT65, and QRA64 signals may be found over much wider ranges of frequencies.

  • 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.

  • Of course, you might prefer to concentrate on one mode at a time, setting your dial frequency to (say) 14.074 for FT8, 14.076 for JT65, or 14.078 for JT9. Present conventions have the nominal JT9 dial frequency 2 kHz higher than the JT65 dial frequency on most bands, and the FT8 frequency 2 kHz lower.

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.
  • Select Tab 2 (below the Decode button) to choose the alternative set of controls for generating and selecting Tx messages.

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.

  • Set Tx frequency to 1600 Hz, Rx to 1442 Hz.

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

Wide Graph Settings:
  • Bins/Pixel = 4, Start = 200 Hz, N Avg = 2

  • Adjust the width of the Wide Graph window so that the upper frequency limit is approximately 2600 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 the 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 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 frequently desirable 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 helpful 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.

7. Making QSOs

7.1. Standard Exchange

By longstanding tradition, a minimally valid QSO requires the exchange of callsigns, a signal report or some other information, and acknowledgments. WSJT-X is designed to facilitate making such minimal QSOs using short, structured messages. The process works best if you use these formats and follow standard operating practices. The recommended basic QSO goes something like this:

CQ K1ABC FN42                          #K1ABC calls CQ
                  K1ABC G0XYZ IO91     #G0XYZ answers
G0XYZ K1ABC –19                        #K1ABC sends report
                  K1ABC G0XYZ R-22     #G0XYZ sends R+report
G0XYZ K1ABC RRR                        #K1ABC sends RRR
                  K1ABC G0XYZ 73       #G0XYZ sends 73

Standard messages consist of two callsigns (or CQ, QRZ, or DE and one callsign) followed by the transmitting station’s grid locator, a signal report, R plus a signal report, or the final acknowledgements RRR or 73. These messages are compressed and encoded in a highly efficient and reliable way. In uncompressed form (as displayed on-screen) they may contain as many as 22 characters. Some operators prefer ro send RR73 rather than RRR. This is workable because RR73 is encoded as a valid grid locator, one unlikely ever to be occupied by an amateur station.

Signal reports are specified as signal-to-noise ratio (S/N) in dB, using a standard reference noise bandwidth of 2500 Hz. Thus, in the example message above, K1ABC is telling G0XYZ that his signal is 19 dB below the noise power in bandwidth 2500 Hz. In the message at 0004, G0XYZ acknowledges receipt of that report and responds with a –22 dB signal report. JT65 reports are constrained to lie in the range –30 to –1 dB, and values are significantly compressed above about -10 dB. JT9 supports the extended range –50 to +49 dB and assigns more reliable numbers to relatively strong signals.

Signals become visible on the waterfall around S/N = –26 dB and audible (to someone with very good hearing) around –15 dB. Thresholds for decodability are around -20 dB for FT8, -23 dB for JT4, –25 dB for JT65, –27 dB for JT9.
Several options are available for circumstances where fast QSOs are desirable. Double-click the Tx1 control under Now or Next to toggle use of the Tx2 message rather than Tx1 to start a QSO. Similarly, double-click the Tx4 control to toggle between sending RRR and RR73 in that message. The RR73 message should be used only if you are reasonably confident that no repetitions will be required.

7.2. Free-Text Messages

Users often add some friendly chit-chat at the end of a QSO. Free-format messages such as “TNX ROBERT 73” or “5W VERT 73 GL” are supported, up to a maximum of 13 characters, including spaces. In general you should avoid the character / in free-text messages, as the program may then try to interpret your construction as part of a compound callsign. It should be obvious that the JT4, JT9, and JT65 protocols are not designed or well suited for extensive conversations or rag-chewing.

7.3. Auto-Sequencing

The 15-second T/R cycles of FT8 allow only about two seconds to inspect decoded messages and decide how to reply, which is often not enough. The slow modes JT4, JT9, JT65, and QRA64 allow nearly 10 seconds for this task, but operators may find that this is still insufficient when workload is high, especially on EME. For these reasons a basic auto-sequencing feature is offered.

Check Auto Seq on the main window to enable this feature:


When calling CQ you may also choose to check the box Call 1st. WSJT-X will then respond automatically to the first decoded responder to your CQ.

When Auto-Seq is enabled the program de-activates Enable Tx at the end of each QSO. It is not intended that WSJT-X should make fully automated QSOs.

7.4. Contest Messages

The new FT8 and MSK144 protocols support special messages optimized for NA VHF and EU VHF contests. FT8 also supports messages for ARRL Field Day and the ARRL RTTY Roundup. The decoders recognize and decode these messages at any time. Configure the program to automatically generate the required message types by selecting a supported operating activity on the Settings | Advanced tab. Model QSOs then proceed as follows, for each event type:

NA VHF Contest

                      K1ABC W9XYZ EN37
                      K1ABC W9XYZ RRR

Either callsign (or both) may have /R appended. You can use RR73 in place of RRR, and the final 73 is optional.

EU VHF Contest

                      G4ABC PA9XYZ JO22
PA9XYZ 570123 IO91NP
                      G4ABC R 580071 JO22DB

Either callsign (or both) may have /P appended.

ARRL Field Day

                      K1ABC W9XYZ 6A WI
                      K1ABC W9XYZ RR73


                      K1ABC W9XYZ 579 WI
                      K1ABC W9XYZ RR73

7.5. Nonstandard Callsigns

FT8 and MSK144

Compound callsigns like xx/K1ABC or K1ABC/x and special event callsigns like YW18FIFA are supported for normal QSOs but not for contest-style messages. Model QSOs look something like this:

                      <PJ4/K1ABC> W9XYZ
W9XYZ <PJ4/K1ABC> +03
                      <PJ4/K1ABC> W9XYZ R-08
                      PJ4/K1ABC <W9XYZ> 73

The compound or nonstandard callsigns are automatically recognized and handled using special message formats. One such callsign and one standard callsign may appear in most messages, provided that one of them is enclosed in < > angle brackets. If the message includes a grid locator or numerical signal report, the brackets must enclose the compound or nonstandard callsign; otherwise the brackets may be around either call.

Angle brackets imply that the enclosed callsign is not transmitted in full, but rather as a hash code using a smaller number of bits. Receiving stations will display the full nonstandard callsign if it has been received in full in the recent past. Otherwise it will be displayed as < . . . >. These restrictions are honored automatically by the algorithm that generates default messages for minimal QSOs. Except for the special cases involving /P or /R used in VHF contesting, WSJT-X 2.0 offers no support for two nonstandard callsigns to work each other.

Using a nonstandard callsign has definite costs. It restricts the types of information that can be included in a message. It prevents including your locator in standard messages, which necessarily impairs the usefulness of tools like PSK Reporter.

JT4, JT9, JT65, and QRA64

In the 72-bit modes, compound callsigns are handled in one of two possible ways:

Type 1 compound callsigns

A list of about 350 of the most common prefixes and suffixes can be displayed from the Help menu. A single compound callsign involving one item from this list can be used in place of the standard third word of a message (normally a locator, signal report, RRR, or 73). The following examples are all acceptable messages containing Type 1 compound callsigns:


The following messages are not valid, because a third word is not permitted in any message containing a Type 1 compound callsign:

ZA/K1ABC G0XYZ -22        #These messages are invalid; each would
G0XYZ K1ABC/4 73          # be sent without its third "word"

A QSO between two stations using Type 1 compound-callsign messages might look like this:

                    ZA/K1ABC G0XYZ
                    K1ABC G0XYZ R–22
                    K1ABC G0XYZ 73

Notice that the full compound callsign is sent and received in the first two transmissions. After that, the operators omit the add-on prefix or suffix and use the standard structured messages.

Type 2 Compound callsigns

Prefixes and suffixes not found in the displayable short list are handled by using Type 2 compound callsigns. In this case the compound callsign must be the second word in a two- or three-word message, and the first word must be CQ, DE, or QRZ. Prefixes can be 1 to 4 characters, suffixes 1 to 3 characters. A third word conveying a locator, report, RRR, or 73 is permitted. The following are valid messages containing Type 2 compound callsigns:

DE W4/G0XYZ -22
DE W4/G0XYZ R-22
DE W4/G0XYZ 73

In each case, the compound callsign is treated as Type 2 because the add-on prefix or suffix is not one of those in the fixed list. Note that a second callsign is never permissible in these messages.

During a transmission your outgoing message is displayed in the first label on the Status Bar and shown exactly as another station will receive it. You can check to see that you are actually transmitting the message you wish to send.

QSOs involving Type 2 compound callsigns might look like either of the following sequences:

                    K1ABC G0XYZ IO91
                    K1ABC G0XYZ R–22
                    K1ABC/VE1 73
                    DE G0XYZ/W4 FM18
                    K1ABC G0XYZ R–22
                    DE G0XYZ/W4 73

Operators with a compound callsign use its full form when calling CQ and possibly also in a 73 transmission, as may be required by licensing authorities. Other transmissions during a QSO may use the standard structured messages without callsign prefix or suffix.

If you are using a compound callsign, you may want to experiment with the option Message generation for type 2 compound callsign holders on the Settings | General tab, so that messages will be generated that best suit your needs.

7.6. Pre-QSO Checklist

Before attempting your first QSO with one of the WSJT modes, be sure to go through the Basic Operating Tutorial above as well as the following checklist:

  • Your callsign and grid locator set to correct values

  • PTT and CAT control (if used) properly configured and tested

  • Computer clock properly synchronized to UTC within ±1 s

  • Audio input and output devices configured for sample rate 48000 Hz, 16 bits

  • Radio set to USB (upper sideband) mode

  • Radio filters centered and set to widest available passband (up to 5 kHz).

Remember that in many circumstances FT8, JT4, JT9, JT65, and WSPR do not require high power. Under most HF propagation conditions, QRP is the norm.

8. VHF+ Features

WSJT-X v2.0 suppports a number of features designed for use on the VHF and higher bands. These features include:

  • FT8, a mode designed for making fast QSOs with weak, fading signals

  • JT4, a mode particularly useful for EME on the microwave bands

  • JT9 fast modes, useful for scatter propagation on VHF bands

  • JT65, widely used for EME on VHF and higher bands

  • QRA64, a mode for EME using a “Q-ary Repeat Accumulate” code, a low-density parity-check (LDPC) code using a 64-character symbol alphabet

  • MSK144, a mode for meteor scatter using a binary LDPC code and Offset Quadrature Phase-Shift Keying (OQPSK). The resulting waveform is sometimes called Minimum Shift Keying (MSK).

  • ISCAT, intended for aircraft scatter and other types of scatter propagation

  • Echo mode, for detecting and measuring your own lunar echoes

  • Doppler tracking, which becomes increasingly important for EME on bands above 1.2 GHz.

  • Optional Auto-Sequencing in JT4, JT9, and JT65 as well as FT8 and QRA64.

8.1. VHF Setup

To activate the VHF-and-up features:

  • On the Settings | General tab check Enable VHF/UHF/Microwave features and Single decode.

  • For EME, check Decode after EME delay to allow for extra path delay on received signals.

  • If you will use automatic Doppler tracking and your radio accepts frequency-setting commands while transmitting, check Allow Tx frequency changes while transmitting. Transceivers known to permit such changes include the IC-735, IC-756 Pro II, IC-910-H, FT-847, TS-590S, TS-590SG, TS-2000 (with Rev 9 or later firmware upgrade), Flex 1500 and 5000, HPSDR, Anan-10, Anan-100, and KX3. To gain full benefit of Doppler tracking your radio should allow frequency changes under CAT control in 1 Hz steps.

If your radio does not accept commands to change frequency while transmitting, Doppler tracking will be approximated with a single Tx frequency adjustment before a transmission starts, using a value computed for the middle of the Tx period.
  • On the Radio tab select Split Operation (use either Rig or Fake It; you may need to experiment with both options to find one that works best with your radio).

  • On the right side of the main window select Tab 1 to present the traditional format for entering and choosing Tx messages.

The main window will reconfigure itself as necessary to display controls supporting the features of each mode.

  • If you are using transverters, set appropriate frequency offsets on the Settings | Frequencies tab. Offset is defined as (transceiver dial reading) minus (on-the-air frequency). For example, when using a 144 MHz radio at 10368 MHz, Offset (MHz) = (144 - 10368) = -10224.000. If the band is already in the table, you can edit the offset by double clicking on the offset field itself. Otherwise a new band can be added by right clicking in the table and selecting Insert.

Station information
  • On the View menu, select Astronomical data to display a window with important information for tracking the Moon and performing automatic Doppler control. The right-hand portion of the window becomes visible when you check Doppler tracking.

Astronomical data

Five different types of Doppler tracking are provided:

  • Select Full Doppler to DX Grid if you know your QSO partner’s locator and he/she will not be using any Doppler control.

  • Select Own Echo to enable EME Doppler tracking of your receive frequency to your own echo frequency. Your Tx frequency will remain fixed and is set to the Sked frequency. This mode can be used when announcing your CQ call on a specific frequency and listening on your own echo frequency. It can also be used for echo testing with Echo mode.

  • Select Constant frequency on Moon to correct for your own one-way Doppler shift to or from the Moon. If your QSO partner does the same thing, both stations will have the required Doppler compensation. Moreover, anyone else using this option will hear both of you without the need for manual frequency changes.

  • Select On Dx Echo when your QSO partner is not using automated Doppler tracking, and announces his/her transmit frequency and listening on their own echo frequency. When clicked, this Doppler method will set your rig frequency on receive to correct for the mutual Doppler shift. On transmit, your rig frequency will be set so that your QSO partner will receive you on the same frequency as their own echo at the start of the QSO. As the QSO proceeds, your QSO partner will receive you on this starting frequency so that they do not have to retune their receiver as the Doppler changes. Sked frequency in this case is set to that announced by your QSO partner.

  • Select Call DX after tuning the radio manually to find a station, with the Doppler mode initally set to None. You may be tuning the band looking for random stations, or to a frequency where a station has been seen on an SDR display. It is usually necessary to hold down the Ctrl key while tuning the radio. From the moment Call DX is pressed, your transmit frequency is set so that your echo will fall on the same frequency you (and the DX station) are listening.

  • See Astronomical Data for details on the quantities displayed in this window.

8.2. JT4

JT4 is designed especially for EME on the microwave bands, 2.3 GHz and above.

  • Select JT4 from the Mode menu. The central part of the main window will look something like this:

VHF Controls
  • Select the desired Submode, which determines the spacing of transmitted tones. Wider spacings are used on the higher microwave bands to allow for larger Doppler spreads. For example, submode JT4F is generally used for EME on the 5.7 and 10 GHz bands.

  • For EME QSOs some operators use short-form JT4 messages consisting of a single tone. To activate automatic generation of these messages, check the box labeled Sh. This also enables the generation of a single tone at 1000Hz by selecting Tx6, to assist in finding signals initially. The box labeled Tx6 toggles the Tx6 message from 1000Hz to 1250Hz to indicate to the other station that you are ready to receive messages.

  • Select Deep from the Decode menu. You may also choose to Enable averaging over successive transmissions and/or Enable deep search (correlation decoding).

Decode Menu

The following screen shot shows one transmission from a 10 GHz EME QSO using submode JT4F.


8.3. JT65

In many ways JT65 operation on VHF and higher bands is similar to HF usage, but a few important differences should be noted. Typical VHF/UHF operation involves only a single signal (or perhaps two or three) in the receiver passband. You may find it best to check Single decode on the Settings → General tab. There will be little need for Two pass decoding on the Advanced tab. With VHF features enabled the JT65 decoder will respond to special message formats often used for EME: the OOO signal report and two-tone shorthand messages for RO, RRR, and 73. These messages are always enabled for reception; they will be automatically generated for transmission if you check the shorthand message box Sh.

Deep on the Decode menu will be automatically selected. You may optionally include Enable averaging, Enable Deep search, and Enable AP.

The following screen shot shows three transmissions from a 144 MHz EME QSO using submode JT65B and shorthand messages. Take note of the colored tick marks on the Wide Graph frequency scale. The green marker at 1220 Hz indicates the selected QSO frequency (the frequency of the JT65 Sync tone) and the F Tol range. A green tick at 1575 Hz marks the frequency of the highest JT65 data tone. Orange markers indicate the frequency of the upper tone of the two-tone signals for RO, RRR, and 73.