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 currently offers two protocols or “modes,” JT65 and JT9. Both are designed for making reliable, confirmed QSOs under extreme weak-signal conditions. They use nearly identical message structure and source encoding. JT65 was designed for EME (“moonbounce”) on the VHF/UHF bands and has also proven very effective for worldwide QRP communication on the HF bands. JT9 is optimized for the LF, MF, and lower HF bands. It is about 2 dB more sensitive than JT65 while using less than 10% of the bandwidth. Both 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. On the HF bands, world-wide QSOs are possible with power levels of a few watts and compromise antennas.

WSJT-X can display a passband as large as 5 kHz and provides dual-mode reception of both JT65 and JT9 signals. If your receiver can be configured with at least 4 kHz bandwidth in USB mode, you can set the dial frequency to one of the standard JT65 frequencies — for example, 14.076 MHz for the 20-meter band — and display the full JT65 and JT9 sub-bands simultaneously on the waterfall. You can then make QSOs in both modes using nothing more than mouse clicks.

Plans for future program development call for WSJT-X and WSJT to merge together. WSJT-X will gradually acquire additional modes such as JT4 that are now supported in WSJT. The entire WSJT-related effort is an open-source project, released under the GNU General Public License (GPL). 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 most communication among the developers takes place on the email reflector wsjt-devel. User-level questions and answers, and general communication among users is found on the WSJT Group email reflector.

2. System Requirements

  • SSB transceiver and antenna

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

  • 1.5 GHz or faster CPU and 100 MB of available memory

  • Monitor with at least 1024 x 780 resolution

  • Computer-to-radio interface using a serial port 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 capable of 48 kHz sample rate

  • 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 are found on the the WSJT Home Page. Click on the WSJT-X link at the left margin, and then select the appropriate package for your operating system.

3.1. Windows

Download and execute the package file wsjtx-1.4.0-win32.exe, following these instructions:

  • Install WSJT-X into its own directory rather than in the conventional location C:\Program Files\WSJTX. Suggested installation directories are C:\WSJTX or C:\WSJT\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 C:\Users\<username>\AppData\Local\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.

  • 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).

  • 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.

3.2. Linux

  • For Debian, Ubuntu, and other Debian-based systems:

    • 32-bit: wsjtx-1.4.0_i386.deb

      • To install: sudo dpkg -i wsjtx_1.4.0_i386.deb

      • Uninstall: sudo dpkg -P wsjtx

    • 64-bit: wsjtx-1.4.0_amd64.deb

      • To install: sudo dpkg -i wsjtx_1.4.0_amd64.deb

      • Uninstall: sudo dpkg -P wsjtx

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

      sudo apt-get install libqt5multimediawidgets5
      sudo apt-get install libfftw3-single3
  • For Fedora, Red Hat, and other rpm-based systems:

    • 32-bit: wsjtx-1.4.0_i686.rpm

      • To install: sudo rpm -i wsjtx-1.4.0_i686.rpm

      • Uninstall: sudo rpm -e wsjtx

    • 64-bit: wsjtx-1.4.0_x86_64.rpm

      • To install: sudo rpm -i wsjtx-1.4.0_x86_64.rpm

      • Uninstall: sudo rpm -e wsjtx

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

      sudo yum install qt5-qtmultimedia
      sudo yum install fftw-libs-single

3.3. Macintosh OS X

  • OS X 10.7 and later: wsjtx-1.4.0-Darwin.dmg

  • After downloading it to your desktopo, double-click on the dmg file 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_previous). You can then proceed to the installation phase.

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

  • 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.

3.4. Source Code

Source code for WSJT-X is available from a public repository at SourceForge. To compile the program you will need to install at least the following packages:

  • Subversion 1.8 or later

  • Qt 5.2 or later

  • g++ 4.8 or later

  • gfortran 4.8 or later

  • fftw3

  • MinGW (for Windows only)

Source code for WSJT-X 1.4.0 can be downloaded with the command:

svn co svn://svn.code.sf.net/p/wsjt/wsjt/tags/wsjtx-1.4.0

and for the current development branch,

svn co svn://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx

If you are interested in contributing to the development and documentation of WSJT and its sister programs, please join the developer’s email list wsjt-devel and let us know of your areas of interest.

4. Settings

Select Settings from the File menu or by typing F2 (on Macintosh, Cmd+,). The following sections describe setup optiions available on each of six 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 call sign and 4-digit or 6-digit grid locator. This information will be sufficient for initial tests.

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

4.2. Radio

WSJT-X offers CAT (Computer Aided Transceiver) control of the 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, Ham Radio Deluxe, Hamlib NET rigctl, or OmniRig, you may select one of those program names. In those 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 machine and/or port, specify it here. Hover the mouse pointer over the entry field to see the required formatting details.

  • Select OmniRig Rig 1 or OmniRig Rig 2 to connect to an OmniRig server running on the same computer. Note that OmniRig 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 used to communicate with your radio.

    • 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.

    • Force Control Lines: A few station setups require the serial port’s RTS and/or DTR control lines to be forced high. Check these boxes only if you are sure they are needed.

  • 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.

  • 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 simulate 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, just before 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 succesful CAT test, toggle the Test PTT button to confirm that your selected method of T/R control is working properly.

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.

Important 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 transmitting them over the air.
  • 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.

  • JT9W Settings: JT9W is an experimental mode designed for EME on the microwave bands, and is not enabled in current release versions.

4.4. Tx Macros

Tx Macros Screen

Tx Macros are an aid for sending brief, frequently used free-text messages.

  • 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 over program invocations.

4.5. Reporting

Reporting Screen
  • Logging: Choose any desired options from this group. For detailed descriptions of their effects, see Configuration in the Command Reference section.

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

4.6. Frequencies

Frequency Screen

Working Frequencies: By default the Frequency table lists the currently recommended dial frequencies for JT65. JT9 frequencies generally start 2 kHz higher. You can modify the frequency table as desired.

  • To change an existing entry, click to select it, type a desired frequency in MHz, and hit Enter on the keyboard. The program will format your frequency value appropriately and add a band designator.

  • To add a new entry, right-click anywhere on the frequency table and select Insert. Enter a frequency in MHz in the popup box, 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.

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.

  • For a simple setup approach 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 multiple 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.

5. Transceiver Setup

Receiver Noise Level
  • Click the Monitor button to return to normal receive operation. The button will be highlighted in green.

  • 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. If necessary you can also use the slider next to the scale, but note that the overall dynamic range will be best with this slider not too far from its mid-point.

Bandwidth and Frequency Setting
  • If your transceiver offers more than one bandwidth setting in USB mode, you should normally choose the widest one possible, up to about 5 kHz. This choice has the desirable effect of allowing the Wide Graph to display the JT65 and JT9 sub-bands simultaneously on most HF bands. Further details are provided in the Tutorial section.

  • 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, you can display the full sub-band generally used for one mode (JT65 or JT9) and part of the sub-band for the other mode.

  • Of course, you might prefer to concentrate on one mode at a time, setting your dial frequency to (say) 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. A checkbox labeled +2 kHz, just below the Band selector, makes the appropriate frequency settings easy.

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.

  • Open the computer’s audio mixer controls for output (“Playback”) devices and adjust the volume slider downward from its maximum until the RF output from your transmitter falls by around ten percent. This will be a good level for audio drive.

  • Alternatively, you can make the Tx audio level adjustment using the digital slider labeled Pwr at the right edge of the main window.

  • Toggle the Tune button once more to stop your test transmission.

6. Basic Operating Tutorial

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 Deepest from the Decode menu.

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

6.2. Wide Graph Settings

  • Bins/Pixel = 4

  • JT65 …. JT9 = 2500

  • Start = 0

  • N Avg = 5

  • Zero = 0

  • Gain = 0,

  • Palette = Digipan

  • Flatten = checked

  • Select Cumulative for data display.

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

6.3. Sample File 1

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\130418_1742.wav. When the file opens you should see something similar to the to the following screen shot:

Main UI and Wide Graph
Decoding Overview

Notice the red and green and markers on the Wide Graph (waterfall) frequency scale. Decoding takes place at the end of a receive sequence and is organized in two stages. The first decodes take place at the selected Rx frequency, indicated by the green marker on the waterfall 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(s) over the displayed frequency range. The red marker 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. 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:

  • Double-click on either of the decoded lines highlighted in green. This action produces 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 and Tx frequency markers are moved to the frequency of the CQing station.

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

    • If you had checked Double-click on call sets Tx Enable on the Setup menu, Enable Tx would be activated and a transmission would start automatically at the proper time.

  • Double-click on the decoded message “K1JT N5KDV EM41”, highlighted in red. Results will be similar to those in the previous step, except the Tx frequency (red marker) is not moved. Such messages 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.

  • By holding down the Ctrl key when double-clicking on a decoded line you can cause both Tx and Rx frequencies to be moved. This behavior can also be forced by checking Lock Tx=Rx.

  • Double-click on the message from KF4RWA in either window. He is sending “73” to K1JT, signifying that the QSO is over. Most likely you want to send 73 to him, so the message “KF4RWA K1JT 73” is automatically generated and selected for your next transmission. (Alternatively, you might choose to send a free text message or to call CQ again.)

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

6.4. Sample File 2

Wide Graph Settings:
  • Set Bins/Pixel = 7

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

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.

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

Wide Graph Decode 130610_2343
Tip Notice the BLUE marker on the waterfall scale, here set at 2500 Hz. Its position is set by the spinner control JT65 nnnn JT9, where nnnn is a frequency in Hz. In JT9+JT65 mode the program will automatically decode JT65 signals below this frequency and JT9 signals above it.

JT9 signals appear in the Cumulative spectrum as nearly rectangular shapes about 16 Hz wide. Although there is no clearly visible sync tone like the one at the low-frequency edge of JT65 signals, by convention the nominal frequency of a JT9 signal is taken to be that of its 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 @). The Band Activity window should contain these decodes (you may need to scroll back in the window to see them all):


Since the Tx mode was set to Tx JT65, signals in that mode were decoded first. If you had selected Tx JT9, JT9 signals would have been decoded first.

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

Tip 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 Tx and Rx frequencies to that of DL7ACA, 975 Hz. If you had checked Double-click on call sets Tx Enable on the Setup menu, the program would configure itself to start a QSO with DL7ACA.

  • 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 2600 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 0 to 2600 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.

Start, Zero, and Gain

Now is a good time to experiment with the Start, Zero, and Gain parameters. Start determines the frequency displayed at the left side of the waterfall scale. Zero sets the baseline level for colors, and Gain sets the sensitivity for color changes. For the receiver setup of this file good values are close to Zero=0, Gain=0. You may want to uncheck Flatten when adjusting the Zero and Gain controls. Re-open the wave file after each change, to see the new results.

Important 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:

UTC Transmitted Message Comment



K1ABC calls CQ



G0XYZ answers



K1ABC sends report



G0XYZ sends acknowledgment and report



K1ABC sends acknowledgment



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.

Signal reports are specified as signal-to-noise ratio (S/N) in dB, using a standard reference noise bandwidth of 2500 Hz. Thus, in example message at UTC 0003 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.

Tip 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 –24 dB for JT65, –26 dB for JT9.

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 nessages, as the program may then try to interpret your construction as part of a compound callsign. It should be obvious that the JT9 and JT65 protocols are not well suited for extensive conversations or rag-chewing.

7.3. Compound Callsigns

Compound callsigns such as xx/K1ABC or K1ABC/x are handled in one of two possible ways:

Type 1 Compound-Callsign Messages

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 message word (normally a locator, signal report, RRR, or 73). Thus, the following examples are all acceptable Type 1 messages with compound callsigns:


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

ZA/K1ABC G0XYZ -22        #These messages will be sent
G0XYZ K1ABC/4 73          #without the 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-Callsign Messages

Prefixes and suffixes not found in the short displayable list can be handled with a Type 2 message. 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 Type 2 messages with compound callsigns:

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

In each case, the message 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.

Tip Remember that during a transmission your transmitted message is always displayed in the first label on the Status Bar, highlighted in yellow. It is displayed there exactly as another station will receive it. Be sure to check 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

Each operator sends his own compound callsign in the first (and possibly also last) transmission, as may be required by licensing authorities. Subsequent transmissions may use the standard structured messages without callsign prefix or suffix.

Important It’s up to you, the operator, to ensure that messages with compound callsigns are composed in the manner described above. Double-clicking on a line of decoded text may not always produce the desired result.

7.4. Pre-QSO Checklist

Before attempting your first QSO with JT9 or JT65, 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

  • Radio set to USB (upper sideband) mode

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

  • Radio’s Split mode activated or not, consistent with your choice on the Radio tab of the Settings window. Verify both VFOs are set to USB if your rig allows each VFO an independent mode setting.

Important Remember that JT9 and J65 generally do not require high power. Under most HF propagation conditions, QRP is the norm.

8. Command Reference

8.1. Wide Graph

The following controls appear at the bottom of the Wide Graph window. With the exception of JT65 nnnn JT9, they affect only the graphical displays — they have no effect on the decoding process.

Wide Graph Controls
  • Bins/Pixel controls the displayed frequency resolution. Set this value to 1 for the highest possible resolution, or to higher numbers to compress the spectral display. Normal operation with a convenient window size works well at 2 to 8 bins per pixel.

  • JT65 nnnn JT9 sets the dividing point for wide-band decoding of JT65 and JT9 signals in JT9+JT65 mode. The decoder looks for JT65 signals below the specified frequency and JT9 signals above it.

  • Start nnn Hz sets the low-frequency starting point of the waterfall frequency scale.

  • N Avg is the number of successive FFTs to be averaged before updating the spectral display. Values around 5 are suitable for normal JT9 and JT65 operation. Adjust N Avg to make the waterfall move faster or slower, as desired.

  • Zero and Gain control the scaling and reference level for waterfall colors. Values around 0 for both parameters are usually about right, depending on the input signal level and your own preferences.

  • A dropdown list below the Palette label lets you select from a wide range of waterfall color palettes.

  • Click Adjust to activate a window that allows you to create a user-defined palette.

  • Check Flatten if you want WSJT-X to compensate for a sloping or uneven response across the received passband.

  • Select Current or Cumulative for the spectrum displayed in the bottom one-third of the Wide Graph window. Current is the average spectrum over the most recent N Avg FFT calculations. Cumulative is the average spectrum since the start of the present UTC minute.

8.2. Main Window

The following buttons appear just under the decoded text windows on the main screen:

Main UI Controls
  • Log QSO raises a dialog window pre-filled with known information about a QSO you have nearly completed. You can edit or add to this information before clicking OK to log the QSO. If you check Prompt me to log QSO on the Setup menu, the program will raise the confirmation screen automatically when you send a 73 or free-text message.

  • Stop will terminate normal data acquisition in case you want to freeze the waterfall or open and explore a previously recorded audio file.

  • Monitor restarts normal receive operation. This button is highlighted in green when the WSJT-X is receiving.

  • Erase clears the right-hand decoded text window. Double-clicking Erase clears both text windows.

  • Decode tells the program to repeat the decoding procedure at the Rx frequency (green marker on waterfall), using the most recently completed sequence of received data.

  • Enable Tx toggles the program into automatic T/R sequencing mode and highlights the button in red. A transmission will start at the beginning of the selected (odd or even) sequence, or immediately if appropriate. A transmission will not be started any later than 24 s into a UTC minute.

  • Halt Tx terminates a transmission in progress and disables automatic T/R sequencing.

  • Tune may be used to switch into Tx mode and generate an unmodulated carrier at the specified Tx frequency (red marker on waterfall). This process may be useful for adjusting an antenna tuner. The button is highlighted in red while Tune is active. Toggle the button a second time to terminate the Tune process.

8.3. Misc Controls Left

Controls related to frequency selection, received audio level, the station being called, and date and time are found at lower left of the main window:

Mist Menu Items
  • A drop-down list of frequencies and bands at upper left lets you select the operating band and sets dial frequency to a value taken from the Frequencies tab on the Settings window. If CAT control is active the radio’s dial frequency will be set accordingly; if not, you must tune the radio manually.

  • Alternatively, you can enter a frequency (in MHz) or band name in recognized ADIF format, for example 630m, 20m, or 70cm. The band-name format works only if a working frequency has been set up on that band, in which case the first working frequency on that band is selected.

  • If you are using CAT control, a small colored square appears in green if the CAT control is activated and functional. The green square contains the character S if the rig is detected to be in Split mode. The square becomes red if you have requested CAT control but communication with the radio has been lost.

Important Many Icom rigs cannot be queried for split status, so you should not change the split status using rig controls when using WSJT-X.
  • If DX Grid is a valid Maidenhead locator, its great-circle azimuth and distance from your location are displayed.

  • The program can maintain a database of callsigns and locators for future reference. Click Add to insert the present call and locator in the database; click Lookup to retrieve the locator for a previously stored call. This feature is mainly useful for situations in which the number of active stations is modest and reasonably stable, such as EME (Earth-Moon-Earth) communication.

8.4. Misc Controls Center

At the center of the main window are a number of controls used when making QSOs:

Misc Controls Center
  • Check Tx even to transmit in even-numbered UTC minutes. Uncheck this box to transmit in the odd minutes. This selection is made automatically when you double-click on a decoded text line, as described in the Basic Operating Tutorial.

  • The Tx and Rx audio frequencies are usually set automatically by double-clicking on decoded text or a signal in the waterfall. They can also be adjusted with spinner controls.

  • You can force Tx frequency to the current Rx frequency by clicking the Tx<Rx button, and vice-versa for Rx<Tx. (Copy is from right to left.) Check the box Lock Tx=Rx to make the frequencies always track one another. The on-the-air frequency of your lowest JT9 or JT65 tone is the sum of dial frequency and audio Tx frequency.

  • The Report control lets you change a signal report that has been inserted automatically. Most reports will fall in the range –26 to +10 dB. Remember that JT65 reports saturate at an upper limit of -1 dB.

Important When signals are close to or above 0 dB, you and your QSO partner should probably reduce power. JT65 and JT9 are supposed to be weak signal modes!

8.5. Tx Messages

Two arrangements of controls are provided for generating and selecting Tx messages. Traditional controls carried over from program WSJT appear on Tab 1, providing six fields for message entry. Pre-formatted messages for the standard minimal QSO are generated when you click Generate Std Msgs or double-click on an appropriate line in one of the decoded text windows.

Traditional Message Menu
  • Select the next message to be transmitted (at the start of your next Tx sequence) by clicking on the circle under Next.

  • To change to a specified Tx message immediately, click on a rectangular button under the Now label. Changing a Tx message in mid-stream will slightly reduce the chance of a correct decode, but it is usually OK if done in the first 10-15 s of a transmission.

  • All six Tx message fields are editable. You can modify an automatically generated message or enter a desired message, keeping in mind the strict limits on message content. See Protocol Specifications for details.

  • Click on the pull-down arrow for message #5 to select one of the pre-stored free-text messages entered on the Settings | Tx Macros tab. Pressing Enter on a modified message #5 automatically adds that message to the stored macros.

The second arrangement of controls for generating and selecting Tx messages appears on Tab 2 of the Message Control Panel:

New Message Menu

With this setup you normally follow a top-to-bottom sequence of transmissions from the left column if you are calling CQ, or the right column if answering a CQ.

  • Clicking a button puts the appropriate message in the Gen Msg box. If you are already transmitting, the Tx message is changed immediately.

  • You can enter and transmit anything (up to 13 characters) in the Free Msg box.

  • Click on the pull-down arrow in the Free Msg box to select a pre-stored macro. Pressing Enter on a modified message here automatically adds that message to the table of stored macros.

Important During a transmission the actual message being sent always appears highlighted in yellow in the first box of the status bar (bottom left of the main screen).

8.6. Status Bar

A Status Bar at the bottom edge of the main window provides information about operating conditions.

New Message Menu

Labels on the Status Bar display such information as the program’s current operating state, operating mode, the content of your most recent transmitted message, and whether Double-click on call sets Tx enable has been selected on the Settings | General tab. The first label (operating state) can be Receiving, Tx (for Transmitting), Tune, or the name of file opened from the File menu; this label is highlighted in green for Receiving, yellow for Tx, and red for Tune. When transmitting, the Tx message is displayed exactly as it will be decoded by receiving stations.

Program menus offer many options for configuration and operation. Most of the items are self-explanatory; a few additional details are provided below. Keyboard shortcuts for some frequently used menu items are listed at the right.

8.7.1. File menu

File Menu

8.7.2. WSJT-X menu

Mac App Menu

On Macintosh, Settings (otherwise found on the File menu) appears here instead, labeled as Preferences, and About WSJT-X appears here rather than on the Help menu.

8.7.3. View Menu

View Menu

8.7.4. Mode Menu

Mode Menu

8.7.5. Decode Menu

Decode Menu

8.7.6. Save Menu

Save Menu

Choose Save all to save received data as audio .wav files. Save decoded will save only those files containing at least one decoded message.

8.7.7. Help Menu

Help Menu