Program Development


WSJT-X implements JT9, a new mode designed especially for the LF, MF, and HF bands, as well as the popular mode JT65.  Both modes were 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 proved very effective for worldwide QRP communication at HF; in contrast, JT9 is optimized for HF and lower frequencies.  JT9 is about 2 dB more sensitive than JT65A while using less than 10% of the bandwidth.  World-wide QSOs are possible with power levels of a few watts and compromise antennas.  A 2 kHz slice of spectrum is essentially full when occupied by ten JT65 signals.  As many as 100 JT9 signals can fit into the same space, without overlap.

WSJT-X offers a "bi-lingual" operating mode in which you can transmit and receive JT65 and JT9 signals, switching between modes automatically as needed.  Displayed bandwidth can be as large as 5 kHz.  If your receiver has as upper-sideband filter at least 4 kHz wide, you can have all the typical JT65 and JT9 activity on screen at once, available for making QSOs with a click of the mouse.  Even with standard SSB-width IF filters, switching between JT65 and JT9 modes is quick and convenient.  Be sure to read the online WSJT-X User's Guide.

Future plans

Plans call for future versions of WSJT-X to include the other popular modes from WSJT: JT4, ISCAT, and FSK441.


Latest WSJT-X User's Guide

Linux: Thanks to AC6SL and KA6MAL, packages for v1.1.1 r3520 on Ubuntu 12.04, 12.10, 13.04, 13.10 are available at
        Ubuntu Linux installation instructions:

1. If you have not obtained packages from this PPA (Personal Package Archive) before:
$ sudo add-apt-repository ppa:jnogatch/wsjtx

2. To obtain the latest version from this PPA:
$ sudo apt-get update
$ sudo apt-get install wsjtx

3. You should also download kvasd and put it in the same directory as executable binaries wsjtx and jt9.  Normally (after running the script /usr/bin/wsjtx once) this directory will be $HOME/.wsjtx.

Macintosh OS X:  Thanks to G4KLA:
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