WSJT-X – JT-65 and JT-9 on OS X

As many of you know, over the last few years JT65 has become one of the most popular digital modes on HF. Developed by Nobel Laureate Joe Taylor (K1JT), JT65 is a weak-signal mode originally designed for EME operation and included in the WSJT software program for Linux and Windows. Thanks largely to the efforts of Joe Large (W6CQZ) and his hugely popular Windows JT65-HF software, JT65 operation was simplified and is now widely used for routine terrestrial contacts on HF. Having attracted a large base of users around the world, JT65-HF added many great features such as multi-decode and a simplified interface that made JT65 more accessible for many.

Continuously experimenting with weak-signal modes, Joe Taylor continued his development of new modes with an eye on improving both signal sensitivity and spectral efficiency, resulting in the release of the new mode JT9.  JT9 is a superior mode for HF operation, being about 2dB more sensitive while operating in approximately 10% of the spectrum space utilized by JT65.  In order to support this new mode as well as a move to a new development environment, Joe Taylor released a new version of WSJT known as WSJT-X.  WSJT-X supports both the JT65 and JT9 modes and incorporates many of the enhancements originally developed by Joe Large for JT65-HF; including multi-decode and simultaneous decode of both JT65 and JT9 modes with seamless transition between the two.

Although the JT65 revolution started on Linux and Windows, there have been attempts to migrate it to OS X as well. Some of these were versions of JT65-HF wrapped in WINE for use on OS X while others compiled WSJT from source to run on OS X.

The best thing to come out of the development of WSJT-X, at least for OS X users, is the release of a native OS X application for the software.  Currently at v1.3 r3673, the OS X version is assembled by John Nelson (G4KLA) and is available for OS X 10.6 – 10.9.  Preparation for running WSJT-X on OS X does require a bit of command line usage, but it is fully-explained, simple and only has to be done during the initial installation.

The OS X version can be downloaded at

Download it, follow the directions in the Readme file, and before long you too will be joining the JT65 revolution!