WSJT-X 2.3.0 released

The WSJT Development Group is pleased to announce the general availability (GA) release of WSJT-X Version 2.3.0. A summary of new features can be found in the WSJT-X 2.3 User Guide here:

You may also wish to consult the Release Notes:

… where the first several sections at the top contain a list of all important program changes since the GA release of WSJT-X 2.2.

Upgrading from earlier versions of WSJT-X should be seamless. There is no need to uninstall a previous version or move any files.

Links to installation packages for Windows, Linux, and Macintosh are available here:

You can also download the packages from our SourceForge site:
It may take a short time for the SourceForge site to be updated.

You may be interested to know that, somewhat unusually, a release candidate for Version 2.4.0 of WSJT-X will also be made available very soon. Its main new feature is a new mode called Q65 with unique capabilities for EME and scatter propagation modes.

WSJT-X is licensed under the terms of Version 3 of the GNU General Public License (GPL). Development of this software is a cooperative project to which many amateur radio operators have contributed. If you use our code, please have the courtesy to let us know about it. If you find bugs or make improvements to the code, please report them to us in a timely fashion.

We hope you will enjoy using WSJT-X Version 2.3.0.

— 73 from Joe, K1JT; Bill, G4WJS; Steve, K9AN; and Nico, IV3NWV
for the entire WSJT Development Group

1.1. New in Version 2.3.0

WSJT-X 2.3.0 introduces FST4 and FST4W, new digital protocols designed particularly for the LF and MF bands. Decoders for these modes can take advantage of the very small Doppler spreads present at these frequencies, even over intercontinental distances. As a consequence, fundamental sensitivities of FST4 and FST4W are better than other WSJT-X modes with the same sequence lengths, approaching the theoretical limits for their rates of information throughput. The FST4 protocol is optimized for two-way QSOs, while FST4W is for quasi-beacon transmissions of WSPR-style messages. FST4 and FST4W do not require the strict, independent phase locking and time synchronization of modes like EbNaut.

The new modes use 4-GFSK modulation and share common software for encoding and decoding messages. FST4 offers T/R sequence lengths of 15, 30, 60, 120, 300, 900, and 1800 seconds, while FST4W omits the lengths shorter than 120 s. Submodes are given names like FST4-60, FST4W-300, etc., the appended numbers indicating sequence length in seconds. Message payloads contain either 77 bits, as in FT4, FT8, and MSK144, or 50 bits for the WSPR-like messages of FST4W. Message formats displayed to the user are like those in the other 77-bit and 50-bit modes in WSJT-X. Forward error correction uses a low density parity check (LDPC) code with 240 information and parity bits. Transmissions consist of 160 symbols: 120 information-carrying symbols of two bits each, interspersed with five groups of eight predefined synchronization symbols.

We recommend that on the 2200 and 630 m bands FST4 should replace JT9 for making 2-way QSOs, and FST4W should replace WSPR for propagation tests. Operating conventions on these LF and MF bands will eventually determine the most useful T/R sequence lengths for each type of operation.