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New WSJT-X Beta Version Offers Significant FT4 and FT8 Upgrades


A new beta version of the WSJT-X software suite has been released that includes the first updates to the popular FT8 and FT4 protocols since last fall. Co-Developer Joe Taylor, K1JT, said the “candidate release” WSJT-X version 2.2.0-rcl represents significant program upgrades to FT8, FT4, and other protocols. The beta version will be valid for a month.

“This candidate release is your first chance to test the new features and provide feedback to the WSJT Development Group,” Taylor advised. A list of program changes since WSJT-X 2.1.2 is available in the cumulative Release Notes and in the updates WSJT-X 2.2.0 User Guide.

The latest beta version corrects bugs that prevented AP (a priori) decoding and/or multi-pass decoding in some circumstances. The algorithm for AP decoding has been improved and extended. FT8 decoding is now spread over three intervals — starting at 11.8 seconds into a receive sequence, typically yielding around 85% of the possible decodes for the sequence. “You, therefore, see most decodes much earlier than before,” the Release Notes explain. A second processing step starts at 13.5 seconds, and a final step at 14.7 seconds.

“Overall decoding yield on crowded bands is improved by 10% or more,” the Release Notes say, although systems with receive latency greater than 0.2 seconds will experience smaller improvements, even while seeing many decodes sooner.

Other changes:

  • The “contest mode” FT4 protocol always uses “RR73” for the TX4 message.
  • The status bar now displays the number of decodes in the most recent receive sequence.

Release candidate WSJT-X 2.2.0-rcl will be available for 1 month (starting on May 10). A general availability release of WSJT-X 2.2.0 is anticipated for June 1.

“For those looking even farther ahead, we are well along in the development of two new modes designed for the LF and MF bands,” Taylor said. “One mode is for WSPR-like activity, and one is for making 2-way contacts.” Both will use 2-minute transmit-receive sequences. The contact-mode protocol reaches threshold signal-to-noise ration of around –31 dB.

Taylor said that upgrading from earlier versions of WSJT-X should be seamless, with no need to uninstall a previous version or to move any files, although he said beta testers may wish to install the beta version in a directory separate from the “general availability” WSJT-X 2.1.2 installation.

Installation packages for Windows, Linux, and Macintosh are available on the WSJT-X Development Group page. Scroll down to “Candidate release: WSJT-X 2.2.0-rc1.” The packages are also available from SourceForge.

The WSJT-X Development Group request those using the new beta version of WSJT-X to alert the developers and to report any bugs or improvements they have implemented, using instructions included in the User Guide.   



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