06/10/2021

WSJT-X version 2.4.0 now is available in general release. According to
co-developer Joe Taylor, K1JT, WSJT-X version 2.4.0, includes a new digital
mode, Q65. This protocol is designed for two-way contacts over especially
difficult propagation paths, including ionospheric scatter, troposcatter, rain
scatter, TEP, EME, and other types of fast-fading signals.

"On paths with Doppler spread more than a few Hertz, the weak-signal
performance of Q65 is the best among all WSJT-X modes," the Quick Start
Guide[1] asserts.

WSJT-X version 2.5.0-rc1 (beta) version has been released. According to the
Release Notes[2], version 2.5.0 "the Q65 decoder has been enhanced to measure
and compensate for linear frequency drift in Q65 signals."

Q65 uses 65-tone frequency-shift keying and builds on the demonstrated
weak-signal strengths of QRA64, a mode introduced to WSJT-X in 2016. Q65 offers
user message and sequencing identical to that in FST4, FT4, FT8, and MSK144. It
includes a unique tone for time and frequency synchronization. As with JT65,
this "sync tone" is readily visible on the waterfall spectral display. In
addition, Q65 provides a sensitive "sync curve" near the bottom of the
waterfall window.

Testing showed that Q65 will enable stations with a modest Yagi and 100 W or
more and to work one another on 6 meters at distances up to ~2000 kilometers on
most days of the year, in dead band conditions.

"An excellent example of targeted uses of Q65 is ionospheric scatter on the
6-meter band," the documentation states. "Extensive tests on the
1,150-kilometer path between K1JT and K9AN have shown that with 300 W power
output, nearly every Q65-30A transmission is copied correctly by the other
station." The 30A refers to the transmit-receive period and spacing width.

For the complete announcement and to download the latest version, visit the
WSJT-X website[3].

[1] https://physics.princeton.edu/pulsar/k1jt/Q65_Quick_Start.pdf
[2] https://physics.princeton.edu/pulsar/k1jt/Release_Notes.txt
[3] https://physics.princeton.edu/pulsar/k1jt/wsjtx.html

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