// Status=review

*_WSJT-X_* is an open source computer program designed to facilitate
basic amateur radio communication using very weak signals. The first
four letters in the program name stand for "`**W**eak **S**ignal
communication by K1**JT**,`" while the suffix "`*-X*`" indicates that
_WSJT-X_ started as an extended branch of an earlier program, _WSJT_,
which was first released by Joe Taylor, K1JT, in 2001.  Bill
Somerville, G4WJS, Steve Franke, K9AN, and Nico Palermo, IV3NWV, have
been major contributors to development of _WSJT-X_ since 2013, 2015,
and 2016, respectively. Bill Somerville died unexpectedly in December
2021; Uwe Risse, DG2YCB, joined the core development team soon
afterward, followed by Brian Moran, N9ADG in 2022, John Nelson, G4KLA
and Charlie Suckling, DL3WDG in 2024, and Roger Rehr, W3SZ, in
2025. Over the years many other hams have contributed to _WSJT-X_
development in more limited ways. We are extremely grateful for all of
these contributions.

_WSJT-X_ provides flexible rig control for nearly all modern radios
used by amateurs and a wide variety of special aids such as automatic
Doppler tracking for Earth-Moon-Earth (EME) QSOs and lunar-Echo
testing.  The program analyzes received passbands up to 5 kHz wide and
runs equally well on Windows, Macintosh, and Linux systems.

*_WSJT-X Improved_* was developed by Uwe Risse, DG2YCB, starting in
2020, and since 2021 it has evolved cooperatively with _WSJT-X_.  The
_Improved_ versions build on the _WSJT-X_ code base and offer three
different arrangements of main-window controls as well as new
features for enhanced operational functionality.  Compatibility
between _WSJT-X Improved_ and standard _WSJT-X_ has been carefully
maintained, so that user transitions between the two programs are
straightforward. Optional settings, station logs, and the like are
consistently preserved and used by both program versions. Innovations
from _WSJT-X Improved_ have been ported back into _WSJT-X_ at various
times; with program release 3.0, all features of _WSJT-X_ and _WSJT-X
Improved_ have been fully merged. Indeed, _WSJT-X 3.0_ and the _WSJT-X
Improved 3.0_ version with original user interface are now
identical. This _WSJT-X User Guide_ applies equally to both programs,
and we use the _Improved_ label only when necessary to make clear
distinctions between the programs.

Development of both _WSJT-X_ and _WSJT-X Improved_ will continue. The
_Improved_ version provides a familiar platform for trying out and
optimizing possible new features. Updates and new releases of _WSJT-X
Improved_ will be more frequent than those for standard _WSJT-X_. If
you are interested in trying and using the very latest features you
should watch for releases of _WSJT-X Improved_. Successful innovations
will be incorporated in _WSJT-X_.

*Version Numbers* for our programs have major, minor, and patch
numbers separated by periods: for example, _WSJT-X 2.7.0_ or _WSJT-X
Improved 2.7.0_. Temporary release candidates are sometimes made in
advance of a new general-availability (GA) release, in order to obtain
user feedback. Release candidates are given version labels such as
2.7.0-rc1, 2.7.0-rc2, etc., leading up to the general availability
(GA) release of version 2.7.0. Release candidates should be used only
during a defined testing period, and they carry an implicit obligation
to provide feedback to the program developers. Release candidates
should not be used on the air after a GA release with the same number.

*_MAP65_* and *_QMAP_* are companion programs written by K1JT to
facilitate Earth-Moon-Earth (EME, or "Moonbounce") communication with
digital protocols developed for _WSJT_ and _WSJT-X_. When used with
radio-frequency hardware providing coherent signal channels for two
orthogonal polarizations, _MAP65_ can yield automatic
polarization-matched reception for every JT65 or Q65 signal in a 90
kHz sub-band. _QMAP_ uses a single polarization channel and only the
Q65 mode, also covering a 90 kHz sub-band. It works cooperatively with
_WSJT-X_ to provide automatic Doppler compensation and other features
important for EME, especially on 1296 MHz and higher amateur bands.
These programs are installed automatically along with _WSJT-X_
(but _MAP65_ only on the Windows platform).

*_Hamlib_* is an independent, open-source software library that
provides a consistent Application Programming Interface (API) for
computer control of radios used by hams. _Hamlib_ is essential to all
features of _WSJT-X_ that control your radio, and the latest stable
version is included with all of our program releases. Like _WSJT-X_,
_Hamlib_ is under constant development by a group of volunteers.  When
necessary -- perhaps when you acquire a very new radio -- you can
update your active _Hamlib_ version from within _WSJT-X_.
