// 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 and worked with us until February 2026. Brian Moran, N9ADG,
joined the team in 2022; John Nelson, G4KLA and Charlie Suckling,
DL3WDG in 2024; Roger Rehr, W3SZ, in 2025; and Terrell Deppe, KJ5HST,
and David Christle, KD0BTO, in 2026. 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.

*Version Numbers* for our programs have major, minor, and patch
numbers separated by periods: for example, _WSJT-X 3.0.0_. 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
3.0.0-rc1, 3.0.0-rc2, etc., leading up to the general availability
(GA) release of version 3.0.0. 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 originally 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_.
