To:      Users of WSJT
From:    Joe Taylor, K1JT
Subject: WSJT 5.9.0
Date:    November 14, 2005

I am pleased to announce that WSJT 5.9.0 is available for free
download from the WSJT Home Page,
http://pulsar.princeton.edu/~joe/K1JT.  It should appear soon
on the European mirror site, http://www.dk5ya.de, as well.

I believe that all reported bugs found in beta-release version 5.8.6
have been fixed.  In addition, new enhancements have taken the program
well beyond the capabilities of the baseline comparison versions,
4.9.8 and 5.8.6.

The new WSJT 5.9.0 is faster and better than previous versions in a
number of ways.  A brief description of the enhancements since version
5.8.6 can be found at
http://pulsar.princeton.edu/~joe/K1JT/UpdateHistory.txt.  There are
many program changes, so be sure to read this information carefully
before trying to use WSJT 5.9.0!

Of course there may be some new bugs, and perhaps I have overlooked an
existing problem that you already know about.  Please let me know if
you find shortcomings in version 5.9.0, or if you have suggestions for
further improvements.

Sorry, I have not yet found time to implement EME Echo mode.  When
that is done, and when I have finished some further enhancements to
the decoders, WSJT 6.0 will be born.  With some luck, there may also
be a new User's Guide at about that time.

With best wishes,
			-- 73, Joe, K1JT


Additional Information for Programmers
-----------------------------------------------------------------------

WSJT versions 5.8+ are the result of a complete re-write of the user
interface, timing control, and audio I/O portions of WSJT 4.9.8.  My
principal motivation was to make the program multi-threaded, both for
real-time operational convenience and for performance reasons.
Another strong motivation was a desire to move the program away from
its dependence on a proprietary compiler (Microsoft Visual Basic) and
a single computer platform (Windows).

The user interface of WSJT 5.8+ is written in Python -- an elegant,
open, cross-platform language that has been a pleasure for me to
learn.  The remainder of the program is written mostly in Fortran,
with some routines coded in C; much of that code has been carried over
directly from WSJT 4.9.8.  

I hope soon to release the source code for WSJT under the GNU General
Public License (GPL).  To this end, I have separated out the one piece
of proprietary code formerly in the program -- the soft-decision Reed
Solomon decoder licensed from CodeVector Technologies (CVT).  A driver
for this decoder, optimized for JT65, has been compiled into a
stand-alone executable that is now distributed as part of the WSJT
installation package, but not part of the program itself.  With this
approach I can honor all provisions of the CVT license, and at the
same time release everything else as an open source program under the
GPL.

WSJT 5.9.0 now includes an open source hard-decision Reed Solomon
decoder based on code written by Phil Karn, KA9Q .  WSJT uses this
decoder automatically if the proprietary CVT decoder is unavailable.
In such instances the "deep search" decodes retain their full
sensitivity, but fully general decoding independent of the callsign
database will be less sensitive by 2 or more dB, depending on signal
fading characteristics.  Separation of the program into two executable
units is transparent to the user.

WSJT 5.9.0 uses the following open source libraries, which are also
available under the GPL:

  1. FFTW, by Matteo Frigo and Steven Johnson, for computing Fourier
     transforms

  2. "Secret Rabbit Code" or "libsamplerate", by Erik de Castro, for
     accomplishing band-limited resampling of data

  3. RS, by Phil Karn, KA9Q, for Reed Solomon encoding and
     hard-decision decoding.

I hope that the open release of WSJT source code will encourage others
to read and understand the code, get involved in improving WSJT, and
perhaps porting it to other platforms.  Versions of the CVT
soft-decision decoder for Linux or Macintosh will be easy to compile
and distribute, if there is demand for them.