Filter
Top Products
Further Reading
1. A separate WSJT 4.6 Technical Manual (in preparation) provides technical
specifications and details on how the WSJT modes work. The Technical Manual
will be posted at
http://pulsar.princeton.edu/~joe/K1JT, the WSJT home
page, when available.
2. In the meantime, technical information can be found in the Version 3.0 WSJT User’s
Guide and Reference Manual, which is still available at
http://pulsar.princeton.edu/~joe/K1JT/WSJT300.PDF.
3. The first WSJT mode, FSK441, was described in QST for December 2001, in an
article starting on p. 36.
4. JT44, a predecessor to the JT65 mode, was described in QST for June 2002 in “The
World Above 50 MHz,” p. 81.
Acknowledgments
An earlier version of this manual was co-authored with Andy Flowers, K0SM. I started over for the
current version, but many remnants of Andy’s hard work remain.
Bob McGwier, N4HY, goaded me into learning something about error-correcting codes, and Phil
Karn, KA9Q, helped me to understand some of their subtleties. Particular thanks are due to Ralf
Koetter and Alexander Vardy, authors of a research paper entitled “Algebraic Soft-Decision
Decoding of Reed-Solomon Codes.” This paper introduced me to the powerful decoding algorithm
now used in the JT65 modes. Through their company CodeVector technologies, Koetter and Vardy
granted a license to adapt their computer code, which is protected under United States patent
6,634,007, for noncommercial purposes within WSJT.
Many users of WSJT have contributed in important ways to the program’s development. Shelby
Ennis, W8WN, ran many dozens of schedules with me during the development FSK441 and JT6M,
and likewise Jack Carlson, N3FZ, for JT65. I learned that if Shelby and Jack can’t make a program
crash, most other users won’t be able to, either. Many other users—far too many to name
individually—provided extremely helpful criticisms, suggestions, and feedback. I should
particularly mention Lance Collister, W7GJ, who has never tired of saying, in effect, “surely you can
still get us one more dB!” All of these efforts are greatly appreciated.
18