Weak Signal Communication SoftwareWSJT, MAP65, and WSPR are open-source programs designed for weak-signal digital communication by amateur radio. Normal usage requires a standard SSB transceiver and a personal computer with soundcard. Some SDR-style hardware including the SDR-IQ, Perseus, SoftRock, and FUNcube Dongle are also supported.
SimJT is a utility that generates simulated signals for test purposes. Ready-to-run Windows versions of all four programs are available for free download. Installation files for Linux are available for WSJT and WSPR. For other operating systems, see the Program Development page.
WSJT (“Weak Signal Communication, by K1JT”) offers specific digital protocols optimized for meteor scatter, ionospheric scatter, and EME (moonbounce) at VHF/UHF, as well as HF skywave propagation. The program can decode fraction-of-a-second signals reflected from ionized meteor trails and steady signals 10 dB below the audible threshold. Check the WSJT page for details about new modes in WSJT 9.3 and the experimental program release WSJT-X.
MAP65 version 2 implements a wideband receiver for JT65 signals. It can be used together with Linrad (by SM5BSZ) or SDR-Radio (by HB9DRV), or with direct input from a soundcard. The program decodes all detectable JT65 signals in a passband up to 90 kHz wide, producing a band map of decoded callsigns sorted by frequency. The principal application of MAP65 is EME on the VHF and UHF bands. In a dual-polarization system, MAP65 optimally matches the linear polarization angle of each decodable signal, thereby eliminating problems with Faraday rotation and spatial polarization shifts. Check the MAP65 page for details on modes JT65B2 and JT65C2 in MAP65 v2.4.
WSPR (pronounced “whisper”) stands for “Weak Signal Propagation Reporter.” This program is designed for sending and receiving low-power transmissions to test propagation paths on the MF and HF bands. Users with internet access can watch results in real time at WSPRnet. Version 2.11 of WSPR includes FMT, a package of command-line utilities that can help you make highly accurate frequency measurements without expensive laboratory equipment.
SimJT generates JT65 and CW test signals with a user-specified signal-to-noise ratio. It is useful for testing the JT65 decoder and the relative capabilities of these two modes.
DescriptionWSJT facilitates basic digital communication using protocols explicitly optimized for a number of different propagation modes.
The latest release, WSJT 9.3, includes several relatively new modes not yet described in the User’s Guide.
ISCAT now has two sub-modes. ISCAT-B is the original ISCAT mode with total bandwidth 1809 Hz. ISCAT-A runs at half the rate, uses half the bandwidth, and (for average decodes on steady signals) is about 1 dB more sensitive. It has been found very effective for making aircraft scatter QSOs at 10 GHz. ISCAT-B probably remains the best mode for 6 meters, but experimentation is encouraged!
JT65B2 and JT65C2 use the same tone spacing as JT65B and JT65C, respectively. They are keyed at twice the rate, and T/R sequences are 30 seconds rather than one minute. Sensitivity of the fast modes is 3 dB worse than the standard modes. The B2 and C2 modes allow EME contest QSOs to be made at twice the rate, up to about 20 QSOs per hour.
WSJT-X is an experimental release implementing JT9, a new mode designed especially for use on the MF and LF bands. Be sure to read its User’s Guide before attempting to use the program!
ProtocolsSee User’s Guide for details.
FSK441 for meteor scatter
JT6M for ionospheric scatter
JT65 for EME at VHF/UHF, and for HF skywave propagation
JT2, JT4, WSPR: experimental modes
Windows WSJT 9.3 (v9.3, r2956)
Linux WSJT 9.0
WSJT 9.0 Supplement to User’s Guide
WSJT-X User’s Guide
Windows WSJT-X (v0.5, r2791)
Archival releases of WSJT7
Windows WSJT 7.07
Linux WSJT 7.06
Archival Windows release WSJT 5.9.8
Archival Windows release WSJT 4.9.8
For Linux and other O/S: see Program Development
Sample files for User’s Guide Tutorial
User’s Guide and Reference Manual
(English version is included with program download.)
DescriptionMAP65 works together with suitable hardware that converts RF to baseband. The hardware/software combination implements a wideband, highly optimized receiver for the JT65 protocol, with matching transmitting features using a standard SSB transceiver. MAP65 can be used in both single-polarization and dual-polarization systems. If two polarization channels are available, MAP65 determines and matches the linear polarization angle of each decodable signal. This capability provides a major advantage for efficient EME (“Moonbounce”) communication on the 144 and 432 MHz bands. A single-channel system works extremely well for 23 cm EME, displaying all signals (both CW and JT65) in the sub-band 1296.000 to 1296.090 MHz and decoding the JT65 signals.
MAP65 can accept input signals directly from a soundcard capable of sampling at 96000 samples per second. Two audio channels (one “stereo” channel) are required for a single polarization system, and four channels for dual polarization. Optionally, Linrad (by SM5BSZ) or SDR-Radio (by HB9DRV) can be used as convenient and highly effective “front ends” between receiver hardware and MAP65’s data input. Linrad offers extremely effective noise-blanking capabilities, especially when strong signals are present in the receiver passband. SDR-Radio offers user-friendly control of supported receiver hardware, as well as many useful and attractive displays. MAP65 also supports the FUNcube Dongle and several all-digital receivers including the SDR-IQ and Perseus.
The latest release, MAP65 2.4.1, includes two new modes not yet described in the User’s Guide. JT65B2 and JT65C2 use the same tone spacing as JT65B and JT65C, respectively. They are keyed at twice the rate, and T/R sequences are 30 seconds rather than one minute. Sensitivity of the fast modes is 3 dB worse than the standard modes. The B2 and C2 modes allow EME contest QSOs to be made at twice the rate, up to about 20 QSOs per hour.
The following hardware and software combinations are known to work well with MAP65:
WSE with Linrad or direct input from 4-channel soundcard
IQ+ with Linrad or direct input from 4-channel soundcard
SDR-IQ, other RFspace radios, or Perseus with Linrad or SDR-Radio
FUNcube Dongle with Linrad, SDR-Radio, or direct USB input
SoftRock or similar with Linrad, SDR-Radio, or direct input from 2-channel soundcard
MAP65 User’s Guide
Italian (translation by IK1UWL)
MAP65 (v2.4.1, r2587) (7 MB)
MAP65 sample file (dual polarization) (20 MB)
MAP65 sample file (single polarization) (10 MB)
DescriptionWSPR implements a protocol designed for probing potential propagation paths with low-power transmissions. Normal transmissions carry a station’s callsign, Maidenhead grid locator, and transmitter power in dBm. The program can decode signals with S/N as low as -28 dB in a 2500 Hz bandwidth. Stations with internet access can automatically upload their reception reports to a central database called WSPRnet, which includes a mapping facility. To see a live version of the map pictured at top right, click here.
WSPR 2.0 introduces a number of new features including a user-friendly setup screen with drop-down selection of audio devices and rig-control parameters, support for compound callsigns, fine selection of the fractional time for transmitting, and a Tune button. A new Advanced setup screen offers optional CW identification and tools for frequency calibration and automated frequency corrections for your radio. Full details are presented in the WSPR 2.0 User’s Guide, which you will need to read in order to use the new features. For the first time, a binary installation package is made available for Ubuntu Linux (versions 8.10 and later), Debian 5.03, and other Debian-based 32-bit Linux distributions.
WSPR 2.11 is a beta release that includes two major enhancements:
Support for software-defined receivers and transceivers that use complex (I-Q) sampling, such as the popular SoftRock kits.
FMT, a package of command-line programs designed for use in the ARRL Frequency Measuring Test and similar frequency-measuring tasks.
Windows: WSPR 2.0 WSPR 2.11 and FMT
Linux (.deb file): WSPR 2.0 WSPR 2.11 and FMT
Other O/S: see Program Development
WSPR 2.1: Supplement to User’s Guide (English)
WSPR 2.1: Supplement to User’s Guide (Italian, IK1UWL)
WSPR 2.1: Supplement to User’s Guide (Spanish, EA2SN)
FMT User’s Guide (English)
WSPR 2.0 User’s Guide (English)
WSPR 2.0 User’s Guide (French, F1ERG)
WSPR 2.0 User’s Guide (German, DL3LST)
WSPR 2.0 User’s Guide (German, DJ6LB)
WSPR 2.0 User’s Guide (Italian, IK1UWL)
WSPR 2.0 User’s Guide (Japanese, JA7UDE)
WSPR 2.0 User’s Guide (Polish, OE1KDA)
WSPR 2.0 User’s Guide (Portuguese, PY3FF)
WSPR 2.0 User’s Guide (Russian, UA6JD)
WSPR 2.0 User’s Guide (Spanish, EA2SN)
DescriptionSimJT is a simulation program. It generates audio-frequency JT65 and CW signals in a background of gaussian white noise, with user-specified signal-to-noise ratio.
Download for Windows
DocumentationSimJT User’s Guide (English version is included in program package)
Operating SystemsWSJT, MAP65, and WSPR can be compiled for Windows, Linux, FreeBSD, Macintosh OS/X, and most other UNIX-like operating systems. The download links on pages for each program retrieve pre-compiled installation packages for Microsoft Windows, and in some cases also for Ubuntu and other Debian-based 32-bit Linux distributions. Users of other operating systems or distributions must compile the programs from source code.
Source CodeWSJT, MAP65, MAP65-IQ, and WSPR are open source programs distributed under terms of the GNU General Public License. Source code for SimJT is available on request. KVASD (a soft-decision Reed Solomon decoder for the JT65 mode) is distributed only in executable form because of licensing restrictions.
The graphical user interfaces (GUIs) for WSJT and WSPR are written in Python. Most of the number-crunching in these programs is done in Fortran, and some system-level functions are implemented in C.
Version 2 of MAP65 represents the most recent (April 2012) shift in WSJT-related programming practices. The MAP65 GUI is written in C++ using the open-source Qt framework. As with WSJT and WSPR, most of the number-crunching is done in Fortran.
Anyone interested in the communication problems addressed by WSJT, MAP65, and WSPR is invited to study, adapt, modify, or enhance the code and contribute to further development of the programs. Source code is maintained under the version control program Subversion (“svn”) in a public open-source repository at Berlios. For updates and other information on the continuing development of WSJT, MAP65, and WSPR, you are invited to subscribe to the WSJT developers email list.
Explicit Downloading InstructionsPresent and past versions of the source code for WSJT, MAP65, MAP65-IQ, and WSPR may be downloaded by using svn commands. For example, the latest revisions of source code for can be “checked out” with the commands
svn co svn://svn.berlios.de/wsjt/trunk
svn co svn://svn.berlios.de/wsjt/branches/map65
svn co svn://svn.berlios.de/wsjt/branches/wspr
You will need to understand svn in order to use the source-code repository effectively.
To compile WSJT and WSPR on a unix-like system (Linux, FreeBSD, Macintosh OS X, …) you may need to install some or all of the following packages:
gfortran or g95
Compiling MAP65 requires Qt rather than Python. Full instructions for building MAP65 and its dependencies will be posted soon.
AcknowledgementThe soft-decision Reed-Solomon decoder used in WSJT and MAP65 is based on an algorithm developed by R. Koetter and A. Vardy and protected under United Stated Patent number 6,634,007. It uses code licensed from CodeVector Technologies, LLC.
“WSJT: New Software for VHF Meteor-Scatter Communication.” (QST, December 2001)
“JT44: New Digital Mode for Weak Signals.” (QST, June 2002)
“EME with JT65” (QST, June 2005)
“The JT65 Communications Protocol” (QEX, September-October 2005).
“WSJT: Meteors, Moonbounce, and More.” (Mid-Atlantic States VHF Conference, September 2005)
“Open Source WSJT: Status, Capabilities, and Future Evolution.” (12th International EME Conference, Wurzburg, August 2006)
“Open Source WSJT.” (PowerPoint presentation)
“How Many Bits are Copied in a JT65 Transmission?” (DUBUS, 3/2006)
“Recommended Procedures for Random Digital EME.” (DUBUS, 3/2006)
“MAP65: A Panoramic, Polarization-Matching Receiver for JT65.” (Microwave Update, October 2007)
“Quest for Optimum Coding and Modulation Schemes for EME.” (13th International EME Conference, Florence, August 2008)
Earth-Moon-Earth (EME) Communication (from ARRL Handbook, 2010)
“Moonbounce from Arecibo Observatory” (QST, August 2010)
“Frequency-Dependent Characteristics of the EME Path” (14th International EME Conference, Dallas, August 2010)
“Frequency-Dependent Characteristics of the EME Path” (PowerPoint slides: 14th International EME Conference, Dallas, August 2010)
“WSPRing Around the World” (QST, November 2010)
“MAP65 Version 2: A Panoramic, Polarization-Matching Receiver for JT65” (15th International EME Conference, Cambridge, August 2012)
“MAP65 Version 2: A Panoramic, Polarization-Matching Receiver for JT65” (PowerPoint Slides: 15th International EME Conference, Cambridge, August 2012)
Recently updated CALL3.TXT and other VHF databases.