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108 lines
5.7 KiB
Plaintext
108 lines
5.7 KiB
Plaintext
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__ __ ______ _____ ________ __ __
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| \ _ | \ / \ | \| \ | \ | \
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| $$ / \ | $$| $$$$$$\ \$$$$$ \$$$$$$$$ | $$ | $$
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| $$/ $\| $$| $$___\$$ | $$ | $$ ______ \$$\/ $$
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| $$ $$$\ $$ \$$ \ __ | $$ | $$| \ >$$ $$
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| $$ $$\$$\$$ _\$$$$$$\| \ | $$ | $$ \$$$$$$/ $$$$\
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| $$$$ \$$$$| \__| $$| $$__| $$ | $$ | $$ \$$\
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| $$$ \$$$ \$$ $$ \$$ $$ | $$ | $$ | $$
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\$$ \$$ \$$$$$$ \$$$$$$ \$$ \$$ \$$
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Copyright (C) 2001 - 2023 by Joe Taylor, K1JT.
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WSJT-X Version 2.6.1 offers eleven different protocols or modes: FT4,
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FT8, JT4, JT9, JT65, Q65, FST4, MSK144, WSPR, FST4W, and Echo. The
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first seven are designed for making reliable QSOs under weak-signal
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conditions. They use nearly identical message structure and source
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encoding. JT65 and Q65 were designed for EME (“moonbounce”), but not
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limited to just that propagation path, on the VHF/UHF bands and JT65
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has also proven very effective for worldwide QRP communication on the
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HF bands. Q65 has a number of advantages over JT65, including better
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performance on the very weakest signals and variants with different
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T/R period lengths. We imagine that over time it may replace JT65 for
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EME use, it has also proved to be very effective for iono-scatter
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paths on 6m. JT9 was originally designed for the LF, MF, and lower HF
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bands. Its submode JT9A is 2 dB more sensitive than JT65 while using
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less than 10% of the bandwidth. JT4 offers a wide variety of tone
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spacings and has proven highly effective for EME on microwave bands up
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to 24 GHz. These four “slow” modes use one-minute timed sequences of
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alternating transmission and reception, so a minimal QSO takes four to
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six minutes — two or three transmissions by each station, one sending
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in odd UTC minutes and the other even. FT8 is operationally similar
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but four times faster (15-second T/R sequences) and less sensitive by
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a few dB. FT4 is faster still (7.5 s T/R sequences) and especially
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well suited for radio contesting. On the HF bands, world-wide QSOs are
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possible with any of these modes using power levels of a few watts (or
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even milliwatts) and compromise antennas. QSOs are possible at signal
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levels 10 to 15 dB below those required for CW. FST4 has similarities
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in use to JT9 but offers more flexibility as it offers different
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period lengths allowing QSO completion time to be traded off against
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sensitivity. In its base form of FST4-60A it has better sensitivity
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than JT9A and should be considered as an upgrade where JT9 has been
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the preferred slow QSO mode.
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Note that even though their T/R sequences are short, FT4 and FT8 are
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classified as slow modes because their message frames are sent only
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once per transmission. All fast modes in WSJT-X send their message
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frames repeatedly, as many times as will fit into the Tx sequence
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length.
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MSK144, and optionally submodes JT9E-H are “fast” protocols designed
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to take advantage of brief signal enhancements from ionized meteor
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trails, aircraft scatter, and other types of scatter
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propagation. These modes use timed sequences of 5, 10, 15, or 30 s
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duration. User messages are transmitted repeatedly at high rate (up to
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250 characters per second, for MSK144) to make good use of the
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shortest meteor-trail reflections or “pings”. MSK144 uses the same
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structured messages as the slow modes and optionally an abbreviated
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format with hashed callsigns.
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WSPR (pronounced “whisper”) stands for Weak Signal Propagation
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Reporter. The WSPR protocol was designed for probing potential
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propagation paths using low-power transmissions. WSPR messages
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normally carry the transmitting station’s callsign, grid locator, and
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transmitter power in dBm, and they can be decoded at signal-to-noise
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ratios as low as -31 dB in a 2500 Hz bandwidth. WSPR users with
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internet access can automatically upload reception reports to a
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central database called WSPRnet that provides a mapping facility,
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archival storage, and many other features.
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FST4W, like WSPR, is a quasi-beacon mode, it targets LF and MF bands
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and offers a number of T/R periods form 2 minutes up to 30 minutes for
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the most challenging weak signal paths. Similarly to WSPR reception
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reports can be automatically uploaded to the WSPRnet.org web service.
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Echo mode allows you to detect and measure your own station’s echoes
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from the moon, even if they are far below the audible threshold.
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WSJT-X provides spectral displays for receiver passbands as wide as 5
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kHz, flexible rig control for nearly all modern radios used by
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amateurs, and a wide variety of special aids such as automatic Doppler
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tracking for EME QSOs and Echo testing. The program runs equally well
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on Windows, Macintosh, and Linux systems, and installation packages
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are available for all three platforms.
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WSJT-X is an open-source project released under the GPLv3 license (See
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COPYING). If you have programming or documentation skills or would
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like to contribute to the project in other ways, please make your
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interests known to the development team. The project’s source-code
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repositories can be found at
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https://sourceforge.net/p/wsjt/wsjtx/ci/master/tree/, and
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communication among the developers takes place on the email reflector
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https://sourceforge.net/p/wsjt/mailman. User-level questions and
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answers, and general communication among users is found on the
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https://wsjtx.groups.io/g/main email reflector.
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Project web site:
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https://wsjt.sourceforge.io/wsjtx.html
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Project mailing list (shared with other applications from the same
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team):
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https://sourceforge.net/projects/wsjt/lists/wsjt-devel
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