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96 lines
5.0 KiB
Plaintext
96 lines
5.0 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 - 2019 by Joe Taylor, K1JT.
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WSJT-X Version 2.1 offers ten different protocols or modes: FT4, FT8,
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JT4, JT9, JT65, QRA64, ISCAT, MSK144, WSPR, and Echo. The first six
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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 QRA64 were designed for EME (“moonbounce”) on the
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VHF/UHF bands and have also proven very effective for worldwide QRP
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communication on the HF bands. QRA64 has a number of advantages over
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JT65, including better performance on the very weakest signals. We
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imagine that over time it may replace JT65 for EME use. JT9 was
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originally designed for the LF, MF, and lower HF bands. Its submode
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JT9A is 2 dB more sensitive than JT65 while using less than 10% of the
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bandwidth. JT4 offers a wide variety of tone spacings and has proven
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highly effective for EME on microwave bands up to 24 GHz. These four
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“slow” modes use one-minute timed sequences of alternating
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transmission and reception, so a minimal QSO takes four to six minutes
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— two or three transmissions by each station, one sending in odd UTC
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minutes and the other even. FT8 is operationally similar but four
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times faster (15-second T/R sequences) and less sensitive by a few
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dB. FT4 is faster still (7.5 s T/R sequences) and especially well
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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.
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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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ISCAT, MSK144, and optionally submodes JT9E-H are “fast” protocols
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designed to take advantage of brief signal enhancements from ionized
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meteor 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”. ISCAT uses free-form
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messages up to 28 characters long, while 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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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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repository can be found at https://sourceforge.net/projects/wsjt, 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://groups.yahoo.com/neo/groups/wsjtgroup/info email reflector.
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Project web site:
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https://www.physics.princeton.edu/pulsar/K1JT/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://groups.yahoo.com/neo/groups/wsjtgroup
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