Merged master 8748

2018-08-05 11:33:30 -04:00
parent 8f8772f1bd
commit 62899069bf
1222 changed files with 70382 additions and 406763 deletions
@@ -0,0 +1,74 @@
+// Status=review
+
+_WSJT-X_ is a computer program designed to facilitate basic amateur
+radio communication using very weak signals. The first four letters in
+the program name stand for "`**W**eak **S**ignal communication by
+K1**JT**,`" while the suffix "`-X`" indicates that _WSJT-X_ started as
+an extended and experimental branch of the program
+_WSJT_.
+
+_WSJT-X_ Version 1.9 offers nine different protocols or modes: *FT8*,
+*JT4*, *JT9*, *JT65*, *QRA64*, *ISCAT*, *MSK144*, *WSPR*, and *Echo*.
+The first five are designed for making reliable QSOs under extreme
+weak-signal conditions. They use nearly identical message structure
+and source encoding.  JT65 and QRA64 were designed for EME
+("`moonbounce`") on the VHF/UHF bands and have also proven very
+effective for worldwide QRP communication on the HF bands.  QRA64 has
+a number of advantages over JT65, including better performance on the
+very weakest signals.  We imagine that over time it may replace JT65
+for EME use.  JT9 was originally designed for the LF, MF, and lower HF
+bands.  Its submode JT9A is 2 dB more sensitive than JT65 while using
+less than 10% of the bandwidth.  JT4 offers a wide variety of tone
+spacings and has proven highly effective for EME on microwave bands up
+to 24 GHz.  These four "`slow`" modes use one-minute timed sequences
+of alternating transmission and reception, so a minimal QSO takes four
+to six minutes — two or three transmissions by each station, one
+sending in odd UTC minutes and the other even.  FT8 is operationally
+similar but four times faster (15-second T/R sequences) and less
+sensitive by a few dB.  On the HF bands, world-wide QSOs are possible
+with any of these modes using power levels of a few watts (or even
+milliwatts) and compromise antennas.  On VHF bands and higher, QSOs
+are possible (by EME and other propagation types) at signal levels 10
+to 15 dB below those required for CW.
+
+*ISCAT*, *MSK144*, and optionally submodes *JT9E-H* are "`fast`"
+protocols designed to take advantage of brief signal enhancements from
+ionized meteor trails, aircraft scatter, and other types of scatter
+propagation. These modes use timed sequences of 5, 10, 15, or 30 s
+duration.  User messages are transmitted repeatedly at high rate (up
+to 250 characters per second, for MSK144) to make good use of the
+shortest meteor-trail reflections or "`pings`".  ISCAT uses free-form
+messages up to 28 characters long, while MSK144 uses the same
+structured messages as the slow modes and optionally an abbreviated
+format with hashed callsigns.  
+
+*WSPR* (pronounced "`whisper`") stands for **W**eak **S**ignal
+**P**ropagation **R**eporter.  The WSPR protocol was designed for probing
+potential propagation paths using low-power transmissions. WSPR
+messages normally carry the transmitting station’s callsign, grid
+locator, and transmitter power in dBm, and they can be decoded at
+signal-to-noise ratios as low as -28 dB in a 2500 Hz bandwidth.  WSPR
+users with internet access can automatically upload reception
+reports to a central database called {wsprnet} that provides a mapping
+facility, archival storage, and many other features.
+
+*Echo* mode allows you to detect and measure your own station's echoes
+from the moon, even if they are far below the audible threshold.
+
+_WSJT-X_ provides spectral displays for receiver passbands as wide as
+5 kHz, flexible rig control for nearly all modern radios used by
+amateurs, and a wide variety of special aids such as automatic Doppler
+tracking for EME QSOs and Echo testing.  The program runs equally well
+on Windows, Macintosh, and Linux systems, and installation packages
+are available for all three platforms.
+
+*Version Numbers:* _WSJT-X_ release numbers have major, minor, and
+patch numbers separated by periods: for example, _WSJT-X_ Version
+1.9.0.  Temporary "`beta`" release candidates are sometimes made in
+advance of a new general-availability release, in order to obtain user
+feedback.  For example, version 1.9.0-rc1, 1.9.0-rc2, etc., would
+be beta releases leading up to the final release of v1.9.0.
+Release candidates should be used _only_ during a short testing
+period. They carry an implied obligation to provide feedback to the
+program development group.  Candidate releases should not be used on
+the air after a full release with the same number has been made.