Updates to the User Guide, mostly related to addition of the FT4 mode.

doc/common/links.adoc

@@ -116,6 +116,7 @@ d). Edit lines as needed. Keeping them in alphabetic order help see dupes.
 :QRA64_EME: http://physics.princeton.edu/pulsar/K1JT/QRA64_EME.pdf[QRA64 for microwave EME]
 :svn: http://subversion.apache.org/packages.html#windows[Subversion]
 :win32: http://physics.princeton.edu/pulsar/K1JT/wsjtx-{VERSION}-win32.exe[wsjtx-{VERSION}-win32.exe]
+:win64: http://physics.princeton.edu/pulsar/K1JT/wsjtx-{VERSION}-win64.exe[wsjtx-{VERSION}-win64.exe]
 :wsjt-devel: https://lists.sourceforge.net/lists/listinfo/wsjt-devel[here]
 :wsjt_repo: https://sourceforge.net/p/wsjt/wsjt_orig/ci/master/tree/[WSJT Source Repository]
 :wspr_code: http://physics.princeton.edu/pulsar/K1JT/WSPRcode.exe[WSPRcode.exe]

doc/user_guide/en/install-windows.adoc

@@ -1,11 +1,12 @@
 // Status=review
 
-Download and execute the package file {win32}, following these
-instructions:
+Download and execute the package file {win32} (WinXP, Vista, Win 7,
+Win 8, Win10, 32-bit) or {win64} (Vista, Win 7, Win 8, Win10, 64-bit)
+following these instructions:
 
 * Install _WSJT-X_ into its own directory, for example `C:\WSJTX` or `
   C:\WSJT\WSJTX`, rather than the conventional location `C:\Program
-  Files (x86)\WSJTX`.
+  Files ...\WSJTX`.
 
 * All program files relating to _WSJT-X_ will be stored in the chosen
   installation directory and its subdirectories.

doc/user_guide/en/introduction.adoc

@@ -7,10 +7,10 @@ K1**JT**,`" while the suffix "`-X`" indicates that _WSJT-X_ started as
 an extended and experimental branch of the program
 _WSJT_.
 
-_WSJT-X_ Version {VERSION_MAJOR}.{VERSION_MINOR} 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
+_WSJT-X_ Version {VERSION_MAJOR}.{VERSION_MINOR} offers ten different
+protocols or modes: *FT4*, *FT8*, *JT4*, *JT9*, *JT65*, *QRA64*,
+*ISCAT*, *MSK144*, *WSPR*, and *Echo*.  The first six are designed for
+making reliable QSOs under 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.
@@ -25,12 +25,17 @@ 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.
+(15-second T/R sequences) and less sensitive by a few dB.  FT4 is
+faster still (7.5 s T/R sequences) and especially well suited for
+radio contesting.  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.
+
+Note that even though their T/R sequences are short, FT4 and FT8 are
+classified as slow modes because their message frames are sent
+only once per transmission.
 
 *ISCAT*, *MSK144*, and optionally submodes *JT9E-H* are "`fast`"
 protocols designed to take advantage of brief signal enhancements from
@@ -65,10 +70,10 @@ 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
+2.1.0.  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.
+feedback.  For example, version 2.1.0-rc1, 2.1.0-rc2, etc., would
+be beta releases leading up to the final release of v2.1.0.
 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

doc/user_guide/en/new_features.adoc

@@ -1,40 +1,17 @@
 === New in Version {VERSION}
 
 For quick reference, here's a short list of features and capabilities
-added to _WSJT-X_ since Version 1.9.1:
+added to _WSJT-X_ since Version 2.0.1:
 
-- New FT8 and MSK144 protocols with 77-bit payloads permit these enhancements:
+- New FT4 protocol, designed especially for radio contesting
 
-* Optimized contest messages for NA VHF, EU VHF, Field Day, RTTY Roundup
+* T/R sequence length 7.5 s
 
-* Full support for "/R" and "/P" calls in relevant contests
+* Bandwidth 80 Hz
 
-* New logging features for contesting
-
-* Integration with {n1mm_logger} and {writelog} for contesting
-
-* Improved support for compound and nonstandard callsigns
-
-* Nearly equal (or better) sensitivity compared to old protocols
-
-* Lower false decode rates
-
-- Improved color highlighting of received messages
-
-- Improved WSPR sensitivity
-
-- Expanded and improved UDP messages sent to companion programs
-
-- Bug fixes and other minor tweaks to user interface
-
-IMPORTANT: Note that for FT8 and MSK144 there is no backward
-compatibility with WSJT-X 1.9.1 and earlier.  Everyone using these
-modes should upgrade to WSJT-X 2.0 by January 1, 2019.
-
-IMPORTANT: _WSJT-X_ Version 2.0 drops support for Apple Mac OS X 10.9
-(Mavericks). It is possible to build from source for this operating
-system version but the DMG installer package requires 10.10 or later.
+* Threshold sensitivity -17.5 dB
 
+- Improvements to accessibility
 
 === Documentation Conventions
 

doc/user_guide/en/protocols.adoc

@@ -12,10 +12,10 @@ Special cases allow other information such as add-on callsign prefixes
 aim is to compress the most common messages used for minimally valid
 QSOs into a fixed 72-bit length.
 
-The information payload for FT8 and MSK144 contains 77 bits.  The 5
-additional bits are used to flag special message types used for FT8
-DXpedition Mode, contesting, nonstandard callsigns, and a few other
-special types.
+The information payload for FT4, FT8, and MSK144 contains 77 bits.
+The 5 additional bits are used to flag special message types used for
+FT8 DXpedition Mode, contesting, nonstandard callsigns, and a few
+other special types.
 
 A standard amateur callsign consists of a one- or two-character
 prefix, at least one of which must be a letter, followed by a digit
@@ -67,18 +67,29 @@ _WSJT-X_ modes have continuous phase and constant envelope.
 [[SLOW_MODES]]
 === Slow Modes
 
+[[FT4PRO]]
+==== FT4
+
+Forward error correction (FEC) in FT4 uses a low-density parity check
+(LDPC) code with 77 information bits, a 14-bit cyclic redundancy check
+(CRC), and 83 parity bits making a 174-bit codeword.  It is thus
+called an LDPC (174,91) code.  Synchronization uses four 4×4 Costas
+arrays, and ramp-up and ramp-down symbols are inserted at the start
+and end of each transmission.  Modulation is 4-tone frequency-shift
+keying with Gaussian smoothing of frequency transitions (4-GFSK).  The
+keying rate is 12000/576 = 20.8333 baud.  Each transmitted symbol
+conveys two bits, so the total number of channel symbols is 174/2 + 16
++ 2 = 105.  The total bandwidth is 4 × 20.8333 = 83.3 Hz.
+
 [[FT8PRO]]
 ==== FT8
 
-Forward error correction (FEC) in FT8 uses a low-density parity check
-(LDPC) code with 77 information bits, a 14-bit cyclic redundancy check
-(CRC), and 83 parity bits making a 174-bit codeword.  It is thus
-called an LDPC (174,91) code.  Synchronization uses 7×7 Costas arrays
-at the beginning, middle, and end of each transmission.  Modulation is
-8-tone frequency-shift keying (8-FSK) at 12000/1920 = 6.25 baud.  Each
-transmitted symbol carries three bits, so the total number of channel
-symbols is 174/3 + 21 = 79.  The total occupied bandwidth is 8 × 6.25
-= 50 Hz.
+FT8 uses the same LDPC (174,91) code as FT4.  Modulation is 8-tone
+frequency-shift keying (8-GFSK) at 12000/1920 = 6.25 baud.
+Synchronization uses 7×7 Costas arrays at the beginning, middle, and
+end of each transmission.  Transmitted symbols carry three bits, so
+the total number of channel symbols is 174/3 + 21 = 79.  The total
+occupied bandwidth is 8 × 6.25 = 50 Hz.
 
 [[JT4PRO]]
 ==== JT4
@@ -227,7 +238,8 @@ which the probability of decoding is 50% or higher.
 |===============================================================================
 |Mode |FEC Type |(n,k) | Q|Modulation type|Keying rate (Baud)|Bandwidth (Hz)
 |Sync Energy|Tx Duration (s)|S/N Threshold (dB)
-|FT8  |LDPC, r=1/2|(174,91)| 8| 8-FSK| 6.25 | 50.0 | 0.27| 12.6 | -21
+|FT4  |LDPC, r=1/2|(174,91)| 4| 4-GFSK| 20.8333 | 83.3 | 0.15| 5.04 | -17.5
+|FT8  |LDPC, r=1/2|(174,91)| 8| 8-GFSK| 6.25 | 50.0 | 0.27| 12.6 | -21
 |JT4A |K=32, r=1/2|(206,72)| 2| 4-FSK| 4.375| 17.5 | 0.50| 47.1 | -23
 |JT9A |K=32, r=1/2|(206,72)| 8| 9-FSK| 1.736| 15.6 | 0.19| 49.0 | -27
 |JT65A |Reed Solomon|(63,12) |64|65-FSK| 2.692| 177.6 | 0.50| 46.8 | -25
@@ -246,6 +258,7 @@ comparable to tone spacing.
 [width="50%",cols="h,3*^",frame=topbot,options="header"]
 |=====================================
 |Mode  |Tone Spacing  |BW (Hz)|S/N (dB)
+|FT4   |20.8333 | 83.3  |-17.5
 |FT8   |6.25 |  50.0  |-21
 |JT4A  |4.375|  17.5  |-23
 |JT4B  |8.75 |  30.6  |-22