First cut at adding FST4, FST4W to the User Guide.

doc/CMakeLists.txt

@@ -30,8 +30,7 @@ set (UG_SRCS
   install-mac.adoc
   install-windows.adoc
   introduction.adoc
-  measurement_tools.adoc
-  protocols.adoc
+  intro_subsections.adoc
   logging.adoc
   make-qso.adoc
   measurement_tools.adoc
@@ -53,6 +52,8 @@ set (UG_SRCS
   tutorial-example2.adoc
   tutorial-example3.adoc
   tutorial-example4.adoc
+  tutorial-example5.adoc
+  tutorial-example6.adoc
   tutorial-main-window.adoc
   tutorial-wide-graph-settings.adoc
   utilities.adoc
@@ -82,6 +83,9 @@ set (UG_IMGS
   images/FreqCal_Graph.png
   images/FreqCal_Results.png
   images/freemsg.png
+  images/FST4_center.png
+  images/FST4_Decoding_Limits.png
+  images/FST4W_RoundRobin.png
   images/ft4_decodes.png
   images/ft4_waterfall.png
   images/ft8_decodes.png

doc/user_guide/en/intro_subsections.adoc

@@ -0,0 +1,40 @@
+=== Documentation Conventions
+
+In this manual the following icons call attention to particular types
+of information:
+
+NOTE: *Notes* containing information that may be of interest to
+particular classes of users.
+
+TIP: *Tips* on program features or capabilities that might otherwise be
+overlooked.
+
+IMPORTANT: *Warnings* about usage that could lead to undesired
+consequences.
+
+=== User Interface in Other Languages
+
+The _WSJT-X_ user interface is now available in many languages.  When
+a translated user interface is available for the computer's default
+System Language, it will appear automatically on program startup.
+
+=== How You Can Contribute
+
+_WSJT-X_ is part of an open-source project released under the
+{gnu_gpl} (GPLv3). If you have programming or documentation skills or
+would like to contribute to the project in other ways, please make
+your interests known to the development team.  We especially encourage
+those with translation skills to volunteer their help, either for
+this _User Guide_ or for the program's user interface.
+
+The project's source-code repository can be found at {devrepo}, and
+communication among the developers takes place on the email reflector
+{devmail}.  Bug reports and suggestions for new features, improvements
+to the _WSJT-X_ User Guide, etc., may be sent there as well.  You must
+join the group before posting to the email list.
+
+
+=== License
+
+Before using _WSJT-X_, please read our licensing terms
+<<LICENSE,here>>.

doc/user_guide/en/introduction.adoc

@@ -3,42 +3,39 @@
 _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_,
-first released in 2001.  Bill Somerville, G4WJS, and Steve Franke,
-K9AN, have been major contributors to program development since 2013
-and 2015, respectively.
+K1**JT**,`" while the suffix "`*-X*`" indicates that _WSJT-X_ started
+as an extended branch of an earlier program, _WSJT_, first released in
+2001.  Bill Somerville, G4WJS, and Steve Franke, K9AN, have been major
+contributors to development of _WSJT-X_ since 2013 and 2015, respectively.
 
-_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.
-QRA64 has some advantages over JT65, including better performance
-for EME on the higher microwave bands.  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.  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.  All fast modes in _WSJT-X_ send their message
-frames repeatedly, as many times as will fit into the Tx sequence
-length.
+_WSJT-X_ Version {VERSION_MAJOR}.{VERSION_MINOR} offers twelve
+different protocols or modes: *FST4*, *FT4*, *FT8*, *JT4*, *JT9*,
+*JT65*, *QRA64*, *ISCAT*, *MSK144*, *WSPR*, *FST4W*, and *Echo*.  The
+first seven 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.  QRA64 has some advantages over
+JT65, including better performance for EME on the higher microwave
+bands.  JT9 was originally designed for the HF and lower 
+bands.  Its submode JT9A is nearly 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.  FT4 is faster still (7.5 s T/R sequences) and
+especially well-suited for radio contesting.  FST4 was added to
+_WSJT-X_ in version 2.3.0.  It is intended especially for use on the
+LF and MF bands; further details can be found in the following
+section, <<NEW_FEATURES,New Features in Version 2.3.0>>.
+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
@@ -51,15 +48,25 @@ 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.  
 
+Note that some of the modes classified as slow can have T/R sequence
+lengths as short the fast modes.  "`Slow`" in this sense implies
+message frames being sent only once per transmission.  The fast modes
+in _WSJT-X_ send their message frames repeatedly, as many times as
+will fit into the Tx sequence length.
+
 *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 -31 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.
+**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 with two-minute
+sequences they can be decoded at signal-to-noise ratios as low
+as -31 dB in a 2500 Hz bandwidth. *FST4W* is designed for
+similar purposes, but especially for use on LF and MF bands.
+It includes optional sequence lengths as long as 30 minutes and
+reaches sensitivity tresholds as low as -45 dB.  WSPR and FST4W 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.

doc/user_guide/en/new_features.adoc

@@ -1,107 +1,31 @@
+[[NEW_FEATURES]]
 === New in Version {VERSION}
 
-*Improvements to decoders*
+_WSJT-X 2.3.0_ introduces *FST4* and *FST4W*, new digital protocols
+designed particularly for the LF and MF bands.  On these bands their
+fundamental sensitivities are better than other _WSJT-X_ modes with the
+same sequence lengths, approaching the theoretical limits for their
+rates of information throughput.  FST4 is optimized for two-way QSOs,
+while FST4W is for quasi-beacon transmissions of WSPR-style messages.
+FST4 and FST4W do not require the strict, independent time
+synchronization and phase locking of modes like EbNaut.
 
-*FT4:* Corrected bugs that prevented AP (_a priori_) decoding and/or
-multi-pass decoding in some circumstances.  Improved and extended the
-algorithm for AP decoding.
+The new modes use 4-GFSK modulation and share common software for
+encoding and decoding messages.  FST4 offers T/R sequence lengths of
+15, 30, 60, 120, 300, 900, and 1800 seconds, while FST4W omits the
+lengths shorter than 120 s.  Submodes are given names like FST4-60,
+FST4W-300, etc., the appended numbers indicating sequence length in
+seconds.  Message payloads contain either 77 bits, as in FT4, FT8, and
+MSK144, or 50 bits for the WSPR-like messages of FST4W.  Message
+formats displayed to the user are like those in the other 77-bit and
+50-bit modes in _WSJT-X_.  Forward error correction uses a low density
+parity check (LDPC) code with 240 information and parity bits.
+Transmissions consist of 160 symbols: 120 information-carrying symbols
+of two bits each, interspersed with five groups of eight predefined
+synchronization symbols.
 
-*FT8:* Decoding is now spread over three intervals.  The first starts
-11.8 s into an Rx sequence and typically yields around 85% of the
-possible decodes, so you see most decodes much earlier than before.  A
-second processing step starts at 13.5 s, and the final one at 14.7 s.
-Overall decoding yield on crowded bands is improved by 10% or more.
-Systems with receive latency greater than 0.2 s will see smaller
-improvements, but will still see many decodes earlier than before.
-
-SNR estimates no longer saturate at +20 dB, and large signals in the
-passband no longer cause the SNR of weaker signals to be biased low.
-Times written to cumulative journal file ALL.TXT are now correct even
-when the decode occurs after the T/R sequence boundary.  In FT8
-DXpedition Mode, AP decoding is now implemented for Hounds when the
-Fox has a compound callsign.
-
-
-*JT4:*  Formatting and display of averaged and Deep Search decodes has
-been cleaned up and made consistent with other modes used for EME and
-extreme weak-signal work on microwave bands.
-
-*JT65:*  Many improvements have been made for averaged and Deep Search
-decodes, and their display to the user.  For details see <<VHF_JT65,JT65>>
-in the <<VHF_AND_UP,VHF+ Features>> section of this guide.
-
-*WSPR:* Significant improvements have been made to the WSPR decoder's
-sensitivity, its ability to cope with many signals in a crowded
-sub-band, and its rate of undetected false decodes.  We now use up to
-three decoding passes.  Passes 1 and 2 use noncoherent demodulation of
-single symbols and allow for frequency drifts up to ±4 Hz in a
-transmission.  Pass 3 assumes no drift and does coherent block
-detection of up to three symbols.  It also applies bit-by-bit
-normalization of the single-symbol bit metrics, a technique that has
-proven helpful for signals corrupted by artifacts of the subtraction
-of stronger signals and also for LF/MF signals heavily contaminated by
-lightning transients.  With these improvements the number of decodes
-in a crowded WSPR sub-band typically increases by 10 to 15%.
-
-*New message format:* When *EU VHF Contest* is selected, the Tx2 and
-Tx3 messages -- those conveying signal report, serial number, and
-6-character locator -- now use hashcodes for both callsigns.  This
-change is *not* backward compatible with earlier versions of _WSJT-X_, so
-all users of *EU VHF Contest* messages should be sure to upgrade to
-version 2.2.0.  See <<CONTEST_MSGS,Contest Messages>> for details.
-
-*Minor enhancements and bug fixes*
-
-- *Save None* now writes no .wav files to disk, even temporarily.
-
-- An explicit entry for *WW Digi Contest* has been added to *Special
- operating activities* on the *Settings | Advanced* tab.
-
-- The contest mode FT4 now always uses RR73 for the Tx4 message.
-
-- *Keyboard shortcuts* have been added as an aid to accessibility:
-*Alt+R* sets Tx4 message to RR73, *Ctrl+R* sets it to RRR.
-
-- The *Status bar* now displays the number of decodes found in the
-most recent Rx sequence.
-
-- As an aid for partial color-blindness, the "`inverted goal posts`"
-marking Rx frequency on the Wide Graph's frequency scale are now in a
-darker shade of green.
-
-=== Documentation Conventions
-
-In this manual the following icons call attention to particular types
-of information:
-
-NOTE: *Notes* containing information that may be of interest to
-particular classes of users.
-
-TIP: *Tips* on program features or capabilities that might otherwise be
-overlooked.
-
-IMPORTANT: *Warnings* about usage that could lead to undesired
-consequences.
-
-=== User Interface in Other Languages
-
-Thanks to Xavi Perez, EA3W, in cooperation with G4WJS, the _WSJT-X_
-user interface is now available the Catalan language.  Spanish will
-follow soon, and other languages when translations are made.  When a
-translated user interface is available for the computer's default
-System Language, it will appear automatically on program startup.
-
-=== How You Can Contribute
-
-_WSJT-X_ is part of an open-source project released under the
-{gnu_gpl} (GPLv3). If you have programming or documentation skills or
-would like to contribute to the project in other ways, please make
-your interests known to the development team.  We especially encourage
-those with translation skills to volunteer their help, either for
-this _User Guide_ or for the program's user interface.
-
-The project's source-code repository can be found at {devrepo}, and
-communication among the developers takes place on the email reflector
-{devmail}.  Bug reports and suggestions for new features, improvements
-to the _WSJT-X_ User Guide, etc., may be sent there as well.  You must
-join the group before posting to the email list.
+*We recommend that on the 2200 and 630 m bands FST4 should replace JT9
+for making 2-way QSOs, and FST4W should replace WSPR for propagation
+tests*.  Operating conventions on these LF and MF bands will
+eventually determine the most useful T/R sequence lengths for each
+type of operation.

doc/user_guide/en/protocols.adoc

@@ -14,7 +14,7 @@ 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 FT4, FT8, and MSK144 contains 77 bits.
+The information payloads for FST4, FT4, FT8, and MSK144 contain 77 bits.
 The 5 new bits added to the original 72 are used to flag special
 message types signifying special message types used for FT8 DXpedition
 Mode, contesting, nonstandard callsigns, and a few other
@@ -54,7 +54,7 @@ were the callsigns `E9AA` through `E9ZZ`.  Upon reception they are
 converted back to the form `CQ AA` through `CQ ZZ`, for display to the
 user.
 
-The FT4, FT8, and MSK144 protocols use different lossless compression
+The FST4, FT4, FT8, and MSK144 protocols use different lossless compression
 algorithms with features that generate and recognize special messages
 used for contesting and other special purposes.  Full details have
 been published in QEX, see {ft4_ft8_protocols}.
@@ -71,6 +71,21 @@ _WSJT-X_ modes have continuous phase and constant envelope.
 [[SLOW_MODES]]
 === Slow Modes
 
+[[FST4PRO]]
+==== FST4
+
+FST4 offers T/R sequence lengths of 15, 30, 60, 120, 300, 900, and
+1800 seconds.  Submodes are given names like FST4-60, FST4-120, etc.,
+the appended numbers indicating sequence length in seconds.  Message
+payloads contain 77 bits, and a 24-bit cyclic redundancy check (CRC)
+appended to create a 101-bit message-plus-CRC word.  Forward error
+correction is accomplished using a (240,101) LDPC code.  Transmissions
+consist of 160 symbols: 120 information-carrying symbols of two bits
+each, interspersed with five groups of eight predefined
+synchronization symbols.  Modulation uses 4-tone frequency-shift
+keying (4-GFSK) with Gaussian smoothing of frequency transitions.
+
+
 [[FT4PRO]]
 ==== FT4
 
@@ -225,6 +240,20 @@ information the least significant. Thus, on a 0 – 3 scale, the tone
 for a given symbol is twice the value (0 or 1) of the data bit, plus
 the sync bit.
 
+[[FST4WPRO]]
+==== FST4W
+
+FST4W offers T/R sequence lengths of 120, 300, 900, and 1800 seconds.
+Submodes are given names like FST4W-120, FST4W-300, etc., the appended
+numbers indicating sequence length in seconds.  Message payloads
+contain 50 bits, and a 24-bit cyclic redundancy check (CRC) appended
+to create a 74-bit message-plus-CRC word.  Forward error correction
+is accomplished using a (240,74) LDPC code.  Transmissions consist of
+160 symbols: 120 information-carrying symbols of two bits each,
+interspersed with five groups of eight predefined synchronization
+symbols.  Modulation uses 4-tone frequency-shift keying (4-GFSK) with
+Gaussian smoothing of frequency transitions.
+
 [[SLOW_SUMMARY]]
 ==== Summary
 
@@ -239,17 +268,28 @@ which the probability of decoding is 50% or higher.
 
 [[SLOW_TAB]]
 .Parameters of Slow Modes
-[width="90%",cols="3h,^3,^2,^1,^2,^2,^2,^2,^2,^2",frame=topbot,options="header"]
+[width="100%",cols="3h,^3,^2,^1,^2,^2,^2,^2,^2,^2",frame=topbot,options="header"]
 |===============================================================================
 |Mode |FEC Type |(n,k) | Q|Modulation type|Keying rate (Baud)|Bandwidth (Hz)
 |Sync Energy|Tx Duration (s)|S/N Threshold (dB)
-|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
+|FST4-15   |LDPC |  (240,101)| 4| 4-GFSK| 16.6667 | 67.7 | 0.25| 9.60  | -20.7
+|FST4-30   |LDPC |  (240,101)| 4| 4-GFSK|  7.14  | 28.6  | 0.25| 22.4  | -24.2
+|FST4-60   |LDPC |  (240,101)| 4| 4-GFSK|  3.09  | 12.4  | 0.25| 51.8  | -28.1
+|FST4-120  |LDPC |  (240,101)| 4| 4-GFSK|  1.46  |  5.9  | 0.25| 109.3 | -31.3
+|FST4-300  |LDPC |  (240,101)| 4| 4-GFSK|  0.56  |  2.2  | 0.25| 286.7 | -35.3
+|FST4-900  |LDPC |  (240,101)| 4| 4-GFSK|  0.180 |  0.72 | 0.25| 887.5 | -40.2
+|FST4-1800 |LDPC |  (240,101)| 4| 4-GFSK|  0.089 |  0.36 | 0.25| 1792.0| -43.2
+|FT4  |LDPC |(174,91)| 4| 4-GFSK| 20.8333 | 83.3 | 0.15| 5.04 | -17.5
+|FT8  |LDPC |(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
+|JT9A |K=32, r=1/2|(206,72)| 8| 9-FSK| 1.736| 15.6 | 0.19| 49.0 | -26
 |JT65A |Reed Solomon|(63,12) |64|65-FSK| 2.692| 177.6 | 0.50| 46.8 | -25
 |QRA64A|Q-ary Repeat Accumulate|(63,12) |64|64-FSK|1.736|111.1|0.25|48.4| -26
 | WSPR |K=32, r=1/2|(162,50)| 2| 4-FSK| 1.465| 5.9 | 0.50|110.6 | -31
+|FST4W-120  |LDPC |  (240,74)| 4| 4-GFSK|  1.46  |  5.9  | 0.25| 109.3 | -32.8
+|FST4W-300  |LDPC |  (240,74)| 4| 4-GFSK|  0.56  |  2.2  | 0.25| 286.7 | -36.8
+|FST4W-900  |LDPC |  (240,74)| 4| 4-GFSK|  0.180 |  0.72 | 0.25| 887.5 | -41.7
+|FST4W-1800 |LDPC |  (240,74)| 4| 4-GFSK|  0.089 |  0.36 | 0.25| 1792.0| -44.8
 |===============================================================================
 
 Submodes of JT4, JT9, JT65, and QRA64 offer wider tone spacings for
@@ -259,12 +299,10 @@ threshold sensitivities of the various submodes when spreading is
 comparable to tone spacing.
 
 [[SLOW_SUBMODES]]
-.Parameters of Slow Submodes
+.Parameters of Slow Submodes with Wider Tome Spacings
 [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
 |JT4C  |17.5 |  56.9  |-21
@@ -272,7 +310,7 @@ comparable to tone spacing.
 |JT4E  |78.75|  240.6 |-19
 |JT4F  |157.5|  476.9 |-18
 |JT4G  |315.0|  949.4 |-17
-|JT9A  |1.736|  15.6  |-27
+|JT9A  |1.736|  15.6  |-26
 |JT9B  |3.472|  29.5  |-26
 |JT9C  |6.944|  57.3  |-25
 |JT9D  |13.889| 112.8 |-24

doc/user_guide/en/tutorial-example5.adoc

@@ -0,0 +1,24 @@
+FST4 is is designed for making 2-way QSOs on the LF and MF bands.  Do
+not confuse it with FT4, which has a very different purpose!  Most
+on-screen controls, auto-sequencing, and other features behave in FST4
+as in other modes.  However, operating conventions on the 2200 and 630
+m bands make it desirable to have additional user controls that set
+the active frequency range for decoding.  Spin boxes labeled *F Low*
+and *F High* set lower and upper frequency limits for the FST4
+decoder.  
+
+image::FST4_center.png[align="center"]
+
+Decoding limits are marked by dark green angle-bracket symbols *< >* on
+the Wide Graph frequency scale:
+
+image::FST4_Decoding_Limits.png[align="center"]
+
+In general the specified range should be no larger than needed, since
+detected transmissions in modes other than the selected FST4 sequence
+length will be undecodable and will slow down the decoding process.
+
+If *Single decode* on the the *File | Settings | General* tab is
+checked, the decoding range is further limited to the *F Tol* range
+around *Rx Freq*.
+

doc/user_guide/en/tutorial-example6.adoc

@@ -0,0 +1,16 @@
+FST4W has significant advantages over WSPR for use on the 2200 and 630
+m bands.  As for WSPR, the default Rx Freq is 1500 Hz and F Tol is
+100 Hz, so the active decoding range 1400 to 1600 Hz.  However, for added
+flexibility you can select different center frequencies and F Tol values.
+We expect that usage conventions will soon be established for FST4 activity on 2200 and 630 m.
+
+A new drop-down control below F Tol offers a round-robin mode for
+scheduling FST4W transmissions:
+
+image::FST4W_RoundRobin.png[align="center"]
+
+If three operators agree in advance to select the options 1/3, 2/3,
+and 3/3, for example, their FST4W transmissions will occur in a fixed
+sequence with no two stations transmitting simultaneously.  Sequence 1
+is the first sequence after 00:00 UTC.  For WSPR-like scheduling
+behavior, you should select Random with this control.

doc/user_guide/en/wsjtx-main.adoc

@@ -32,6 +32,9 @@ include::introduction.adoc[]
 [[NEW_FEATURES]]
 include::new_features.adoc[]
 
+[[INTRO_SUBSECTIONS]]
+include::intro_subsections.adoc[]
+
 [[SYSREQ]]
 == System Requirements
 include::system-requirements.adoc[]
@@ -162,6 +165,14 @@ include::tutorial-example3.adoc[]
 === FT4
 include::tutorial-example4.adoc[]
 
+[[TUT_EX5]]
+=== FST4
+include::tutorial-example5.adoc[]
+
+[[TUT_EX6]]
+=== FST4W
+include::tutorial-example6.adoc[]
+
 [[MAKE_QSOS]]
 == Making QSOs
 include::make-qso.adoc[]