Partial updates of User Guide for 2.4.0. Much more is still required!

doc/user_guide/en/decoder_notes.adoc

@@ -118,7 +118,7 @@ summarized in the following Table:
 |JT9     | @            |      |
 |JT65    | #            |      |
 |JT65 VHF| #            | *, # | f, fN, dCN
-|QRA65   | :            |      | qP
+|Q65     | :            |      | qP
 |MSK144  | &            |      |
 |===========================================
 Sync character::

doc/user_guide/en/introduction.adoc

@@ -10,34 +10,34 @@ contributors to development of _WSJT-X_ since 2013 and 2015, respectively.
 
 _WSJT-X_ Version {VERSION_MAJOR}.{VERSION_MINOR} offers eleven
 different protocols or modes: *FST4*, *FT4*, *FT8*, *JT4*, *JT9*,
-*JT65*, *QRA65*, *MSK144*, *WSPR*, *FST4W*, and *Echo*.  The
+*JT65*, *Q65*, *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
+encoding.  JT65 was designed for EME ("`moonbounce`") on VHF and
-the VHF/UHF bands and have also proven very effective for worldwide
+higher bands and is mostly used for that purpose today.  Q65 replaces
-QRP communication on the HF bands.  QRA64 has some advantages over
+an earlier mode, QRA64; it is particularly effective for tropospheric
-JT65, including better performance for EME on the higher microwave
+scatter, rain scatter, ionospheric scatter, TEP, and EME on VHF and
-bands.  JT9 was originally designed for the HF and lower bands.  Its
+higher bands, as well as other types of fast-fading signals.  JT9 was
-submode JT9A is 1 dB more sensitive than JT65 while using less than
+originally designed for the HF and lower bands.  Its submode JT9A is 1
-10% of the bandwidth.  JT4 offers a wide variety of tone spacings and
+dB more sensitive than JT65 while using less than 10% of the
-has proven highly effective for EME on microwave bands up to 24 GHz.
+bandwidth.  JT4 offers a wide variety of tone spacings and has proven
-These four "`slow`" modes use one-minute timed sequences of
+highly effective for EME on microwave bands up to 24 GHz.  These four
-alternating transmission and reception, so a minimal QSO takes four to
+"`slow`" modes use one-minute timed sequences of alternating
-six minutes — two or three transmissions by each station, one sending
+transmission and reception, so a minimal QSO takes four to six minutes
-in odd UTC minutes and the other even.  FT8 is operationally similar
+— two or three transmissions by each station, one sending in odd UTC
-but four times faster (15-second T/R sequences) and less sensitive by
+minutes and the other even.  FT8 is operationally similar but four
-a few dB.  FT4 is faster still (7.5 s T/R sequences) and especially
+times faster (15-second T/R sequences) and less sensitive by a few dB.
-well-suited for radio contesting.  FST4 was added to _WSJT-X_ in
+FT4 is faster still (7.5 s T/R sequences) and especially well-suited
-version 2.3.0.  It is intended especially for use on the LF and MF
+for radio contesting.  FST4 was added to _WSJT-X_ in version 2.3.0.
-bands, and already during its first few months of testing
+It is intended especially for use on the LF and MF bands, and already
-intercontinental paths have been spanned many times on the 2200 and
+during its first few months of testing intercontinental paths have
-630 m bands.  Further details can be found in the following section,
+been spanned many times on the 2200 and 630 m bands.  Further details
-<<NEW_FEATURES,New Features in Version 2.3.0>>.  On the HF bands,
+can be found in the following section, <<NEW_FEATURES,New Features in
-world-wide QSOs are possible with any of these modes using power
+Version 2.4.0>>.  On the HF bands, world-wide QSOs are possible with
-levels of a few watts (or even milliwatts) and compromise antennas.
+any of these modes using power levels of a few watts (or even
-On VHF bands and higher, QSOs are possible (by EME and other
+milliwatts) and compromise antennas.  On VHF bands and higher, QSOs
-propagation types) at signal levels 10 to 15 dB below those required
+are possible (by EME, scatter, and other propagation types) at signal
-for CW.
+levels 10 to 15 dB below those required for CW.
 
 *MSK144*, and optionally submodes *JT9E-H* are "`fast`"
 protocols designed to take advantage of brief signal enhancements from

doc/user_guide/en/make-qso.adoc

@@ -60,12 +60,10 @@ or rag-chewing.
 
 === Auto-Sequencing
 
-The 15-second T/R cycles of FT8 allow only about two seconds to inspect 
+The T/R cycles of many _WSJT-X_ modes allow only a few seconds to
-decoded messages and decide how to reply, which is often not enough.
+inspect decoded messages and decide how to reply.  Often this is not
-The slow modes JT4, JT9, JT65, and QRA64 allow nearly 10 seconds
+enough time, so for FST4, FT4, FT8, MSK144, and Q65 the program
-for this task, but operators may find that this is still insufficient
+offers a basic auto-sequencing feature.
-when workload is high, especially on EME. For these  reasons a basic
-auto-sequencing feature is offered.
 
 Check *Auto Seq* on the main window to enable this feature:
 
@@ -77,7 +75,8 @@ responder to your CQ.
 
 NOTE: When *Auto-Seq* is enabled, the program de-activates *Enable Tx*
 at the end of each QSO.  It is not intended that _WSJT-X_ should make
-fully automated QSOs.
+fully automated QSOs.  *Auto-sequencing is an operator aid, not an
+operator replacement.*
 
 [[CONTEST_MSGS]]
 === Contest Messages
@@ -160,7 +159,7 @@ guidelines for contest logging with FT4, FT8, and MSK144:
 [[COMP-CALL]] 
 === Nonstandard Callsigns
 
-*FT4, FT8, FST4, and MSK144*
+*FST4, FT4, FT8, MSK144, and Q65*
 
 Compound callsigns like xx/K1ABC or K1ABC/x and special event
 callsigns like YW18FIFA are supported for normal QSOs but not for 
@@ -196,7 +195,7 @@ the types of information that can be included in a message.  It
 prevents including your locator in standard messages, which
 necessarily impairs the usefulness of tools like PSK Reporter.
 
-*JT4, JT9, JT65, and QRA64*
+*JT4, JT9, and JT65*
 
 In the 72-bit modes, compound callsigns are handled in one of two
 possible ways:

doc/user_guide/en/new_features.adoc

@@ -1,39 +1,15 @@
 [[NEW_FEATURES]]
 === New in Version {VERSION}
 
-_WSJT-X 2.3.0_ introduces *FST4* and *FST4W*, new digital protocols
+_WSJT-X 2.4.0_ introduces *Q65*, a new digital protocol designed for
-designed particularly for the LF and MF bands.  Decoders for these
+minimal two-way QSOs over especially difficult propagation paths.  On
-modes can take advantage of the very small Doppler spreads present at
+paths with Doppler spread more than a few Hz, the weak-signal
-these frequencies, even over intercontinental distances.  As a
+performance of Q65 is the best among all WSJT-X modes.
-consequence, fundamental sensitivities of FST4 and FST4W are better
-than other _WSJT-X_ modes with the same sequence lengths, approaching
-the theoretical limits for their rates of information throughput.  The
-FST4 protocol 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 phase locking and time
-synchronization of modes like EbNaut.
-
-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.
-
-*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. We also expect that the 60 second variant of FST4
-(FST4-60) will outperform JT9 for DX QSOs on HF bands due, in part,
-to the FST4 decoder's ability to use AP decoding for messages received
-from a QSO partner. In addition, FST4 provides the added benefits 
-associated with 77-bit messages and auto-sequencing. 
 
+Q65 uses message formats and sequencing identical to those used in
+FST4, FT4, FT8, and MSK144.  Submodes are provided with a wide variety
+of tone spacings and T/R sequence lengths 15, 30, 60, 120, and 300 s.
+A new, highly reliable list-decoding technique is used for messages
+that contain previously copied message fragments.  Message averaging
+is provided for situations where single transmissions are too weak or
+signal enhancements too sparse for a signal to be decoded.

doc/user_guide/en/transceiver-setup.adoc

@@ -31,7 +31,7 @@ TIP: The PC audio mixer normally has two sliders, one for each
   conventional JT65 and JT9 sub-bands simultaneously on most HF bands.
   Further details are provided in the <<TUTORIAL,Basic Operating
   Tutorial>>.  A wider displayed bandwidth may also be helpful at VHF
-  and above, where FT8, JT4, JT65, and QRA64 signals may be found over
+  and above, where FT8, JT4, JT65, and Q65 signals may be found over
   much wider ranges of frequencies.
 
 - If you have only a standard SSB filter you won’t be able to display

doc/user_guide/en/vhf-features.adoc

@@ -11,8 +11,8 @@ higher bands.  These features include:
 
 - *JT65*, widely used for EME on VHF and higher bands
 
-- *QRA65*, another mode for EME, also used for tropo-, and
+- *Q65*, for propagation modes including tropospheric scatter, rain
-   iono-scatter propagation on VHF and higher bands
+scatter, ionospheric scatter, TEP, and EME
 
 - *MSK144*, for meteor scatter
 
@@ -175,9 +175,13 @@ RO, RRR, and 73.
 
 image::JT65B.png[align="center",alt="JT65B"]
 
-=== QRA64
+=== Q65
 
-QRA64 is designed for EME on VHF and higher bands; its
+Q65 is designed for propagation paths that produce signals exhibiting fast
+fading, including tropospheric scatter, rain scatter, ionospheric scatter,
+trans-equatorial propagation (TEP), and EME.  
+
+EME on VHF and higher bands; its
 operation is generally similar to JT4 and JT65.  The following screen
 shot shows an example of a QRA64C transmission from DL7YC recorded at
 G3WDG over the EME path at 24 GHz.  Doppler spread on the path was 78
@@ -186,7 +190,7 @@ broadened enough to make them hard to see on the waterfall.  The
 triangular red marker below the frequency scale shows that the decoder
 has achieved synchronization with a signal at approximately 967 Hz.
 
-image::QRA64.png[align="center",alt="QRA64"]
+image::Q65_6m_ionoscatter.png[align="center",alt="QRA64"]
 
 The QRA64 decoder makes no use of a callsign database.  Instead, it
 takes advantage of _a priori_ (AP) information such as one's own