Editorial work on parts of the User Guide related to FT4.

doc/user_guide/en/introduction.adoc

@@ -34,8 +34,10 @@ 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.
+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.
 
 *ISCAT*, *MSK144*, and optionally submodes *JT9E-H* are "`fast`"
 protocols designed to take advantage of brief signal enhancements from

doc/user_guide/en/new_features.adoc

@@ -1,17 +1,11 @@
 === New in Version {VERSION}
 
-For quick reference, here's a short list of features and capabilities
-added to _WSJT-X_ since Version 2.0.1:
-
-- New FT4 protocol, designed especially for radio contesting
-
-* T/R sequence length 7.5 s
-
-* Bandwidth 80 Hz
-
-* Threshold sensitivity -17.5 dB
-
-- Improvements to accessibility
+The most important feature added to _WSJT-X_ since Version 2.0.1 is
+the new *FT4 protocol*, designed especially for radio contesting.  It
+has T/R sequence length 7.5 s, bandwidth 80 Hz, and threshold
+sensitivity -17.5 dB.  Version 2.1.0 also has improvements to FT8
+waveform generation, contest logging, rig control, the user interface,
+and accessibility, as well as a number of bug fixes.
 
 === Documentation Conventions
 

doc/user_guide/en/protocols.adoc

@@ -13,9 +13,10 @@ 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 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 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
+possibilities.
 
 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
@@ -76,7 +77,7 @@ Forward error correction (FEC) in FT4 uses a low-density parity check
 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 (4-GFSK) with Gaussian smoothing of frequency transitions.  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.

doc/user_guide/en/tutorial-example4.adoc

@@ -14,7 +14,8 @@ frequency limit is approximately 4000 Hz.
 - Select *File | Open* and navigate to
 +...\save\samples\FT4\000000_000002.wav+.  The waterfall and Band
 Activity window should look something like the following screen shots.
-Most of the decoded messages use the *RTTY Roundup* message formats.
+This sample file was recorded during a practice contest test session, so
+most of the decoded messages use the *RTTY Roundup* message formats.
 
 [[X15]]
 image::ft4_waterfall.png[align="left",alt="Wide Graph Decode FT4"]