User Guide updates in preparation for pending release of v1.7.0-rc3.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7344 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

doc/user_guide/en/controls-functions-center.adoc

@@ -37,11 +37,13 @@ TIP: Consider reducing power if your QSO partner reports your
 signal above -5 dB in one of the _WSJT-X_ slow modes.  These are
 supposed to be weak signal modes!
 
-* With *Rx frequency offset with "CQ nnn"* checked on the *Settings ->
-General* tab and *Split operation* activated on the *Settings ->
-Radio* tab, you can activate the spinner control *CQ Rx nnn* by
-checking the box to its right.  The program will then generate
-something like `CQ 285 K1ABC FN42` for your CQ message, and it will
-handle the appropriate frequency switching between a CQ on the
-conventional calling frequency and completing your QSO on the
-specified offset frequency.
+* With *Split operation* activated on the *Settings -> Radio* tab, you
+can activate the spinner control *Tx CQ nnn* by checking the box to
+its right.  The program will then generate something like `CQ nnn
+K1ABC FN42` for your CQ message, where `nnn` is the kHz portion of
+your current operating frequency.  Your CQ message *Tx6* will then be
+transmitted at the calling frequency selected in the *Tx CQ nnn* spinner
+control.  All other messages will be transmitted at your current
+operating frequency.  On reception, when you double-click on a message
+like `CQ nnn K1ABC FN42` your rig will QSY to the specified frequency
+so you can call the station at his specified response frequency.

doc/user_guide/en/odds_and_ends.adoc

@@ -32,7 +32,7 @@ End of line information::
  `f` - Franke-Taylor or Fano algorithm +
  `M` - Message length (characters) +
  `N` - Number of Rx intervals or frames averaged +
- `R` - Amount of _a priori_ information used by decoder +
+ `R` - Return code from QRA64 decoder +
  `T` - Length of analyzed region (s)
 
 === Reference Spectrum

doc/user_guide/en/protocols.adoc

@@ -126,12 +126,11 @@ separation is 110250/4096 = 26.92 Hz multiplied by n for JT65A, with n
 
 QRA64 is an experimental mode intended for EME and other extreme
 weak-signal applications.  Its internal code was designed by IV3NWV.
-The protocol uses a (63,12) Q-ary Repeat Accumulate code that is
-inherently better than the Reed Solomon (63,12) code used in JT65,
-yielding a 1.3 dB advantage. A new synchronizing scheme is based on
-three 7 x 7 Costas arrays.  This change yields another 1.9 dB
-advantage.  A few details of the QRA64 protocol are still subject to
-change, as more experience is gained.
+The protocol uses a (63,12) **Q**-ary **R**epeat **A**ccumulate code
+that is inherently better than the Reed Solomon (63,12) code used in
+JT65, yielding a 1.3 dB advantage. A new synchronizing scheme is based
+on three 7 x 7 Costas arrays.  This change yields another 1.9 dB
+advantage. 
 
 In most respects the current implementation of QRA64 is operationally
 similar to JT65.  QRA64 does not use two-tone shorthand messages, and
@@ -141,8 +140,7 @@ QSO progresses -- for example, when reports are being exchanged and
 you have already decoded both callsigns in a previous transmission.
 QRA64 presently offers no message averaging capability, though that
 feature may be added.  In early tests, many EME QSOs were made using
-submodes QRA64A-E on bands from 144 MHz to 10 GHz.  Optimum processing
-of signals with large Doppler spread remains to be implemented.
+submodes QRA64A-E on bands from 144 MHz to 24 GHz.  
 
 [[SLOW_SUMMARY]]
 ==== Summary

doc/user_guide/en/vhf-features.adoc

@@ -159,13 +159,28 @@ _WSJT-X_.  The mode is designed especially for EME on VHF and higher
 bands; operation is generally similar to 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
-Hz, so although the signal is reasonable strong its tones are
+Hz, so although the signal is reasonably strong its tones are
 broadened enough to make them hard to see on the waterfall.  The red
 curve shows that the decoder has achieved synchronization with a
-signal at about 970 Hz.
+signal at approximately 967 Hz.
 
 image::QRA64.png[align="center",alt="QRA64"]
 
+The QRA64 decoder makes no use of a callsign database.  Instead, it
+takes advantage of _a priori_ (already known) information such as the
+one's own callsign and the encoded form of message word `CQ`.  In
+normal usage, as a QSO progresses the available _a priori_ (AP)
+information increases to include the callsign of the station being
+worked and perhaps also his/her 4-digit grid locator.  The decoder
+always begins by attempting to decode the full message using no AP
+information.  If this attempt fails, additional attempts are made
+using available AP information to provide initial hypotheses about the
+message content.  At the end of each iteration the decoder computes
+the extrinsic probability of the most likely value for each of the
+message's 12 six-bit information symbols.  A decode is declared only
+when the total probability for all 12 symbols has converged to an
+unambiguous value very close to 1.
+
 === ISCAT
 
 ISCAT is a useful mode for signals that are weak but more or less