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
-broadened enough to make them hardto see on the waterfall.  The red
+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