Add a link to G3WDG doc on using QRA64 for microwave EME.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@8060 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

doc/common/links.adoc

@@ -104,6 +104,7 @@ d). Edit lines as needed. Keeping them in alphabetic order help see dupes.
 :nh6z: http://www.nh6z.net/Amatuer_Radio_Station_NH6Z/Other_Peoples_Software.html[here]
 :omnirig: http://www.dxatlas.com/OmniRig/Files/OmniRig.zip[Download]
 :osx: http://physics.princeton.edu/pulsar/K1JT/wsjtx-{VERSION}-Darwin.dmg[wsjtx-{VERSION}-Darwin.dmg]
+:QRA64_EME: http://physics.princeton.edu/pulsar/K1JT/QRA64_EME.pdf[QRA64 for microwave EME]
 :svn: http://subversion.apache.org/packages.html#windows[Subversion]
 :win32: http://physics.princeton.edu/pulsar/K1JT/wsjtx-{VERSION}-win32.exe[wsjtx-{VERSION}-win32.exe]
 :wsjt_svn: http://sourceforge.net/p/wsjt/wsjt/HEAD/tree/[WSJT Source Repository]

doc/user_guide/en/protocols.adoc

@@ -149,13 +149,12 @@ separation is 110250/4096 = 26.92 Hz multiplied by n for JT65A, with n
 [[QRA64_PROTOCOL]]
 ==== QRA64
 
-QRA64 is an experimental mode intended for EME and other extreme
+QRA64 is intended for EME and other extreme weak-signal applications.
-weak-signal applications.  Its internal code was designed by IV3NWV.
+Its internal code was designed by IV3NWV.  The protocol uses a (63,12)
-The protocol uses a (63,12) **Q**-ary **R**epeat **A**ccumulate code
+**Q**-ary **R**epeat **A**ccumulate code that is inherently better
-that is inherently better than the Reed Solomon (63,12) code used in
+than the Reed Solomon (63,12) code used in JT65, yielding a 1.3 dB
-JT65, yielding a 1.3 dB advantage. A new synchronizing scheme is based
+advantage. A new synchronizing scheme is based on three 7 x 7 Costas
-on three 7 x 7 Costas arrays.  This change yields another 1.9 dB
+arrays.  This change yields another 1.9 dB advantage.
-advantage. 
 
 In most respects the current implementation of QRA64 is operationally
 similar to JT65.  QRA64 does not use two-tone shorthand messages, and

doc/user_guide/en/vhf-features.adoc

@@ -158,15 +158,14 @@ image::JT65B.png[align="center",alt="JT65B"]
 
 === QRA64
 
-QRA64 is an experimental mode in Version 1.8 of _WSJT-X_.  The mode is
+QRA64 is designed for EME on VHF and higher bands; its
-designed especially for EME on VHF and higher bands; its operation is
+operation is generally similar to JT4 and JT65.  The following screen
-generally similar to JT4 and JT65.  The following screen shot shows an
+shot shows an example of a QRA64C transmission from DL7YC recorded at
-example of a QRA64C transmission from DL7YC recorded at G3WDG over the
+G3WDG over the EME path at 24 GHz.  Doppler spread on the path was 78
-EME path at 24 GHz.  Doppler spread on the path was 78 Hz, so although
+Hz, so although the signal is reasonably strong its tones are
-the signal is reasonably strong its tones are broadened enough to make
+broadened enough to make them hard to see on the waterfall.  The
-them hard to see on the waterfall.  The triangular red marker below
+triangular red marker below the frequency scale shows that the decoder
-the frequency scale shows that the decoder has achieved
+has achieved synchronization with a signal at approximately 967 Hz.
-synchronization with a signal at approximately 967 Hz.
 
 image::QRA64.png[align="center",alt="QRA64"]
 
@@ -192,12 +191,13 @@ initially, as the QRA64 tones are often not visible on the waterfall.
 The box labeled *Tx6* switches the Tx6 message from 1000Hz to 1250Hz
 to indicate to the other station that you are ready to receive messages.
 
-
 TIP: QRA64 is different from JT65 in that the decoder attempts to find
 and decode only a single signal in the receiver passband.  If many
 signals are present you may be able to decode them by double-clicking
 on the lowest tone of each one in the waterfall.
 
+TIP: G3WDG has prepared a more detailed tutorial on using {QRA64_EME}. 
+
 === ISCAT
 
 ISCAT is a useful mode for signals that are weak but more or less