diff --git a/doc/building on MS Windows.txt b/doc/building on MS Windows.txt
index 8bae6a658..9e954285c 100644
--- a/doc/building on MS Windows.txt	
+++ b/doc/building on MS Windows.txt	
@@ -17,6 +17,7 @@ Here is an overview list, details are filled out below:
      * libusb usb device library
      * MSYS2 *nix like command line environment
      * Hamlib rig control library
+     * Pkg Config Lite
      * Boost C++ libraries
 
 Qt Framework
@@ -64,8 +65,9 @@ You only need the 64-bit package.
 libusb library
 --------------
 
-This  library  is  available  from  https://libusb.info/,  unzip  this
-package into C:\Tools.
+This library is available  from https://libusb.info/, download the .7z
+archive  as  the  .zip  archive  does not  contain  the  libraries  we
+require. Unzip this package into C:\Tools.
 
 MSYS2
 -----
@@ -76,6 +78,8 @@ installed and  updated you will  need to install some  packages, these
 are needed to provide the necessary  *nix tools and utilities to build
 Hamlib from sources.
 
+    pacman -S autoconf automake libtool make
+
 Hamlib
 ------
 
@@ -88,7 +92,78 @@ up  to date  with the  official  project master  branch, we  recommend
 building from the 'integration' branch of that fork. The fork is a git
 repository which can be cloned with this command:
 
-git clone git://git.code.sf.net/u/bsomervi/hamlib hamlib
-cd hamlib
-git checkout integration
+    mkdir -p ~/src/sf/bsomervi
+    cd !$
+    git clone git://git.code.sf.net/u/bsomervi/hamlib hamlib
+    cd hamlib
+    git checkout integration
+
+Next you must build Hamlib using the MinGW compiler tools bundled with
+Qt. As you  will build Hamlib again when there  are updates you should
+set  up  you  Msys2  command  line  environment  for  this.  I  use  a
+$HOME/.bash_profile file containing these lines:
+
+    dll_paths_64bit=/c/Tools/libusb-1.0.23/MinGW64/dll
+    export PATH=/c/Qt/Tools/mingw810_64/bin:$dll_paths_64bit:$PATH
+
+Test the amended ~/.bash_profile file by opening a new Msys2 shell and
+typing:
+
+    which gcc
+    which libusb-1.0.dll
+
+The first time you checkout the  Hamlib sources you must bootstrap the
+configuration script,  this is done with  a script at the  root of the
+Hamlib sources:
+
+    cd ~/src/sf/bsomervi/hamlib
+    ./bootstrap
+
+Now you need to configure and build Hamlib from an Msys2 shell. Create
+a build directory outside of the  Hamlib sources you have just cloned,
+then change working directory to that build directory.
+
+    mkdir -p ~/build/hamlib/release
+    cd !$
+    ~/src/sf/bsomervi/hamlib/configure --disable-shared \
+        --prefix=$HOME/local/hamlib/mingw64/release \
+	CFLAGS="-DNDEBUG -g -O2 -fdata-sections -ffunction-sections -I/c/Tools/libusb-1.0.23/include" \
+	CXXFLAGS="-DNDEBUG -g -O2 -fdata-sections -ffunction-sections" \
+	LDFLAGS="-Wl,--gc-sections" \
+	LIBUSB_LIBS="-L/c/Tools/libusb-1.0.23/MinGW64/dll -lusb-1.0"
+
+Then build and install the Hamlib package into a local directory:
+
+    make & make install-strip
+
+If you wish  you can make a debug configuration  build of Hamlib which
+can be useful if you intended  to contribute to the Hamlib project, or
+for tracking down issues:
+
+    mkdir -p ~/build/hamlib/debug
+    cd !$
+    ~/src/sf/bsomervi/hamlib/configure --disable-shared \
+        --prefix=$HOME/local/hamlib/mingw64/debug \
+	CFLAGS="-g -O0 -I/c/Tools/libusb-1.0.23/include" \
+	CXXFLAGS="-g -O0" \
+	LIBUSB_LIBS="-L/c/Tools/libusb-1.0.23/MinGW64/dll -lusb-1.0"
+    make && make install
+
+To update the Hamlib sources to the latest commit and rebuild:
+
+    cd ~/src/sf/bsomervi/hamlib
+    git pull
+    cd ~/build/hamlib/release
+    make & make install-strip
+    cd ~/build/hamlib/debug
+    make && make install
+
+Pkg Config Lite
+---------------
+
+This package allows the WSJT-X CMake configuration to locate and learn
+the options needed to consume the  Hamlib package. You can download it
+from  https://sourceforge.net/projects/pkgconfiglite/files/0.28-1/ and
+unzip it into a convenient location, as with other ancillary tools and
+libraries I put these under C:\Tools\.