* Copyright (C) 2007 Dietmar Krause, DL2SBA
*                    eMail: [email protected]
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your option) any later
* version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
* Place, Suite 330, Boston, MA 02111-1307 USA
********************************************************************************
Support:
   Currently this application is provided as-is.
   Feel free to modify and redistribute.
   Would appreciate feedback and bug-reports.

Prerequisites:
   JAVA
      You have to download a SUN JAVA Runtime environment of at least V5.
      You can download the JRE at
            http://java.sun.com/javase/downloads/index.jsp
      Application should also run with a JRE V6 but not yet tested.

   Serial driver
      You have to download the serial driver support for JAVA from
            http://users.frii.com/jarvi/rxtx/download.html
      I propose the version 2.1.7-r2

Installation
   1. Download the vna.xx.jar into a local directory and rename the file to vna.jar
      from Sourceforge at
         http://sourceforge.net/projects/vna-j
   2. Download the run.cmd into the same local directory as the vna.jar.
   3. Copy the files
      - RXTXcomm.jar and
      - rxtxSerial.dll
      to the same directory you downloaded the file vna.jar
   4. execute the batch file run.cmd
   5. Enjoy ...

Settings:
   All settings are initialized from a default set. After first program termination
   the settings are stored in a XML-file with the name vna.xml. The file is located
   in the users home directory.

   The settings can be edited using the menu File/Settings/Configuration dialog.
   But be cautious!

   To select your specific serial port, use the menu entry Interface/Search...
   After selection (30s) in the Interface-menu all available serial ports on your
   system are display. Select the appropriate port.

Open issues
   Scales
      Types
         Currently only three scales (SWR, RL and Phase) are implemented. The other
         scales will come later.
      Autoscale
         Currently not supported.

   Serial driver:
      Currently there exist problems with the RXTXcomm package for Java. When
      virtual COM ports are present in the system (FTDI, ...) the initial setup
      of the serial subsystem takes about 30s to complete.

      On my system i get sporadic errors when opening the VNA com port. I also
      get this error using the VISUAL BASIC applications as well as ZPlots.
      So i guess its a general error in the FTDI drivers...

   Export
      Currently no export functionality supported.

   Printing
      Printing currently not supported

   Window resizing
      Resizing the main window will result in a partially filled window (enlarge)
      or only parts of the data is displayed (reduce). Running a new scan solves
      this issue.

   Number of samples
      Currently the number of samples for the VNA scan is determined by size of
      the diagram frame in the window. A larger window will result in more sample
      and will take longer time.

Change history
   0.3
      First version published which is a little bit useable