Here is the source for the transmission line applet. I stuck a copyright and GNU public license on it. This makes it legal to copy and modify it as much as you want. It mostly only requires you to label any changes as your own and make the source available if you distribute it. Read the copying file for details. If this is a problem for someone, let me know, and we can discuss it. I'm afraid the comments are few and far between, and since I'm new to object oriented programming the style isn't great. The source files are: Tran.java = the main applet code. This sets up the GUI stuff, calculates the equations and calls the plotter routines. Complex.java = a class the implements complex numbers and a subset of operations on them that are needed for this applet. TEMLine.java = an interface that defines the routines I want for a transmission line. SimpleLine.java = a class that defines the simple transmission line model used to determine the complex Z0 and attenuation. I think this is equivalent to what Dean Straw N6BV used in TL.EXE. GenLine.java = a class that uses the same input Z0 and propagation constant at all frequencies. This is used for userline 2. TranWindow.java = This is a wrapper that pops up a window and puts the applet in it. You also need the ptplot source or at least the class files. Both are available free from http://ptolemy.eecs.berkeley.edu/java/ptplot. Now type (assuming you have a Java Development Kit installed) javac *.java or whatever your equivalent command is to compile all the java files to class files and you can then type java TranWindow or equivalent to run it, or install Tran.class as an applet. You can also use the Makefile provided if you run unix. 73 Kevin w9cf