The June 2014 edition of QST (pp38-40) has an article by Joel Hallas (W1ZR) reporting on an updated version of the venerable Transmission Line Program for Windows (TLW), by Mr. R. Dean Straw (N6BV). The previous version was last released in 2006. Owners of the ARRL Antenna Handbook receive the program on the included CD/DVD, and are eligible for a free upgrade if you have a previous version. The Zip file can be downloaded from the ARRL website. If you are not eligible but would like to read the user's manual, download the Zip file and extract just the PDF file since the one available elsewhere on the Web is for the 2006 version.
According to Joel's review, the main changes in TLW are refinements in the manufacturer's data used for curve fitting and in the electrical parameter calculations. Results obtained from extreme source and load impedance scenarios could cause some strange values of loss, voltage and current distribution along the transmission line, etc.
I have managed to lose my CD so I cannot produce any examples of my own. However, the following couple images are screen shots from the user's manual that might whet your appetite for the program. As far as I know, it is available only with the purchase of the ARRL Antenna Handbook, which is currently selling for under $50. The software itself is worth that much if you require such calculations. According to Joel: "I can state that among all the programs and data on The Antenna Handbook CD, I find Transmission Line for Windows (TLW) to be the program that I use the most."
Posted on July 5, 2015