When I asked for some references to simulation programs I got some really helpful responses. As promised, I will summarize the most promising ones here. FREE: Bob Perlman was very helpful and has written a simulation in MathCAD. MathCAD has the ability to generate an .avi file which is really neat. I upgraded my version of MathCAD and the technique is truly elegant. I wish Excel and Quattro had the same capability. Reach Bob (with his permission) at http:/www.best.com/~bobperl/course1.htm HP has an outstanding resource for technical training stuff at http://www.tmo.hp.com/tmo/iia/edcorner/English There is much stuff here, but the transmission line simulation is under Spectral Simulation AC Circuits Wave propagation along a transmission line the specific URL is as above plus /Sexp8.html There is also an excellent java simulation and small tutorial at http://www.ecse.rpi.edu/Courses/F97/35210/java/Transline/tr_lines.htm Commercial with some demos (none of which I have evaluated) http://www.sonnetusa.com http://www.hyperlynx.com http://www.intusoft.com http://www.aplac.com This looks interesting, but the demo is 7.6 Megs and the handbook another 5 megs or so. Haven't tried to download it yet. http://www.artech-house.com This is a book publisher/reseller with numerous titles. One is TRAVIS Pro which is a computer transmission line simulator with a price of $295 !! Thanks to those who helped me put this list together Doug Brooks . **************************************************** Doug Brooks, President [log in to unmask] UltraCAD Design, Inc. http://www.ultracad.com ################################################################ DesignerCouncil E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE DesignerCouncil <your full name> To unsubscribe: SIGNOFF DesignerCouncil ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################