Hi Dave, there is no doubt that, in your suggested experiment, the reflections cause a change in the generator load-line. The real question is what causes the change in the generator load-line when there is no transmission line? My question is: What besides reflections, among the known laws of physics, can cause a change in the load-line? Nobody has presented a mechanism for that change that doesn't involve information feedback from the changed impedance. It is a very simple question having to do with information transfer theory which cannot be transferred at faster than the speed of light. Source------any length except zero------impedance change Given: The source load-line doesn't change at the instant of the impedance change. There is a speed-of-light delay between the impedance change and the change in the load-line. Exactly what is the nature of the speed-of-light feedback from the impedance change to the source load-line? What mechanism of physics can explain such behavior except for reflections? I have asked that question a dozen times and the silence of the replies is deafening. Seems to me, reflections win the argument by default, since there is no other phenomenon known to physics that can explain the speed-of-light delay involved in the process. If the lumped-circuit model was correct, the load-line would change the instant that the impedance is changed, but we know it doesn't. Therefore, the lumped-circuit model is incorrect and must be discarded in attempting to answer the question of what mechanism of physics causes the speed-of-light feedback delay from the changed impedance. The lumped-circuit model does not support speed-of-light delays. In the above simple example, the only energy that exists in the system is source energy, forward-traveling energy, and reverse-traveling energy. Of those three types of energy, reverse-traveling energy is the only one that could possibly transfer information from the impedance change back to the source. If this were EM light energy instead of EM RF energy, the answer would be "obvious". Light source------any length except zero------mirror (index of refraction) change There is no conceptual difference in the feedback mechanism between this light example and the RF example above.