How can I build a simple pulse generator to demonstrate transmission lines

Summary

I am going to answer my own question. Feel free to offer alternatives. I won't accept my answer. When I was a junior engineer, a senior engineer demonstrated transmission lines in the lab with a pulse generator, a scope, and a few BNC cables. I learned more playing with real circuits than I learned in school. Later, I would repeat the demonstration for other engineers. A typical home lab won't have a pulse generator with a fast rise time (my function generator has a rise time of 20 ns). Fortunately, it is not hard to build one. This circuit has a measured rise time of 3 ns (could be limited by the scope, it may be a little faster). And if you build a pulse generator that can create pulses shorter than the propagation time of your cable, the behavior is easier to understand. For a demonstration setup, there are three important parameters: pulse rise time, scope bandwidth, and cable length. With this circuit and a 50 MHz scope, you need about 50 ft of cable to get nice waveforms. With 20 ft of cable, the short pulse are more like humps. I built the circuit on a PCB with a solderless breadboard layout. I only had top mount connectors, but I wanted them mounted on the edge. I improvised (hacked) an edge mounting. Wire to connector should be just long enough to connect a scope probe. Terminators: RF TV Coax is cheaper than BNC cable, so I bought 100 feet of TV Coax. If you want pretty plots, you need to fine-tune the termination resistances. Cheap cables may be off by 10%. I have saved plots of 5 simple configurations, each with short and long pulses. Short being defined as a width less than the propagation time of the cable. Note that there are people here who understand this better than me, and can explain it better than me. The Q&A is the pulse circuit, the scope plots and descriptions are a bonus. 1. Source Impedance = 0, Load Impedance = Infinite: Short pulse: The pulse is reflected at the load non-inverted, and at the source inverted. At the load, the incident volt...