Hi Stephen, >Yeah, I'll probably fiddle around some more with this, just because it >seems like the "pre-ring" is going the wrong way and I'd like to >understand why.
That's good. While the scope precludes you from doing any interesting shock wave experiments ( way too slow ) you can certainly do some faster-than-light type experiments using lumped constant transmission lines. As regards the wire impedence, use a 400ohm carbon film resistor as your termination. This is good enough for basement work. When I worked with this I used aluminum foil to make ground planes, suspending wire above it in whatever form was important. Google around a bit on the term "time domain reflectometery" and you'll learn about how to characterize the line more accurately. But again, the scope is too slow to work such a small physical structure. BTW, the rule of thumb with aircore xmission line is 1ns/ft. Easy to remember, and it's always nice to put the kings feet in there somewhere... While you're chewing on yesterdays comments, take a few moments to read that section in Feynmans QED, http://press.princeton.edu/titles/8169.html where he talks about the photon taking all possible paths from the sender to the receiver. Strange, huh? Now think about that experiment you just did and that precursor signal I pointed out. Not so strange now... K.
