Comment by IndrekR

I am using Leo Bodnar’s fast pulse generator (SMA) in my lectures to teach transmission lines. With sufficient length (I use ~1m) it works quite well to demo with a low cost scope. I originally bought it for TDR with 40GSPS/15GHz scope, which works very well with few orders of magnitude smaller lengths. Old on has upper length limit with 10MHz fixed frequency. There is a new one available with external sync and variable frequency, but I have not bought/tested it.