End current without touching wire Say I am sending a pulse down a five foot wire.  If I want the pulse to not reach the end of the wire, but instead reflect at say the two foot mark, how could I achieve this without physically touching the wire?
I thought to use magnets, but I'm not sure if I'm on the right track.
Any help is appreciated.
Thanks!
 A: If, as your comment indicates, you're talking about a coaxial cable such as 75\$\Omega\$ RG-59, it's virtually impossible realistically to affect it as you suggest (the coax keeps signals in and interference out). Well, you could heat it (perhaps with an induction heater) until the insulation vaporizes and the copper melts which technically would not be touching it, but I don't think that's what you want. 
If a straight pin were to find its way between the outer shield and the inner conductor such that the two were shorted together, it would accomplish what you say you want. If it broke off flush, it could be fairly hard to detect, though a TDR (time domain reflectometer)  would point to the general location within maybe 50cm. (RG-59 Image from Wikipedia commons) 

A: If you can make two kinds of wires a 3 foot one and a 2 foot one, then you can try attaching them, and make sure the impedence is mismatched.  If you can adjust the temperature at one end severly and make your wire(s) out of something that has a temperature induced conductivity change that might get a nice effect.
