how about something thathas to do with reflected swr...standind wave ratio.? am modulation? just a thought.....tim -----Original Message----- From: Des Bromilow To: PICLIST@MITVMA.MIT.EDU Date: Sunday, September 19, 1999 6:18 PM Subject: reflectometry.. measuring the length of a cable >Anyone got any bright ideas on a device which can be plugged into the end of a single wire (say one core in a power cable) and the device will return a length from the end of where the cable ends. > >the use would be for finding the break in a cable, so if you have a 20m cable, and the device says the end of the active (hot) is 20m, and the length of the neutral is 15m, and the length of the earth is 20m, then you would know that the neutral has a break in it 5m from the other end of the cable. > >You could also use it to measure (approximate) the length of a spooled cable, or the kink in an underground cable. > >anyone know how to build such a beastie? Anyone ever built one? >I envisage something along the lines of a pulse with a delay which is then translated to length, but the detection of the echo, and processing speed may make it harder. Would a PIC be able to keep up? > >Any ideas? > >Thanks , >Des Bromilow >