It depends on alot of things. What is the brand of tdr? I personally like a 1205c and have found that the blind spot is no more than ten feet out. Try to experiment w/ your tdr on a roll of cable and play w/ it a little.Good practice is at least 50 feet of jumper. Also throw out the aligator clips and use a baff connector,"for catv". And always shoot from both ends. w/ practice your trenches will become smaller and smaller until finally they are holes.
Rich
>Could anyone give me their thoughts on what is the proper length jumper for an accurate TDR measurement. I would think that 30 meters would be good