The TDS8000 does not provide the set cursor to zero function. To make the measurements with a TDS8000 and the cursors use magnification and magnify each end of the cable. The scope now displays Mag 1 and Mag 2, assign the cursors to each Mag and read the delta. For better accuracy use the delay measurement feature and assign the Delay measurement to Mag 1 and Mag 2. The TDS8000 has 3 time basses so there is no loss in resolution when using multi magnification windows..