AbstractThe influences of coaxial measuring cables on waveform parameters have been neglected in lightning impulse measurements. This is partly because the tolerable uncertainty for determining the front timeT1in the reference measuring system is 3% and the induced influence due to using a long measuring cable is expected to be much smaller than the margin. The authors have suspected the validity of the expectation as a result of experience. This paper proposes an analytical treatment of the impulse response at the end of a lossy measuring cable. Using the proposed technique, the measured parameter errors are compared to numerically evaluated ones and it is confirmed that the two are in good agreement. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(6): 1–7, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10288