In order to maintain the integrity and safe operation of a power system, a state-of-the-art wiring diagnostic technique is imperative. Joint Time-Frequency Domain Reflectometry (JTFDR) is proposed as an ideal solution due to it's customizable reference signal and unique time-frequency cross-correlation function. The reference signal depends on three parameters: center frequency, bandwidth, and time duration. Previously, these parameters were chosen based on the frequency characteristics of the cable under test. This paper will fully analyze the changing effects of a wide-range of parameter combinations on two different types of defects. It is determined that there exist optimal reference signal parameters for particular defect types. With this knowledge, JTFDR is able to more sensitively detect various defect types over a longer distance than previously possible.