[en] RRCAT has recently completed fabrication of the first Beta-0.92, 5-Cell, Nb SCRF cavity. A large number of such multi-cell cavities are required for the future high energy superconducting proton accelerators proposed at RRCAT. In addition, these cavities will be a part of deliverables from RRCAT to Fermilab under Indian Institutes Fermilab Collaboration (IIFC). The multi-cell cavity is formed by electron welding of several half cell structures in multiple steps. In order to ensure that the final welded cavity resonates at the correct frequency and has good field flatness; measurement of resonant frequency is conducted at various development stages (half cell, dumbbell, end cell). These measurements are carried out using a VNA and measurement setup developed in house. A novel method has been developed to precisely identify the difference in frequency between the two halves of dumbbell structure which allows the identification of the tuning and trimming needed to bring the structure at correct resonant frequency and length. A dedicated dumbbell tuning fixture has also been developed to correct the errors at the dumbbell stage itself. (author)