Among all measuring devices developed, the so-called ambient vibration method has been often used to determine the cable force with the identified natural frequencies from the measured ambient vibration signal of the stay cable. This method mainly takes advantage of the simple and straightforward relationship between the internal force and natural frequency of longer stay cables if the usually negligible effect of flexural rigidity in vibration is not considered. For shorter stay cables, however, this ignorance may not be acceptable because the flexural rigidity and boundary conditions can significantly affect the corresponding cable vibration. In this case, the ambient vibration method turns to be more complicated, and consequently needs to be further explored. This paper documents the methods used to measure the ambient vibration signals of shorter stay cables for determining the internal force of the cable system, both in the stressing and service stages. Two extradosed bridges under construction and recently completed were extensively investigated. The subsequent analysis of the measured cable signals is presented in the other companion paper.