Frequency Modulated Continuous Wave radar systems offer a very large dynamic measurement range, while at the same time they can be fabricated very compact and cost efficient. Due to this, FMCW-sensors are a feasible alternative to costly measurement equipment like vector network analyzers. Applying calibration techniques and algorithms from the VNA domain, they can also be used to characterize materials with very high precision. At the same time, the short measurement time allows their use in mobile high precision measurement setups. This paper presents such a mobile setup that is easily calibrated an can be used for in-situ material parameter estimation and data collection for e.g. channel models. For this purpose, a SiGe-radar system in the lower THz range from 200 GHz to 250 GHz is used.