In this paper, we evaluated the SNR gains of UWB receivers performance. The optimum and isotropic template receivers satisfied constant noise power condition between input and output are considered. The biconical antennas are used as the transmitter (Tx) and receiver (Rx) antennas. The rectangular passband, which is satisfied the full band of UWB signal definition and FCC indoor and outdoor limit spectral masks, is used as the transmitted UWB signal. The channels are measured in an anechoic chamber by using a vector network analyzer (VNA). The frequency range of measurement is form 3 GHz to 11 GHz. The path losses are evaluated and investigated for considering the SNR gains. The SNR gains of optimal and isotropic template receivers are shown and compared. The results are discussed in the conclusion.