The absolutely known useful radar signal algorithm is examined. The useful radar signal is presented in the form of the second order wideband signal (SOWS). It is assumed that radar SOWS is radiated and reflected from the non-movable point target in the distant zone and is received in the additive mixture with the interfering embodiment. The properties of the SOWS ensembles are used during the processing. Each SOWS of the ensemble is the couple of the aggregate signals of the first order. These properties of the SOWS ensemble allow forming signal and interfering processing channels in the receiver end. The signal and interference amount is isolated in the signal channel and the interference is isolated in the interference channel. The SOWS useful signal detection algorithm is examined. It allows to process the weal signals using the indicated peculiarities. At the information about the intensity of the received SOWS is necessary. It is shown that the use of this information allows increasing the SOWS detection efficiency. To detect the intensity of the weak signals the results of the two-channel processing are offered to use. It is pointed out that the following cases are of the most interest: when the measured signal height is less than the fineness of the used measuring device and when its intensity is less than intensity of the additive interference component. The signal height measurement of the fineness influence on the efficiency of the suggested detection algorithm is examined.