The problem of efficient hardware implementation of spectrum sensing algorithm is still highly investigated. In this paper the double-threshold energy-detection algorithm was analysed, which effectiveness was tested with the cooperative use of USRP platforms. In the real-time experiments a set of sensing nodes check continuously the occupancy of the frequency band, trying to detect the presence of DVB-T or PMSE signals. The obtained results showed that cooperative spectrum sensing have to tackle with hardware limitations and noise uncertainty.