Dynamic detection of primary users is one of the main functions of spectrum sensing for Cognitive Radio (CR) communications aiming to increase the use of radio spectrum. In this work the performance of the so-called Candidate power detector is reported. The main objective of this detector is the proper spectrum labelling of primary users in cognitive radio scenarios. The Candidate detector is tuned in order to detect Digital Video Broadcasting Terrestrial (DVB-T) signals, providing accurate power level estimates and frequency location in presence of interference signals or secondary users transmissions. The advantages of the resulting candidate detector are shown with respect to the existing alternatives based on energy detection and cyclo-stationary based detectors.