A method and apparatus are provided for creating a pilot channel in an opportunistic radio communication system whose frequency spectrum comprises a set of frequency bands and for which system the successive frames of a radio communication channel are divided into time intervals. The method includes the steps of: opportunistically selecting a free frequency band from the frequency spectrum, so as to support the pilot channel; sending a beacon signal over at least one time interval of the successive frames of the pilot channel and probing the free frequency band over at least one time interval distinct from the previous one.