The commercial certificated pilot was transporting a radio techinian to a remote radio repeater site in a helicopter. The area near the repeater site was snow covered. During the landing, one main rotor blade on the accident helicopter struck a radio antenna. The pilot was not aware of any collision with the antenna at the time of the landing, but discovered damage to a main rotor blade later in the day. The damaged rotor blade was removed and a replacement blade installed. The damaged rotor blade was returned to the manufacturer in France for repair.