At a radio transmitting station at Puckeridge , Herts , the Rt Hon Alfred Barnes MP , Minister of Transport , officially brought into action the Decca Navigator Identification Service . An invaluable innovation for air and sea traffic , this system of radio lanes sent out from the station to form a lattice work of waves are recorded on two Decometers by which the ship can establish its position within tens of yards at a considerable distance from the station , Photo shows: After putting the system into action Mr Barnes is seen signing the station's first log . On left is the inventor Mr William J O'Brien of Chicago . 19th January 1949