 Early in its return to 620 kHz it was able to increase its power by being the first AM radio station in the world to add a second tower and use placement and spacing along with divided power from the main tower to directionalize its broadcast coverage area.The state of the art at the time thought the signal was traveling west to the Mississippi River and then north to interfere with the WTMJ 620 kHz station in Milwaukee.The British engineer phased the new antenna array to produce a null to the radiated signal directly to wards Milwaukee.