As the first station in the world to broadcast at this strength, WLW received numerous complaints from around the United States and Canada that it was interfering with other stations, most notably from CFRB, then on 690 kHz, in Toronto, Ontario. In December 1934, WLW was instructed to cut back to 50 kilowatts at night until it had eliminated the interference. The station began construction of two shorter towers 1850 feet (560 m) southwest from the main tower in order to create a directional antenna, which successfully reduced the signal broadcast towards Canada. With these antenna towers in place, full-time broadcasting at 500 kilowatts resumed in early 1935. However, WLW was continuing to operate under special temporary authority that had to be renewed every six months; each renewal brought complaints about interference, and undue domination of the market, by such a high-power station.