Some fun reading in the WLW wiki article....
"WLW's 500,000-watt "RCA 1" transmitter was in operation between 1934 and 1939, and was the highest power ever used in the United States for public, domestic radio broadcasting. It was designed as an amplifier of the regular 50 kW transmitter. It operated in class C with high-level plate modulation, and required two dedicated 33 kilovolt electrical substation lines and a large cooling pond complete with spray fountains. It operated with a power input of about 750 kW (plus another 400 kW of audio for the modulator) to produce 500 kW. Even after 1939, when regular WLW programming was prohibited from operating with more than 50,000 watts, the station continued post midnight high-powered operation as experimental station W8XO, which helped to greatly improve the RCA 1 transmitter's power and reliability. By the end of World War II, it was capable of producing one million watts, and it "loafed along" at 600 kW.[47]
WLW's 500,000-watt authorization included the requirement that the station limit its nighttime skywave signal toward Canada to the equivalent of 50,000 watts, which led to the construction of two shorter towers, electrically a quarter wavelength in height and separated by a half wavelength, that were located 1850 feet (560 m) southwest of the main tower. The two shorter towers were fed using trolley car wire to produce an 85 kW signal at 96 degrees out-of-phase with the principal signal, which produced a null in the opposite direction from the main tower.[70]
Many reports have surfaced over the years, from those who lived near the 500-kilowatt transmitter, of power fluctuations. Residents would see their lights flicker in time to the modulation peaks of the transmitter. It was widely reported that the signal was so overpowering that some people picked up WLW radio on the metal coils of mattresses and boxed bedsprings.[71] Arcing often occurred near the transmission site.[72]"
