sentences:  The 1941 North American Regional Broadcasting Agreement (NARBA) mandated a change in frequency to 1240 kHz.In the late 1950s, most stations on "Class IV" (local) frequencies were allowed to increase their daytime power to 1,000 watts, and WSOC increased their daytime power as well.Also in the 1950s the owners of WSOC brought to the air WSOC-FM at 103.7 MHz, and WSOC-TV on VHF channel 9.