Make the following text more logical.
Because WCHK was on the AM band with a daytime-only operation, it was required to sign-off by sunset, allowing clear-channel stations to take over the airwaves. On August 1, 1964.
Because WCHK was on the AM band with a daytime-only operation, it was required to sign-off by sunset, allowing clear-channel stations to take over the airwaves. Therefore, on August 1, 1964.