ATSC A/65 provides for signaling date and time in System Time Tables (STT) as event start times in Event Information Tables (EITs) using a 32-bit unsigned integer value that specifies the number of GPS seconds that have elapsed since 00:00:00 AM on January 6, 1980.
This tool converts a UTC date/time to the appropriate ATSC system_time with the results given as a 'raw' 32-bit unsigned integer and the hexadecimal respresentation of that value. This tool automatically determines the approriate GPS_UTC_offset using the leap seconds published by International Bureau of Weights and Measures. http://www.bipm.org/en/home/
Select the date and time of day, then press 'calculate'
For date and time values later than the current date and time, the greatest published value for GPS_UTC_offset is used in determing the date and time