People do listen to the radio all day, and some of them all night, but prime time listening on shortwave is still during local morning and evening hours.
It is possible to broadcast programs of 1 hour, programs of 45 minutes or programs of 30 minutes.
Programs can be broadcast only one day per week, from Monday to Friday or every day of the week.
The length of a contract can be either 3 months, 6 months or 1 year.
Since local times vary depending on where you are, UTC (Universal Time Coordinated) is used to determine the time you want to broadcast your program.