Once tracking mode is activated then TrackPings will be sent out by the transponder according to the Trackping rate for that transponder type.

In order to keep tracking mode activated, the transponders must communicate with a Track Box at least once every 5 hours (3 hours for ActivePro V2 / MotorKart V2), and pass at least one Active Loop every 25 hours (12 hours for ActivePro V2 / MotorKart V2). If you used Channel 8 / Loop 8 to activate tracking mode (not using a management box), then the first interval between tracking activation and Track Box communication is 1 hour. 

After these delays, tracking mode will be automatically deactivated, this is to prevent tracking mode from staying enabled permanently and draining the battery life of the transponder.

Remember that these values are the MAXIMUMS, and so should be calculated on your slowest expected participants. When data is critical for safety it is advisable to build in a buffer of an additional 20% to your maximum expected time.