Page "LORAN" Paragraph 17

Every LORAN chain in the world uses a unique Group Repetition Interval, the number of which, when multiplied by ten, gives how many microseconds pass between pulses from a given station in the chain.

( In practice, the delays in many, but not all, chains are multiples of 100 microseconds.

) LORAN chains are often referred to by this designation ( e. g., GRI 9960, the designation for the LORAN chain serving the Northeast United States ).