For Loran-C pulse, a master station and the secondary stations can receive only one pulse to measure simply the pulse arrival time difference (TD). However, multiple (eight to nine) pulse groups are transmitted in practice. This is to provide more energy to the receiver side without increasing the output of the transmitter.

First, the pulse group launched from the master station is composed of nine pulses. The first eight pulses are transmitted at intervals of 1,000 μs. The last 9th pulse is transmitted at 2,000 μs after the transmission of the 8th pulse.

The purpose is to identify the master station signals and use blink. For secondary stations, a secondary station transmits only eight pulses and uses 100 kHZ as the carrier frequency in order to increase precision. This is called "cycle matching."