ABSTRAKSI: Kata Kunci : ABSTRACT: Tsunami Early Warning System is a comprehensive system that consist of various communication system. One of them is a satellite communication system that used to transmit data from buoy to gateway. The transmitted data are very important because it carries information needed to analyze the probability of the tsunami occurence. So a good performance from the satellite communication system is needed. One of the parameter used to measure the performance in the satellite communication system is link margin. The value of link margin depends on C/N total and C/N required from the system. To get a good performance, C/N total has to be higher than C/N required.
Link Calculation is a way to analyze the performance of the satellite communication system in tsunami early warning system in Indonesia. The inputs are data of buoy distribution in Indonesia and the specification of satellite, buoy, and gateway. While the output is a link margin value that represents performance of the satellite communication system of the Tsunami Early Warning System.
Performance of the satellite communication of Tsunami Early Warning System in Indonesia in general is good because from the calculation obtained C/N total that has higher value then C/N required. C/N required is 7,9 dB while C/N total 11,82, so the link margin is 3,91 dB.Keyword: Tsunami Early Warning System, buoy, gateway, link margin, C/N