Abstract :
Satellites communication are located at altitude of thousands kilometers above the earth's surface, so the signal is transmitted by satellite to earth station is very susceptible to interference. Every equinox of March and September or when sun crosses the earth's equator for several days, the earth station occurs a naturally interference called sun outage. At this time, satellite and sun reach the closest distance because satellite position is same direction with the sun. Interference makes the signal received by earth station weaken and even disappears due to temperature noise which increases drastically according to the duration of sun outage. Loss of signal on the downlink side caused by noise greatly affects to the performance of satellite communication system. This study aims to analyze the effect of sun outage on performance Telkom 3S satellite communication system and satellite orbit to determine the sun outage period. The results obtained, parameters that indicate signal quality of Telkom 3S satellite communication system is changes during sun outage. This is represented by degradation result in Carrier to Noise Ratio (C/N) from 14,777 dB to 6,0 dB, Energy bits per Noise Ratio (Eb/No) from 11,515 dB to 2,738 dB, and increase the Bit Error Rate (BER) from 8,29×10-7 to 11,08×10-3 . In addition, sun outage makes lost of satellite communication traffic and affecting link availability to 99,855324%. Meanwhile, the result of satellite orbit calculation for sun outage period based on ITU-R S.1525 standard resulting more appropriate accuracy with measurement data than manual calculations based on handbook. And results of this calculation, if diameter of antenna is getting smaller, then interference of sun outage is getting longer. Keywords: Telkom 3S satellite, equinox, sun outage, C/N, Eb/No, BER, link availability, sun outage period