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By Prima Setiyanto Widodo
Satellite Communications Systems are infrastructures that can be used for broadband multimedia applications. In the communication satellite field, the C-band (4-6 GHz) frequencies have been used since the beginning and are now saturated. The Ku-band (11-18 GHz) has been used also for communication satellite systems, because with this frequency a bigger bandwidth can be applied. The Ku-band has other advantages, such as avoidance of interference with terrestrial microwave systems that often use the C-band frequency. However, for Indonesia, the use of the Ku-band needs a thorough examination because frequencies above 10 GHz are vulnerable to rain, especially heavy rain that often occurs in Indonesia. This article examines the possibility of using the Ku-band for satellite communication systems in Indonesia.

In 1976 President Soeharto of the Republic of Indonesia, gave the name PALAPA to the first Indonesian satellite. At that time Indonesia was the 3rd nation in the world to use satellites as its telecommunications infrastructure. Indonesia can be proud of this fact, because Indonesia’s neighbors Singapore, Malaysia, the Philippines and Thailand had not yet shown any interest in having their own satellites.
Indeed, considering Indonesia’s geographical features: consisting of islands stretching from West to East and from South to North, it is reasonable for Indonesia to adopt a satellite platform for its communications system. By using satellites one can obtain wide coverage, quick rollout of facilities (compared to buried optic fiber cables) unconstrained by natural conditions and distance.
Indonesia is now not alone in South-east Asia/East Asia in utilizing satellite services for voice, video and data. Twenty years after the historic launch of its first satellite in 1976, Malaysia and Thailand have launched their own satellites, followed by Singapore and Taiwan constructing their satellite cooperatively. In addition are Hongkong, Korea (Koreasat) and Japan (JCSAT).
The frequency bands used for satellite communications have also developed. Besides using the Cband, the use of the Ku-band has become more and more popular, even though Indonesian satellite operators are still unsure about the technical feasibility of using the Ku-band in Indonesia.
Breakthroughs in the satellite field should allow Indonesiato use frequencies higher than 10 GHz, i.e. the Ku-band (11 – 18 GHz) and Ka-band (20 – 30 GHz). The advantage is that the higher the frequency used, the larger the bandwidth. The limitation is that frequencies higher than 10 GHz are subject to higher rain
attenuation, thereby causing a decrease in communication “availability.”

The International Telecommunication Union, ITU, has categorized Indonesia as Region P, countries with very high rain precipitation. According to ITU’s version, rain intensity that will cause the interruption of a communication link for 0.01% per year is 145 mm/ hour. Such rain intensity can cause 28 db rain attenuation for a link working in the 14 GHz band; that is pretty high. Such an attenuation should be compensated for with powerful RF equipment at the transmit side. The value can be calculated by using link-budget analysis. Should we be pessimistic that we cannot use such frequencies? Let us study it carefully. We should ask ourselves whether it will rain all year long. Of course not. And will the rain attenuation be 28 db consistently? This is also not the case, because the rain attenuation is dependent on the rainfall at a certain location. There is still hope for the use of frequencies above 10 GHz in Indonesia.
http://satjournal.tcom.ohiou.edu/issue8/pers_setiyanto.html

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3 comments

  1. Lilian // December 25, 2008 at 7:33 PM  

    interesting content very informative...cheers!

  2. pinaykeypoint // December 31, 2008 at 1:22 AM  

    Happy New year!! Wishing you the best of 2009. Good Life & Good health to you and your family. More blessings to all of us. Cheers!! :)

  3. Wilson // December 3, 2009 at 6:23 PM  

    My Company already use 5 Node of Ku-Band VSAT and it's running smoothly till now days and it's a budgeted Internet solutions by paying Rp. 2.000.000,- you can have up to 512Kbps.

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