2010-10-26 Network Design and Engineering Guide 105Outdoor Unit and Satellite Link DesignLink Budget ExamplesUsing a 3.8m antenna for the Casablanca earth station we can achieve the following modula-tion and coding parameters:Table 3-10 Scenario 2 - Optimized Carrier Coding and BandwidthTable 3-11 Scenario 2 - Optimized Power RequirementsConclusionCompared to the situation with a 2.4 m antenna in Casablanca the following parameters havechanged:- ODU hardware cost is higher because of using a bigger antenna in Casablanca.- Amplifier cost is unchanged because the 30 W amplifier is now used in Tunis instead ofCasablanca.- Due to higher FEC coding on both carriers the transponder bandwidth for the network isagain reduced by 1200 kHz.- Power and bandwidth usage on the transponder is now equilibrated for both carriers.The bandwidth saving should again compensate the higher antenna and installation cost inCasablanca within a short time provided that the site in Casablanca allows the installation of a3.8 m antenna.Further carrier optimization is not possible, because we have reached on both carriers maxi-mum modulation and FEC. Putting bigger antennas on other sites than Casablanca would re-duce power classes on the earth stations, but probably not the overall ODU cost for thenetwork.Star Network;3.8 m AntennaCasablancaCarrier 1 Carrier 2 Total bandwidth re-quired ( carrier spac-ing = 1.2) [KHz]Modulation 8PSK 8PSKFEC 6/7 6/7 4649Estimated SymbolRate [ksps]2138 1736Star Network; 3.8 m An-tenna CasablancaMadrid Berlin Rome Casablanca TunisHome Channel 1 1 2 2 2Power requirement [W] 16.7 11.6 16.3 17.7 22.6Amplifier power class [W] 20 20 20 20 30Power equivalent band-width [kHz]with UPC (Home Channel)1982 1831 1870 1501 1836Carrier bandwidth [kHz](Home Channel)2566 2566 2083 2083 2083
