Interference and Compatibility Analysis of ARABSAT vis-à-vis EUTELSAT Systems and Networks

The paper presents an electromagnetic Interference and Compatibility Analysis for ARABSAT and Eutelsat Networks. The analysis suggests that ARABSAT has to accept certain constraints required to protect Eutelsat. An EIRP spectral density of -34 dBW/Hz in the direction of the Eutelsat space station is proposed in the uplink bands 14.0 14.5 GHz. In the downlink bands, an EIRP spectral density of -34 dBW/Hz towards the Earth. In addition, in the uplink band 13.75 14.0 GHz Eutelsat has imposed a constraint of -28 dBW/Hz. Although slightly over protective when using the larger bandwidth ARABSAT carriers, this limit is considered reasonable taking into account footnote 5.502, which limits EIRP in the 13.75 14.0 GHz band to between 68 and 85 dBW . The uplink constraint of -28 dB/W/Hz offered by Eutelsat should be accepted. The results show that it will be possible for Arabsat to operate provided larger carrier bandwidths and antennas are used. The results demonstrates that for 27 and 36 MHz carriers, with antenna size of 3.5m, there is a positive C/I margin of around 4 dB. This is further improved with a 64 MHz carrier and 4.5m antenna size. In downlink direction Arabsat has priority for the majority of carriers and total priority in the band 12.2 – 12.5 GHz. However, where Eutelsat has priority (carriers 300KG9X and 35 M0G7W), analysis shows that EIRP of the 12.8 kHz ARABSAT carrier would need to be limited to 6.4 dB in order to meet the spectral density limit of -34 dBW/Hz. This is a reduction of 17 dB on the currently filed ARABSAT parameters. In the converse case, there are constraints on Eutelsat-3 required to protect Arabsat. In the uplink bands 14.0 14.5 GHz, an EIRP spectral density of -38 dBW/Hz in the direction of the ARABSAT space station. In the downlink bands, an EIRP spectral density of -28 dBW/Hz towards the Earth.