A Study on the Effects of Rain Attenuation for an X-Band Satellite System Over Malaysia

Abstract

In this paper, the effect of rain attenuation on the FSS allocation in the 7250-7750 MHz in the Space-to-Earth direction is studied for a satellite at 78.5 • E longitude. A simulation model based on the ITU-R P618-10 rain model is used to predict the rain attenuation in the C-, Ku-and X-bands in 15 different locations with varying rainfall intensities of between 145-300 mm/hr in East and West Malaysia. The simulations assume a 1.8 m receive antenna with 65% aperture efficiency, QPSK modulation and use of either vertical or horizontal polarization. The downlink centre frequencies used in this study are 4200 MHz, 7750 MHz and 11200 MHz for C-, X-and Ku-bands respectively. The average free-space path loss calculated for each band is used to estimate the signal attenuation due to rain and the corresponding E b /N o (dB) is computed at varying rain intensities. The results show that when using vertical receive polarization, all 15 locations of study with a rainfall intensity of up to 200 mm/hr could receive the X-band signal. At 200 mm/hr rain intensity in the horizontal receive, most of the X-band links could achieve the threshold E b /N o of 7.68 dB with a ULPC adjustment of approximately 1.5 dB where required. At 300 mm/hr rain intensity, video signals in the X-band were no longer receivable in both polarizations. At 145 mm/hr rain intensity, only one location with high satellite elevation and greater height above mean sea level maintained the Ku-band link in the horizontal receive. In the vertical receive, the Ku-band link was receivable at all locations at 145 mm/hr but were no longer receivable at 200 mm/hr. The study concluded that the elevation angle towards the satellite is a major factor in determining the quality of the signal in the X-band. The other factors that affected the receive E b /N o was the polarization, depth of rain and height of the earth station above

Effect of Phosphorus and Polyamine Fertilizers on Kufi Apple Transplants Growth

“…The results in Tables (2,3) showed that phosphorus fertilizer at a concentration of 200 mg P kg -1 soil significantly increased transplant leaves area and sction length as compared with control and 100 mg P kg -1 soil treatments. The obtaind results was in line with those obtaind by [6,8,10,12], and [13]. These results may be due to the function of phosphorus which is presented in all living tissue, however it is concentrated more in the juvenile plant sections.…”

“…[12] stating that the application on NPK (15:15:15) fertilizer at levels of 1,2,3, and 4 gm transplant -1 of Punica granatum planting in bags containing 23.3 kg of soil significantly increased leaves number, plant height, leaf area with an increase in the fertilizer amount compared to the control. [13] noticed that the application of phosphorus to mustard apple at level of 187 gm plant -1 with the combination of nitrogen and potassium at a level of 388 and 187 gm plant -1 respectively significantly increased plant height, canopy volume, stem girth and leaf area index. At the present time, the fertilization of transplants and various fruit trees with solid and liquid organic fertilizers has increased, including fertilizers that contain amino acids, which are among the nitrogen fertilizers that are characterized by their cheap price, ease of use, low pollution, and their contribution to improving the physical and chemical properties of the soil, which contributes to improve the production and growth of the plants treated with it, and the quantities added depend on soil texture, species and variety of the plant, the prevailing environmental conditions in the region, and other factors [14].…”

Study on the Delay of UAV Data-Link Based on TDMA and Aloha Channel Access Protocol

“…Rainfall will bring signal attenuation to the performance of the radio system; meanwhile the scattering effect due to rainfall will cause inter-system interference. Under uniform rainfall conditions, the calculation of clouds and rain attenuation is relatively simple; but in most cases, rainfall is not uniform in time and space, and the unevenness of the cloud/rain medium shows the randomness, which brings great difficulty into the calculation [4]. Therefore, we need to find a precise mathematical model to describe the non-uniformity of the cloud/rain medium, and achieve simulation on clouds and rain fading through establishing a convenient and practical empirical formula.…”