نتایج جستجو برای: rain attenuation
تعداد نتایج: 65792 فیلتر نتایج به سال:
Rain rate and rain attenuation predictions are one of the vital steps to be considered when analyzing a microwave satellite communication links at the Ku and Ka bands. In this paper, tools for the prediction of rain rate and rain attenuation are presented in the form of contour maps for Nigeria using a massive rainfall data bank of 30 years which are taken from measurements made from the coast ...
The Advanced Communications Technology Satellite (ACTS) propagation experiment has collected four years of propagation data at 20.185 and 27.505 GHz. The objective of the experiment is to develop long-term statistics and modeling techniques for predicting atmospheric propagation effects in the Ka band. The experiment includes seven identical earth stations at different locations in North Americ...
Abstract A fundamental quantity in the calculation of rain attenuation statistics is the specific attenuation (attenuation per unit distance). The power-law form of rain specific attenuation is very convenient and is commonly used. It is expressed as α R k ⋅ , where k and α are the power-law parameters, and R is the rain rate in mm/h. Limited number of power-law parameters were available in the...
Rain attenuation is an important aspect of signal propagation above 10GHz frequency. The attenuation time series generation from point rain rate measurement is crucial due to unavailability of actual signal measurements. In this paper, a simple and realistic approach has been demonstrated for better estimation of rain attenuation using Ku-band signal propagation data and ground rain rate measur...
This paper presents the experimental results of rain rate and rain attenuation measurements on six terrestrial microwave links in tropical Malaysia. The rain attenuation data were collected from six DIGI MINI-LINKs (DiGi Telecommunications Sdn. Bhd., Malaysia, Shah Alam, Selangor Darul Ehsan, Malaysia) operating at 15 GHz with 99.95 % availability. The experimental results were compared with th...
The campaign to collect rain attenuation data on terrestrial links had commenced in Malaysian tropical climates for almost two decades. The terrestrial data so far collected have been greatly utilized to derive useful statistics for various microwave applications, such as frequency scaling, rain rate conversion factor, 1-min rain rate contour maps, wet antenna losses, and fade slope duration an...
Rain over the oceans causes attenuation of communication and radar signals for satellites and backscatter to satellite radars. To determine the attenuation and backscatter, one must know the height of the rain in a storm, and must be able to find it from a satellite measurement likely to be available. Microwave radiometers on satellites can provide estimates of rain rates, and therefore relatin...
Attenuation measurement on Kuband satellite signal in a tropical site, Fiji is presented. Rain-attenuation prediction by ITU-R and the Crane Global models showed noticeable deviation to the measured values. Unlike the monotonic decrease predicted by these models, exceedance of rain-rate and attenuation in Fiji and other tropical regions showed the presence of breakpoints. For Suva, the breakpoi...
Short Title: Spatial-Temporal Statistics of Rain. Abstract Rain rate near the ground can be interpreted as a collection of random variables forming a random field parameterised by three coordinates: two spatial coordinates and one temporal. Interest among the radio propagation community has been focused on the first order statistics of these random variables, principally on the average annual p...
Brightness temperatures at 22.234, 23.834 and 30 GHz and corresponding rain rates were measured using a ground based radiometer and a fast response optical rain gauge co-located with the radiometer during the year 2009 at Cauchuria, Paulista (22.57 0 S, 89 0 W), Brazil. A statistical analysis reveals that the number of occurrences goes beyond 200 times for rain rate up to 15 mm/hr. It was obser...
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