【正文】 Satellite G/TEnter the Figure of Merit (G/T) of the on board satellite receiver in units of dB/K. This should be the value in the direction of the earth station. Values may be obtained from satellite operators or satellite directories in the form of G/T contour maps.輸入衛(wèi)星接收器的品質(zhì)因數(shù)G/T，這個(gè)值應(yīng)該是地球站地理位置所對(duì)應(yīng)的那個(gè)值。（衛(wèi)星文件記錄不超過(guò)18個(gè)字符）如Astra 2aSatellite Longitude衛(wèi)星經(jīng)度Enter the longitude corresponding to the subsatellite point of the satellite on the equator. This should be in decimal degrees with the suffix E for East and W for West. Examples or 輸入該衛(wèi)星赤道星下點(diǎn)的經(jīng)度。在AUTO模式下，它用來(lái)計(jì)算輸出回退的典型值和轉(zhuǎn)發(fā)器的交調(diào)干擾。衛(wèi)星部分satelliteTransponder Type Radio Buttons轉(zhuǎn)發(fā)器種類(lèi)These radio buttons set the transponder type, which can be either a TWTA (Traveling Wave Tube Amplifier) or SSPA (Solid State Power Amplifier). The default is TWTA. This is used in determining typical values for output backoff and transponder intermodulation interference if the AUTO mode is selected.這個(gè)單選按鈕設(shè)置轉(zhuǎn)發(fā)器種類(lèi)，可以是TWTA(Travelling Wave Tube Amplifier)或SSPA(Solid State Power Amplifier)。但是如果上下行在同一個(gè)城市或者地區(qū)，可能受同一個(gè)降雨云影響，你可能需要計(jì)算上行和下行同時(shí)受到雨衰的影響的情況。如果不想計(jì)算雨衰值可以輸入0.注：這個(gè)值是不能在Graph或者Table里面查的。雖然通常不必要。Crane模型也可以使用，這種模型你無(wú)須尋找降雨地圖，系統(tǒng)會(huì)自動(dòng)計(jì)算。選擇相關(guān)的復(fù)選框即可。Tables39。Graphs39。雨衰Rain modelsHere you can select the rain model to use. Check the checkbox relevant to the model you wish to use.The ITU/DAH rain model is remended since it is probably the most accurate model to date. The Crane models are also provided if you prefer them. You do not need to consult rainzone maps with the latter, the zones are determined automatically.The ITU/DAH model employs a * degree lat/long grid of rainfall data and uses bilinear interpolation to achieve an improved estimate for a location from it39。輸入動(dòng)態(tài)的系統(tǒng)變化值。注意這個(gè)值越高表示干擾越小。HPA Intermodulation Interference C/IM功放交調(diào)干擾Enter a value for the intermodulation interference expected from the uplink earth station HPA. This parameter is sometimes neglected in many programs. If you wish to make this parameter effectively void enter 60dB or more.. Note that the higher this value is in dB, the lower the interference level.輸入一個(gè)上行功放交調(diào)干擾值，以dB為單位。如果不需要同時(shí)傳多個(gè)載波的話(huà)就輸入1。典型值在17dB之間。Earth Station HPA Output BackOff地球站高功放輸出回退To reduce uplink interference it is customary to back off the output of the earth station HPA. This tradeoff leads to a higher HPA power capability being required. Typical values range from 1 to 7dB.為了防止上行的噪聲一般要對(duì)地球站的高功放進(jìn)行回退。上行和下行的典型值在2430dB之間。Cross Polarization Interference C/XPI極化干擾Enter a value for the carrier to cross polarization interference noise ratio C/XPI in dB. This parameter specifies the expected interference level with respect to the wanted carrier. A typical value to enter here for either uplink or downlink is between 24 and 30dB. Note that the higher this value is in dB, the lower the interference.輸入一個(gè)交叉極化干擾噪聲C/XPI，以dB為單位。上行和下行的典型值在1830dB之間。Adjacent Satellite Interference C/ASI相鄰衛(wèi)星干擾Enter a value for the carrier to adjacent satellite interference noise ratio due to interfering signals to/from adjacent satellites in dB. This parameter specifies the expected interference noise with respect to the wanted carrier..A typical value to enter here for either uplink or downlink is between 18 and 30dB. Note that the higher this value is in dB, the lower the interference.輸入一個(gè)相鄰衛(wèi)星干擾噪聲C/ASI，以dB為單位。很多工程不需要這些參數(shù)，如果不希望考慮它，輸入60dB以上的值。這個(gè)參數(shù)指定一個(gè)所需載波的干擾程度。如果沒(méi)有廠(chǎng)家提供的參數(shù)，使用CalculateEstimate Antenna Noise Temperature進(jìn)行計(jì)算。比較凹的天線(xiàn)反射面會(huì)減少大地噪聲，而天線(xiàn)頭部分也會(huì)增加噪聲，因?yàn)樗部梢钥醋骱痛蟮赜幸粯拥脑肼?。天線(xiàn)仰角降低，大地噪聲就升高（天線(xiàn)的衍射效果）。2） 大地噪聲。因?yàn)榇髿馐且环N（電磁波）吸收媒介所以肯定會(huì)有噪聲。天線(xiàn)的總噪聲=天電噪聲+地電噪聲。 radiation (). Since the atmosphere is an absorbing medium it must be a noise source so sky noise increases with decreasing elevation due to the longer path through the atmosphere.2) Ground Noise The dominant contribution to antenna noise at low elevations is ground noise pick up through side lobes. Noise temperature increases as the elevation angle decreases since the antenna will pick up more ground noise due to side lobes intercepting the ground (diffraction effects at the antenna rim). This may be reduced by various methods of feed illumination and the dish design itself. A deep dish picks up less ground noise at lower elevations than do shallow ones also prime focus mounted head units will add to noise since it is seen at the same temperature as the Earth. Estimating Antenna Noise TemperatureSince antenna noise temperature has so many variable factors, an estimate is perhaps the best we can hope for. In the absence of a specific manufacturer supplied figure, a reasonable estimate may be obtained by selecting Calculate|Estimate Antenna Noise Temperature from the menu.天線(xiàn)噪聲溫度天線(xiàn)的噪聲溫度通常標(biāo)注在廠(chǎng)家的說(shuō)明書(shū)中。s specifications. The total noise temperature of the antenna depends mainly on the following factors:1) Sky Noise The total antenna noise, Tant = Tsky+Tgnd. The sky noise, Tsky, consists of two main ponents, absorption and the background 39。C波段的通常為30K。通常使用噪聲因數(shù)表示Ku和Ka波段的LNB噪聲，噪聲溫度表示。 character it will be automatically interpreted as a Noise Temperature instead.It is conventional to quote the noise figure of an LNB in dB for Ku and Ka bands and the equivalent noise temperature in Kelvin for S and C bands. It is usually more difficult and expensive to achieve low noise figures the higher the frequency. For Kuband low cost LNB39。.LNB Noise Figure (LNB Noise Temperature)The default interpretation of this input parameter is Noise Figure. However, if you prefix the input value with a 39。大型天線(xiàn)發(fā)射窄波束時(shí)會(huì)相對(duì)于小天線(xiàn)更加不穩(wěn)定。Antenna misspointing lossThis parameter allows for the pointing loss between the ground station antenna and the satellite antenna. It is unlikely in practice that the antenna will be targeted exactly due to initial installation errors, factors such as the stability due to wind and the station keeping accuracy of the satellite. A large antenna, having a narrow beamwidth and being relatively unstable in wind inherit a disadvantage ov