衛(wèi)星鏈路計(jì)算軟件Satmaster幫助精

1、上下行部分Site Name / LocationEnter the literal name of the site where the earth station is located up to a maximum of 40 characters (18 for country data filesExample input for country data files (18 characters maximumLiverpoolExample input for all other forms (40 characters maximumLiverpool, Merseyside,

2、 England.基站名稱輸入基站所處位置的名稱，最多40個(gè)字母。國(guó)家數(shù)據(jù)文件名舉例(最多18個(gè)字母Liverpool其他格式輸入舉例：Liverpool, Merseyside, England.Site LatitudeEnter the latitude of the site where the earth station is located. This must be entered in decimal degrees with the suffix N for north and S for South. No spaces are allowed. Examples 53.3

3、3N or 27.89SImportant Note:When entering data into country data files latitudes are required in degrees and minutes format as obtained from maps and atlases. In this case the fractional part represents the number of minutes and cannot exceed 59. In all other cases input in decimal degrees are assume

4、d. A conversion facility is provided under the calculate menu.基站緯度輸入地面站的緯度。必須以小數(shù)后跟 N或S表示。不能輸入空格。比如53.33N或27.89S注意事項(xiàng)當(dāng)輸入國(guó)家數(shù)據(jù)文件時(shí)緯度需要以地圖上的度和分為單位。這種情況下，小數(shù)部分為分的表 示，不能超過59。在其他情況下，都是以度來(lái)表示的。Caculate菜單中 有一個(gè)轉(zhuǎn)換工具。Site LongitudeEnter the longitude of the site where the earth station is located. This must be ente

5、red in decimal degrees with the suffix W for west and E for East. No spaces are allowed. Examples 3.00W or 29.79EImportant Note:When entering data into country data files longitudes are required in degrees and minutes format as obtained from maps and atlases. In this case the fractional part represe

6、nts the number of minutes and cannot exceed 59. In all other cases input in decimal degrees are assumed. A conversion facility is provided under the calculate menu.基站經(jīng)度輸入基站的經(jīng)度。必須以小數(shù)后跟 E或W表示。不能輸入空格。比如 3.00W或29.79E注意事項(xiàng)當(dāng)輸入國(guó)家數(shù)據(jù)文件時(shí)緯度需要以地圖上的度和分為單位。這種情況下，小數(shù)部分為分的表 示，不能超過59。在其他情況下，都是以度來(lái)表示的。Caculate菜單中 有一個(gè)轉(zhuǎn)換工

7、具。Altitude of SiteEnter the altitude of the earth station above sea level. This is primarily used in the calculation of rain attenuation and atmospheric absorption. The units are kilometres.5.0 km is the maximum altitude allowed. Enter zero if you will prefer a slightly pessimistic worst case link b

8、udget calculation.基站海拔輸入基站的海拔。這主要是用來(lái)計(jì)算雨衰和大氣吸收值，單位是千米。最大允許輸入的海拔為5km。如果需要比較悲觀鏈路預(yù)算可以輸入00Frequency頻率Enter the centre frequency of the carrier in GHz. For the uplink, typical values are around 6GHz and 14GHz for C and Ku band respectively. For the downlink, values of 4GHz and 12GHz are typical. The accep

9、ted range is 1GHz to 50GHz輸入上行載波的中心頻率，以Ghz為單位。典型C波段和Ku波段的值為6GHz 和14GHz。下行的典型頻率為4Ghz和12GHz?？奢斎氲姆秶鸀?Ghz到50GHz。PolarizationThis is simply the polarization system adopted by the wanted satellite transponder and is either linear (ie vertical & horizontal or circular. Enter the letter V for vertical polar

10、ization, H for horizontal polarization or C for circular polarization.極化這就是所需衛(wèi)星轉(zhuǎn)發(fā)器的極化方式，可以選線性(垂直和水平或圓極化。輸入“ V為垂直極化，“ F*水平極化，“斜圓極化。Signal AvailabilityDepending on your system design requirements a choice of signal availability should be specified. For typical domestic satellite TV systems, a figure o

11、f 99.5% availability is normally sufficient. In fact most packaged fixed dish systems are designed around this figure. For SMATV you may require a higher figure of 99.9% and cable head even higher. The upper limit provided is 99.999% but this level of performance is rarely necessary or even achievab

12、le. The parameter is used in calculating an appropriate fade margin based on the rain-rate statistics for the site. If you like to work with worst month statistics a conversion to average year signal availability is provided under the Calculate menu.With link budgets using uplink power control syste

13、ms a higher availability is often specified for the uplink than the downlink.信號(hào)可用度（年平均根據(jù)你的系統(tǒng)設(shè)計(jì)需求，信號(hào)可用度應(yīng)該是確定的。典型的國(guó)內(nèi) TV系統(tǒng)，這個(gè) 數(shù)到99.5%為宜。實(shí)際上大多集成的碟形天線系統(tǒng)按照這個(gè)數(shù)字設(shè)計(jì)。SMATV（衛(wèi)星公共接收電視需 要高到99.9%的可用度，電視終端機(jī)則更高。最高可以設(shè)為 99.999%但是這種程度的可用度不常用也不可行。這個(gè)數(shù)值經(jīng)常用來(lái)計(jì)算合適的雨 衰。如果你愿意通過“ worstmonthft糟糕的一個(gè)月”數(shù)值轉(zhuǎn)換為年平均信號(hào)可用度， 可以通過Calculatec

14、菜單下的工具進(jìn)行換算。如果鏈路使用上行功率控制系統(tǒng)，經(jīng) 常要設(shè)置一個(gè)較高的系統(tǒng)可用度。Antenna ApertureAntenna aperture is normally taken as the overall diameter of a parabolic dish, the major dimension if an offset focus antenna. Units are always metric （in metres to conform to international engineering practice. The lower limit handled is 0

15、.2 metres and the highest 50 metres.天線口徑通常是拋物線天線的直徑，偏饋天線的主要直徑。單位都是米。最少 為0.2米，最大為50米。Antenna EfficiencyAntenna efficiency is the amount of incident signal actually collected by the dish and feed, expressed as a percentage. Quality of construction, signal blockage by head units, and method of feed aff

16、ects this parameter. Most antennas have efficiencies of between 60% and 70%. If you do not know the efficiency of the antenna then enter 60% as a worst case value.With link budget and dual feed forms, the value entered may be prefixed with a + character so the value will be interpreted as a gain, in

17、 dBi, rather than efficiency.天線效率天線效率就是入射信號(hào)唄反射面和饋源收集到得數(shù)量，表示為一個(gè)百分比。建設(shè)施工質(zhì)量，前饋部分的遮擋還有饋源材料會(huì)影響這項(xiàng)參數(shù)。多數(shù)天線的效率在 60-70%之間。如果你不知道則輸入60%作為最悲觀估計(jì)在鏈路預(yù)算和雙饋形式中，這個(gè)值必須加一個(gè)“+前綴以便程序?qū)⑵浣庾x為增益， 以dBi為單位，而不是天線效率。Coupling lossThis parameter is the total loss due to the insertion of waveguide components and polarizers. Values ar

18、e expected in dB and are typically in the order of 0.3dB. You should add all the insertion losses of waveguide components, such as OMTs and polarizers, that you intend to use.耦合衰減這個(gè)數(shù)值是波導(dǎo)原件、偏振器引起的一切衰減。單位是 dB，典型值為0.3dB o 你應(yīng)該輸入整體的波導(dǎo)元器件的衰減，如OMT和偏振器。Antenna misspointing lossThis parameter allows for the

19、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

20、narrow beamwidth and being relatively unstable in wind inherit a disadvantage over a small one.A typical allowance for mispointing is 0.3 dB. This may need to be increased to 0.5dB for very large antennas particularly in windy areas.天線偏離損耗這個(gè)數(shù)值是對(duì)星不準(zhǔn)引起的地面站和衛(wèi)星間的損耗。實(shí)際中因?yàn)槌跏及惭b誤差，很難將天線 完全對(duì)準(zhǔn)衛(wèi)星，如風(fēng)穩(wěn)和地面保持精度等因素

21、。 大型天線發(fā)射窄波 束時(shí)會(huì)相對(duì)于小天線更加不穩(wěn)定。典型值為0.3dB。大型天線處于多風(fēng)地帶的話可能需要加到0.5dB.LNB Noise Figure (LNB Noise TemperatureThe default interpretation of this input parameter is Noise Figure. However, if you prefix the input value with a + character it will be automatically interpreted as a Noise Temperature instead.It is c

22、onventional 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 Ku- band low cost LNBs are in the range 0.8dB to 1.0dB or

23、30K for C band.Note: We use the term LNB in the generic sense here, LNA, LNC etc is equally valid.LNB噪聲默認(rèn)的解讀法是讀為噪聲因數(shù)，但如果在數(shù)值前加上“ 十號(hào)則程序?qū)⑵渥x為噪聲 溫度。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。頻率越 高，通常來(lái)講就 越難以達(dá)到很低的噪聲。比如 Ku波段比較便宜的LNB噪聲都是在 0.8-1.0dB , C波段的通常 為30K。Antenna noise temperatureA value for the antenna noise te

24、mperature is often quoted in manufacturers specifications. The total noise temperature of the antenna depends mainly on the following factors:Sky Noise The total antenna noise, Tant = Tsky+Tgnd. The sky noise, Tsky, consists of two main components, absorption and the background big bang radiation (2

25、.7K. 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.Ground Noise The dominant contribution to antenna noise at low elevations is ground noise pick up through side lobes. Noise temper

26、ature 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 groun

27、d 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 f

28、or. 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.天線噪聲溫度天線的噪聲溫度通常標(biāo)注在廠家的說(shuō)明書中。天線的總噪聲主要受以下幾個(gè)方 面影響：1天電噪聲。天線的總噪聲 二天電噪聲+地電噪聲。天天電噪聲，Tsky，包含 兩部分，空氣吸收和大爆炸背景輻射。因?yàn)榇髿馐且环N（電磁波吸收媒介所以肯定會(huì) 有噪聲。所以

29、 海拔降低大氣噪聲就會(huì)增加，因?yàn)樵陔姶挪ㄔ诖髿庵袀鞑サ母h(yuǎn)。2大地噪聲。在低仰角的情況下對(duì)天線噪聲影響最大的是旁瓣吸收的大地噪 聲。天線仰角降低，大地噪聲就升高（天線的衍射效果。它有可能通過饋源和反射 面的特殊設(shè)計(jì)而 減小。比較凹的天線反射面會(huì)減少大地噪聲，而天線頭部分也會(huì)增 加噪聲，因?yàn)樗部?以看作和大地有一樣的噪聲。估算天線噪聲溫度因?yàn)樘炀€噪聲溫度受很多因素影響，我們只好算出一個(gè)估計(jì)值。如果沒有廠家 提供的參數(shù)，使用 Calculate-Estimate Antenna Noise Temperatur進(jìn)行計(jì)算。Adjacent Channel Interference C/ACI相鄰信

30、道干擾Enter a value for the carrier to adjacent-carrier interference noise ratio C/ACI in dB. This parameter specifies the expected interference level with respect to the wanted carrier. A typical value to enter for either uplink or downlink is between 24 and 30dB. Some link programs do not use this pa

31、rameter so if you wish to void it enter 60dB or more. Note that the higher this value is in dB, the lower the interference.輸入一個(gè)相鄰信道干擾噪聲 C/ACI,以dB為單位。這個(gè)參數(shù)指定一個(gè)所需載 波的干擾程度。上行和下行的典型值在24-30dB之間。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。注意這個(gè)值越高表示干擾越小。Adjacent Satellite Interference C/ASI相鄰衛(wèi)星干擾Enter a value for the c

32、arrier 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 tha

33、t 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。這個(gè)參數(shù)指定一個(gè)所需載 波的干擾程度。上行和下行的典型值在18-30dB之間。注意這個(gè)值越高表示干擾 越小。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

34、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。這個(gè)參數(shù)指定一個(gè)所需載波 的干擾程度。上行和下行的典型值在24-30dB之間。注意這個(gè)值越高表示干擾越 小。Eart

35、h Station HPA Output Back-Off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 trade-off 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。這種權(quán)衡的做法會(huì)導(dǎo)致需求功放的 功率變大。典型值在1-7dB之間。Num

36、ber of HPA Carriers高功率放大器載波數(shù)量Enter the number of carriers simultaneously transmitted by the uplink earth station HPA. Normally this is set to 1 unless you need to size the HPA for multiple carriers. This has no effect other than to increase the HPA power requirement.輸入地球上行功率放大器同時(shí)傳輸?shù)妮d波數(shù)量。如果不需要同時(shí)傳多個(gè)載波

37、的 話就輸入1。這個(gè)數(shù)值只會(huì)影響功率放大器的功率需求。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 th

38、at 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。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。注意這個(gè)值越高表示干擾越小。Uplink Power Control / Manual Power Boost上行功率控制/ 手動(dòng)功率控制Uplink Power Control (UPC also known as Dynamic Carrier Control is used to compensate for instantaneous rain

39、attenuation on the uplink. Enter the dynamic range of the system here. If UPC is not used or site diversity plans are in operation you can enter zero here. UPC systems usually require a high HPA power capability.上行功率控制(UPC又叫動(dòng)態(tài)載波控制，是用來(lái)抵消上行偶爾的雨衰。輸入動(dòng)態(tài) 的系統(tǒng)變 化值。UPC系統(tǒng)需要更大的功放功率。雨衰 Rain modelsHere you can s

40、elect the rain model to use. Check the checkbox relevant to the model you wish to use.The ITU/DAH rain model is recommended 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

41、 are determined automatically.The ITU/DAH model employs a 1.5*1.5 degree lat/long grid of R0.01 rainfall data and uses bilinear interpolation to achieve an improved estimate for a location from its grid neighbours.Although not normally necessary, a better accuracy may result with the ITU/DAH model i

42、f a localized R0.01 value is obtained. To use this, check the checkbox labelled ITU mm/h then enter your locally obtained R0.01 value into the input field below it. A value of zero may be input if you wish to temporarily remove any rain effects from the budget.Note: This option is not available for

43、items under the Graphs and Tables menus.Dual Fade Checkbox (only present on some link budget formsWhere uplink and downlink stations are separated by several km, it is not normally assumed there is a rainstorm on the uplink and downlink simultaneously as this is statistically unlikely. However, if t

44、he uplink and downlink are in the same city or an area which may be covered by a large tropical storm, you may like to check this checkbox so rain attenuation is calculated both on the uplink AND downlink simultaneously. In general, Ku band is not so suitable as C band for tropical regions due to hi

45、gh rain attenuation.你可以在這里選擇雨衰模型。選擇相關(guān)的復(fù)選框即可。推薦使用ITU/DAH雨衰模型，因?yàn)樗鼞?yīng)該是最精確的模型。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。ITU/DAH使用1.5*1.5經(jīng)緯度的方格來(lái)統(tǒng)計(jì)各地區(qū)的 R0.01降雨數(shù)據(jù)，而且使用 雙線性插值法來(lái)得到更精確的估計(jì)。雖然通常不必要，但是如果有相關(guān)r0.01數(shù)據(jù)的話ITU/DAH是更精確的。點(diǎn)選 ITU mm/h來(lái)手動(dòng)輸入R0.01值。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。雙重雨衰選項(xiàng)（只有一部分鏈路預(yù)算需要如果上下行站相距幾千米，

46、一般上行下行同時(shí)下雨的情況為統(tǒng)計(jì)上的不可能。 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。因?yàn)橛晁?，Ku波段總體來(lái)講不如C波 段適合熱帶地區(qū)的通信。衛(wèi)星部分satelliteTransponder Type Radio Buttons轉(zhuǎn)發(fā)器種類These radio buttons set the transponder type, which can be either a TWTA (Traveling Wave Tube Amplifier or SSPA (Solid State Power Amplifier.

47、The default is TWTA. This is used in determining typical values for output back-off 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，可以是TWTA(Travelling Wave Tube Amplifier 或 SSPA(SolidState Power Amplifier。默認(rèn)是TWTA 。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。Satellite Nam

48、e衛(wèi)星名稱Enter the literal name of the target satellite up to a maximum of 40 characters. (18 for satellite data recordsExample Astra 2a輸入衛(wèi)星名稱，不超過40字符。(衛(wèi)星文件記錄不超過18個(gè)字符如 Astra 2aSatellite Longitude衛(wèi)星經(jīng)度Enter the longitude corresponding to the sub-satellite point of the satellite on the equator. This should

49、 be in decimal degrees with the suffix E for East and W for West. Examples 19.2E or 125.00W輸入該衛(wèi)星赤道星下點(diǎn)的經(jīng)度。這個(gè)值是10進(jìn)制的小數(shù)，單位是度。如19.2E 或 125.00W。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. V

50、alues 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。它可以在衛(wèi)星運(yùn)營(yíng)商的G/T等高線圖那里得到。Satellite Saturation PFD(SFD衛(wèi)星飽和通量密度Enter the Saturation Flux Density (SFD value, in dBW/m2, required to saturate the satellites transpo

51、nder from the earth station. The program assumes this input value corresponds to a reference 0dB attenuator pad setting here. SFD can be thought of as the input sensitivity of the transponder where the more negative the value the higher the sensitivity. (Example: -89 dBW/m2Some satellite operators d

52、o not supply SFD contour maps, in which case the SFD(effective at a specific site may be deduced using the following simple expession:SFD(effective = SFD(ref - (G/T - G/T(refwhereSFD(ref and G/T(ref can be any known pair of reference values such as beam peak or beam edge.When the transponder is oper

53、ated in power limited mode for multi-carriers it is common practice for the satellite operator to set the attenuator pad to a nominal 10dB or 16dB to increase the number of carriers the transponder can support at the expense of earth station uplink power. The attenuator pad, commandable from the gro

54、und, affects all carriers sharing the transponder. Important Note: Some satellite operators specify the SFD at a nominal attenuator pad setting typically, 10dB or 16dB. You should alwaysenter the SFD assuning the reference attenuator pad setting is 0dB here. The attenuator pad may be set separately

55、to 10dB or 16dB within the program. You can, of course, set the SFD at any given attenuator pad setting but if you do, you must set the attenuator pad input field to 0dB. If in any doubt contact your satellite operator for SFD and attenuator pad settings.輸入飽和通量密度(Saturation Flux Density值,單位是dBW/m2,這

56、個(gè)值是使衛(wèi)星轉(zhuǎn)發(fā)器達(dá)到飽和的通量密度。程序會(huì)認(rèn)為這個(gè)值是對(duì)應(yīng)衰減器為 0dB情況。SFD 可以看做一個(gè)輸入 的敏感度。這個(gè)值越小敏感度越高。有些衛(wèi)星運(yùn)營(yíng)商不提供SFD等高線圖，SFD可以由以下公式算出。SFD(effective = SFD(ref - (G/T - G/T(refSFD(ref and G/T(ref可以是任意一對(duì)值比如波束中心或者波束邊緣值。當(dāng)轉(zhuǎn)發(fā)器工作于功率限定模式的多載波模式，衛(wèi)星運(yùn)營(yíng)商經(jīng)常將衰減跳到10dB 或16dB來(lái)增加支持的載波數(shù)，這會(huì)增大地球站上行的功率。衰減器可以在地球上 控制來(lái)改變轉(zhuǎn)發(fā)器支持的載波數(shù)。提示:有些運(yùn)營(yíng)商給的SFD數(shù)據(jù)是加了他們常用的衰減10d

57、B、或16dB。但這 里需要輸入衰 減為0的情況。衰減器10dB或者16dB是在程序的其他地方進(jìn)行設(shè) 置的。你也可以輸入衰 減器為任何dB的情況，但這是就要把衰減器設(shè)為0dB。如 果對(duì)SFD和衰減有疑問，和你的衛(wèi)星運(yùn)營(yíng)商聯(lián)系。Satellite Attenuator Pad Setting衛(wèi)星衰減器設(shè)置Enter the value of the attenuator pad setting in dB. This is set by the satellite operator for the transponder depending on its use. This program as

58、sumes you have entered the SFD corresponding to an attenuator setting of 0dB and adds this value to it.Example: Suppose the SFD, with 0dB attenuator pad setting is given as -90dBW/m2.The overall SFD with the 10dB attenuator pad included is, -90dBW/m2 +10dBW/m2 =- 80dBW/m2Important note: If you have

59、already allowed for a nominal attenuator pad setting in the SFD input field you must set this parameter to 0dB otherwise you could severely over dimension the link.輸入衛(wèi)星衰減器衰減，以dB為單位。這個(gè)值是衛(wèi)星運(yùn)營(yíng)商根據(jù)需 要設(shè)定的。這個(gè)程序默認(rèn) 你輸入的SFD中不包括衛(wèi)星衰減器的衰減。舉例:比如SFD在0dB衰減的時(shí)候?yàn)?90dBW/m2?？偟腟FD在10dB衰減的 情況下就是-80dBW/m2注意:如果SFD中已經(jīng)考慮了衛(wèi)星衰減

60、器，這個(gè)值要設(shè)為00否則這個(gè)鏈路計(jì)算 會(huì)錯(cuò)誤。Satellite ALC衛(wèi)星 ALC (Automatic Level ControlOn some satellites, there is an option for a transponder to be switched from conventional fixed gain mode to an AGC system known as Automatic Level Control. This helps to reduce the effects of uplink rain by setting a constant drive