移动通信基站铁塔与机房的设计优化

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1、 移动通信基站铁塔与机房的设计优化本文仅讨论移动通信基站铁塔和机房建筑的一般设计要则和优化原则，不涉及铁塔及机房的结构计算等问题；尽管结构计算是设计优化的重要途径，但因其有规范可依，本文不再赘述。一、基站选址的优化原则1、满足通信网络规划要求。2、场地平坦，附近无高大建筑物阻挡。3、工程地质良好，避开断层、故河道及可能塌方、滑坡的地段。4、选择安全的环境，避开易燃易爆的场所和粉尘及有害气体的污染源。5、机场航道附近要注意铁塔限高。6、远离各种无线干扰源。7、避开低洼地，防止雨水淹灌。8、尽量不选在中小学校院里，避免儿童攀援铁塔。 二、 基站铁塔与机房形式的选择基站是否需要建设铁塔，取决于移动通

2、信天线的挂高；当基站所在的建筑物满足挂高要求时，可利用屋顶设置天线抱杆，无须建塔。基站铁塔因结构形式不同，可分为自立塔、拉线塔（桅杆）。基站铁塔因所建地点不同，有地面塔、屋顶塔之别。地面塔通常采用的塔型有角钢塔、钢管塔(四柱或三柱)、钢独管塔、拉线塔（桅杆）。角钢塔是最普遍的塔型，它制作安装简便，经济适用，应是铁塔建设的首选。钢管四柱（或三柱）塔因其根开可以做得很小（2米左右），适用于狭窄场地或距建筑物较近的情况，但造价高于角钢塔。独管塔多用于城市风景区或其他要求美观的场所，因为独管塔馈线引下和人员攀登都不方便，加之造价较高，仅用于特殊要求的环境。拉线塔的优点是用钢量小，但占地面积大，是否经济

3、应综合考虑；另外拉线塔易受外力破坏，一旦拉线受损即造成倒塔；拉线塔受风力作用还会发生摆动和水平扭动，采用微波传输的基站慎用。屋顶塔一般采用角钢塔较多，塔的设置有两种情况，一是建筑物设计时已考虑了铁塔的荷载并设置了预埋件（如电信机房楼顶），二是在旧建筑物上加建铁塔。第二种情况要对原建筑进行验算，对结构进行改造，增设铁塔的锚固措施；铁塔的根开往往不等，塔高也受限制，还要认真修复因施工受到破坏的屋面防水层，设计时应格外慎重。当天线挂高比建筑屋面高出不多时（10米左右），可采用简易的屋面铁架方式，在建筑的梁（墙）处浇筑混凝土墩作为配重（计算混凝土重量足以抵抗铁架倾覆力），铁架固定于混凝土墩，可不必破坏

4、屋面防水层，此方式造价低，施工简便。也可采用拉线方式固定屋面铁架，不做混凝土墩配重，但拉线的锚固点一定要慎重处理。基站机房有两种情况：新建机房、利旧机房（或租用机房）。新建机房面积一般为20平方米左右，市区容量大的机房可适当加大。按其与铁塔的相对位置可分为 塔侧机房、塔下机房。塔下机房是将机房建在根开较大的铁塔下，因为与铁塔坐落在同一基础上，机房自重可平衡部分铁塔的倾覆力，铁塔基础可以做的较小，从而节省投资，另外还具有占地面积小、馈线较短、不需设置室外走线架等优点，应优先采用。在铁塔根开较小时，采用塔侧机房，缩小机房与铁塔间距有利于节省土地、缩短走线架和馈线长度，但机房基础应避免建在铁塔基坑的

5、回填土上。利用旧机房或租用机房一般采用屋顶抱杆、屋顶铁架或屋顶塔安装天线，如建筑高度不够则需建地面塔，建塔时应注意铁塔基础开挖不能影响临近建筑的安全。租用机房一般为民用建筑，如楼面承载力不足，还要对原房屋进行加固。还有一种新建机房形式是夹心复合板房，采用成品夹心复合板（彩色镀锌钢板与聚苯乙烯制成）装配成基站机房，优点是工期短，缺点是寿命短（一般15年左右）。三、基站用地面积根据各地情况，基站一般采用征用或租用土地两种形式，以塔高50-60米为例，用地范围大约为：角钢塔+塔下机房13x13米（若采用桩基础，10x10米即可满足）；角钢塔+塔侧机房13x18米；钢管四柱塔+塔侧机房7x16米。租用

6、机房需建地面塔时，所需场地仅为铁塔基础(含基坑开挖放坡)占地：角钢塔13x13米，钢管四柱塔6x6米，独管塔5x5米。拉线塔用地为边长85米的等边三角形，用地很不经济。确定用地范围时应注意，铁塔一定要与附近建筑留出安全距离。四、 新建基站机房的设计优化基站机房为无人值守机房，除满足设备安装外，还应满足防盗、防水、防潮，防震、防雷击等要求。1、机房平面形式：机房一般为正方形或长方形平面，在面积相同的情况下，长方形平面更有利于基站设备的布置。当机房位于塔下时，要注意与铁塔的空间关系。2、机房内净高一般为2.7米；室内外高差为0.30-0.45米，地势低洼时应适当提高。3、机房门为外开防盗门，门洞宽

7、1米高2.1米，门上设雨蓬。机房馈线窗下沿距室内地面2.3米，馈线窗平面位置与基站通信设备机列的轴线对齐。除馈线窗外，机房不设其它窗户。4、机房采用现浇钢筋混凝土屋盖，应做好保温和防水。5、机房室内装饰做法为水泥砂浆墙面、水泥砂浆防潮地面，天棚可不做面层；墙面和天棚也可不刷涂料。机房外墙面可设计为：清水墙、水刷石、水泥砂浆抹面等，内外装饰一律从简。6、基站机房采用能自动启闭的分体式商用空调，室外机可挂于外墙或置于屋顶。在通信设备机列前后的天棚上各设白帜灯一盏，用于机房照明。于不同的两面墙上各设1个单向电源插座，用于设备安装和维护。机房内设有接地铜排，与铁塔、机房综合接地系统连接。7、有的基站设

8、有远程控制系统，对基站的设备、电源、空调、消防、安保、门禁等实施远程监控。8、基站机房的定位原则：机房的门宜朝南或朝向开阔地。塔下机房的馈线窗应与铁塔爬梯在同一侧。塔侧机房的馈线窗应面对铁塔的爬梯，机房与铁塔间距应尽量接近。五、 利旧机房和租用机房的设计优化1、 利旧机房是在原有的通信机房内设置基站，楼面荷载大都能满足要求，应重点解决好馈线引入问题。2、 租用机房情况比较复杂，所租房屋大小不同、层高不同、结构各异、位置也千差万别；一般民用建筑的楼面荷载不能满足基站设备的要求，通常要采取加固措施。首先要对原有结构进行验算，加固设计要因地制宜。要想将租用房屋的楼面承载能力加固到满足通信机房要求的6

9、kN/m2是不现实的，且不说梁、板、柱的全面加固造价高、工期长、施工复杂，仅仅因机房相邻及楼下的房间系其他单位使用，也使加固施工难以进行。优化方案是在通信设备机列下进行局部加固，将设备用型钢支撑于房间两侧的梁或承重墙上，架空于楼板之上，因此不必对楼板进行加固。由于一般基站设备不太多，按照设备的实际荷载进行结构验算，大多数房屋的承重墙、梁、柱不必加固即能承载型钢传来的设备重量（如验算不能满足承载要求，应当采取加固措施）。此种加固方式造价低、工期短、施工简便。3、 利旧机房或租用机房采用上走线方式，不设架空地板，也无需做装饰装修。4、 租用机房一般要靠近外墙，便于馈线引入。有可能的话，应封堵原有外

10、窗，有利于保温、防晒、防尘、防水，房门应改为外开防盗门。六、 室外走线架天线的馈线通过固定于爬梯的馈线支架，自铁塔上部垂直引下，再通过室外走线架水平引入基站机房。1、上人走线架（桥架）：走线架距地面高度大于4米时采用，走线架宽500-600毫米，设计时应考虑馈线重量和两个人的工作荷载，并设高1.2米的护栏，将馈线固定在护栏上。2、不上人走线架：走线架距地面高度小于4米时采用，宽度同上，工作人员使用梯子布线，馈线固定在走线架上，不必设护栏。单层基站机房应采用不上人走线架。3、走线架两端分别固定在铁塔爬梯和机房外墙的支架上。外墙支架位于馈线窗下；为防止雨水流向机房，走线架以大于1%的坡度向外倾斜。

11、4、 走线架为型钢制作，型材规格通过计算确定；宜采用与铁塔同规格的型材，以便充分利用铁塔的下脚料；走线架采用热镀锌防腐。5、走线架跨度不宜太大，当跨度大于8米时，宜增设钢支柱或从铁塔上加设斜拉线，以缩小走线架的跨度，达到节省钢材的目的。6、利旧机房或租用机房的移动通信天线很多是设在屋顶上，因此要设置屋顶的水平走线架和沿外墙而下的竖向走线架。屋顶水平走线架一般架空于屋面或固定于女儿墙，路由尽量简短，以节省钢材和馈线。竖向走线架要考虑上人荷载，与梁或实心砖墙要有可靠锚固。因事关人身安全，竖向走线架不应锚固于轻质墙上。七、移动通信铁塔1、铁塔设计原则：满足天线及馈线安装的要求，便于操作维护；符合国家

12、钢结构规范，保证结构安全，抗风、抗震、防锈、防雷；优化设计，合理选型，便于制作、安装，缩短施工周期，降低工程投资。2、合理选择塔型：不同塔型的造价悬殊较大，合理选择塔型是节省投资的关键，以下表为例。某内陆地区高度43米的塔型比较一览表（地形、地质条件相同）塔型铁塔造价（万元）基础造价（万元）机房造价（万元）总造价（万元）占地面积（含新建机房占地）优点缺点角钢塔（塔下机房）7.902.901.9012.70100m2(1010m)造价低，结构合理，技术成熟，安全度高，适于爬梯、馈线安装。占地稍大钢管四柱塔（塔侧机房）11.602.852.3016.7560m2(106m)结构合理，技术成熟，安全

13、度高，适于爬梯、馈线安装，占地省。造价较高钢独管塔（塔侧机房）16.905.502.3024.7060m2(106m)占地省。造价高，不便于攀登和馈线引下。拉线塔（塔侧机房）1.801.402.305.50851m2(2337m)造价低。占地面积大，安全度差。优先选择角钢塔，角钢塔自重轻、造价低、结构合理、技术成熟、安全度高，被广泛采用。选择合理的铁塔根开，根开的大小影响钢材用量和基础造价，须经结构计算优化确定。采用角钢塔时优先选择塔下机房，造价低，占地少。3、合理确定铁塔的荷载和高度：这也是降低造价的重要途径。风荷载：以国标建筑结构荷载规范中“全国基本风压图”确定基本风压值为设计依据，不要随

14、意超规范加大安全储备，造成不必要的浪费。针对不同地区的风压值（如山东沿海地区基本风压值为0.5至0.65kN/m2，内陆地区为0.35至0.45kN/m2），因地制宜，分别提供不同的铁塔设计，可以大幅度降低造价。切忌一套铁塔图纸打遍天下的不负责任的现象。微波天线的荷载:对于需要微波传输的基站,可以事先提出要求,有针对性地设计相应的铁塔。因多数移动通信基站采用光缆传输,可不考虑微波天线荷载,以免造成浪费。天线平台的数量：早期设计的铁塔多采用三层平台，后来改为两层或一层平台,事实上两层平台即能满足基站的远期发展需求,大多数位于农村地区的基站，一层平台即可。每减少一层平台,能节省0.7万元左右。铁塔

15、高度：铁塔高度取决于移动通信天线的挂高，天线挂高和通信基站的密度、无线信号覆盖强度以及地形地势有关，合理确定铁塔高度对降低造价意义很大。根据有关部门对GSM900无线信号场强测试的结果，在40米以内天线高度的变化对无线信号覆盖影响较大，超过40米后，再增加天线挂高对无线信号覆盖影响不明显，因此在农村地区天线挂高为40米左右较合理；城区基站的天线挂高还要适当降低。4、铁塔平台设计的优化：移动通信铁塔平台尺寸不需太大，最窄处便于人员通过，约600毫米即可，活荷载也比微波塔平台小，建议2kN/M2较合理。以往平台多为零星构件高空组装，现场工作量大、工期较长，现在改进为整体装配式结构，预制成4块扇形平

16、台，安装简便，施工快捷。平台钢板也改为钢板网，减轻了重量，减少了风阻。移动通信铁塔平台的栏杆高1.2米，因需悬挂天线抱杆，栏杆的扶手应与塔身水平拉接，以防止栏杆外倾。5、铁塔安全设计：铁塔的防雷设计应严格执行移动通信基站防雷与接地设计规范。铁塔的防锈蚀采用热镀锌方式，施工现场不得打孔、焊接，以免破坏镀锌层。加强铁塔的防盗措施至关重要，螺栓或塔材的被盗可能引发倒塔事故，铁塔的最下一段塔身应采用防盗螺栓；地脚螺栓应焊防盗钢帽或浇筑混凝土保护层。铁塔的爬梯应设安全护圈；距地3米内不设爬梯，以防他人攀援。八、铁塔基础设计的优化铁塔基础设计中主要考虑的问题是如何使基础在满足抗倾覆、抗压及抗滑移（位于山坡

17、地势）的前提下，使基础造价降到最低，且便于施工。1、 基础设计前，一定要做工程地质勘察，切不可盲目设计，以免酿成事故。2、 角钢塔基础的设计优化：独立基础是在角钢塔四脚分别做独立的基础，再以连系梁连接；因其施工简便，造价低廉，应作为首选方案。当地下水位较高或岩石埋藏较浅时，可考虑采用筏基，筏基的优化途径是改通常的实体筏基为箱式筏基，中部回填土或砂石代替混凝土做配重，可降低造价20% 左右。地下水位高或土质软弱时应选用桩基，桩基造价较高但安全可靠。岩石埋藏较浅时，也可将钢筋锚入岩石，结合做独立基础或筏基，可大大减少混凝土量，从而降低造价。3、 钢管四柱塔基础的设计优化：钢管四柱塔根开很小（2米左

18、右），多用于场地狭小或临近建筑物的环境；一般采用混凝土墩式基础，基础面积不大，深度较大，靠混凝土自重和土壤侧压力、摩阻力来抵抗铁塔的倾覆力；缺点是混凝土用量较大，因开挖较深施工中容易塌方，或危及附近建筑的安全。优化设计改进为浅墩+人孔短桩的新型墩式基础，埋深2.5米以上是墩式基础，2.5米以下改为四棵直径1米的人工挖孔短桩，总深度略大于实心墩基；由于此种基础能充分地发挥土壤的力学作用，混凝土量大大减少，使基础造价减少30% 以上。独管塔基础也可采用此优化方案。4、基础工程的不可预见因素设计文件提供的工程预算，是根据施工图和预算定额计算出来的，很难涵盖工程中实际发生的各种不可预见费用，由于每个工

19、程所处的环境不同，遇到的不可预见因素也不尽相同，应严格控制。有的建设场地需做三通一平（即通路、通电、通水及场地平整），必须投入一部分资金。还有的基站位于无路的山区，所有的建材及设备需要进行二次搬运，将产生二次搬运费。有的场地比较狭窄，挖出的土方无处堆放，发生土方外运及回运的费用。或因土质原因造成地基塌方增加了土方工程量。有的基站局部有影响施工的障碍物（如院墙、道路、地下管道等），在基础施工时只能将障碍物拆除，待基础施工完成后再予修复，此时就出现了拆除与重建的费用。有的基站需修建院墙及大门。因场地接地电阻过高，采取额外的降阻措施往往追加较大的费用。还有人为干扰造成的费用增加，如当地居民对工程的阻

20、挠等等。九、基站安全设计移动通信基站为无人值守机房，很多基站位于旷野，安全问题至关重要。许多不安全因素通过设计已经得到预防，如防震、防雷、防腐、防水等，唯有防盗措施难以周全，前述铁塔安全设计可使铁塔钢构件不易拆卸，但盗窃行为仍然防不胜防。有的基站修建围墙用于防盗，投资不少，未必见效，一旦窃贼潜入墙内，反使偷盗行为更加隐蔽。在治安欠佳的地区，建议机房设双层防盗门，并加设局部钢制栅栏，用以保护空调室外机。十、其它优化措施1、设计：通信铁塔应有完善的设计，设计要委托有资质、有经验的设计单位承担，未经设计而任由铁塔厂制作是不符合基建程序的。某些铁塔厂随意加大塔重增加盈利，或使用库存材料以降低成本，看似

21、节省了一笔设计费用，其实因小失大。增加铁塔的重量不一定意味着安全却必然会加大工程投资，任何设计不周都会构成结构隐患。铁塔的设计费与铁塔的价格相比是很微薄的，经过科学地设计、计算，既保证安全又节省投资。2、监理：铁塔的制作安装工程、基础及机房土建工程都应全过程监理，以保证质量。3、验收：验收环节非常重要，能发现问题并及时解决。4、结算：建议统一按设计的理论重量结算，而不以过磅重量为结算依据；因为过磅称重有作弊的可能，镀锌和焊缝重量也会增加不少，往往出现同一设计不同厂家的铁塔称重不同；个别不法厂家还可能以大代小，随意加大用钢量意图按铁塔价格出售。5、责任：设计单位、监理单位、铁塔厂、土建施工单位均

22、应按照责任分工签署责任文件，对铁塔质量实行终身责任制。4、 维护：在铁塔竣工一年后，应对铁塔进行一次全面维护，调整变形，紧固全部螺栓。以后应由专业人员每年巡检一遍（清理平台杂物，补充缺失的螺栓，除锈防锈）。在强风暴过后应重点巡检。 十一、建议移动通信铁塔的设计、施工、验收尚未形成规范，建议有关部门尽快制订。Design Optimization of Iron Tower and Apparatus Room for Mobile Base StationHan Bingzhong(Shandong P&T Planning and Designing Institute Co., Ltd J

23、inan 250001)Abstract Aiming at improving the investment results of mobile network construction, this paper discusses the key points on the design of iron tower and apparatus room for mobile base station. And ideas of design optimization are presented.Keywords mobile base station iron tower apparatus

24、 room optimization The construction of mobile network is spreading countrywide in an unprecedented quantity and speed. It is a focus to improve the investment results of project greatly that means advancing the quality, saving the cost, and fastening the period of project (it is a focus to maximize

25、the benefit of the investment of projects, which means to improve quality, save costs, and shorten the period of projects). Because the projects of iron tower and apparatus room for mobile base station are large number and big investment, optimization on the design of iron tower and apparatus room i

26、s very significance for benefit. (It is very significant for economic benefit to optimize the design of iron towers and apparatus rooms of mobile base stations, because the projects of them are in large number and involving big investment.) This paper discusses only the general key points on the des

27、ign of iron tower and apparatus room for mobile base station and principles of design optimization. (This paper mainly focused on the general key points about the design of iron towers and apparatus rooms and the principles of design optimization of them.) Not mention structure calculation by the re

28、ason of it can be in accordance of specifications, even though the structure calculations is a main way for design optimization. (Although the structure calculation was another important aspect of design optimization, this paper did not set foot in it by the reason that it could be referred to the n

29、ational codes.)1. The optimization principles of selecting locations (Optimization principles of location selection of site)a. Satisfying the plans of telecom networks. (To meet the planning of telecom networks)b. Flat field and not near by (far away) tall buildings.c. Fine geology of engineering, a

30、voiding fault, old river-way and the sites maybe occur accidents of landslide. (Fine geologic conditions for construction, avoiding the sites on faults, old river-ways, and those that may occur landslides)d. Safety circumstance, keeping away from the places with tinder or explosive and the pollute s

31、ources of dust and exhaust gas.e. The height of iron tower is restricted under the skyway near airports. (If near airports, restricting the height of iron towers under skyways)f. Far away any radio jamming.g. Avoiding the low land to prevent from flood. h. Not to set base stations in the yard of gra

32、de schools, to prevent children from climbing iron tower.2. Selecting forms of iron tower and apparatus roomWhether the iron tower should be set depends on the height of mobile antennas. If the building that base station set in is enough tall, the antennas are mounted on the roof and iron tower is n

33、eedless. (If the building that a base station is set in is tall enough, the antennas are usually mounted on the roof, and iron tower is not needed.)The iron towers have two forms in different structure, named self-stand tower and mast. (According to the structure of iron towers, their forms can be c

34、lassified into two kinds: self-stand tower and mast.)Also the iron towers can be divided into ground-tower and roof-tower according to their positions.The forms of ground-tower include angle iron tower, steel tubes tower (four or three tubes), single tube tower, mast etc. The angle iron tower is a c

35、ommon type for use and should be the first choose, since it is simple for manufacture and installation, economic and applicable. Steel tubes tower (four or three tubes) suits for places of narrow or near building, with its little spans (about 2 meters). Single tube tower is often used at landscape s

36、pots or the sites required good-looking. Because it is inconvenience for fixing antenna feeders and climbing, in addition to its higher cost, the single tube tower applies special places only. The mast saves steel materials but needs a large area, whether or not economy should be considered syntheti

37、cally. Otherwise the mast might be damaged easily by outside forces and maybe lie down once the mast-rope broken. Under the force of wind the mast could be shaken or twisted, so carefully be used in the base stations transmitted by microwave. Commonly the angle iron tower is often chosen as roof -to

38、wer. There are two conditions about roof-tower, one of them the permissible load and preset-bolts had been considered in the building design (for example on the roof of a telecom building), another one is built on the roof of generic old building. In the second case, the structure of the building mu

39、st be checked and added base anchors; usually the spans of two directions are unequal and the height of iron tower is limited by the allowed load of building, it is not easy to repair the water proofing broken during fixed the tower, so the design should be carefulness. When the antenna height over

40、the roof not more (about 10 meters), a simple iron frame could be selected, the footings of the frame fixed on concrete blocks set on the wall or beam of the building as the balance weight against overturn. This type has a lower cost and set up easy without breaking water- proofing. The iron frame c

41、ould be also fixed by drawing ropes and need not concrete blocks, but the fasten points of ropes must be reliability. There are two cast about apparatus rooms: new apparatus house and old apparatus room (or rented room).The area of new apparatus house is about 20 sq. m. some house in the city zone w

42、ith larger apparatus capacity could be more than this. According to the relative position, the apparatus houses are divided into “house by tower” or “house under tower”. “House under tower” that sets on a same foundation with iron tower having enough spans can balance a part of overturning force of

43、tower by its weight, so the foundation could be small for saving investment. Otherwise it has many advantages such as smaller field, shorter feeder, without feeder lever rack etc. should be considered to apply first. “House by tower” would be used when the spans of tower are not enough to hold a hou

44、se. Decreasing the distance between tower and house avail to save lands and shorten feeders and racks. Notice: the house must be not on the backfilled ground of tower base. The antennas are fixed at holding pole up roof or roof-tower and roof-iron frame for old apparatus room (or rented room). If th

45、e building that apparatus room set-in is not tall enough for antenna, the ground tower would be need. Pay attention to the excavating work of tower doesnt endanger the safety of building nearby. The rented rooms are often in civil building and the allowed load of floor does not satisfy the apparatus

46、, to reinforce the structure is needed. There is other type of new apparatus house made of sandwich panels composed by the galvanized iron and polystyrene. That can be reduced the time of project but the life of house is shorter (about 15 years).3. The field area of mobile base stationThe field of m

47、obile base station are purchased or leased generally. For example, the field area of base station with tower at the height of 50-60 meters is about: angle iron tower + “house under tower”- 13x13 meters (if using pile foundations10x10 meter), angle iron tower + “house by tower”13x18 meters, steel tub

48、es tower (or single tube tower) + “house by tower”7x16 meters. When rented apparatus room requires to set a ground tower the area is only for tower foundation (include excavating needs), it is about: angle iron tower13x13 meters, steel tubes tower6x6 meters, single tube tower6x6 meters. The mast occ

49、upies a triangle field with each sideline of 85 meters, and it is not economy about land.When selecting the site for mobile base station, it must be paid attention to keep a safety distance between the tower and exist building near by. 4. Design optimization of new apparatus houseThere is nobody on

50、duty in the apparatus house of base station, so the house should meet the needs of theft-proof, waterproof, damp-proof, quakeproof and prevent lightning strike beside requires of equipment installation.a. The floor of apparatus house could be planed as square or rectangle; the rectangle floor can av

51、ail to arranging apparatus more with same area. When the house set under tower, please give attention to the space each other.b. The clear height of apparatus house is 2.7 meters in general. The height between floor and ground outside is 0.3-0.45 meters and it would be more at lowland.c. The outward

52、 theft-proof door would be used which dimensions are width of 1 meter and height of 2.1 meters. The canopy should set up the door. There are no other windows except feeder-window that located with the height of 2.3 meters from its downside to floor and at a same line with the axis of apparatus rank.

53、 d. The flat roof of apparatus house adopts reinforced concrete in-situation with fine heat insulator and waterproof. e. Decoration of apparatus house should be simple, such as cement internal plaster, cement damp-proof screed, ceiling without coat, and external rendering could be: stone-chipping pl

54、aster, exposed brick wall, or cement plaster. f. Using air-condition with automatic control, its external part put on roof or hang on wall. Setting two lamps under ceiling front and back the apparatus rank and two double-pole sockets on different walls for apparatus installing and repairing, and a c

55、opper earth- plate connected with composite earth system. g. Some base stations have remote control system for equipments, power, air condition, fire protection, safety, gating etc.h. The principles for location of base station house: the door toward south or wide field, the feeder window toward the

56、 ladder of tower. The house should be close to tower when “house by tower” is adopted.5. Design optimization of old apparatus room or rented apparatus room.a. Old apparatus rooms are set in existing telecom buildings that the load capacity of most floors could meet the apparatus. The feeder leading

57、in should be resulted. b. The instance of rented apparatus room is complex with different area, height, structure and position. The load of floor in a common civil building could not fill the requirement of apparatus, so the reinforcing works are unavoidable. The structure of building should be chec

58、king calculated and strengthening design must accord with vary conditions. It is unpractical to strengthen the floor to 6kN/m2, the standard load of apparatus room. Besides strengthening all around is very complex, expensive and taking time, only because the rooms near by belong to others the whole

59、strengthening works are very difficulty. The optimization scheme is strengthening the part under apparatus rank using shelves made of profiled bars fixed on bearing wall or beam, the floor does not need to strengthen because the shelves across over it. Commonly, there are a few of equipments in the

60、room so the checking calculation should accord to their practical weights. In most case the wall or beams and columns without strengthening could bear the apparatus load passed from shelves. (Of course, strengthening should be done if the check results are not fulfilled.) This method is simple, chea

61、p and quick.c. To adopt wire racks above apparatus without rising floors and need not decorating in old or rented apparatus rooms.d. Rented apparatus room must be near external wall for feeders leading in. If possible to wall up the existing windows in order to heat insulator, sunshine-obstructing,

62、dustproof and waterproof. The door of room should be changed by outward theft-proof door.6. Outside feeder rackAntenna feeders are leading from top of tower to below along the towers ladder and get in room by outside feeder rack. a. Body loads feeder rack (bridge rack): It is chosen when the tallnes

63、s above ground exceeds 4 m. Its width is 500-600 mm. Loads of feeders and two bodies should be considered. The feeders are fixed on handrails with height of 1.2m.b. Nobody loads feeder rack: It has no handrails and is used when the tallness less than 4m above ground. Its width is same as above. The

64、feeders are fixed on it and workers put feeders by ladder. The one-store house often adopts it.c. The ends of rack are fastened at towers ladder and walls shelf under feeder window respectively, and the rack leaned toward tower by rate of more than 1% to prevent rainwater flowing into room. d. Racks are made of profiled bars determined by calculation, and the gauges of bars should be similar to tower for using spare materials. Heating zincification is applied for antirust.