01-08 preparing for auxiliary facilities of the bts3812e antenna system

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8 Preparing for Auxiliary Facilities of theBTS3812E Antenna System

About This Chapter

Before installing the BTS3812E antenna system, you need to prepare auxiliary facilities such as

the tower, antenna support, and feeder window in compliance with the scenario.

8.1 Tower Requirements

A tower for telecommunication purpose is required when the NodeB in a network covers a wide

area and the antennas are installed high.

8.2 Installing the Antenna Support on the Tower

Different types of antenna supports can be installed on the tower. Appropriate antenna supports

should be selected and installed according to factors such as the antenna type and the installation

scenario. This describes only one type of antenna support. For more details about types of antenna

supports and installation methods, you may refer to the engineering design and instructions of

the supports.

8.3 Installing the Pole on the Rooftop

Different types of antenna supports can be installed on the rooftop. Appropriate antenna supports


scenario. This part describes the structure of some typical antenna supports and the procedure

for installing the support on the rooftop. For more details about types of antenna supports and

installation methods, you may refer to the engineering design and instructions of the supports.

8.4 Installing the Feeder Window

Feeders are led into the equipment room from outdoors through the feeder window. There are

two types of feeder window: 12-hole window and 27-hole window. The 12-hole window is

commonly used.

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8 Preparing for Auxiliary Facilities of the BTS3812E

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8.1 Tower Requirements

A tower for telecommunication purpose is required when the NodeB in a network covers a widearea and the antennas are installed high.

Figure 8-1 shows a tower for telecommunication purpose.

Figure 8-1 Tower for telecommunication purpose

The tower requirements are as follows:

l The height of the tower depends on the field requirements of the NodeB.

l Typically, the tower has one to three platforms with a round or hexagon structure. The

minimum diameter of the platform should be 4 m and the space between two platforms

should be 6 m. The guard rails on the platforms should be 1 m high. The minimum load

capacity of the platforms should be 150 kg/m2.

l For the load capacity of the tower, the tower should carry 27 directional antennas and 27

7/8-inch feeders; each antenna should weigh 30 kg with the front face area of 0.5 mm

2

; thefeeder should be 0.49 kg/m with the diameter 28 mm.


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l A ladder should be installed on the tower for maintenance. The reinforced angle steel should

be installed for the feeders every 1 m on both sides of the ladder and the angle steel should

extend 0.5 m out of the ladder on each side.

l A lightning rod should be installed on the tower. The lightning rod should be located 8 m

higher than the upper platform to ensure that all the antennas are within the coverage of thelightning rod.

l The maximum axial wobble and torsion of the tower body should be within ±1° in the

maximum wind speed that may happen every 30 years.

l The tower, earthquake intensity of which should be one degree higher than that stipulated

in local regulations, should be devoid of any distortion that affects the quality of

communication.

l The cable rack should be installed on the tower and the load capacity of the rack should be

cable to the weight of a person.

l Lightning protection and surge protection devices should be installed on the tower.

l

Solar-powered lamps should be applied to the tower.– Power cables with metal jackets should be used for the beacons that use AC power.

Ensure that the metal jackets are grounded at the top of the tower and at the entry to the

equipment room.

– Surge protection devices should be installed on the control cables of the tower lamps

and on the phase wires of the power cables at the entry to the equipment room. The

neutral wires should be directly grounded.

8.2 Installing the Antenna Support on the Tower

Different types of antenna supports can be installed on the tower. Appropriate antenna supports


scenario. This describes only one type of antenna support. For more details about types of antenna

supports and installation methods, you may refer to the engineering design and instructions of

the supports.

Context

Figure 8-2 shows the structure of the antenna support.

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Figure 8-2 Structure of the antenna support on the tower (unit: mm)

(1) Bolt M12 x 220 (2) Connecting plate (3) Bolt M12 x 45 (4) Dead lever

(5) Rotating lever (6) Stiffener (7) Expansion lever

When installing the antenna support on the tower, adhere to the following principles:

l The installation plane of the antenna support should be perpendicular to the horizontal plane.

l The pole for the lightning rod should be installed separately on the tower. Ensure that the

lightning rod is placed high enough to bring the protection areas of all the antennas below

45°.

l The antenna support should be correctly installed to guarantee the receiving and

transmitting performance and direction adjustment of the directional antenna.

l The rotating lever should be reinforced by using a stiffener. Length of the expansion lever

and the rotating lever depends on the field situation. Ensure that the cut on each lever is

soldered with a cover plate for waterproof purpose.

l

Dry and open welds are not allowed. Ensure that the support is made of galvanized steeland is coated with antirust paint.





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Figure 8-4 Structure of the antenna support directly installed on the rooftop

(1) Lightning rod (2) Soldering point (3) Support lever 1 (4) Expansion bolt M10 x 80

(5) Stiffener (6) Support lever 2 (7) Base of the antenna support (8) Stiffener anchor

l If the antenna support cannot be directly installed on the rooftop with parapets higher than

1,200 mm, you may use expansion bolt assemblies and fixing clips to secure the antenna

support. Figure 8-5 shows the antenna support that is installed on the parapet. Figure

8-6 shows the methods of installing the fixing clip for the antenna support.





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Figure 8-5 Antenna support installed on the parapet (height of the parapet > 1,200 mm)

Figure 8-6 Installing the fixing clips on the parapet

(1) Expansion bolt M12 x 120 (2) V-shaped connecting piece (3) 180° connecting piece

(4) Expansion bolt M12 x 140 (5) Nut M12

l When the rooftop is unable to directly bear the antenna support and the parapet is lower

than 1,200 mm, you may secure one anchor point on the support lever to the parapet by

using an expansion bolt assembly and a fixing clip and secure the other anchor point to the

rooftop. Figure 8-7 shows the antenna support installed on the parapet.

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Figure 8-7 Antenna support installed on the parapet (height of the parapet < 1,200 mm)

When installing the antenna support on the rooftop, adhere to the following principles:

l Installation of connecting pieces for the stiffeners should not affect adjustment of the

antenna direction or downtilt.

l The antenna support should be placed vertical to the horizontal plane.

l When the directional antenna is installed on the rooftop, a lightning rod should be installed

on the antenna support and the support should be connected with the lightning protection

grid of the building.

l When the omnidirectional antenna is installed on the rooftop, typically, the lightning rod

should be installed on a separate pole to protect the antenna from lightning.

l If the lightning rod is installed on the support of the omnidirectional antenna, the antenna

should stretch out of the support for 1 m to 1.5 m.

l All the soldering points on the antenna support should be coated with antirust paint. Ensure

that each part is securely soldered and there is no dry or open weld.

Procedure

Step 1 Determine the installation position of the antenna support on the rooftop in compliance with theinstallation procedure for the antenna system in the engineering design.

Step 2 Solder the lightning rod to the support lever with their center aligned.

Step 3 Use eight expansion bolt M10 x 45 to secure the base of the antenna support vertically on therooftop, as shown in Figure 8-8.





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Figure 8-8 Base of the antenna support

(1) Hexagon bolt M10 x 50 (2) Connecting piece for the stiffener (3) Support lever 1

(4) Base of the antenna support (5) Expansion bolt M10 x 45

Step 4 Use the connecting piece to link the stiffener and the support lever, and then install the stiffener anchors on the stiffeners. Ensure that each stiffener anchor is secured by using two expansion

bolts M10 x 45, as shown in Figure 8-4.

NOTE

Length of the stiffener depends on the length of the support lever.

Step 5 Use six expansion bolt M10 x 80 to connect the support lever 1 and the support lever 2, as shownin Figure 8-4.

Step 6 If the antenna support on the rooftop is not soldered with the outdoor cable rack or if the antennasupport is soldered with the cable rack that is not connected to the lightning protection grid of

the building, use a connecting plate to fix the base of the antenna support to the lightning

protection grid. Note that the connecting plate for lightning protection is delivered with the

outdoor cable rack.

Step 7 Use antirust paint to coat all the soldering points and surface of the antenna support base.

Step 8 Use concrete to reinforce the base of the antenna support on the rooftop, stiffener anchors, andthe expansion bolts that connect the stiffener anchors to the rooftop.

----End

8.4 Installing the Feeder Window

Feeders are led into the equipment room from outdoors through the feeder window. There are

two types of feeder window: 12-hole window and 27-hole window. The 12-hole window iscommonly used.

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Context

NOTE

The following description is based on the installation of feeders through the 12-hole feeder window.

Figure 8-9 and Figure 8-10 shows the dimensions and the structure of the 12-hole feeder window respectively.

Figure 8-9 Dimensions of the 12-hole feeder window (unit: mm)

Figure 8-10 Structure of 12-hole feeder window

(1) Encapsulating gasket (2) Sealing sleeve (3) Steel hoop (4) Window plate

When installing the feeders through the feeder window, adhere to the following principles:





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l The feeder window should be installed as near to the cable rack as possible.

l The feeder window should be installed interior or exterior wall, but the side with steel hoops

should face outdoors.

l If feeders are led into the room from the rooftop, the feeder window should be installed on

the rooftop and the side with steel hoops should face outdoors.

Procedure

Step 1 Determine an installation position on the wall for the feeder window in compliance with theengineering design and the size of the feeder window, and mark anchor points for the expansion

bolts.

Step 2 Drill a hole on the wall for the feeder window and eight holes around the opening for expansion bolts, as shown in Figure 8-11.

Figure 8-11 Holes for securing the feeder window (unit: mm)

Step 3 Use expansion bolts to secure the window plate, as shown in Figure 8-12.

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Figure 8-12 Installing the feeder window

(1) Expansion bolt M8 x 80 (2) Window plate

NOTE

Install the encapsulating gaskets and sealing sleeves when the feeders are led into the equipment room.

----End




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