Ahad, 11 Ogos 2013

SATELLITE TVRO INTERNATIONAL CHANNEL

Considerations for Foundation Preparation

The foundation design based upon this document is suitable for plain areas where the basic wind pressure remains within 80kg/m2.  Areas that do not conform to this condition should be dealt with appropriately, for example, by increasing the depth of the foundation to 1.5m, incorporating bar-mat reinforcement within the concrete cubic, etc.
  1. The foundation should be built on plains usually with a ground endurance of 8000kg/m2.  It should be 100mm high above the ground with minimum embedment depth of 1000mm.
  2. The foundation made of 300m3 concrete can be molded by a single casting. The construction should comply with the corresponding construction specifications and test standards.
  3. The anchor bolts should be embedded in strict accordance with the marked size.  The absolute value of positive and negative errors should not be more than 1.0mm.  The 6 anchor bolts adopt Q235 steel.
  4. The antenna should be installed with reliable lighting protection facilities.
  5. The foundation should be installed firmly with a pull resistance of no less than 16 ton/m2, and a horizontal force resistance of no less than 8 ton/m2.
  6. If the foundation is built on the top of a building, the anchor bolts should be welded firmly with the reinforcing steel bar of the building beam.  The thickness of the foundation in this case can be 400 - 500mm.
  7. In the areas frequently visited by hurricane or typhoon, the depth of the foundation can be up to 1500mm and it should be reinforced with bar-mat and welded firmly with the anchor bolts.
  8. The foundation can be molded into a whole body.  If a split one required, mold it according to the size as shown in Figure 1.

Preparation for the Antenna Installation

Unpack all the parts and accessories shipped with the antenna. Follow the Packing List to identify and classify them at the scene of the installation for the antenna. Clean the surface of each piece of parts and put the antirust grease to all copulate interfaces and screw holes. Clean the dust with cotton yarn from all painted surfaces.
Make sure all necessary tools and accessory materials are well prepared at the installation field. We have included a list in this manual for recommended installation tools for your convenience.

Antenna Installation

Installing Pedestal

  1. First, check the built foundation to make sure its azimuth approximates the azimuth of the satellite to be pointed to, so that the adjustment of the azimuth will be easier.
  2. Install the pedestal onto the foundation by putting it vertically on the foundation with preinstalled bolts going through the corresponding holes at the bottom and fastening the nuts. Make sure the pedestal is perpendicular to the ground. Refer to Figure 3 and Figure 4 for this procedure.
  3. Install the azimuth actuator. Please note the azimuth adjusting screw has been preinstalled on the pedestal.
  4. Install the elevation adjusting screw for the elevation actuator.

Installing Reflectors

There are two ways to install the reflectors depending on the installation conditions. The first one is to assemble the reflectors at the field, then hoist it onto the pedestal with a crane. The second one is to directly install on the pedestal piece by piece.

Installing Pivot Body

If installing in the field, first find a flat ground of about 5m by 5m. Raise the pivot body from the bottom with three wooden or concrete pads with the same height of more than 300mm.
If installing directly onto the pedestal, connect and secure the joints on the elevation actuator and the joints on the tripod, fastening with the taper pins; then install the elevation and azimuth actuators properly.

Installing Radial Girders

Put each numbered radial girder into the corresponding position with the same number on the pivot body. Insert the taper pin to secure each girder and fasten it with the bolt, gasket and nut. Refer to Figure 1 for this step.
Figure 1 - Side View of Pedestal and Foundation
Figure 2 - Top View of Pedestal and Foundation

Installing Reflector Segments

Put each numbered reflector sector to the corresponding position on the radial girder with the same number. Insert the taper pin on the sector into the corresponding hole on the girder. Put the screw on the joint board and adjust the gap and position between sectors to make sure the gaps are equal and the sectors are at the same height. Fasten the nuts onto the bolts. Repeat the above steps until all 12 sectors are all installed properly.

Installing Circular Girder-Pull Rods

Fasten the 12 inner circular/ring rods and 12 outer circular/ring rods with the bolts, gaskets and nuts, as shown in Figure 3.
Figure 3 - Installing pivot body, radial girders and reflector sectors

Installing Sub-Reflector and Support Struts

As shown in Figure 4, install the sub-reflector and the support struts onto the corresponding position. Secure them by fastening the bolts.
Figure 4 - Installing sub-reflector and support poles

Installing Feed and Feed Sleeve

On the flat ground, connect the feed and waveguide together. Put and secure them into the feed sleeve. Hoist the assembly into the pivot body and fasten it in place. Please see Figure 5 for this step.
Figure 5 - Installing Feed and Feed Glove

Adjusting Sub-reflector

Use the appropriate tools to adjust the installed sub-reflector to make it positioned on the designed location. Please refer to Figure 6 for this step.
Figure 6 - Adjusting Sub-reflector

Hoisting and Installing Reflector Assembly

Use two wire ropes, making a circle on one end and tightening another end on the crane hook. Put two wire rope circles through the pivot body. Insert two V-shaped steel bar (#7) or pipe (j70) with length of 1300mm into the circle of two wire ropes under the bottom of the pivot body. Use another 4 steel wires to hold the crane hook and the edge of antenna, with the mouth of the paraboloid upward, to make the hoisting stable. Hoist the reflector assembly onto the pedestal and secure it in place.

Installing OMT

Match the OMT flange to the flange of the waveguide tube and put the seal ring in between. Fasten the bolts at the last.

Adjusting Antenna Stance

Check all over the installation process. Make sure all screws and bolts are fastened. Adjust the azimuth and elevation by tuning the both actuators to make the antenna pointing to the designated satellite. Finally, fasten all backup nuts.
At this step, all installation work is finished and ready for tuning up.

Tuning up Polarization Device

The new polarization unit adopted by RT-CK450 is our patent proprietary device, which features easy tuning up and larger range of adjustment.

Identifying Polarizing Direction

The rectangular waveguide tube is the interface between the antenna feed and the receiving device. The waveguide tube determines the polarizing direction for receiving or transmitting Hertzian waves.
In the rectangular waveguide tube, the electric field direction of the dominant mode transmitting is perpendicular to the wide side of the tube, as shown in Figure 9. The polarizing of the antenna is determined by the electric field direction in the waveguide tube. So, the polarizing direction can be tuned by adjusting the waveguide tube.
Figure 7 - Electric Field Direction
As shown in Figure 8, it is called vertical polarization if the electric field direction is perpendicular to the ground and horizontal polarization if the electric field direction is parallel to the ground.
Figure 8 - Vertical and Horizontal Polarization

Structure of Rotating Polarization Device

The structure of the rotating polarization device is shown in Figure 9.
Figure 9 - Polarizing Device

Adjusting Polarization

  1. Embed the flange block in the rotating polarization device into the notch of the connected circular waveguide.
  2. Connect and Secure the two flanges together by inserting the bolts and fasten the nuts, as shown in Figure 10.
Figure 10 - Adjusting Polarization

Tiada ulasan:

Catat Ulasan

KETURUNAN SIAM MALAYSIA.

Walaupun saya sebagai rakyat malaysia yang berketurunan siam malaysia,saya tetap bangga saya adalah thai malaysia.Pada setiap tahun saya akan sambut perayaan di thailand iaitu hari kebesaraan raja thai serta saya memasang bendera kebangsaan gajah putih.

LinkWithin