Common TV antenna system installation
1 scope
The technology standard is applicable to buildings receive common TV antenna, the front-end equipment and machine room equipment, distribution of transmission parts and user terminal installation project.
2 construction preparation
2.1 material requirements:
2.1.1 TV receiving antenna selection requirements: according to different receiving channel, field intensity, the receiving environment and community antenna television system facility size to choose the antenna, in order to meet the receive the television image is clear, colorful, and have product certification.
2.1.2 should adopt galvanized iron pieces processing. Can't galvanized processing, should be the embalming process. If use 8 # galvanized iron wire and wire rope and all kinds of iron pipe, Angle steel, channel steel, flat iron, round steel, 14 # binding wire, wire rope card, flower basket bolt, TAB, etc are galvanized processing should be adopted. All kinds of machine screws, metal pipe bolt, wood screw, washer, spring washer, etc shall be galvanized.
2.1.3 user boxes (also known as the junction box or terminal box) is a system with the user connection port of the television, the user box is divided into light and dark, dark box and plastic box and tin box installed two kinds, with the commonly used plastic box, box should not have broken deformation, jack must impedance and impedance matching of the television, the box body and cover the same color, and the product certificate.
2.1.4 parallel flat feeder (300 Ω flat feeder) simple structure, low cost, and easy and reduced oscillator antenna connection, thus has been widely applied in VHF. It is suitable for the TV and community antenna television socket, and the product certificate.
2.1.5 coaxial cable of the feeder. It is composed of inner and outer conductor of coaxial, inner conductor for solid conductor, outer conductor for the metal mesh, cushion between inner and outer conductors with poly (PVC high frequency dielectric material, the outermost layer of the protective layer of PVC. The characteristic impedance of 50 Ω; 75 Ω; 100 Ω three, impedance requirement should be paid attention to when choose, and the product certificate.
2.1.6 distributor: usually a binary, three points, four points and distributor of six classification, when the choice, should according to the design requirements, the use and the product certificate.
2.1.7 should choose according to the design requirements, the corresponding channel model and the performance of the antenna amplifier, mixer, converter, branches, trunk amplifier, branch (distribution) amplifier, circuit amplifier, chassis, cabinets, etc. Should check whether the instrument appearance intact, the items within the machine whether complete, then electricity experiment was carried out, check whether the work is normal. Complete product specifications and technical data, and the product certificate.
2.1.8 other materials: electrode, waterproof elbow, solder, flux, connectors, insulators, etc.
2.2 the main equipment:
2.2.1 hand electric drill, impact drill, wire clamp, a word screwdriver, cross screwdriver, electric knife, sharp mouth pin, flat cutting pliers.
2.2.2 level drops, line, rope, high stool, tool bag, etc.
2.3 operation conditions:
2.3.1 with civil engineering structure, build by laying bricks or stones wall embedded pipe and user box, box is complete.
2.3.2 civil pulp live completing construction of interior paint.
2.3.3 coaxial cable has been laying completed.
3 operation process
3.1 process:
Antenna installation to front-end equipment and machine room equipment installation, transmission and distribution part of installation and user terminal installation
Cable and bright (dark) line distribution line and Ming (dark) line equipped to system grounding, system unit adjustment acceptance
3.2 antenna installation:
3.2.1 antenna installation general requirements
3.2.1.1 antenna position choice
A choice in the reception level highest position, in front of the antenna installation, application field strength meter the measured field strength size, choose the best location and installation height of antenna.
B in the empty place when putting up the aerial, to avoid the obstructions on the wave propagation direction.
C set up in the building group of hills or mountains, to the high point of the antenna pedestal edge should leave the building more than 3 m.
D should stay away from disturbance sources. Don't road too close, for example, to avoid metal, away from power lines, elevator machine room.
E should avoid interference between antennas. Disturbed and antenna gain decline, make the image appear pulse Angle bar. Several kinds of antenna can be a total stem erect, also can separate set up separately. Must keep a certain distance between antennas, generally for VHF band antenna, parallel to the distance between stud shall not be less than 5 m; In the same direction before and after poling distance should not be less than 15 m. Generally do not use before and after the aerial, the same root poling antenna spacing should be not less than two layer lambda / 2 as shown in figure 3-72.
F antenna position wants moderate, in CATV system, according to the requirements of the chosen antenna installation location, and select a location in the center of the whole system, so easy to erect trunk, reduce transmission trunk line length, to expand the size of the system.
3.2.1.2 antenna height of choice:
The height of the antenna ground or roof should not be less than one wavelength. Waves should be considered in the process of transmission, has reflected not only, should also be considered for air medium inhomogeneity of refraction phenomenon, should properly adjust the horizontal position and height, the received signal quality best shall prevail.
3.2.1.3 antenna direction choice:
The selection of the strongest level antenna direction. Is usually the biggest receive direction on TV receiving antenna towers. But sometimes in order to avoid the interference sources, or because there are obstructions ahead, according to the actual situation, make the biggest receive direction of the receiving antenna slightly adjusting some, can even receive the reflected wave.
3.2.2 antenna installation:
3.2.2.1 antenna pedestal buried:
Antenna pedestal (base) should be with the civil engineering structure construction, was in a roof plate, bolts or bottom top buried bolt will be well kept. Embedded bolts should not be less than phi 25 * 250 mm; Ground down lead round steel diameter should not less than 8 mm phi; Connection with steel plate thickness should not less than 6 mm; Should be not less than 200 mm base; With cement mortar base plane, elevation level. Good embedded anchor at the same time, three o 'clock in the 120 ° Angle position, made from TAB with phi is more than 8 mm diameter galvanized round steel, and at the bottom of the steel welding structure, welding length of round steel diameter 6 times, at the same time get rid of welding flux, and with cement mortar is flat and level.
3.2.2.2 antenna vertical rod and anchor installation:
More than a day like a rod shaft rod: the vertical of the multi pole set from bottom to top is presented.the thinner and shorter, as shown in figure 3-73.
(a) DC two length is not less than the sum of a wavelength (average 2.5 ~ 6 m; otherwise may also affect the normal receiving antenna;
(b) b section of part of fixed antennas, its length is associated with the number of fixed antennas, general is about 3 m;
(c) A section for the lightning rod, generally in more than 2 m.
B prevent antenna erection electric shock accidents caused by wind, earthquake collapsed. Require large line and flare path and keep far away from high tension line, as shown in table 3-42.
Antenna and aerial spacing table 3-42
Electricity crushing empty wire kind of class and TV antenna distance (m)
Low voltage overhead lines
Bare wire
Low pressure insulated wire or cable
High voltage insulation wire or low voltage power more than 1
More than 0.6
More than 0.3
High voltage overhead lines
Bare wire
High voltage insulation
High voltage power supply more than 1.2
More than 0.8
More than 0.4
C: stem live to clean and tidy, has nothing to do with the vertical bar component in not impede vertical pole outside. Personnel and tools should be prepared to complete, generally there are 1 command, stem staff 4 ~ 5 people. First turn on the next bar connection, which is good, fastening screws, then mast anchor tie tight set, hang on the rod; Each wire rope card should be strong; The middle insulating porcelain ball socket; Turn buckle to the appropriate location, and on the thread scheduled anchor position, put the mast pole position, rod end on the basic location; All ready. On-site command issued a password unified action, will be set up, lever up the strength should be balanced, prevent shaft twitched. Then using basket bolt tightness calibration guy. With # 8 ~ 10 # lead wire basket bolt seal. Stay with the Angle of the stem usually 45 ° to 30 ° ~; At a close distance antenna interval, every less than a quarter of center wavelength range string a porcelain insulator, each pull string into 2 ~ 3 porcelain insulator.
3.2.2.3 antenna installation:
Before putting up the aerial, a response to the antenna itself a serious check and test. For example: antenna vibrator should be placed. To the antenna or oscillator can be placed parallel to the ground, also can vertically up and down, should be parallel to the adjacent oscillator, to maintain oscillator spacing correct; Antenna and feeder should match, solid and reliable; Feeder should be fixed well in order to avoid the wind, etc. The antenna electrical performance test available instrument to detect the standing wave ratio index, pattern and gain. Do not have the condition of the place where available are connected to the TV antenna, the antenna for receiving quality have improved obviously, if there is improved obviously shows that can be set up. If rod antenna receiving quality is worse than the TV itself, it must be replaced qualified antenna to receive.
B qualified through inspection of the antenna assembly on the cross arm, antenna parts assembled, with a rope through the peak of pulley, to assemble the antenna cross arm of the lift to the predetermined position, the bar staff on the mold clamp connected with the antenna is firm.
C each channel antenna according to the practice at proper positions on the mast assembly; In principle two antenna of high channel in above, low channel antenna below, more than three pairs of high channel antenna on the cross arm, the lower channel antenna on the mast, the distance between layer and layer than 1/2 lambda.
D after the antenna position tracking that meet the requirements of receiving, finally will last fastening parts in antenna.
3.2.2.4 ground wire making:
Building lightning protection network, can use flat or round steel mast, base and building lightning protection network electric welding connection for an organic whole. Particular way to see the chapter about the lightning rod. Grounding resistance should be less than 4 Ω, antenna must be within the lightning rod protection Angle.
3.3 the front-end equipment and machine room equipment installation:
3.3.1 operating conditions:
3.3.1.1 room construction decoration completed, foundation channel steel finished.
3.3.1.2 dark machine box body install.
3.3.1.3 dark outfit finished wire has been laying pipeline, and introduce the room (the case).
All 3.3.1.4 220 v ac power pipeline laying out.
3.3.2 rainfall distribution on 10-12 operation process
3.3.2.1 machine room equipment installation
A cabinet stability on the basis of channel steel, and bolt and washer is fixed, desktop cabinet placed directly in the computer room on the ground.
B according to the requirements of design drawings (producing factory assembly diagram), amplifier, mixer, such as channel converter assembly within the cabinet.
C with coaxial cable and F type plug the equipment according to the system diagram connection, drew 220 v power supply to regulated power supply for the use of the equipment.
3.3.2.2 chassis to install
A first according to the system diagram (production plant equipment installation drawing) will all equipment installed on the front board core, using coaxial cable and F type plug properly connected devices.
B, then there will be a chassis plate core equipment in the casing, brought the coaxial cable and connecting the antenna of the transmission lines.
C pick good 220 v ac power cord.
3.4 distribution of transmission part of the installation:
3.4.1 track circuit amplifier (or the trunk amplifier), and extend the installation of the amplifier
3.4.1.1 small antenna systems engineering
Buildings are centered, shorter cable transmission, small loss level, line amplifier can be installed in the front-end equipment cabinets.
3.4.1.2 large antenna system engineering
Buildings are scattered, in order to compensate the signal level loss caused by the cable remote transmission, generally in the middle of the transmission should be equipped with trunk amplifier.
: when a surface mounted by pole aerial cable, trunk amplifier, lifting on the pole, the distance bar at the top of the overhead lines below 1 m or so, and should be fixed on the suspension wire, wild type amplifier should be used in sealing rubber waterproof sealing gasket, the shell of the junction surface appropriate USES mesh metal shielding, high frequency to ensure good contact with the ground, the shell can use aluminum shell, plug to have good waterproof and corrosion resistance, the outermost using rubber waterproof.
Does not have waterproof conditions amplifier (including distributors and branch) to install in a waterproof box.
When dark outfit b: according to the regulation of the design, set relay amplify standing in the middle of the transfer and use cable and or special hollow bricks, can be placed inside a trunk amplifier and distribution board. Well or tablet should notice moistureproof, above indicate the cable and the direction of the signal input and output level, so that maintenance checks.
C circuit amplifier and trunk amplifier have built-in power supply, some itself is not power, but by the front-end equipment share in the regulated power supply by cable feed. Must be connected the power supply according to the concrete situation.
D extension of the amplifier is to complement each distributor or branch within the building, and cable transmission and increase the level of consumption. At the service entrance of the building generally placed a signal distribution box, box, besides put an extension of the amplifier will need to be equipped with magnetic brake chamber (power fuse with), and equipped with a power socket and distributor or branch.
The installation of 3.4.2 distributor and branch
3.4.2.1 with:
Installation method is according to the installation of the components of a hole, use phi alloy bit and 6 mm, stuffed into the plastic expansion tubes, again with wood screws on the mounting hole tighten. Plastic type, splitter or mounting holes in the lid of the metal distribution, branch, is to lift the lid, aim at installation box of drilling; Die casting type distribution, branch, is aimed at the installation hole drilling.
B for non waterproof device and branch distributor, with the location of the general is below the distribution share or in the corridor, the balcony, drench, be affected with damp be affected with damp, must pay attention to prevent part connecting cable level set aside about 250-300 mm long allowance, and then wire bending down, in case of rain along the cable into the parts inside.
3.4.2.2 dark outfit:
Dark is equipped with two kinds of wooden and iron box, and the door is equipped with single or double fan, the same color with metope. In wooden cases with distributor or branch, can press mounting holes position, directly use wood screws. Structure of the iron box, will be available on the second floor plate distributor or branch is fixed on the second floor board, then on the second floor board is fixed on the iron box.
3.5 user terminals installed
3.5.1 track of check repair box:
Check box has uneven mouth place, should be timely maintenance level. Will be needed in the mouth of the cassette and metope level; Box level should comply with the design specification requirements; Shall be fixed tightly with the box. Adjacent two users box installed as shown in figure 3-74.
3.5.2 junction line pressure
Box cable joint first cut into 100 ~ 150 mm in length, and then the 25 mm cable outer insulation stripping, and the outer conductor is copper net set as roll sleeve roll over 10 mm, set aside the insulation of the 3 mm and 12 mm wire, the wire core pressure on a terminal, use Ω conformity of prison copper net place as shown in figure 3-75.
3.5.3 fixed lifted the lid
General user box of the impedance of the socket for the 75 Ω (also 300 Ω), color TV set the antenna input jack impedance is 75 Ω, at the same time can match CT - 75 type plug and SYKV - 75-5 l white coaxial cable as shown in figure 3-76 and shown in figure 3-77. The wires fixed panel (i.e., lifted the lid) fixed at the two attachment points of dark box packing, at the same time adjust good panel fixed tightly again.
3.6 cable and wiring open wire laying
3.6.1 track the open wire of the cable laying
3.6.1.1 built rod construction: outdoor overhead cable laying, stem erect available communication cable. Lever for specially built, the choice of the wooden poles and stem from the relationship between 43 and table are shown in table 3-3-44.
3.6.1.2 pole embedment depth: in the general area into full stem long 1/6, at least not less than 1 m depth; In the paddy field and the loose soil, embedment length is long 1/5 bar; Hard soil in the mountains, the embedment depth of rod length of 1/6. The concrete method of the stem see section about construction.
Wooden poles and end diameter (two pole span 40 m) in table 3-43
Length (cm) in diameter at the end of the end
(m) 8 9 10 11 12 13 14 15
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5 15
14
14
13
13
13
20
19
18
17
17
17
25
24
23
22
22
21
32
30
29
28
27
26
39
36
35
34
35
32
48
45
43
41
40
39 58
54
51
49
48
47
45
44, 69
65
61
59
57
55
53
52
A different cable length, stem from table 3-44
Two pole distance (m)
25 to 30 to 35 40 to 50
Dry line
SYKV - 75-9-5 ~ 6
6.5 ~ 7.5 9
9 10
10 10
11 11
11 to 12
12
Dry line
SYKV - 75-7 5 ~ 6
6.5 ~ 7.5 9
9 9
9 10
10 10
10 of 11
11
Distribution line
SYKV - 75-5 of 5 ~ 6
6.5 ~ 7.5 7
July 7
7 8
8 8
8 and 9
9
Distribution line
SYKV - 75-5 of 5 ~ 6
6.5 ~ 7.5 8
9 9
9 10
10 of 11
11
3.6.1.3 aerial cable installation: in order not to make the cable to bear large pulling force, need to lift the cable with a steel wire cord. The practice see chapter 9.
A coaxial cable erection and height of the rules are shown in table 3-45.
Coaxial cable erection and highly table 3-45
The ground, it is necessary to set up height (m)
And on the road more than 5.5
General cross the road more than 5.5
On the other road more than 4.5
Across the road bridge more than 3.0
Across the railway more than 6.0
Across the river to meet the largest ships
C the outdoor water tank is shown in figure 3-79.
D wire hanging installation level spacing of 0.6 m; Vertical spacing of 0.75 m; Should wear casing wall protection.
E cable sag should not be greater than 50 mm, pull the rope between the two bar to adjust.
3.6.2 dark laying of cables:
3.6.2.1 set patio dark installation, every 100 m set patio, mark the cable manhole covers, cable joint must be equipped with water tank.
3.6.2.2 buried cable, embedding location, should be paid attention to avoid the drains water flows through a place, and stead in every 200 ~ 300 m points, turning points, bifurcation, plate bend instead of pipeline crossing, cross the road, railway marks shall be set up on both sides. The depth of the buried cable are shown in table 3-46.
Table 3-46 cable buried depth
Embedding field by embedding depth (m) to find
Frequent traffic location
Less traffic
The pavement
1.2 no vertical load location
0.60
0.60
0.60 wear steel pipe installation in the cable trench
Wear a hard vinyl tube
Wear a hard vinyl tube
Directly buried
Pipe laying, out of the ground 2.5 m, should wear casing should be fixed in the building, cable joint to waterproof processing.
3.7 distribution system of open wire installation and wiring installation
3.7.1 distribution system of open wire laying
See chapter 8 of the sheath line wiring installation wiring requirements and practices.
3.7.2 distribution system wiring installation
Refer to chapter 4 steel pipe laying engineering wiring requirements and practices.
3.8 in the system grounding:
3.8.1 shielding layer and metal grounding device:
In order to reduce the interference for CATV system device and prevent lightning shielding grounding device metal parts requirement, namely, line set in the amplifier, attenuator, mixer, and distributor of metal shielding layer, cable shielding layer of cable sling and metal case shall all be connected device, ensure good grounding.
3.8.2 metal pipe main line and branch line and building lightningproof grounding should have good overall.
3.8.3 in use, in order to ensure safety, the thunderstorm weather TV should be Shared antenna plug from the socket power plug and pull out.
TV aerial maintenance personnel 3.8.4 requirement, the lightning protection grounding do regular inspection.
3.9 acceptance: tracking system
3.9.1 adjust antenna system:
3.9.1.1 antenna erection is completed, check the receiving channel installation location is normal.
3.9.1.2 output of 75 Ω coaxial cable to connect the antenna field intensity meter input, size measurement signal, fine-tuning the antenna direction field intensity meter indicating maximum. If, when the rotating antenna level indicates no change, the antenna installation, impedance transformer has a problem, check the troubleshooting.
3.9.1.3 measurement level, normal TV receiver check the image and sound quality. Ghosting, repeated trimming antenna direction until eliminate ghosting.
3.9.1.4 antenna adjustment after the completion of each channel, in order to access the community antenna front-end equipment.
3.9.2 front-end equipment debugging
3.9.2.1 antenna signal into each channel mixer
Access to put large mixer input active, adjust the input potentiometer, make the output level difference at about 2 db.
Passive mixer 3.9.2.2 access input end (in the strong signal channel mixer input attenuator) added, adjust the mixer output side, the channel control within + 2 db level difference.
3.9.2.3 adjustment, intermodulation interference:
A mixer output into the circuit amplifier input, in order to improve the TV signal output level.
1 scope
The technology standard is applicable to buildings receive common TV antenna, the front-end equipment and machine room equipment, distribution of transmission parts and user terminal installation project.
2 construction preparation
2.1 material requirements:
2.1.1 TV receiving antenna selection requirements: according to different receiving channel, field intensity, the receiving environment and community antenna television system facility size to choose the antenna, in order to meet the receive the television image is clear, colorful, and have product certification.
2.1.2 should adopt galvanized iron pieces processing. Can't galvanized processing, should be the embalming process. If use 8 # galvanized iron wire and wire rope and all kinds of iron pipe, Angle steel, channel steel, flat iron, round steel, 14 # binding wire, wire rope card, flower basket bolt, TAB, etc are galvanized processing should be adopted. All kinds of machine screws, metal pipe bolt, wood screw, washer, spring washer, etc shall be galvanized.
2.1.3 user boxes (also known as the junction box or terminal box) is a system with the user connection port of the television, the user box is divided into light and dark, dark box and plastic box and tin box installed two kinds, with the commonly used plastic box, box should not have broken deformation, jack must impedance and impedance matching of the television, the box body and cover the same color, and the product certificate.
2.1.4 parallel flat feeder (300 Ω flat feeder) simple structure, low cost, and easy and reduced oscillator antenna connection, thus has been widely applied in VHF. It is suitable for the TV and community antenna television socket, and the product certificate.
2.1.5 coaxial cable of the feeder. It is composed of inner and outer conductor of coaxial, inner conductor for solid conductor, outer conductor for the metal mesh, cushion between inner and outer conductors with poly (PVC high frequency dielectric material, the outermost layer of the protective layer of PVC. The characteristic impedance of 50 Ω; 75 Ω; 100 Ω three, impedance requirement should be paid attention to when choose, and the product certificate.
2.1.6 distributor: usually a binary, three points, four points and distributor of six classification, when the choice, should according to the design requirements, the use and the product certificate.
2.1.7 should choose according to the design requirements, the corresponding channel model and the performance of the antenna amplifier, mixer, converter, branches, trunk amplifier, branch (distribution) amplifier, circuit amplifier, chassis, cabinets, etc. Should check whether the instrument appearance intact, the items within the machine whether complete, then electricity experiment was carried out, check whether the work is normal. Complete product specifications and technical data, and the product certificate.
2.1.8 other materials: electrode, waterproof elbow, solder, flux, connectors, insulators, etc.
2.2 the main equipment:
2.2.1 hand electric drill, impact drill, wire clamp, a word screwdriver, cross screwdriver, electric knife, sharp mouth pin, flat cutting pliers.
2.2.2 level drops, line, rope, high stool, tool bag, etc.
2.3 operation conditions:
2.3.1 with civil engineering structure, build by laying bricks or stones wall embedded pipe and user box, box is complete.
2.3.2 civil pulp live completing construction of interior paint.
2.3.3 coaxial cable has been laying completed.
3 operation process
3.1 process:
Antenna installation to front-end equipment and machine room equipment installation, transmission and distribution part of installation and user terminal installation
Cable and bright (dark) line distribution line and Ming (dark) line equipped to system grounding, system unit adjustment acceptance
3.2 antenna installation:
3.2.1 antenna installation general requirements
3.2.1.1 antenna position choice
A choice in the reception level highest position, in front of the antenna installation, application field strength meter the measured field strength size, choose the best location and installation height of antenna.
B in the empty place when putting up the aerial, to avoid the obstructions on the wave propagation direction.
C set up in the building group of hills or mountains, to the high point of the antenna pedestal edge should leave the building more than 3 m.
D should stay away from disturbance sources. Don't road too close, for example, to avoid metal, away from power lines, elevator machine room.
E should avoid interference between antennas. Disturbed and antenna gain decline, make the image appear pulse Angle bar. Several kinds of antenna can be a total stem erect, also can separate set up separately. Must keep a certain distance between antennas, generally for VHF band antenna, parallel to the distance between stud shall not be less than 5 m; In the same direction before and after poling distance should not be less than 15 m. Generally do not use before and after the aerial, the same root poling antenna spacing should be not less than two layer lambda / 2 as shown in figure 3-72.
F antenna position wants moderate, in CATV system, according to the requirements of the chosen antenna installation location, and select a location in the center of the whole system, so easy to erect trunk, reduce transmission trunk line length, to expand the size of the system.
3.2.1.2 antenna height of choice:
The height of the antenna ground or roof should not be less than one wavelength. Waves should be considered in the process of transmission, has reflected not only, should also be considered for air medium inhomogeneity of refraction phenomenon, should properly adjust the horizontal position and height, the received signal quality best shall prevail.
3.2.1.3 antenna direction choice:
The selection of the strongest level antenna direction. Is usually the biggest receive direction on TV receiving antenna towers. But sometimes in order to avoid the interference sources, or because there are obstructions ahead, according to the actual situation, make the biggest receive direction of the receiving antenna slightly adjusting some, can even receive the reflected wave.
3.2.2 antenna installation:
3.2.2.1 antenna pedestal buried:
Antenna pedestal (base) should be with the civil engineering structure construction, was in a roof plate, bolts or bottom top buried bolt will be well kept. Embedded bolts should not be less than phi 25 * 250 mm; Ground down lead round steel diameter should not less than 8 mm phi; Connection with steel plate thickness should not less than 6 mm; Should be not less than 200 mm base; With cement mortar base plane, elevation level. Good embedded anchor at the same time, three o 'clock in the 120 ° Angle position, made from TAB with phi is more than 8 mm diameter galvanized round steel, and at the bottom of the steel welding structure, welding length of round steel diameter 6 times, at the same time get rid of welding flux, and with cement mortar is flat and level.
3.2.2.2 antenna vertical rod and anchor installation:
More than a day like a rod shaft rod: the vertical of the multi pole set from bottom to top is presented.the thinner and shorter, as shown in figure 3-73.
(a) DC two length is not less than the sum of a wavelength (average 2.5 ~ 6 m; otherwise may also affect the normal receiving antenna;
(b) b section of part of fixed antennas, its length is associated with the number of fixed antennas, general is about 3 m;
(c) A section for the lightning rod, generally in more than 2 m.
B prevent antenna erection electric shock accidents caused by wind, earthquake collapsed. Require large line and flare path and keep far away from high tension line, as shown in table 3-42.
Antenna and aerial spacing table 3-42
Electricity crushing empty wire kind of class and TV antenna distance (m)
Low voltage overhead lines
Bare wire
Low pressure insulated wire or cable
High voltage insulation wire or low voltage power more than 1
More than 0.6
More than 0.3
High voltage overhead lines
Bare wire
High voltage insulation
High voltage power supply more than 1.2
More than 0.8
More than 0.4
C: stem live to clean and tidy, has nothing to do with the vertical bar component in not impede vertical pole outside. Personnel and tools should be prepared to complete, generally there are 1 command, stem staff 4 ~ 5 people. First turn on the next bar connection, which is good, fastening screws, then mast anchor tie tight set, hang on the rod; Each wire rope card should be strong; The middle insulating porcelain ball socket; Turn buckle to the appropriate location, and on the thread scheduled anchor position, put the mast pole position, rod end on the basic location; All ready. On-site command issued a password unified action, will be set up, lever up the strength should be balanced, prevent shaft twitched. Then using basket bolt tightness calibration guy. With # 8 ~ 10 # lead wire basket bolt seal. Stay with the Angle of the stem usually 45 ° to 30 ° ~; At a close distance antenna interval, every less than a quarter of center wavelength range string a porcelain insulator, each pull string into 2 ~ 3 porcelain insulator.
3.2.2.3 antenna installation:
Before putting up the aerial, a response to the antenna itself a serious check and test. For example: antenna vibrator should be placed. To the antenna or oscillator can be placed parallel to the ground, also can vertically up and down, should be parallel to the adjacent oscillator, to maintain oscillator spacing correct; Antenna and feeder should match, solid and reliable; Feeder should be fixed well in order to avoid the wind, etc. The antenna electrical performance test available instrument to detect the standing wave ratio index, pattern and gain. Do not have the condition of the place where available are connected to the TV antenna, the antenna for receiving quality have improved obviously, if there is improved obviously shows that can be set up. If rod antenna receiving quality is worse than the TV itself, it must be replaced qualified antenna to receive.
B qualified through inspection of the antenna assembly on the cross arm, antenna parts assembled, with a rope through the peak of pulley, to assemble the antenna cross arm of the lift to the predetermined position, the bar staff on the mold clamp connected with the antenna is firm.
C each channel antenna according to the practice at proper positions on the mast assembly; In principle two antenna of high channel in above, low channel antenna below, more than three pairs of high channel antenna on the cross arm, the lower channel antenna on the mast, the distance between layer and layer than 1/2 lambda.
D after the antenna position tracking that meet the requirements of receiving, finally will last fastening parts in antenna.
3.2.2.4 ground wire making:
Building lightning protection network, can use flat or round steel mast, base and building lightning protection network electric welding connection for an organic whole. Particular way to see the chapter about the lightning rod. Grounding resistance should be less than 4 Ω, antenna must be within the lightning rod protection Angle.
3.3 the front-end equipment and machine room equipment installation:
3.3.1 operating conditions:
3.3.1.1 room construction decoration completed, foundation channel steel finished.
3.3.1.2 dark machine box body install.
3.3.1.3 dark outfit finished wire has been laying pipeline, and introduce the room (the case).
All 3.3.1.4 220 v ac power pipeline laying out.
3.3.2 rainfall distribution on 10-12 operation process
3.3.2.1 machine room equipment installation
A cabinet stability on the basis of channel steel, and bolt and washer is fixed, desktop cabinet placed directly in the computer room on the ground.
B according to the requirements of design drawings (producing factory assembly diagram), amplifier, mixer, such as channel converter assembly within the cabinet.
C with coaxial cable and F type plug the equipment according to the system diagram connection, drew 220 v power supply to regulated power supply for the use of the equipment.
3.3.2.2 chassis to install
A first according to the system diagram (production plant equipment installation drawing) will all equipment installed on the front board core, using coaxial cable and F type plug properly connected devices.
B, then there will be a chassis plate core equipment in the casing, brought the coaxial cable and connecting the antenna of the transmission lines.
C pick good 220 v ac power cord.
3.4 distribution of transmission part of the installation:
3.4.1 track circuit amplifier (or the trunk amplifier), and extend the installation of the amplifier
3.4.1.1 small antenna systems engineering
Buildings are centered, shorter cable transmission, small loss level, line amplifier can be installed in the front-end equipment cabinets.
3.4.1.2 large antenna system engineering
Buildings are scattered, in order to compensate the signal level loss caused by the cable remote transmission, generally in the middle of the transmission should be equipped with trunk amplifier.
: when a surface mounted by pole aerial cable, trunk amplifier, lifting on the pole, the distance bar at the top of the overhead lines below 1 m or so, and should be fixed on the suspension wire, wild type amplifier should be used in sealing rubber waterproof sealing gasket, the shell of the junction surface appropriate USES mesh metal shielding, high frequency to ensure good contact with the ground, the shell can use aluminum shell, plug to have good waterproof and corrosion resistance, the outermost using rubber waterproof.
Does not have waterproof conditions amplifier (including distributors and branch) to install in a waterproof box.
When dark outfit b: according to the regulation of the design, set relay amplify standing in the middle of the transfer and use cable and or special hollow bricks, can be placed inside a trunk amplifier and distribution board. Well or tablet should notice moistureproof, above indicate the cable and the direction of the signal input and output level, so that maintenance checks.
C circuit amplifier and trunk amplifier have built-in power supply, some itself is not power, but by the front-end equipment share in the regulated power supply by cable feed. Must be connected the power supply according to the concrete situation.
D extension of the amplifier is to complement each distributor or branch within the building, and cable transmission and increase the level of consumption. At the service entrance of the building generally placed a signal distribution box, box, besides put an extension of the amplifier will need to be equipped with magnetic brake chamber (power fuse with), and equipped with a power socket and distributor or branch.
The installation of 3.4.2 distributor and branch
3.4.2.1 with:
Installation method is according to the installation of the components of a hole, use phi alloy bit and 6 mm, stuffed into the plastic expansion tubes, again with wood screws on the mounting hole tighten. Plastic type, splitter or mounting holes in the lid of the metal distribution, branch, is to lift the lid, aim at installation box of drilling; Die casting type distribution, branch, is aimed at the installation hole drilling.
B for non waterproof device and branch distributor, with the location of the general is below the distribution share or in the corridor, the balcony, drench, be affected with damp be affected with damp, must pay attention to prevent part connecting cable level set aside about 250-300 mm long allowance, and then wire bending down, in case of rain along the cable into the parts inside.
3.4.2.2 dark outfit:
Dark is equipped with two kinds of wooden and iron box, and the door is equipped with single or double fan, the same color with metope. In wooden cases with distributor or branch, can press mounting holes position, directly use wood screws. Structure of the iron box, will be available on the second floor plate distributor or branch is fixed on the second floor board, then on the second floor board is fixed on the iron box.
3.5 user terminals installed
3.5.1 track of check repair box:
Check box has uneven mouth place, should be timely maintenance level. Will be needed in the mouth of the cassette and metope level; Box level should comply with the design specification requirements; Shall be fixed tightly with the box. Adjacent two users box installed as shown in figure 3-74.
3.5.2 junction line pressure
Box cable joint first cut into 100 ~ 150 mm in length, and then the 25 mm cable outer insulation stripping, and the outer conductor is copper net set as roll sleeve roll over 10 mm, set aside the insulation of the 3 mm and 12 mm wire, the wire core pressure on a terminal, use Ω conformity of prison copper net place as shown in figure 3-75.
3.5.3 fixed lifted the lid
General user box of the impedance of the socket for the 75 Ω (also 300 Ω), color TV set the antenna input jack impedance is 75 Ω, at the same time can match CT - 75 type plug and SYKV - 75-5 l white coaxial cable as shown in figure 3-76 and shown in figure 3-77. The wires fixed panel (i.e., lifted the lid) fixed at the two attachment points of dark box packing, at the same time adjust good panel fixed tightly again.
3.6 cable and wiring open wire laying
3.6.1 track the open wire of the cable laying
3.6.1.1 built rod construction: outdoor overhead cable laying, stem erect available communication cable. Lever for specially built, the choice of the wooden poles and stem from the relationship between 43 and table are shown in table 3-3-44.
3.6.1.2 pole embedment depth: in the general area into full stem long 1/6, at least not less than 1 m depth; In the paddy field and the loose soil, embedment length is long 1/5 bar; Hard soil in the mountains, the embedment depth of rod length of 1/6. The concrete method of the stem see section about construction.
Wooden poles and end diameter (two pole span 40 m) in table 3-43
Length (cm) in diameter at the end of the end
(m) 8 9 10 11 12 13 14 15
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5 15
14
14
13
13
13
20
19
18
17
17
17
25
24
23
22
22
21
32
30
29
28
27
26
39
36
35
34
35
32
48
45
43
41
40
39 58
54
51
49
48
47
45
44, 69
65
61
59
57
55
53
52
A different cable length, stem from table 3-44
Two pole distance (m)
25 to 30 to 35 40 to 50
Dry line
SYKV - 75-9-5 ~ 6
6.5 ~ 7.5 9
9 10
10 10
11 11
11 to 12
12
Dry line
SYKV - 75-7 5 ~ 6
6.5 ~ 7.5 9
9 9
9 10
10 10
10 of 11
11
Distribution line
SYKV - 75-5 of 5 ~ 6
6.5 ~ 7.5 7
July 7
7 8
8 8
8 and 9
9
Distribution line
SYKV - 75-5 of 5 ~ 6
6.5 ~ 7.5 8
9 9
9 10
10 of 11
11
3.6.1.3 aerial cable installation: in order not to make the cable to bear large pulling force, need to lift the cable with a steel wire cord. The practice see chapter 9.
A coaxial cable erection and height of the rules are shown in table 3-45.
Coaxial cable erection and highly table 3-45
The ground, it is necessary to set up height (m)
And on the road more than 5.5
General cross the road more than 5.5
On the other road more than 4.5
Across the road bridge more than 3.0
Across the railway more than 6.0
Across the river to meet the largest ships
C the outdoor water tank is shown in figure 3-79.
D wire hanging installation level spacing of 0.6 m; Vertical spacing of 0.75 m; Should wear casing wall protection.
E cable sag should not be greater than 50 mm, pull the rope between the two bar to adjust.
3.6.2 dark laying of cables:
3.6.2.1 set patio dark installation, every 100 m set patio, mark the cable manhole covers, cable joint must be equipped with water tank.
3.6.2.2 buried cable, embedding location, should be paid attention to avoid the drains water flows through a place, and stead in every 200 ~ 300 m points, turning points, bifurcation, plate bend instead of pipeline crossing, cross the road, railway marks shall be set up on both sides. The depth of the buried cable are shown in table 3-46.
Table 3-46 cable buried depth
Embedding field by embedding depth (m) to find
Frequent traffic location
Less traffic
The pavement
1.2 no vertical load location
0.60
0.60
0.60 wear steel pipe installation in the cable trench
Wear a hard vinyl tube
Wear a hard vinyl tube
Directly buried
Pipe laying, out of the ground 2.5 m, should wear casing should be fixed in the building, cable joint to waterproof processing.
3.7 distribution system of open wire installation and wiring installation
3.7.1 distribution system of open wire laying
See chapter 8 of the sheath line wiring installation wiring requirements and practices.
3.7.2 distribution system wiring installation
Refer to chapter 4 steel pipe laying engineering wiring requirements and practices.
3.8 in the system grounding:
3.8.1 shielding layer and metal grounding device:
In order to reduce the interference for CATV system device and prevent lightning shielding grounding device metal parts requirement, namely, line set in the amplifier, attenuator, mixer, and distributor of metal shielding layer, cable shielding layer of cable sling and metal case shall all be connected device, ensure good grounding.
3.8.2 metal pipe main line and branch line and building lightningproof grounding should have good overall.
3.8.3 in use, in order to ensure safety, the thunderstorm weather TV should be Shared antenna plug from the socket power plug and pull out.
TV aerial maintenance personnel 3.8.4 requirement, the lightning protection grounding do regular inspection.
3.9 acceptance: tracking system
3.9.1 adjust antenna system:
3.9.1.1 antenna erection is completed, check the receiving channel installation location is normal.
3.9.1.2 output of 75 Ω coaxial cable to connect the antenna field intensity meter input, size measurement signal, fine-tuning the antenna direction field intensity meter indicating maximum. If, when the rotating antenna level indicates no change, the antenna installation, impedance transformer has a problem, check the troubleshooting.
3.9.1.3 measurement level, normal TV receiver check the image and sound quality. Ghosting, repeated trimming antenna direction until eliminate ghosting.
3.9.1.4 antenna adjustment after the completion of each channel, in order to access the community antenna front-end equipment.
3.9.2 front-end equipment debugging
3.9.2.1 antenna signal into each channel mixer
Access to put large mixer input active, adjust the input potentiometer, make the output level difference at about 2 db.
Passive mixer 3.9.2.2 access input end (in the strong signal channel mixer input attenuator) added, adjust the mixer output side, the channel control within + 2 db level difference.
3.9.2.3 adjustment, intermodulation interference:
A mixer output into the circuit amplifier input, in order to improve the TV signal output level.
No comments:
Post a Comment