Section – Two Part – 20
Electrical Specification Central Antenna Television System
PART – 20
CENTRAL ANTENNA TELEVISION SYSTEM
1.0 GENERAL
The contractor shall supply, install, test and commission a central antenna television system for distribution of Television signal and AM/FM to all MATV outlets as indicated in the drawing. The layout drawing does not indicate a separate accessories for the central antenna system. However the contractor shall price for the complete system with the dish and central console located in the roof.
Central Antenna TV system shall include but not limited to TV antennas, satellite dish antennas, amplifiers, combiners, modulators, receivers, tap off unit splitters, conduits and cabling with all necessary accessories complete as herein specified.
The system shall be capable of providing AM/FM and television reception of all local, neighboring and international channels broadcasted and receivable in this area. Provision shall also be made for the distribution of Orbit and Showtime programs in IF.
The Central Antenna TV system supplier shall be an authorized distributor of such equipment, maintaining a local staff of specialists and trained technicians for engineering assistance, installation and maintenance of the equipment. All equipment included in the system shall be manufactured by the same manufacturer except for items not included in their manufacturing range. Items not included in the range of manufacture shall be proposed to and be separately approved by the Engineer.
2.0 ANTENNAS AND ANTENNA MOUNTINGS
The antennas shall be mounted on gateways telescopic tubular mast providing a total height of 585 cm in extended position and 230 cms. in retracted position. The mast shall allow for passing of coaxial cables within its central core, thus protecting the coaxial antenna cables from the weather. Proper bracing shall be provided to the mast to enable it to withstand to gather with antennas, the strongest local wind pressures.
Separate antennas shall be provided for each channel with adequate number of elements needed for clear reception of all specified channels.
Channelized aerials shall be used for VHF channels and channel grouped areas for UHF channels. The UHF aerials for remote stations shall have a minimum gain of 16 dB.
3.0 SATELLITE DISHES
The dishes for the satellite reception shall be of solid or mesh aluminium construction with thermoset powder coat finish to provide maximum protection from UV exposure and weather to ensure a long life. The satellite dishes shall be warrantied for a minimum period of five years and shall have the following minimum specification:
Band:CB and 3.7 - 4.2 GHZ
Diameter:8 ft.
Gain:40.4 dB
Polarization:Linear or circular
Operating temperature:Upto 60 degree C.
Mounting:Horizon to horizon
Wind local capability:145KmpH
I/D ration:Less than 0.3
The feedhours and LNB's shall be robust construction to withstand local atmospheric conditions. The noise temperature of LNB's shall not exceed 25 deg. C.
4.0 LIGHTNING PROTECTION
The contractor shall be responsible for providing correct lightning protection for all roof top equipment and the main equipment of the system. For the roof top equipment, the protection should include lightening arresters for antenna mast. The satellite dishes shall be fitted with an adequate surge arrester at the point where the cables gross into the building from the roof.
5.0 HEADEND EQUIPMENT
1)General
a.The basic function of this equipment is to accept the input signal from the various aerials, amplify them, diples them and feed them to the main drop-in cables. The equipment shall contain its own LV operated power supply.
b.The equipment shall be double shielded and be in conformity with VDE or similar standards.
The main equipment should be of the modular channel type each national TV channel should have its specific amplifier and each satellite TV channel should have its specific receiver and specific amplifier. It should allow easy expansion for the national as well as for the satellite TV programs. On free TV channel should be provided between two distributed channels. Converters are to be used to provide this separation of TV channels. Mid-band and super-band channel could be used to allocate the large number of channels. For weak signals, mast pre-amplifiers should be installed. One single output of the system, protected by a coaxial surge arrester, should drive the distribution equipment. One filtered power surge arrester, to block surge currents getting into the electricity network from the system, should be provided.
c.If interference is experienced or expected from transmitters on adjacent channels to those for which equipment is initially installed, pass and/or stop filters shall be installed as part of the head end equipment. Adjacent channels must be converted.
d.Amplifier and/or converter-modules shall be used for each channel. All modules, except for the local stations, shall have an AGC-Range of +/- 25 dB.
2)Head End Diplexer
a.The main diplexer shall accept and combine all aerial outputs if necessary with the addition of sub-diplexers.
b.Through-loss on any channel shall not exceed 1.5 dB.
c.Return loss on any channel shall not be less than 20 dB.
3)Equalizers
Equalizers shall be installed if necessary to achieve the specified performance criteria, differences in attenuation of aerial to head end equipment cables, the characteristics and length of the riser cables as well as changes in cable characteristics due to temperature shall be considered.
4)Static Temperature Range
From 10oC to + 50oC.
5)Wall Mounting Plates
Wall mounting plates shall be of unique type to allow installation of amplifiers or satellite receivers or satellite splatters or relative power supplies, in elements of five positions allowing side by side installation while giving a continuous link for the powering of the above units, providing correct different paths for 12 vdc or 24 vdc.
6)Power Supplies
Units to provide from 220 V, input electronically stabilized power, so that output voltage shall not wary by more than 2% short-circuit and over-load protected, capacities around 4500 mA in 12 Vdc or 2000 mA in 24 Vdc.
7)Satellite Splitter
Four ways active type (internal amplification circuitries to rebalance the division into four directions), input to provide 15 to 18 Vdc power to the LNBs through the relative coaxial cable. Each LNB cable shall be terminated to such a splitter to provide immediate future reception of a new program reaching the relative LNB.
8)Satellite Receivers
Industrial type for continuous duty, without any external controls or remote control, wall type mount through above wall mount plates, internal switches to select IF frequency video and audio types and frequencies to process signals for the S/C/Ku bands, internal modulator to provide output directly on a UHF TV channel in the higher TV UHF band possibility to provide the coded video output to decoders and return the decoded video signal to the internal modulator.
9)Satellite Decoders
Industrial type for continuous duty, to decode Italian RAI programs.
10)Amplifiers (Satellite and national TV Programs )
Channel type amplifiers shall be with a gain of minimum 48 db and with all output level above 120 dbV. It shal be suitable for mixed inputs ot allow one antenna to feed more than one channel amplifier by using coaxial bridge. One input shall allow direct powering of mast Converters or mast pre-amplifiers. Through coaxial cable. Mixed output shall allow coupling of several channel amplifiers by the use of coaxial bridges.
11)Converters
Converters shall given TV channel into a different channel distant from any adjacent TV channel mast or wall type installation.
12)Preamplifiers
Low noise, mast or wall type installation shall boost the relative weak signal to a level above 60 db uv prior to final channel amplification.
13)Coaxial Bridges
Coaxial bridged shall allow the coupling of the inputs of two adjacent amplifiers to be driven by a single antenna with minimum loss and shall allow the coupling of the outputs of two adjacent amplifiers with minimum loss.
14)Coaxial Cable Surge Arrester
Coaxial cable surge arrester shall protect the coaxial down cable surge diversion capacity above 5 kA., static ignition below 75 V, dynamic ignition below 800 V, input/out impedance 75 ohms., installed at the single output of the Main Equipment.
15)Power Supply Filtered Surge Arrester
Power Supply Filtered Surge Arrester protect the up to 10 A., power supply source of the main equipment and block any electric surge to drive into the electricity network of the residence from the system with voltage clipping at 400 V, response time in few picoseconds and capacity 5 kA.
16)Wiring
1.Cables
a.Cables for the MATV system shall consist of a single solid annealed copper wire with a solid polythene insulation and an outer conductor consisting of a copper foil and/or copper strip braid. The cable shall be protected by an outer PVC sheath. The screening factor for the main riser cable shall not be less than 75 dB. For lower level distribution cable 55 dB Min. Cable shall be coaxial with 75 ohms impedance loss per 100 m to be around, 6 dB at 50 MHZ, 10 dB at 300 MHz, 14 dB at 500 MHZ and 10 dB at 800 MHZ. The cable minimum bending radius as specified by the manufacturer shall be adhered to.
b. **All cables inside the building shall be run in 25 mm plastic conduits.
Terminating resistors = 75 ohms.
c.Joints and cable terminations shall be adequately sealed against ingress of moisture and migration along with the cable.
2.Outlets
FM, TV & IF signals shall be received on triple outlets flush mounted and properly terminated. The splitting to Radio + TV + IF frequencies shall be done by frequency - Dependent components. The shielding factor shall be 55 dB min between FV and TV output of same socket.
Safety isolation rating between outlets shall be 200 VAC.
Receive Matching Plugs The receiver matching plugs shall be suitable for TV sockets with matching transformer and 120 cm connecting cable. One such plug shall be supplied with each end socket indicated on the drawings.
3.Splitters, TV Distribution and Tap-Offs
Splitters, TV Distributions and tap-offs shall be of the directional type and the return loss shall be such that removal of television set connectors has a minimal effect on the whole system. The shielding factor shall be 65 dB Min. Riser cables shall be securely clamped at each splitter, TV Distribution and tap-off positions. All components included in the distribution network shall be suitable for distribution of signals in IF (upto 2050 MHZ).
4.End of System Leads
These shall have the following specifications and be of such dimensions as to accept standard Din coaxial connecting devices:
a.Impedance tolerance: +/- 3%
b.Attenuation : Maximum 30 dB/100m at 500 mHZ.
c.Dielectric : Solid Polythene
d.Inner Conductor : Solid or standed copper at least 6 mm dia.
e.Outer Conductor : Copper or tinned copper wire braid
f.Sheathing : PVC at least 1 mm thick
g.Operating Temperature : 0-50 deg. C.
Antenna Earthing: The antenna equipment shall be grounded through and appropriate connection with the mast. Minimum size of conductor shall be 10 mm2 bare copper.
Operational Test The Contractor shall provide a Television Testing Receiver for carrying out acceptance test on the system.
The receiver shall have a pointer instrument for aligning aerials to show rising and falling levels accurately. A level measurement between 34 dbuV and 130 dbuV shall be possible.
6.0 WORKSHOP DRAWINGS
Contractor shall submit workshop drawing giving full details of system installation and signal level calculation on a riser diagram, for the approval of the engineer.
7.0 LOCAL AND NEIGHBORING CHANNEL
Central Antenna system shall provide a clear reception to the following minimum local and neighboring TV channels. The offered system shall, however, have capability for expansion and additional channels without changing the system distribution.
Terrestrial
1.Radio:FM/AM
2.Dubai:2, 10, 33
3.Abu Dhabi:6, 43
4.Sharjah:22,54
5.Ajman: --
I.Asiasat
1.Starplus
2.V-TV
3.Zee TV
4.PTV
5.Provision for Star Movies & Zee Movies
IIArabsat - 2
1.Saudi Arabia - 1
2.Saudi Arabia - 2
3.Egypt
4.MBC
5.LBC
6.Future
7.Oman
8.Kuwait
9.Moroco
10Jordan
11.CNN
12.Abu Dhabi TV
13.Dubai TV
14.Al Jazira
15.Bahrain
16.Qatar
IIIPanamset:
BBC
Sony
MTV
ABN
TNT
IVOrbit & Showtime
Provide dish, LNB, etc., for IF distribution.
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