TELEVISION/RADIO FREQUENCY SYSTEMS

Transcription

1 SECTION TELEVISION/RADIO FREQUENCY SYSTEMS PART 1 GENERAL 1.01 SUMMARY A. Section Includes: 1. Installations at new facilities without operational television/radio frequency systems and requiring a complete system. 2. Installations at additions/renovations with adjacent operational television/radio frequency systems, requiring wiring and connection to the headend of the existing system, with conduit, cables, and broadband amplifiers as needed. NOTE TO SPECIFIER: The diagrams referenced in the following paragraph are located in M- DCPS Design Criteria Book TV Radio Frequency System Headend Block Diagrams - Basic Installation and Alternate Installation, attached to and a part of this section. B. Related Sections: Cast-In-Place Concrete Sound Intercom and Clock Systems Raceways and Conduits Wires and Cables Outlet, Pull, and Junction Boxes SYSTEM DESCRIPTION A. Provide a television system, with Radio Frequency (RF) levels at all locations for channels specified, meeting minimum requirements as outlined in this section. NOTE TO SPECIFIER: Edit the following items in brackets to comply with paragraph 2.03M of this section. B. Provide a [guy wire supported galvanized metal antenna structure and antenna] [precast concrete antenna pole and Project No. SPECIFICATIONS GUIDELINES

2 antenna] according to the Drawings SUBMITTALS A. Submit shop drawings necessary for review by A/E and to show compliance with this section. B. Submit operating and maintenance manuals complete with replacement parts data. C. At project completion, provide shop drawings and as-builts of TV system installation for final review, site test, and maintenance operations. Include locations of amplifiers and conduit identification. D. Provide proof of compliance, sealed and signed by a Florida registered structural engineer, that the entire assembly of the new tower with antennas, and the like, meet the design requirements for wind loads based on wind velocity pressures determined by American Society of Civil Engineers E. Quality Assurance/Control Submittals: Florida registered engineer shall submit signed and sealed drawings indicating; 1. Structural/wind load calculations. 2. Mounting details. 3. Grounding and lightning protection QUALITY ASSURANCE A. Notification: Notify the A/E before the start and at completion of the work. B. Items shall be listed by Underwriters Laboratories (UL), bearing the UL seal and marked according to referenced standards. PART 2 PRODUCTS 2.01 MANUFACTURERS A. Instructional Television Fixed Service (ITFS): 1. ITFS Downconverter: Model No by California Amplifier or accepted equivalent. 2. VHF High Pass Filter: Fastrap Model No.5KHP-216 by Microwave Filter Company, or accepted equivalent. Project No. SPECIFICATIONS GUIDELINES

3 3. Parabolic Antenna: Model No.P-2548GR by Mark Antenna Products or accepted equivalent. B. VHF Antenna: BTY series by Blonder-Tongue Laboratories, Inc. or accepted equivalent. 1. VHF Low Pass Filter: Fastrap Model No.5KLP-72 by Microwave Filter Company or accepted equivalent. C. UHF Antenna: BTY series by Blonder-Tongue Laboratories, Inc. or accepted equivalent. D. TV Amplifiers: 1. Broadband Amplifiers: Quality R.F. Services Inc. or accepted equivalent. 2. Frequency Agile Television Processors for Education, Commercial Television Broadcast Stations: O.T. Olson Technology Incorporated or accepted equivalent. 3. Frequency Agile Television Closed Circuit Modulators: AM by Blonder-Tongue Laboratories, Inc. or accepted equivalent. E. Splitter/Combiners: CRS Series by Blonder-Tongue Laboratories, Inc. or accepted equivalent. F. Tapoffs: CRT series by Blonder-Tongue Laboratories, Inc. or accepted equivalent. G. TV Outlets: 1. Walltaps with 1 output: a. Model No.V3488 by Blonder-Tongue Laboratories, Inc. b. Model No.4691 (TF-GF-FT) by Blonder-Tongue Laboratories, Inc. H. UHF to VHF Single Channel Converter (Channel 17 to Channel 5): MCX-UB by Blonder-Tongue Laboratories, Inc. or accepted equivalent. I. Headend Equipment Enclosure: Model No.V8505 by Winsted or accepted equivalent. J. Coaxial Cable TV Signal Distribution: 1. Dropline, Type RG6/U: Model No.1189A by Cooper Industries, Belden Division or accepted equivalent. 2. Main and Sub-Trunk Lines, Type RG11/U: Model No.9064 by Cooper Industries, Belden Division or accepted Project No. SPECIFICATIONS GUIDELINES

4 equivalent. 3. Main and Sub-Trunk Underground Lines (Always in conduit): RG11 Duobond Plus by Cooper Industries, Belden Division or accepted equivalent. K. TV Guyed Towers: Model No.25G by Rohn Communication Tower or accepted equivalent. L. TV Channel Modulator: AM by Blonder-Tongue Laboratories, Inc. or accepted equivalent. 1. Elementary Schools: Supply in a cabinet configuration. 2. Middle and High Schools: Supply in a rack mounting configuration MATERIALS A. Signal Level: 1. Minimum available at the output of any receptacle using specific normally viewed open circuit television channels, and all closed circuit channels: +3 dbmv. 2. Maximum available at the output of any receptacle, using specific normally viewed open circuit television channels and all closed circuit channels: +10 dbmv. a. Level Difference Between Adjacent Channels: 1.5 db. b. Level Difference Between All Channels: 7 db. 3. Operate all distribution amplifiers at maximum rated output. B. Bandwidth of the System, Exclusive of Amplifiers: From 5 MHZ to 500 MHZ flat within db across any 6 MHZ portion of the system. C. Television channels to be used include: 1. Channel 2 Educational television. 2. Channel 3 Fed via cable TV converter box. 3. Channel 4 Commercial channel, emergency broadcast service. 4. Channel 5 Educational channel 17 down-converted to channel Channel 8 School closed circuit modulator (elementary schools only). 6. Channel 12 School closed circuit modulator (elementary schools only). 7. ITFS channels 24 through Channels 8, 9, 11, and 12 in school closed circuit Project No. SPECIFICATIONS GUIDELINES

5 modulators (middle schools). 9. Channel 8, 9, 11, 12, 13 and mid band (channel A through I) in school closed circuit modulators (high schools only). D. 20 channel wireless television signals (horizontal polarity) are available from the main transmitter site located atop the Miami-Dade Center at 111 NW 1st Street, Miami, FL. OFF-AIR CHANNEL Channel 24 Channel 25 Channel 26 Channel 27 Channel 28 Channel 29 Channel 30 Channel 31 Channel 32 Channel 33 Channel 34 Channel 35 Channel 36 Channel 37 Channel 38 Channel 39 Channel 41 Channel 43 Channel 45 Channel 47 GROUP NUMBER A1 B1 A2 B2 A3 B3 A4 B4 C1 D1 C2 D2 C3 D3 C4 D4 F1 F2 F3 F4 E. Instructional Television Fixed Service (ITFS) Conversion: Provide a weatherproof microwave-down converter, I.F. frequency MHZ. Use outdoor 50 ohm cable between parabolic dish and converter input. Cable shall not exceed 3 feet SYSTEM EQUIPMENT A. ITFS and FM antennas with Ch17-Ch5 converter/processor and modulators as specified. 1. Comply with TV/Radio Frequency System Headend Block Diagrams - Basic Installation for schools where CATV service is available. a. Provide processors for educational and commercial channels as specified. Project No. SPECIFICATIONS GUIDELINES

6 2. Comply with TV/Radio Frequency System Headend Block Diagrams - Alternate Installation for schools where CATV service is not available. B. VHF Antenna: a. Provide VHF low band and UHF antenna systems as specified. 1. Heavy duty, with built-on 75 ohm coaxial cable connector: a. High strength aluminum alloy. b. Antenna Wind Resistance: Wind pressure velocities determined by ASCE Low Band Antenna for Channels 2 through 6: a. Gain Over Isotropic: 9 db. b. Return Loss: 14 db. c. VSWR 1.5:1. d. Impedance: 75 ohms unbalanced. e. Polarization: Horizontal. f. Bandwidth: 54 to 88 MHZ. 3. FM Band Antenna: Gain of 6.7 db front to back ratio of 18 db. Interface antenna with public address system. C. UHF Antenna: 1. Impedance output of 75 ohm at antenna and a gain of 10 db. 2. Channels: 14 to Return Loss: 18 db. 4. Front to Back Ratio: 21 db. D. TV Amplifiers: 1. Broadband amplifiers will be the final main amplifier to feed the school system. Comply with the following: a. Bandwidth: 50 to 450 MHZ. b. Frequency Response: db. c. Max Gain: 50 db. d. Output Level: 55 dbmv. e. Distortions: 1) Cross Mod.: 62 -db. 2) Comp. Tr. Bt.: 62 -db. Project No. SPECIFICATIONS GUIDELINES

7 3) Sec Order: 72 -db. f. Gain Range: 6 db. g. Slope Range: 6 db. h. Return Loss: 1) Input: 16 db. 2) Output: 16 db. i. Test Points: db. j. Noise Figure: 7.5 db. k. Current DC: 0.55 amps. l. Powering: 23 watts. 2. Provide channel frequency agile television processors for educational and commercial television broadcast stations. Comply with the following: a. Input. 1) VHF/UHF/CABLE/HRC/IRC: 54 to 890 MHZ including all cable channels selectable by front panel DP switch in 0.25 MHZ increments. 2) RF Input Level: a) -10 dbmv to +25 dbmv off-air. b) -10 dbmv to +10 dbmv cable. 3) Adjacent Channel Rejection: >60 db. b. Output. 1) Output Frequency Range: VHF Channel 2 to 13 or Cable Channel to YY ( MHZ) selectable in 1 MHZ increments by front panel DIP switch from MHZ to MHZ video carrier frequency. 2) FCC Offset Requirements: Front panel DIP switch selectable for KHz and +25 KHz. 3) Output Power Level: +60 dbmv typical, +55 dbmv minimum. 4) Aural Carrier Level: -12 db to -20 db below video carrier by front panel adjust. 5) Audio Intercarrier Stability: 4.5 MHZ + 2 KHz. 6) Frequency Stability/Accuracy: <+ 5 KHz of selected channel. 7) Spurious Output: >60 db below output visual carrier level. 8) Carrier to Out-of-Band Noise: >80 db as measured in a 4.0 MHZ noise bandwidth. Project No. SPECIFICATIONS GUIDELINES

8 9) Video Specifications Measured at 80 Percent Modulation: a) Differential Gain: <10 percent. b) Differential Phase: <3 percent. c) Video Output: 1 volt p-p (75 ohms). 10) Audio Performance: 300 mv p-p audio for 25 KHz deviation <1 percent T.H.D. 11) BTSC Stereo/Mono: Automatic Functions. 12) Size: 1.75" H by 19" W by 8" D. 13) Power Requirements: 115 VAC at 60 Hz to 17 watts. 14) RF Connectors: Type F. 3. Provide frequency agile television closed circuit modulators. a. True vestigial sideband output via saw filter. b. Full 60 dbmv output. c. RF carrier on video and aural outputs on any broadcast or CATV channel on the full 50 to 450 MHZ range. d. Video AGC. E. ITFS Downconverter: Provide state of the art reception of 2500 MHZ television signals and down-convert to I.F. Frequency to 222 to 408 MHZ, channels 24 to Input Bandwidth: 2500 to 2686 MHZ. 2. Output Bandwidth: 222 to 408 MHZ. 3. Response Flatness: 0.25 db/ch, 2.5 db/band. 4. Input Impedance: 50 ohms. 5. Output Impedance: 75 ohms. 6. Frequency Stability: + 25 KHz. 7. Gain: 32 db. 8. Maximum Noise: 1.7 db. F. ITFS: 1. Parabolic Antenna: Single grid dish type capable of receiving 2500 MHZ television signals. a. Aperture: 4 feet. b. Gain: 28.0 db + 2 db at 2600 MHZ. c. Vertical Beamwidth: 7 degrees or less. d. Horizontal Beamwidth: 7 degrees or less. G. Splitter/Combiners: 2-Way 4-Way 8-Way Project No. SPECIFICATIONS GUIDELINES

9 1. Bandwidth MHZ MHZ MHZ 2. Thru loss 4.2dB max 7.2dB max 11.9dB max 3. Isolation 25dB min 27dB min 20dB min 4. Return Loss 18dB min 18dB min 16dB min 5. Radiation Shielding -80 db -80 db -80 db H. Tapoffs: Multi-tap directional couplers. 1. Two Output Taps: Isolation (db) Thru loss +/-0.2dB Four Output Taps: Isolation Thru loss +/- 0.2 db Common Specs 500 MHZ: a. Isolation db: 1) Tap to Tap: ) Out to Tap: -21. b. Return Loss db: 1) In: ) Out: ) Tap: Radiation Shield Bandwidth: MHZ -100 db. I. TV Outlets: 1. Walltaps with 1 outputs: Model No.V3488. Project No. SPECIFICATIONS GUIDELINES

10 Impedance Connector Bandwidth RF 1SO Thru Loss 75 F 5-600MHz 12dB 0.9dB 16dB 0.7dB 20dB 0.6dB 24dB 0.6dB 28dB 0.6dB 30dB 0.6dB 2. Product Name: TF-GF-FT (Model No.4691). a. Impedance: 75. b. Connector: F. c. Bandwidth: 5-600MHz. J. UHF to VHF single channel converter (Channel 17 to Channel 5): 1. Designed for adjacent channel operation. 2. Balanced mixer. 3. Oscillator input and output. 4. Meets FCC radiation spec. 5. Crystal controlled. 6. Band pass filter. K. Headend Equipment Enclosure: 1. Heavy gage steel construction, ventilated, vertical rack with lockable front door located in the media distribution center. a. Provide 2 racks (at elementary and middle schools). b. Provide 3 racks (at high schools). 2. Each rack shall have one 115 VAC 12 outlet strip, capable of 20 ampere. L. Coaxial Cable TV Signal Distribution: 1. Type: RG6/U. a. Frequency: 600MHz b. Attenuation (db/100 max): c. Use: Dropline (maximum length 100 ft.) d. Conductor Material and Diameter: 18 AWG solid bare copper covered steel, 0.040". e. Dielectric gas injected foam polyethylene. f. Shield Type: Duobond, 60 percent aluminum braid. Duofoil, 40 percent aluminum braid. g. Jacket Material and Diameter: PVC (black color) 0.295". Project No. SPECIFICATIONS GUIDELINES

11 h. Nominal Velocity of Propagation: 82 percent. i. Impedance: 75 ohms. j. 100 percent shielded coverage. k. 100 percent sweep tested 5 MHZ to 600 MHZ. l. UL/NEC and CSA Rating: CATV and FT-1. m. Flame Test: UL 1581 Vertical tray. 2. Type: RG11/U. a. Frequency: 600 MHZ. b. Attenuation (db/100 max): c. Use: Main and Sub Trunk lines. d. Conductor Material and Diameter: 14 AWG solid bare copper covered steel 0.064". e. Dielectric Material and Diameter: Gas injected foam polyethylene 0.285". f. Shield Type: Bonded duofoil, 77 percent aluminum braid, bonded foil-shorting fold. g. Jacket Material and Diameter: PVC (black) 0.405". h. Nominal velocity of propagation: 82 percent. i. Impedance 75 ohms. j. 100 percent shielded coverage. k. 100 percent sweeptested 5 MHZ to 600 MHZ. l. UL/NEC and CSA Rating: CATV and FT-1. m. Flame Test: UL 1581 vertical tray. 3. Type: RG11 Duobond Plus. a. Frequency: 600 MHZ. b. Attenuation (db/100 max): c. Use: Main and Trunk under ground lines. d. 77 percent braid product code e. Flooded direct burial cable. f. Impedance ohms. g. Nominal velocity of propagation 82 percent. h. Nominal delay 1.2 ns/ft. i. Attenuation 600 MHZ 3.18 db/100 ft. NOTE TO SPECIFIER: Select either version of paragraph M. to suit the requirements of M-DCPS Media Programming Department and M-DCPS Design Criteria. Coordinate paragraph 3.01 G of this section. M. Guy wire supported galvanized metal antenna structure and antenna. M. Precast concrete antenna pole and antenna. N. TV Channel Modulator: Frequency agile audio/video Project No. SPECIFICATIONS GUIDELINES

12 modulator. 1. True vestigial sideband output via saw filter. 2. Full 60 dbmv output. 3. RF carrier on video and aural outputs on any broadcast or CATV channel on the full 50 to 450 MHZ range. 4. Video AGC. O. Lightning Protection System: Copper or bronze components, UL listed and of the size weight and construction for use according to UL requirements and manufacturer's recommendations or according to the Drawings SOURCE QUALITY CONTROL A. Verification of Performance: 1. Signal Parameters: a. Peak video carrier to noise level in 4.0 MHZ bandwidth. Required system operating limit 45 db minimum. b. Level difference of 6 MHZ spaced visual carriers. Required system operating limit + 3 db. c. Level Difference Between All Channels: 7 db. d. Visual carrier to coherent spurious signal ratio. Required operating limit >46 db. e. Visual carrier/interfering carrier co-channel ratio. Required operating limit 45 db. 2. RF Isolation Between RF Signal Outlet and Distribution Cable: Minimum 12 db. PART 3 EXECUTION 3.01 INSTALLATION A. Install the TV system according to applicable codes, accepted shop drawings and wiring diagrams, and as specified in this section. 1. In an existing school, keep the use of rigid conduit to a minimum. Where dropped ceilings are available, all cables shall be fed by way of the dropped ceiling and wiremold shall be used to feed it, wiring from the ceiling down to a wall mounted junction box. 2. Use conduit in exposed areas such as hallways. B. System Wiring: Install according to manufacturer's wiring Project No. SPECIFICATIONS GUIDELINES

13 diagram as required for proper operation of TV system. Install wiring in conduit. C. Ground the system as indicated on the drawings as prepared by a Florida registered professional engineer. D. Cable Television Conduit: 1. CATV Service available at time of project completion: Bury a 2-inch PVC type conduit between the nearest cable TV pole and route to the media center as designated on Drawings. 2. CATV service not available at time of project completion: Bury a 2-inch PVC type conduit between the nearest telephone pole and route to the media center as designated on Drawings. E. Provide communications from each class room to the media distribution center by telephone or the central public address system. F. TV Channel Modulator: 1. Elementary Schools: Provide 2 modulators, Television Channel 8 and Channel Middle Schools: Provide 4 modulators, Television Channels 8, 9, 11, and High Schools: Provide 14 modulators, Television channels 8, 9, 11, 12, and midband (A through I). NOTE TO SPECIFIER: Select either version of paragraph G to suit the requirements of M-DCPS Media Programming Department and M-DCPS Design Criteria. Conform with the selection made for paragraph 2.03 M of this section. G. Install and mount guy wire supported galvanized metal antenna structure and antenna according to the Drawings. G. Install and mount precast concrete antenna pole and antenna according to the Drawings. H. Lightning Protection System: 1. Install according to NEC, NFPA 78, UL 96A, Lightning Protection Institute (LPI) standards, other applicable codes and standards, and according to the Drawings. 2. Connections made in lightning protection system shall be electrically continuous to ground rods. Project No. SPECIFICATIONS GUIDELINES

14 3.02 FIELD QUALITY CONTROL A. Site Tests: 1. Check and test the system for shorts, grounds, continuity, and proper functioning and operation. 2. Perform final connections of equipment, testing of system, and other necessary adjustments by a certified factory trained technician, employed by or under the direct supervision of the equipment manufacturer. 3. Upon completion of installation, test entire system in presence of A/E and the Board. 4. Furnish RF meter, receiver, and spectrum analyzer acceptable to A/E, demonstrating signal strength and quality at each outlet. END OF SECTION Project No. SPECIFICATIONS GUIDELINES