OUS835A-66000-Watt UHF Transmitter

INSTRUCTION MANUAL 835A 4, 5, 6 kW UHF SOLID-STATE TRANSMITTER AXCERA, LLC 103 FREEDOM DRIVE P.O. BOX 525 LAWRENCE, PA 15055-0525 USA (724) 873-8100 • FAX (724) 873-8105 www.axcera.com • [email protected]

835A 4 kW, 5 kW or 6 kW UHF Transmitter Table of Contents - Page 1 of 2 - 1. Introduction: 2. System - 835A:..................................................................................................................................................1316-1000 A. System Description B. Specifications C. Site Considerations D. Unpacking and Installation Procedures E. Transmitter Set Up and Operation Procedure F. Meters, Switches and Indicators G. Transmitter Detailed Alignment Procedure H. Remote Control Interface Connections I. Drawings: 1. Transmitter Block Diagram...........................................................................................................1278-3000 2. Transmitter Interconnect ...............................................................................................................1278-8000 3. Single UHF Exciter Assembly:.......................................................................................................................1278-1400 A. Drawings: 1. Interconnect ...................................................................................................................................1278-8400 4. AC Distribution Assembly, Exciter Assembly..................................................................................................1245-1500 A. Drawings: 1. Interconnect ...................................................................................................................................1245-8500 5. UHF Exciter Tray...............................................................................................................................................1245-1100 A. Drawings: 1. Block Diagram...............................................................................................................................1245-3100 2. Interconnect ...................................................................................................................................1245-8100 6. Variable Gain/Phase Tray, one Tray per Amplifier Array Assembly...............................................................1245-1200 A. Drawings: 1. Block Diagram...............................................................................................................................1245-3200 2. Interconnect ...................................................................................................................................1245-8200 7. Metering Control Panel ......................................................................................................................................... 1136811 A. Drawings: 1. Block Diagram...............................................................................................................................1245-3400 2. Interconnect ...................................................................................................................................1245-8400 8. Amplifier Array Assembly:.............................................................................................................................1278-1300 A. Drawings: 1. Block Diagram...............................................................................................................................1278-3300 2. Interconnect ...................................................................................................................................1278-8300 835A 4 kW, 5 kW or 6 kW UHF Transmitter Table of Contents - Page 2 of 2 - Your Transmitter contains either the Single Phase or the Three Phase AC Distribution Assembly. Choose the correct one below. 9. AC Distribution Assembly, Single Phase, One in each Amplifier Array .........................................................1278-1200 A. Drawings: 1. Interconnect ...................................................................................................................................1278-8200 OR: AC Distribution Assembly, Three Phase, One in each Amplifier Array ..........................................................1278-1100 A. Drawings: 1. Interconnect ...................................................................................................................................1278-8100 Your Transmitter contains the Low Band, Mid Band or High Band UHF Amplifier Trays. Choose the correct one below. 10. UHF Amplifier Tray (Low Band, Mid Band or High Band): ..................................... 1294-1112/1294-1113/1294-1114 A. Drawings: 1. Block Diagram...............................................................................................................................1281-3100 2. Interconnect ...................................................................................................................................1281-8100 11. Subassemblies: Refer to the Subassembly Section of the Instruction Manual for the Schematics of the Boards and Modules, which make up the 835A. The Subassembly Drawing List, which is a list of the drawings in the order they appear in the Section, is located in the front of the Subassembly Section. 12. Maintenance This section contains information on the operation and maintenance of the 835A.

UHF Solid State Transmitters 835A-3, 835A-4, 835A-5, 835A-6 The 835A represents the state of the art in solid state UHF transmitters. High performance, redundancy, and simplicity are combined in a very reliable unit. Using parallel high gain amplifiers, the 835A can be configured for 3kW, 4kW, 5kW, or 6kW operation. Combined aural/visual amplification is achieved with very good intermodulation performance, thanks to highly linear amplifiers and extensive correction capability. Front panel samples, status, and metering, most of which are remote controllable, allow for convenient system monitoring. As with all Axcera products, servicing is made easy with slide out assemblies that require no extender cards. This allows the circuits to be accessed for maintenance or adjustments even while on the air. www.axcera.com • 724-873 -1500 UHF Solid State Transmitters High Performance Exciter The exciter, designed and built by Axcera, contains the circuitry to convert the input video and audio signals to a combined, modulated RF signal which drives two very linear phase and gain modules. An optional second exciter with automatic exciter switcher is available for added redundancy. Video/Visual Modulation The video signal is processed in several ways prior to modulation. Sync tip clamping is provided to restore proper DC level. Sync and white clipping are also included to limit video transient faults. Back porch clamping is also available for some scrambling systems. The video signal is then applied to a double balanced diode modulator, providing modulation UHF Solid State Transmitters capability to 1% at standard intermediate frequency (IF). A SAW filter is employed for precise sideband filtering with minimal group delay error. Audio/Aural Modulation The audio signal is applied to a very wideband, linear FM modulator which operates at intercarrier frequency (4.5 MHz for system M). The high performance modulator accepts a full range of multichannel audio including stereo, mono, and second audio programming (SAP). Standard aural IF is achieved by heterodyne conversion of the modulated intercarrier signal with the visual IF. IF Processing The visual and aural modulated IF signals are combined and applied to IF processing stages. These stages provide outstanding signal precorrection to yield a very linear transmitter output. Amplitude linearity, incidental carrier phase modulation (ICPM), and frequency response correction are all adjustable. Upconversion The IF signal is upconverted to final channel frequency through heterodyning with a very stable local oscillator. The oscillator is crystal and oven temperature controlled for excellent frequency stability. The exciter is controlled with an Automatic Level Control (ALC) loop which ensures stable signal levels. After upconversion the signal is amplified to provide the exciter output. Power Amplifiers The parallel 600 watt power amplifiers are high gain units (45-50 dB), which provide redundant paths from the exciter to the output. Redundancy is enhanced with independent power supplies and cooling for each amplifier assembly. The output stage of each amplifier module utilizes eight transistors in parallel for added redundancy and on-air reliability. A high degree of protection is provided with each amplifier. Individual circulators, overdrive protection, VSWR cutback, and overtemperature protection are all included. Automatic Gain Control around each amplifier ensures that the transmitter output remains stable. The output of each RF cabinet is fed into a low loss hybrid combiner. Output bandpass and trap filtering is included to provide superior out of band rejection. www.axcera.com • 724-873 -1500 UHF Solid State Transmitters Features and Benefits 24 Hour Field Supprt Standard with all Axcera products is 24 hour/day, 7 day/week field support. This service operates as a direct telephone line during business hours, and on a pager system at all other times. Since all our products are designed and built at our facility just south of Pittsburgh, Pennsylvania, we are able to offer quick turnaround on most replacement modules, and timely shipping from the Pittsburgh International Airport.
Utilizes 100% solid state circuitry for high reliability and low maintenance costs
Configured with parallel high gain amplifiers for total system redundancy and maximum on-air reliability, including driver stages
Provides standard ±1 kHz frequency stability for stations with an offset frequency
Independent power supplies and cooling for cost-effective and reliable operation
Configured with broadcast quality exciter that includes full BTSC sound capability
Provides output circulator amplifier protection and isolation for high VSWR conditions
Experienced field service/support team is ready to help you 24 hours a day, 7 days a week PA PA PA PA PA PA PA PA PA PA Splitter 5-Way Combiner IPA Splitter Hybrid Combiner Splitter 5-Way Combiner IPA Exciter Switcher Exciter Exciter Bandpass/ Trap Filter Optional Second Exciter with Automatic Exciter Switcher Combined RF Combined RF RF Output 5kW Peak Visual 500W Average Aural Video Audio Video Audio UHF Solid State Transmitters Block Diagram - 835A UHF 5kW Transmitter B0008 1101R1-E 835A-3, 835A-4, 835A-5, 835A-6 Visual Performance Power Output (Peak)3000, 4000, 5000, or 6000 watts Output Impedance50 ohms Output Connector3 1/8" EIA Frequency Range470 to 860 MHz Carrier Stability±1 kHz (standard) ±350 Hz (optional) Regulation of RF Output Power3% Output Variation (over 1 frame)2% Sideband Response (System M/N-others on request) -3.58 MHz-42 dB -1.25 MHz and below-20 dB -0.5 to +3.58 MHz±0.5 dB 3.58 MHz to 4.18 MHz+0.5, -1.0 dB Freq Response vs. Brightness±0.5 dB Visual Modulation Capability1% Differential Gain5% Incidental Phase Modulation±3° Linearity (Low Frequency)5% Differential Phase±3° Signal-to-Noise Ratio55 dB 2t K-Factor2% Env. DelayPer CCIR or FCC Standard Video Input75 ohms (loop through) Video AGC Range1V, ±6 dB Harmonics-…

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835A 4 kW, 5 kW or 6 kW UHF Transmitter Site Considerations - Page 1 of 3 - There are special considerations that need to be made before installing the 835A and this section will help you plan ahead. The Transmitter consists of three cabinet assemblies, the Exciter Cabinet Assembly and two Amplifier Array Assemblies. The Exciter Cabinet Assembly requires an AC Input of 208/240 VAC, Single Phase with a rating of 20 Amps. Each of the Amplifier Array Assemblies requires an AC Input of 208/240 VAC, Three Phase with a rating of 55 Amps or 208/240 VAC, Single Phase with a rating of 100 Amps . Check that the site has the voltage requirement needed. The 835A is designed and built to provide long life with a minimum of maintenance. The environment in which it is placed is important and certain precautions must be taken. The three greatest dangers to your Transmitter are heat, dirt and moisture. Heat is usually the greatest problem, followed by dirt and then moisture. Over-temperature can cause heat related problems such as thermal runaway and component failure. Each Amplifier Tray in the Transmitter contains a Thermal Interlock Protection Circuit that will shut down that Tray until the temperature drops to an acceptable level. To begin to design a suitable environment for your new Transmitter it is imperative that you understand what an "Ideal Environment" is and how it can enhance the overall performance and reliability of your Transmitter, thereby maximizing revenues by minimizing down time. A properly designed facility will have an adequate supply of cool clean air, free of airborne particulates of any kind, and without excessive humidity. An Ideal Environment will require temperature in the range of 40° F to 70° F year round, reasonably low humidity and a dust free room. It should be noted that this is rarely if ever attainable in the real world. However, the closer your environment is to the Ideal Environment the greater the operational elevation. A heat related problem may not surface for many months if the installation is completed during cool weather, but may suddenly appear during the heat of summer. The fans designed and built into your Transmitter will remove the heat from within the Trays but additional means are required for removing this heat from the building. In doing this a few considerations should be noted. The first step is to determine the amount of heat to be removed. There are generally three sources of heat that must be considered. The first and most obvious is the heat from the Transmitter it self. 'The following example is for a 5kW Transmitter. The heat can readily be determined by subtracting the Average Power to the Antenna (3225 Watts) from the AC Input Power (20000 Watts). These numbers will be different for the 4 kW and 5 kW Transmitters but can be found by referring to the published literature or directly from Axcera. This number in Watts (16775) is then multiplied by 3.41 which gives (57202.75) the BTU's to be removed every hour. 12,000 BTU's per hour equals one ton, so a five ton air conditioner will cool a 5 kW Transmitter. The second source of heat is other equipment in the same room. Calculate this number as you did above. The third source of heat is equally obvious but not as simple to calculate. This is the heat coming through the walls, roof and windows on a hot summer day. Unless the underside is exposed, the floor is usually not a problem. Determining this number is usually best left up to a qualified HVAC Technician. There are far too many variables to even estimate this number without detailed drawings of the site showing all construction details. The sum of these three sources is the total amount of heat that must be removed. There may be other sources of heat, such as personnel, and all should be taken into account. Now that you know the amount of heat that must be removed we will consider how this can be accomplished. Your options are air conditioning, ventilation or a combination of the two. Air conditioning is always the preferred method and is the only way to approach the Ideal Environment. Ventilation will work quite well if the ambient air temperature will be below 100° F or about 38° C and the humidity should be at a reasonable level. In addition, the air stream must be adequately filtered to ensure that no airborne particulate of any kind will be carried into the Transmitter. The combination of air conditioning for summer and ventilation during the cooler months is acceptable when the proper cooling cannot be obtained through the use of ventilation alone and air conditioning year round is not feasible for whatever reason. However, operation of air conditioning and ventilation simultaneously is not recommended because this can cause condensation in Transmitters. For tube type Transmitters this can be especially serious if the condensation forms in the tube cavity and creates damaging arcs. A few precautions should be observed concerning an air conditioning system. 1. Air conditioners have an ARI nominal cooling capacity rating. In selecting your air conditioner do not assume you can equate this number to your requirements. Make certain that your contractor uses the actual conditions you wish to maintain in determining the size of the unit. With desired conditioned room temperature under 80° F the unit must be derated, possibly by a substantial amount. 835A 4 kW, 5 kW or 6 kW UHF Transmitter Site Considerations - Page 2 of 3 - 2. Do not have the air conditioner blowing directly onto the Transmitter. Condensation may occur on, or worse, in the Transmitter under certain conditions. 3. Do not isolate the front of the Transmitter from the back with the thought of air conditioning the front only. Cooling air is drawn in the front of all Transmitters and in the front and back of others. Any attempt to isolate the front from the rear will adversely affect the cooling air flow. 4. Interlocking the Transmitter with the air conditioner is recommended to …

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835A 4 kW, 5 kW or 6 kW UHF Transmitter, Internally Diplexed Unpacking and Installation - Page 1 of 2 - Air conditioning and any related heat exhaust ducts should be in place before continuing with the installation of the Transmitter. Installation of Cabinets and Trays Please inspect the Cabinets and all other material thoroughly upon arrival. Axcera certifies that upon leaving our facility the equipment was undamaged and in proper working order. The shipping containers should be inspected for obvious damage that indicates rough handling. Check for dents, scratches, broken switches, meters or connectors. Any claims against in-transit damage should be directed to the Carrier. Also please inform Axcera as to the extent of the damage. Remove the Cabinets, Trays, Hybrid Combiner, Bandpass Filter, Trap Filter and Output Couplers along with the Installation Material that make up the 835A from the crates and boxes. Remove the straps which hold the Cabinets to the shipping skids and slide the Cabinets from the skids. Remove the plastic wrap and foam protection from around the Cabinets. Do not remove any labeling or tags from any cables or connectors, for these are identification markers which make reassembly of the Transmitter as easy as possible. There are three Cabinets, (A1) the Single UHF Exciter Assembly, (A2) the Side A 2-3 kW Amplifier Array Assembly and (A3) the Side B 2-3 kW Amplifier Array Assembly. These Cabinets should be arranged from left to right with you facing the front, the A1 Single UHF Exciter Cabinet, the A2 Side A Amplifier Cabinet and the A3 Side B Amplifier Cabinet. The cabinets should be positioned with consideration taken for adequate air intake and exhaust, the opening of the rear door, access to the Trays including sliding them out for testing, the AC hook up and the installation of the Output Transmission Line. The Cabinets should be Grounded using copper strapping material and also should be permanently mounted to the floor of the Site using the holes in the bottom of the Cabinets. Remove the two L-brackets, mounted on the front panel rails of the Single Exciter Cabinet, which hold the Trays in place during shipment. The UHF Amplifier Trays are shipped separately from the Amplifier Array Cabinets because of the weight of each Tray. The Trays are mounted in the cabinet using Chassis Trak cabinet slides. The Tray Slides are on the Top and Bottom of the UHF Amplifier Trays and on the sides of the UHF Exciter Tray and the Variable Phase/Gain Trays. Inspect for any loose hardware or connectors, tightening where needed. Open the rear door, the key to unlock the door, if the door has the Optional lock, is found in a tan envelope taped to the door, and inspect the interior for packing material. Carefully remove any packing material that is found. Slowly slide each Tray in and out to verify that they do not rub against each other and have no restriction to free movement. Note: The UHF Amplifier Trays must be placed into the Cabinets in the proper location according to the labeling on each Tray or the Gain and the Phasing will not be maximized. The UHF Amplifier Trays are labeled to indicate where they are positioned in the Side A or the Side B Amplifier Cabinets. They are mounted in each Cabinet from bottom left to top right, with A1 the bottom left Tray and A6 the top right Tray. Locate the Tray labeled A1 and slide it into the Side A Cabinet, the bottom left position. Locate the Tray labeled A2 and slide it into the Side A Cabinet, the bottom right position. Locate the Tray labeled A3 and slide it into the Side A Cabinet, the center left position. Locate the Tray labeled A4 and slide it into the Side A Cabinet, the center right position. Locate the Tray labeled A5 and slide it into the Side A Cabinet, the top left position. Locate the UHF Amplifier Tray labeled B1 and slide it into the Side B Cabinet, the bottom left position. Locate the Tray labeled B2 and slide it into the Side B Cabinet, the bottom right position. Locate the Tray labeled B3 and slide it into the Side B Cabinet, the center left position. Locate the Tray labeled B4 and slide it into the Side B Cabinet, the center right position. Locate the Tray labeled B5 and slide it into the Side B Cabinet, the top left position. All of the Amplifier Trays should now be installed. Slowly slide each Tray in and out to verify that they do not rub against each other and have no restriction to free movement. Caution: Each UHF Amplifier Tray has a hard-line coaxial cable connected to the rear panel and will not slide out without first removing this connection. In order to pull out the Tray for test purposes or other reasons, use the test cable included in the Installation Material Kit for connection from the Tray to the Output Cable. Adjustments to the position of the Trays may be necessary, and are accomplished by loosening the cabinet slide mounting bolts that hold the front of the slide to the mounting frame of the Cabinet and moving the Tray, up or down, left or right, as needed to correct for the rubbing. 835A 4 kW, 5 kW or 6 kW UHF Transmitter, Internally Diplexed Unpacking and Installation - Page 2 of 2 - November 7, 2002 Main AC Inputs Once the Cabinets are in place and the Trays are checked for damage and alignment, the Main AC Hook-Up is ready to be made. Before connecting the 208/240 VAC, make certain that all of the circuit breakers associated with the Transmitter are switched Off. There are three AC Input circuits to the Transmitter, one 208/240 VAC 20 Amp for the Exciter Cabinet and two 208/240 VAC 100 Amp for single phase or two 208/240 VAC 55 Amp for three phase, one to each of the Amplifier Cabinets. The 20 Amp, 208/240 VAC Input connections are made to the Terminal Block A8-TB1, which is part of the AC Distribution Assembly, Exciter Cabinet (1245-1500), located near the center right hand side, rear portion of Cabinet #1. Terminal 1 Line 1, Terminal 3 Line 2 (208/240 VAC) and Terminal 2 (Chassis Ground). Thr…

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835A 4 kW, 5 kW or 6 kW UHF Transmitter Set Up and Operation Procedure - Page 1 of 2 - Initially the Transmitter should be turned on with the RF Output at J2 of the (A11) Coupler Assembly terminated into a dummy load of at least the power rating of the Transmitter. If a load is not available, check that the Output of the Coupler Assembly at J2 is connected to the Antenna for your System. If your Transmitter contains the Receiver Option, it provides the operator the ability to select either the Combined IF Output from the Receiver Tray or from the Modulator. The switching of the IF Relay, located on the ALC Board, is accomplished by applying or removing a jumper on Jack J8 Pins 10 & 11 located on (A9) the Remote Interface Assembly. To select the output from the Modulator, J8-10 and 11, must be connected together. To select the output from the Receiver Tray, J8-10 and 11, must not be connected together. Connect the On Channel RF Signal Input to the "N" Connector Jack (J1), for 50Ω Input, or to the "F" Connector Jack (J3), for 75Ω Input, located on (A9) the Remote Interface Assembly, mounted on the top, rear of the cabinet. With Receiver selected, the Transmitter uses the IF Output from the Receiver Tray. Connect the Baseband Balanced Audio Input to the Terminal Block (TB1) located on (A9) the Remote Interface Assembly, mounted on the top, rear of the Single UHF Exciter Cabinet. If Composite Audio, Stereo, is used instead of Balanced Audio, connect the Composite Audio Input to the BNC Jack (J6). Connect the Baseband Video Input to the BNC Jack (J2) also located on (A9) the Remote Interface Assembly. Switch On the Main AC Circuit Breaker located on the AC Distribution Assembly mounted toward the rear of the Single UHF Exciter Assembly. Switch On the Main AC Circuit Breakers located on the AC Distribution Assemblies mounted toward the rear of the Amplifier Cabinets. Switch On the CB2-CB6 Circuit Breakers, for the individual UHF Amplifier Trays, on the AC Distribution Assemblies mounted in each Amplifier Cabinet. Switch the Operate/Standby Switch located on the UHF Exciter to Standby and the Auto/Manual Switch also on the UHF Exciter to Auto. Normal operation of the Transmitter is with the switch in Automatic. Automatic operation of the Exciter uses the Video Input to the Exciter as an Operate/Standby Switch. In Auto, if the Input Video is lost, the Exciter will automatically revert the Transmitter to Standby and when the Video Signal is restored, the Exciter will automatically return the Transmitter to Operate. Move the Operate/Standby Switch on the Exciter to Operate. Note the power supply readings on the front panel Meters of the UHF Amplifier Trays in each Amplifier Cabinet Assembly, they should be +26.5 VDC. Note: If the Transmitter does not switch to Operate, when the Operate/Standby Switch is switched to Operate, check that there is an External Interlock Plug connected to Jack (J7), located on the Remote Interface Assembly mounted in the top, rear of the Single UHF Exciter Cabinet, and that it has a Jumper from Pins 1 to 2 which provides the interlock for the Exciter. The Interlock must be present for the Transmitter to Operate. Observe the Front Panel Meter located on the Metering Panel with the switch in the Combined Visual Output Power position, it should read 100%. If needed, adjust the Power Adjust screwdriver pot located on the front panel of the UHF Exciter to attain 100% Output on the Front Panel Meter located on the Metering Panel with the switch in the Combined Visual Output Power position. As you are checking the output Power Level, check the Meter Readings on the Transmitter Metering Panel in the % Reflected Power Position for the Side A and also the Side B Amplifier Assemblies and the Combined position for the Transmitter. If the % Reflected Power for any of the readings is very high, above 20%, a problem with the Output Coaxial Lines in the problem Side Amplifier Assembly or in the Output Lines for the System is present and needs to be checked and corrected. A center bullet missing from the 1-5/8" or 3-1/8" Rigid Coax Lines or loose bolts on the connections can cause this problem. Return the Operate/Standby Switch to Standby. Observe the % Exciter Power reading of the Meter on the Exciter, it should read the same as written on the Test Data Sheet for your Transmitter. Move the Operate/Standby Switch, located on the Exciter, to Standby. The Gain and Phase controls located on the front panels of the individual UHF Amplifier Trays were adjusted at the factory to attain 100% Output of the Transmitter and should not need readjusted. The Forward Meter readings for Side A and for Side B may not be the same but should be the same as the values written on the Test Data Sheet for your Transmitter. Side A and Side B are combined to give the correct Peak of Sync Output, which is 100% in the Combined Visual position. 835A 4 kW, 5 kW or 6 kW UHF Transmitter Set Up and Operation Procedure - Page 2 of 2 - The readings on each of the individual UHF Amplifier Trays may not be the same. Refer to the Test Data Sheet for your Transmitter and compare the final readings from the Factory on the Test Data Sheet with the readings on each of the Trays after the Set Up. They should be very close to the same. If a reading is way off, refer to the Phasing and Power Adjustment Procedure for the UHF Amplifier Trays in the Detailed Alignment Procedure before trying to adjust. If a dummy load is connected to the Transmitter, switch the Transmitter to Standby and switch Off the Main AC Circuit Breakers found on the AC Distribution Panels in each Cabinet. Remove the dummy load and make all connections needed to connect the Transmitter to the Antenna for your System. Switch the Main AC Circuit Breakers On and the Operate/Standby Switch to Operate. Adjust the Exciter Power Adjust pot to attain 100% Combined Output. If the Transmitter is already connected to the Antenna, check that the Combined Output is 100%. …

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835A 4 kW, 5 kW or 6 kW UHF Transmitter Meters, Switches, Indicators and Samples Name Function - Page 1 of 3 - Receicer Tray (Optional) Samples - BNC Connectors mounted on front panel. f(IF) Output A Sample of the IF Output taken from the IF Filter/ALC Board. f(s) Oscillator A Sample of the Channel Oscillator Output taken from the Sample Jack of the Channel Oscillator Assembly. UHF Exciter Tray Meters Meter (A1-A18) Reads power in terms of a percentage of the calibrated Output Power level. A full scale reading is 100% which is equivalent to the full rated Peak of Sync Exciter Output P…

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