MBE*/* Mini-Bridger Express Three-Output Amplifier. Installation and Operation Manual MBE S J A K E POWER. -20dB JXP COMMON MDR JXP IN BODE MAN.

Transcription

1 STARLINE 00 SERIES MBE*/* Mini-Bridger Express Three-Output Amplifier Installation and Operation Manual MBE IN S J A K E G MINI-BRIDGER EXPRESS JXP IN MDR MAN -db BODE JXP COMMON JXP ADU H L -db PORT 2 JXP 2 -db H L FWD EQ DRIVE UNIT JXP 3 db MAN REFER TO MANUAL FOR FUSE VALUES RTN EQ -db JXP 4 POWER CHECK VOLTAGE SELECTOR REFER TO MANUAL -db T J H XE P R M JXP -db -db TDU ADU -db ADU PORT 3 L H JXP 3 JXP 4 L H CAUTION: CONTAINS PARTS AND ASSEMBLIES SUSCEPTIBLE TO DAMAGE BY ELECTROST ATIC DISCHARGE (ESD) PORT 4 ASSEMBLED IN MEXICO

2 Caution These servicing instructions are for use by qualifined personnel only. To reduce the risk of electricaln shock, do not perform y anservicing other than that contained in the Installation and Troubleshooting Innstructions unless you are qualified to do so. Refenr all servicing to qualif ied service personnel. This symbol means that dangerous voltage levels aren present within the equipment. These voltages are nnot insulated, and may be of sufficient strength to cause serious bodinly injury if touched. The symbol may also appear onn schematics. The exclamation point, within an equilateral triangnle, is intended to alert the user to the presence onf important installation, servicing, and operating instructions in the documennts accompanying the equipment. For continued protection against fire, replace all nfuses only with fuses having the same electrical rantings marked at the location of the fuse. The symbol shown on the left, a reaching hand in a ntriangle with a slash through, it is intended to alnert the user and service personnel of the possibility of equipment damage orn degradation of performance due to an electrostaticn discharge (ESD) event. Copyright 00 by General Instrument Corporation. All rights reserved. No part of this publication mayn be reproduced in any form or by any means or used nto make any derivative ork w (such as translation, transformation or adaptation) without written perminssion from General Instrument. General Instrument reserves the right to revise thins publication and to make changes in content from tnime to time without oblig ation on the part of General Instrument to provide notification of such nrevision or change. General Instrument provides thins guide without warranty of any kind, either implied or expressed, including, but not limited, tno the implied warranties of merchantability and fitnness for a particular pur pose. General Instrument may make improvements or changes in the product(s) dnescribed in this manual at any time. General Instrument, the General Instrument logo, andn STARLINE are registered trademarks and Cableoptics is na trademark of Gener al Instrument Corporation.

3 Contents Section 1 Introduction Using This Manual...i...i Related Documentation...i...i Document Conventions...i...i If You Need Help...i...i Calling for Repairs...i...i Section 2 Overview Assemblies and Modules...i...i Housing Power Control Options Forward Amplifier Return Amplifier, RA-Kit/H or RA-Kit/L Forward Output Level Control...i Amplifier Level Control...i...i Options and Accessories...i...i Section 3 Pre-Installation Procedures Configuring the MBE*/*...i...i Cable Equalizer Input and Midstage Pads Powering and Surge Protection Options ADU/TDU Drive Units Flatness Return Path Configuration Sweep Response and Gain Testing Measuring Forward Gain Testing Return Gain and Response Completing the Test Procedures MBE*/*

4 ii Contents Section 4 Installation Mounting the Housing...i...i Housing Connections...i...i Installing the Unit...i...i Balancing the Amplifier...i...i Tilt and Flatness Manual Gain Control Thermal Drive Unit Automatic Level Control Closing the Housing...i...i Appendix A Specifications MBE*/Silicon RF General...i...i... A-1 MBE87/Silicon - Distortion...i... A-2 MBE75/Silicon - Distortion...i... A-3 Abbreviations and Acronyms Figures Figure 1-1 MBE*/* Mini-Bridger Express...i Figure 2-1 MBE*/* amplifier module...i Figure 2-2 MBE*/*functional block diagram...i Figure 2-3 MB-HSG housing and dimensions(top)...i Figure 2-4 MB-HSG housing and dimensions (side view)...i Figure 2-5 MPPS-II power pack block diagram...i Figure 2-6 MPPS-II power pack...i Figure 2-7 Voltage range selector location...i Figure 2-8 Forward amplifier module-major components...i Figure 2-9 MBE*/* amplifier module-options and accessories...i Figure 3-1 Cable versus tilt...i Figure 3-2 Frequency versus cable slope...i Figure 3-3 Location of voltage selector...i Figure 3-4 TDU cable selector...i Figure 3-5 ADU-* and ADU-* pad location...i Figure 3-6 Drive unit selector...i Figure 3-7 *EDR/* EDR/*/* board...i...i MBE*/*

5 Contents iii Figure 3-8 Effects of flatness controls on the *EDR/*/* board...i Figure 3-9 Effects of flatness controls on the main board...i Figure 3-10 Return amplifier components...i Figure 3-11 Typical test equipment and connections...i Figure 3-12 Test equipment connections for bench sweeping...i Figure 4-1 Pin-type connector...i Figure 4-2 MB-HSG housing torque specifications...i Tables Table 2-1 Options and accessories for the MBE*/*...i Table 3-1 Forward equalizer losses vs. frequency...i MBE*/*

6 Section 1 Introduction The General Instrument STARLINE 00 Series Mini-Bridgers amplify television signals in broadband distribution systems. The Mini-Bridger Express (MBE*/*) amplifies analog and digital signals carried in the bandpass through 870 MHz. Depending on the digital modulation carrier-to-noise requirement, the relative amplitude of each digital carrier is set at the headend to normally operate 6 db to 10 db below standard television channels. The MBE*/* features: 60/90 Vac line power option Thermal or auto-controlled Bode equalization db directional test points Two-way operation 15 A power passing Figure 1-1 illustrates the MBE*/*: Figure 1-1 MBE*/* Mini-Bridger Express

7 1-2 Introduction Using This Manual The following sections provide information and instructions to bench test, install, and operate the MBE*/*: Section 1 Section 2 Section 3 Section 4 Appendix A Abbreviations and Acronyms Introduction provides a product description, related documentation, the technical helpline, and repair/return information. Overview describes the MBE*/* and includes details on the various options and their functions. Pre-Installation Procedures provides information to select and install optional components. It also provides configuration and bench-test procedures that are recommended before installing the unit. Installation provides instruction for installing the MBE*/* and performing field alignment. Specifications lists the applicable technical specifications for the MBE*/* and options. The Abbreviations and Acronyms list contains the full spelling of the short forms used in this manual. This manual uses standard NTSC analog channel information. Refer to catalog specifications for further details pertaining to signal levels of digital channels above 550 MHz. This manual also uses 870 MHz as the reference frequency for cable loss and other values unless another frequency is given. Related Documentation This installation manual is complete and you should not require any additional documentation to install, test, or operate the MBE*/*. Although not required, the Return Path Level Selection, Setup, and Alignment Procedure Reference Guide provides information that you can use when setting up the MBE*/*. Document Conventions Before you begin using the MBE*/*, familiarize yourself with the stylistic conventions used in this manual: SMALL CAPS Denotes silk screening on the equipment, typically representing front- and rear-panel controls, input/output (I/O) connections, and LEDs * (asterisk) Indicates that several versions of the same model number exist and the information applies to all models; when the information applies to a specific model, the complete model number is given Italic type Used for emphasis If You Need Help If you need assistance while working with the MBE*/*, call the General Instrument Technical Response Center (TRC) at HELP ( ). TheTRCisopenfrom 8:00 AM to 7:00 PM Eastern Time, Monday through Friday. When the TRC is closed, emergency service only is available on a call-back basis. When contacting the TRC from outside the United States, call the main switchboard number, , and ask for extension 40.

8 Introduction 1-3 Calling for Repairs If repair is necessary, call the General Instrument Repair Facility at for a Return for Service Authorization (RSA) number before sending the unit. The RSA number must be prominently displayed on all equipment cartons. The Repair Facility is open from 7:00 AM to 4:00 PM Pacific Time, Monday through Friday. When calling from outside the United States, use the appropriate international access code and then call , extension3194, to contact the Repair Facility. When shipping equipment for repair, follow these steps: 1 Pack the unit securely. 2 Enclose a note describing the exact problem. 3 Enclose a copy of the invoice that verifies the warranty status. 4 Ship the unit PREPAID to the following address: General Instrument Corporation c/o William F. Joffroy, Inc. Attn: RSA # 1480 North Industrial Park Dr. Nogales, AZ 85621

9 Section 2 Overview The MBE*/* is a three output amplifier with one output port dedicated to trunk level performance and two output ports for distribution levels. For improved performance, the trunk port uses two hybrid amplifiers to enable cascades of greater length. The distribution ports employ high-gain, three-stage hybrid amplifiers to drive both a limited cascade and a local distribution system. The amplifier provides up to 132 channel capability using silicon and gallium arsenide (GaAs) technology. The S-split version of the MBE*/* uses a forward bandpass from 52 through 870 MHz and a return path from 5 through 40 MHz (65/85, 42/54, 30/47, and 55/70 MHz diplex filter splits are also available). The high-gain feature 37 db distribution and 28 db operational trunk makes the amplifier suitable for drop-in replacement of trunk amplifiers that were originally spaced for 22 db at 550 MHz. The expanded reach of the MBE*/* enables you to cascade several of its trunk-level outputs. This feature is beneficial in rural areas where you can maintain the total number of subscribers, per fiber-optic node, at a target level. The attenuation of coaxial cable, as used in Community Antenna Television (CATV) systems, changes with variations in temperature. The interstage Bode board is an electrically controlled equalizer. It receives its control input from either the Automatic Drive Unit (ADU) or the Thermal Drive Unit (TDU) control boards. The Bode board compensates for coaxial cable attenuation changes caused by temperature variations. It also compensates for hybrid changes over the entire temperature range. If necessary, you can control the Bode board manually with a potentiometer, however, we do not recommend permanent operation of the MBE*/* in manual mode. The MBE*/* maintains its distortion performance over wide temperature ranges using the Bode equalizer and hybrid thermal-compensation network with ADU control. The standard MBE*/* is shipped in housing model MB-HSG and includes all necessary components for a fully functional one-way amplifier. The forward cable equalizer, model EQ-*-*, is not included.

10 2-2 Overview Figure 2-1 illustrates the MBE*/* amplifier module: Figure 2-1 MBE*/* amplifier module MBE IN S J A K E G MINI-BRIDGER EXPRESS JXP IN MDR MAN -db BODE JXP COMMON JXP ADU H L -db PORT 2 JXP 2 -db H L FWD EQ DRIVE UNIT JXP 3 db MAN REFER TO MANUAL FOR FUSE VALUES POWER CHECK VOLTAGE SELECTOR REFER TO MANUAL -db RTN EQ -db T J H XE P R M JXP JXP 4 -db -db TDU ADU PORT 3 -db L H JXP 3 JXP 4 ADU L H CAUTION: CONTAINS PARTS AND ASSEMBLIES SUSCEPTIBLE TO DAMAGE BY ELECTROSTATIC DISCHARGE (ESD) PORT 4 ASSEMBLED IN MEXICO Figure 2-2 illustrates the functional interconnections of all stages in the MBE*/*: Figure 2-2 MBE*/*functional block diagram Manual Auto ** ADU ** JXP TP Input port 1 RF/ RF AC AC TP ** H L ** ** ** ** ** EQ JXP EDR BODE JXP ** JXP ** JXP ** H L ** H L TP Port RF/ 2 RF AC AC Port 3 RF/ RF AC AC TP Surge protector ** ** ** 24 Vdc SEE THERM JXP LPF Surge protector ** JXP ** JXP TP TP ** H L TP Port 4 RF/ RF AC AC ** Fuse Power supply ** JXP TP ** Fuse ** ** Fuse Fuse ** Plug-in module

11 Overview 2-3 Assemblies and Modules The following subsections describe each of the major components and subassemblies associated with the MBE*/*: Housing The housing protects the electronics from the elements and serves as a radiator to dissipate internally generated heat. The amplifiers are shipped with the model MB-HSG housing. Coaxial cable connections to the housing are made using conventional 5/8 inch 24 threads per inch stinger-type connectors. The included clamp and bolt assemblies enable strand mounting of the housing. Surface mounting requires suitable auxiliary brackets. For pedestal or surface mounting, use the two 1/4 threaded holes cast in the lower housing. A combination woven-wire/silicone-rubber gasket between the body and the cover provides efficient ground continuity, RF shielding, and weather protection for all housings. Factory-inserted, plastic cap plugs protect the input and output ports. Discard these plugs after you install the cable connectors. Figure 2-3 illustrates a top view and the dimensions of the MB-HSG housing: Figure 2-3 MB-HSG housing and dimensions(top)

12 2-4 Overview Figure 2-4 illustrates a side view and the dimensions of the MB-HSG housing: Figure 2-4 MB-HSG housing and dimensions (side view) 5.6 Power Control Options The distribution amplifier uses fuses to direct and limit power from the input port to the feeder port. The maximum permissible ac current through any port is 15 A. A fuses are in series with the input and outputs to protect the amplifier from overcurrent. These fuses also serve the additional function of a switch. You can eliminate power by pulling the appropriate fuse. The model MPPS-II 60/90 power pack includes a heavy-duty gas discharge tube that you can replace with the optional fast-trigger electronic crowbar (FTEC) surge protector. The FTEC crowbar circuit fires at approximately 230 V and presents a short circuit to the line during periods of overvoltage. After the ac input voltage returns to normal, the FTEC resumes its open state. Figure 2-7 illustrates the MPPS-II power pack and the location of the optional components. The cover of the amplifier houses the model MPPS-II 60/90 power pack. It provides a regulated 24 Vdc output at 2.5 A maximum over an ac input voltage range from 38 Vac through 90 Vac rms. The MPPS-II has an extended voltage range. The supply continues to deliver regulated power to the load up to 0 Vac however, the power factor will degrade. The input-voltage waveshape is either a quasi-squarewave or a sinewave. The surge protector and the electromagnetic interference (EMI) filter protect the power pack and amplifier from transient spikes. An integral fast-acting zener diode provides additional surge protection. A 5 A fuse in the ac line offers further protection in case of catastrophic power pack failure. The preregulator is a fixed frequency switching regulator that presents a near perfect power factor to the input line and provides overvoltage and overcurrent protection. A precision output regulator provides a precise output voltage and is also protected against overcurrent and short circuits. If a short circuit is detected, the power supply shuts down and the regulator initiates a sequence of line test pulses at approximately one-half second intervals. The regulator continues these pulses for the duration of the short circuit but returns to normal operation when the fault is cleared.

13 Overview 2-5 Figure 2-5 illustrates a block diagram of the MPPS-II power pack: Figure 2-5 MPPS-II power pack block diagram 60/90 Vac EMI Filter Bridge rectifier Preregulator Isolation transformer Precision regulator 24 Vdc Overvoltage and power-factor correction Figure 2-6 illustrates the MPPS-II power pack installed in the upper half of the MB-HSG-housing: Figure 2-6 MPPS-II power pack HI LO NO USER SERVICABLE PARTS INSIDE USE CAUTIONWHENMAKING INTERNALADJUSTMENTS WITHCOVERREMOVED SEE INSTALLATION MANUAL FOR SERVICE CAUTION VOLTAGES IN EXCESS OF 300 VOLTS ARE PRESENT UNDER COVER AND MAY BE PRESENTFORSEVERAL MINUTES AFTER POWER IS REMOVED AC TEST POINT FTEC 24V TEST POINT MPPS-II

14 2YHUYLHZ In the MBE*/* an internal voltage selector (J1) enables operation over an input voltage range from 38 Vac through 60 Vac (LO) or from 55 Vac through 90 Vac (HI). Units are shipped with the selector set for 60 Vac (LO). Section 3, Pre-installation Procedures, explains changing the setting of this selector to meet system requirements. You must remove the power-pack cover to access the selector illustrated in Figure 2-7: )LJXUHÃ 9ROWDJHÃUDQJHÃVHOHFWRUÃORFDWLRQ Voltage selector Surge protector HI LO J1 )RUZDUGÃ$PSOLILHU The forward amplifier s electronics consist of a single two-stage trunk path and two parallel three-stage distribution paths. The first two stages are common to all three paths. The pre-amplifier stage provides a low noise figure, while the output stage contributes the desired power at low distortion. The amplifier input provides a facility to install a cable equalizer and a socket for a model JXP-*A attenuator. Both the attenuator and equalizer are customer-installed options. Several circuits comprise the intermediate amplifier stages. The Bode equalizer is a voltage-controlled device that, in the standard configuration form, receives its input from the manual gain control. It also receives its input from the ADU-* or TDU-* board when either of these options is employed. A flatness-control circuit precedes the Bode board and enables optimization of the frequency response. The standard *EDR/*/* board serves two functions: it controls flatness and provides equalization producing 12.5 db of tilt for the amplifier output. This tilt is equivalent to approximately 16 db of PIII 0.75-inch cable at 870 MHz. Following the Bode board, a JXP facility adjusts the RF level into the interstage hybrid amplifier. 0%(Ã,QVWDOODWLRQÃDQGÃ2SHUDWLRQÃ0DQXDO

15 Overview 2-7 Figure 2-8 illustrates the location of the major components on the amplifier module: Figure 2-8 Forward amplifier module-major components *EDR/*/* EQ/BCS BODE equalizer AUTOMATIC DRIVE UNIT ADU/ ADU-* Accurate -db directional-coupler test points are available at the input and at the output of the amplifier. Because these test points are 75-ohm source impedance, they do not require special test probes. After the interstage hybrid amplifier, a directional coupler on the trunk path provides a signal for the distribution paths. A second directional coupler provides a signal to the optional ADU board. This signal is used only with the ADU board; you do not need to terminate this port when the ADU is not installed. The distribution path passes through a two-way splitter. Each output then provides signal to drive the output hybrid amplifiers. You can place appropriate value pads between the splitter output legs and the hybrids to balance the signal level.

16 2-8 Overview Return Amplifier, RA-Kit/H or RA-Kit/L The circuit board of the forward amplifier accommodates the optional return amplifier. Installing the return amplifier kit RA-Kit/H or RA-Kit/L equips the MBE*/* amplifier to pass signals in the return or upstream direction. The return amplifier kit includes a return-amplifier hybrid and jumpers. Optional SEE-/* return equalizers compensate for cable attenuation and are available in 2 db increments from 0 db through 12 db. S-split SEE-/* return equalizers are available in 1 db increments. The main amplifier board contains all components, including the diplex filters with extended return bandwidth, for the amplifier input and output. All items are plug-in and easily installed. The output of the return amplifier includes two JXP-*A pad facilities. Selection of the output-pad value normally controls the return-signal level into the next upstream amplifier. A JXP-*A pad facility is included in each return input leg. Select an appropriate input pad to attenuate excessive input signal. You can also use either pad socket as a test point or a signal injection point using the F/JXP- directional coupler. Forward Output Level Control Use the drive-unit select jumper to manually or automatically control the forward output level and gain. The gain potentiometer controls the gain of the amplifier when the drive-control select jumper is in the manual position. Figure 2-1 illustrates the location of this jumper. If the amplifier cover is in place, the access hole to the gain potentiometer is labeled MAN. UsetheMAN position in underground cable installations that do not require thermal compensation. However, ADU control may be preferred in cascaded trunk applications. Generally, cable attenuation in underground installations is constant. When the associated amplifier is located in a pedestal above ground compensation is not essential. Refer to Section 4, Installation, Manual Gain Control for the set-up procedure. The STARLINE 00 Series MBE*/* uses a Bode design that compensates for temperatureinduced hybrid gain changes and coaxial cable changes. In buried plant installations, the thermal-compensation attenuator compensates for hybrid gain changes with temperature. Amplifier Level Control In a cable system, signal levels vary with temperature primarily because cable attenuation changes with temperature. Other components, such as passives and amplifier hybrids, are also affected. One of the following options is selected to automatically compensate for these signal fluctuations: The ADU board, an optional plug-in module, monitors the amplitude of the selected pilot frequency. The pilot frequency is an available television channel not scrambled by sync suppression. Any changes in amplitude are fed back to the Bode equalizer, which makes appropriate corrections.

17 Overview 2-9 Although less accurate than the ADU, the optional TDU board compensates for signal-level changes by sensing housing temperature and signaling needed changes to the Bode equalizer. Place the jumper on the TDU to the 10 db, db, or 30 db position. Choose the setting that best represents the aerial cable loss at the highest frequency preceding the amplifier station. Select manual control of the Bode board if the ADU or TDU board fails. Figure 2-1 illustrates the location of the MAN potentiometer on the main circuit board. Because signals vary and distortion performance changes, we do not recommend manual gain control during normal operation. Options and Accessories The amplifier is shipped without an input forward equalizer or return equalizer. When configured appropriately for the field location requirements the wire jumpers must be removed for proper operation. You must also install the correct equalizer or broadband cable simulator to place the unit into service. Use model JXP-* pads to control field signal levels. To compensate for temperature, install the model ADU or TDU. These items are necessary for proper operation. Install other items such as a return amplifier and additional surge protection at your discretion; these options do not render the unit inoperative if they are not included. Table 2-1 provides a comprehensive list of optional equipment that works in conjunction with the MBE*/*. To assist you in the selection process, the table also provides a brief description and basic function of each item. Section 3, Pre-Installation Procedures, provides information to help you select the correct equalizer or cable simulator. Select the equipment that satisfies individual system requirements. Qualified technicians can install all optional equipment at field locations. Table 2-1 Options and accessories for the MBE*/* Model Description Function ADU-* Automatic control board This board provides automatic output-level control and requires the selection of a pilot frequency. Install either an ADU or TDU in the unit. TDU Thermal control board This board controls amplifier gain and slope by compensating for temparature-induced changes in cable attenuation. Install either an ADU or TDU in the unit. RA-Kit/H or L Return amplifier kit This kit enables two-way operation and includes a return hybrid and jumpers. The RA-Kit/H hybrid has 30 db of gain while the RA-Kit/L hybrid has 24 db of gain. EQ-75-* EQ-87-* Cable equalizers These equalizers compensate for cable attenuation in 1 db increments from 2 through 22 db. See the product catalog for additional information and install the appropriate value. BCS-* Broadband cable simulator This option simulates the property of cable when insufficient cable exists. JXP-*A Fixed attenuator This pad attenuates excessive input signal in ½ db increments from 1 db through 22 db. Install the appropriate value.

18 2-10 Overview Model Description Function FTEC Crowbar overvoltage protection Use this option to replace the existing surge protector. SEE-*-* Return equalizer This option compensates for cable attenuation in 2 db increments (1 db for S-split) from 0 db through 12 db. See the product catalog for additional information and install the appropriate value. JXP-TH2 or JXP-TH3 Thermal attenuators This option compensates for gain changes with temperature in the return path. BAF-* Feeder line fuse This automotive-type fuse powers the output port and provides protection against overcurrent. F/JXP- -db directional coupler Use this test adapter to inject signal or measure level at any JXP location Heat sink compound This compound helps dissipate equipment heat. Figure 2-9 illustrates the location of options and accessories in the MBE*/*: Figure 2-9 MBE*/* amplifier module-options and accessories EQ/BCS *EDR/*/* BODE equalizer AUTOMATIC DRIVE UNIT ADU/ SEE-*-* ADU-* or TDU Return hybrid

19 6HFWLRQà 3UH,QVWDOODWLRQÃ3URFHGXUHV Before you begin, you must obtain system records that include signal levels, equalizer values, initial pad values, and fuse or circuit breaker details. It is helpful to have a cable simulator that you can construct by cutting and measuring various lengths of cable, that when interconnected, add up to the desired cable value. Add the components required by your system-layout documentation. Configure the unit and perform bench testing before installing the MBE*/*. If you have access to a network analyzer, use it in place of a bench sweep system. The pre-installation procedure ensures proper alignment of all components and simplifies field installation and balancing. &RQILJXULQJÃWKHÃ0%( Before you install the unit, configure the amplifier to suit your system requirements. Configuration includes selecting and installing the components that are described in the following subsections. Major components include: Œ Œ Œ Cable equalizer, model EQ-*-*, or broadband cable simulator, model BCS-* Powering and surge protection options Control board option, model ADU-* or TDU Œ Two-way option return amplifier model RA-Kit/H or RA-Kit/L and return equalizer model SEE-*-* The MBE*/* is shipped with A blade-type fuses for over-current protection. You must remove these fuses to avoid applying 60/90 Vac to the test equipment during testing. Before you install the selected options, unplug the power cord from the amplifier module. Press the locking tab of the connector and pull until it releases. Loosen the screws holding the cover in place and remove the cover. Component locations are now accessible. &DEOHÃ(TXDOL]HU The MB*/* is factory configured with an interstage *EDR/*/* board installed. The standard version (Model *EDR/8/12) compensates for 16 db of cable at the highest frequency. For optimum performance with a flat input slope, the *EDR/*/* should provide the total amount of output slope required between the lowest and highest frequencies in the forward path. A forward equalizer or cable simulator is required for additional compensation as the result of cable and passive losses prior to the input of the amplifier. Equalizers are available in 1 db increments from 2 db through 22 db. To select the proper forward input equalizer for bench alignment prior to field installation, refer to system design maps. Determine the calculated input signal levels to the MBE*/*. Subtract the lowest from the highest frequency inputs. If the resulting number is positive a cable equalizer is required to reduce the signal levels into the amplifier at the lower frequencies. Conversely, a negative number indicates the selection of a cable simulator, usually occurring when small amounts of cable occur between amplifiers. 0%(Ã,QVWDOODWLRQÃDQGÃ2SHUDWLRQÃ0DQXDO

20 3-2 Pre-Installation Procedures Refer to Table 3-1 for equalizer selection and Table 3-2 for cable simulator selection. Locate the column labeled Slope (Low vs. High Frequency.) Find the value closest to the slope calculated above and select the corresponding equalizer value. If an exact match does not occur select the next lowest equalizer value. If the amplifier is being aligned in a field location, follow the same procedure. Remember to compensate for outside temperature variations in aerial plant. If system design maps are not available, measure the input signal levels and proceed. Select and install the appropriate equalize value. Measure the output slope between the lowest and highest frequencies and compare with the preferred slope for unity gain. If the measured output slope is greater than preferred, reduce the input equalizer value and, conversely, increase the input equalizer if more slope is required. Another available tool is to determine the slope required or measured and multiply by a conversion factor. This provides the equivalent amount of cable corresponding to the slope. Multipliers are: 550 MHz = 1.43 Figure 3-1 Cable versus tilt 650 MHz = MHz = MHz = Tilt versus Cable db of Cable MHz 650 MHz 750 MHz MHz db of Tilt To determine the proper cable for bench testing, subtract the interstage equalizer value (10 db) from the cable connected to its input. The output is flat with a flat signal source.

21 Pre-Installation Procedures 3-3 Table 3-1 Forward equalizer losses vs. frequency Equalizer Product Number & Value Frequency (MHz) vs. Insertion Loss (db) Slope (Low vs. High Frequency) EQ EQ

22 3-4 Pre-Installation Procedures Equalizer Product Number & Value Frequency (MHz) vs. Insertion Loss (db) Slope (Low vs. High Frequency) Table 3-2 and Figure 3-2 help you choose the correct simulator: Table 3-2 Broadband cable simulator values Slope Frequency (MHZ) vs. Insertion Loss (db) Cable simulator BCS value 50 vs vs vs

23 3UH,QVWDOODWLRQÃ3URFHGXUHV Figure 3-2 illustrates the information presented in Table 3-2 in graph form: )LJXUHÃ )UHTXHQF\ÃYHUVXVÃFDEOHÃVORSH 0 BCS BCS-*insertion loss (db) Frequency (MHz) The following two examples present several alternatives: ([DPSOHÃ The amplifier location includes db of cable (at 870 MHz) between its input and the preceding amplifier. Consider cable loss only. Exclude any flat loss due to splitters or other passive devices. The internal equalizer, Model *EDR/8/12, compensates for 16 db of cable. Subtract this cable length from the db of this example ( 16 = 4). The EQ is the proper equalizer in this case. With this equalizer installed, the amplifier reproduces the output tilt of the last upstream amplifier. ([DPSOHÃ The MBE*/* is used in a link following a fiber node. The fiber receiver output is flat and connects to the input of the amplifier through 18 db of cable plus passive loss. Determine which is the proper equalizer to achieve the 12.5 db output tilt from the amplifier. Calculate the equalizer value using: SLOPE eq = TILT out + SIG lo SIG hi SLOPE ieq where: SLOPE eq = required EQ-87-* slope TILT out = required amplifier output tilt SIG lo = signal input level at 54 MHz (channel 2) SIG hi = signal input level at 870 MHz SLOPE ieq = interstage equalizer slope (12.5 db) 0%(Ã,QVWDOODWLRQÃDQGÃ2SHUDWLRQÃ0DQXDO

24 3-6 Pre-Installation Procedures At an operating frequency of 870 MHz, 18 db of cable produces approximately 3.9 db of loss at 54 MHz. This suggests that the channel 2 signal input to the MBE*/* is 14.1 db greater ( = 14.1) at channel 2 than at 870 MHz. Our example assumes that the high-end frequency level into the amplifier is +12 dbmv. Substituting this information into the above equation gives: 11 db db 12-dBmV 12.5 db = 12.6 db The slope of the required equalizer is 12.6 db. Translate this to an equivalent cable value by consulting Figure 3-1 or using the appropriate multiplier. The multiplier in this case is 1.28 db ( = 16.13). Therefore, the correct equalizer is the EQ-87-16, the closest available equalizer value. Multipliers to convert tilt to cable equivalent are: 550 MHz = MHz = MHz = MHz = 1.28 Because of errors in cable attenuation, slope in passive devices, and other independent variables, you may need to change the final value of the equalizer before installing the unit. Input and Midstage Pads Install model JXP-*A pads to attenuate the signal per system design drawings. Generally, this consists of attenuating excessive input levels. Select and install the specified pad in the socket labeled JXP-FWD IN. The midstage pad normally remains at 0 db. System performance calculations should be thoroughly reviewed before changing this pad value.

25 Pre-Installation Procedures 3-7 Powering and Surge Protection Options In conventional applications the MBE*/* is powered through the input port. A A, blade-type fuse is furnished in the amplifier module and provides overcurrent protection for ac power applied to the input. You can power the MBE*/* from the output without passing power through to the input port. To block power from the input port remove the fuse. WARNING! To avoid possible injury to personnel or damage to the equipment, remove 60/90 V ac power from the system before you remove any components from the housing. The supplied MPPS-II 60/90 power pack has two voltage ranges: 38 Vac through 60 Vac (LO) and 55 Vac through 90 Vac (HI). Figure 3-3 illustrates the power pack and the location of the 60/90 V range selector, three vertical board-mounted pins, and suitcase jumper: Figure 3-3 Location of voltage selector Voltage selector Surge protector HI LO J1 The MBE*/* is shipped from the factory configured for 38 Vac through 60 Vac powering. To configure the mini-bridger for 55 Vac through 90 Vac operation: 1 Remove the power-supply cover. 2 Move jumper J1 on the power-supply board from the LO to HI position. Figure 3-3 illustrates the jumper location. 3 Re-install the power-supply cover. The MPPS-II power pack is furnished with a heavy-duty, 230-V, gas discharge surge protector. In some cases, the preferred method of surge protection is the model FTEC. The FTEC has a firing potential of approximately 230 V. You can install this electronic option in the MPPS-II power pack as a replacement for the surge protector.

26 3-8 Pre-Installation Procedures To install the FTEC: 1 Remove the power supply cover. 2 Remove the gas-tube surge protector illustrated in Figure Replace it with the FTEC. 4 Re-install the power supply cover. ADU/TDU Drive Units There are three methods to control the amplifier output level: ADU, TDU, or manual gain. The ADU operates by monitoring the amplitude of a chosen, clear, pilot channel. Changes in signal level are fed back to the Bode board. Typically, the encountered signal-level change is the result of changing temperature and the subsequent change in cable attenuation. The Bode board responds by changing its insertion loss to maintain a constant output level. This module maintains the most precise output level of the three available methods. For automatic output-level control by the ADU, the jumper must be in the DRIVE UNIT position. The TDU senses temperature and controls the Bode board. Typically, the cable is subjected to the same or similar temperature as the Bode board. The TDU then compensates for the amount of cable chosen with the selector on the TDU circuit board: 10,, or 30 db. Place the drive-unit-select jumper in the DRIVE UNIT position for automatic output-level control by the TDU. Figure 2-1 illustrates the module cover and the location of the TDU. Figure 3-4 illustrates the TDU cable selector: Figure 3-4 TDU cable selector db 10 db 30 db The single control (potentiometer) on the TDU controls gain. Use this control to adjust the Bode equalizer. To adjust the TDU: 1 Apply power to the unit and check the power-supply output. The voltage at the power-supply test point must be +24 Vdc ± 0.2 V. 2 Connect a signal level meter to the output test point. Use the manual level control to reduce the level of the highest frequency channel by the required gain reserve. When you install an ADU or TDU, line up the pins carefully before you press the unit into place. Excessive force is not required and can result in bent pins.

27 Pre-Installation Procedures 3-9 You can operate the MBE*/* in the manual mode if the ADU-* or TDU fails. Select manual mode by placing the gain-select jumper, illustrated in Figure 2-1, in the MAN position. The control marked MAN on the cover now governs the output of the mini-bridger. General Instrument recommends that you use the ADU-* or TDU for improved output-level stability. Do not use manual mode for extended periods. Figure 3-5 illustrates the ADU-* circuit-board and ADU-* pad location in the amplifier: Figure 3-5 ADU-* and ADU-* pad location C115 C108 BODE equalizer ADU-* pad 7.5A AUTOMATIC DRIVE UNIT ADU/ EQ/BCS *EDR/*/* ADU-*

28 3-10 Pre-Installation Procedures To insert the board, carefully mate the pins on the ADU-* with the socket on the main circuit board. The keyed-socket pins enable entry in one position only. To enable the ADU-*, place the drive-unit select jumper in the DRIVE UNIT position. To disable automatic level control at any time, place the drive-unit select jumper in the MAN position. Figure 3-6 illustrates the drive unit selector: Figure 3-6 Drive unit selector MAN DRIVE UNIT MAN -db The supplied ADU-* is tuned to the pilot-frequency channel. This non-sync suppressed modulated or unmodulated channel must be present on the system continuously. It is not practical to retune the ADU-* to an alternate frequency. Flatness Adjust the *EDR/*/* board and trimmer capacitors C115 and C108 on the main board to correct peak-to-valley response variations. Figure 3-5 illustrates the location of these two capacitors. Replace the equalizer if the response exhibits tilt. Figure 3-7 illustrates the location of the controls on the *EDR/*/* board: Figure 3-7 * EDR/*/* board (C3) MHz (C2) MHz (C7) 52 MHz (C6) MHz (C4) 750 MHz and up (R2) MHz (R3) MHz (R4) MHz (C1) MHz (R5) MHz

29 Pre-Installation Procedures 3-11 Figures 3-8 and 3-9 illustrate the approximate effects on the frequency response of the amplifier: Figure 3-8 Effects of flatness controls on the *EDR/*/* board CH 1 S 21 /M log MAG 2 db/ REF db C2 and R3 C3 and R4 C6 R5 C7 and R2 C1 C4 START MHz STOP MHz The changes in response, as they are shown, were obtained by comparison against a normalized trace to emphasize the effect of the various controls.

30 3-12 Pre-Installation Procedures Figure 3-9 Effects of flatness controls on the main board CH1 S 21 /M log MAG 2dB/ REF 41.35dB Cor C CH 1 START MHz STOP MHz CH1 /M log MAG 2dB/ REF 41.35dB S 21 Cor C CH 1 START MHz STOP MHz

31 Pre-Installation Procedures 3-13 Return Path Configuration To implement two-way service, install the return amplifier kit (model RA-Kit/*). The return amplifier kit contains a hybrid gain block and a selection of jumpers. Install these items in the module locations illustrated in Figure Remove power from the MBE*/* and install the hybrid gain block carefully to ensure that all pins are straight and aligned with the appropriate sockets on the circuit board. To facilitate thermal conductivity, use heat-sink compound between the hybrid flange and the housing. Because its use is optional, heat-sink compound is not furnished with the kit. Secure the hybrid gain block to the circuit board using the furnished screws. To test and align the return system, use the directional coupler test points provided. These test-point signal levels are db below the actual levels. See Figure 2-2 for test point locations. You can also use the optional F/JXP- that can be installed in any three-pin JXP pad facility to test and align the return system. Refer to the product catalog for SEE-*-* specifications. Figure 3-10 illustrates the return amplifier components: Figure 3-10 Return amplifier components EQ/BCS *EDR/*/* BODE equalizer AUTOMATIC DRIVE UNIT ADU/ SEE-*-* ADU-* or TDU Return hybrid

32 3-14 Pre-Installation Procedures Sweep Response and Gain Testing Figures 3-11 and 3-12 illustrate typical test equipment and the interconnections required for pre-installation testing and bench sweeping: Figure 3-11 Typical test equipment and connections MBE*/* under test 4 2 Sweep generator Sweep comparator Cable simulator Power combiner 5 6 Detector and display Vac ac power supply

33 Pre-Installation Procedures 3-15 Figure 3-12 Test equipment connections for bench sweeping Pilot generator (modulator) Oscilloscope Sweep generator Signal level meter RF Out H V H V RF Out DET RF In Atten. no. 1 Atten. no " Cable See text SSP-PIN 60/90Vac Power supply Input port 1 Unit under test Port 2 Port 3 Port 4 Note: Terminate all unused outputs. Dashed line represents alternate connections for ADU-* testing. Measuring Forward Gain To measure the forward gain of the amplifier: 1 Determine whether the power-supply jumper (J1) is positioned for LO (60 Vac) or HI (90 Vac) operation. Connect the MBE to the test equipment and apply power. Verify that the B+ voltage is 24 V ± 0.4 V. Apply the sweep signal and adjust the test equipment as needed. 2 To select manual gain, place the jumper in the proper position and turn the MANUAL LEVEL control fully clockwise. 3 Measure the gain at a forward frequency using the procedure outlined in the operator manual provided with the test equipment in use. To correct this number, add the insertion loss of the SSP-PIN power combiner (0.5 db at 550 MHz, 0.6 db at 750 MHz, or 0.7 db at 870 MHz), the loss of the cable simulator at the forward frequency, and the loss of the cable equalizer (1.0 db) if it is installed.

34 3-16 Pre-Installation Procedures Example The test equipment indicates a measured gain of 12.5 db with the MBE*/* and the cable simulator set to db. 0.8 db (power combiner) db (cable equalizer) +.0 db (cable simulator) db (measured gain) 34.3 db (unit gain) The result must meet advertised specifications for the unit. By setting the operational gain of the MBE*/* 4 db below minimum full gain, the unit operates in the proper region of the Bode board. Testing Return Gain and Response After you configure the return path you can test the return bandpass to ensure compliance with specifications. The return amplifier is a flat amplifier; therefore, the cable simulator must remain in the test set-up and set to the same cable equivalent as in the forward sweep test. This provides an approximate indication of the frequency response that you can achieve in the field. To test for return gain and response: 1 Reconnect the test equipment and switch the sweep input and sweep output leads of the MBE*/* under test. Re-adjust the test equipment to sweep from 4 MHz through 50 MHz. 2 The expected response is flat. Tilt that is due to the return equalizer must average out to a flat response in a cascade of amplifiers. A slope adjustment is not available in the return bandpass. 3 Measure the gain at 40 MHz. The amplifier gain is the sum of: the measured gain, the insertion loss of the return cable equalizer at 40 MHz, the insertion loss of the power combiner, any pads installed in either the input or output pad locations, plus the cable simulator loss at 40 MHz. The measured gain must meet advertised specifications for the return amplifier. Example 14.0 db (measured gain) db (equalizer insertion loss) db (power combiner) +0.0dB(pads) db (cable simulator at 40 MHz).4 db (unit gain) Completing the Test Procedures The amplifier is now approximately tailored for a specific field location. Additional adjustments after installation are minor in nature. Re-install the fuse, jumper, or circuit breaker removed during testing. To complete the station records, record pertinent information. Remove test-equipment connections and close the housing.

35 Section 4 Installation The field installation procedures presented in the following subsections assume that the amplifier was tested and bench-aligned. Cable power and signal must be available on the system. Although it is advantageous to have a full complement of channels available for balancing, you can adjust the MBE*/* adequately with a limited number of channels. If the unit you are installing was not bench-aligned, follow the procedures outlined in Section 3, Pre-Installation Procedures. Mounting the Housing Power down the cable before you install the housing to avoid blown fuses, tripped circuit breakers, and personal injury. Remove the amplifier module to avoid damage to the expensive electronics during installation. Consider the entry point of the input cable and all output cables before you decide on the final unit location. If you use the conventional method of installation, suspend the unit by clamping it to the strand that supports the coax cable. Position the two strand clamps on either side of the housing to permit convenient curbside entry. To avoid water ingress, torque aluminum connectors to the specifications recommended by the connector manufacturer. As an alternative method you can mount the housing in a pedestal using the pre-drilled mounting plate and messenger clamp bolts provided. Pedestal installation is similar to the aerial pole installation, with one exception. In a pole installation, the cable and amplifier are subject to the same temperature environment. In contrast, pedestal installation provides a stable temperature environment for the buried cable while subjecting the above ground amplifier to higher temperatures. The ADU, if installed, functions the same as in an aerial installation and does not require further attention. Manual thermal compensation provided by the TDU can be inaccurate in a pedestal location and result in signal level changes with ambient temperature change. You can select the least amount of cable on the TDU (10 db) as one approach to this problem. This results in minimal gain change with temperature. Manual level control provides another viable alternative.

36 4-2 Installation Housing Connections Form customary expansion loops and make connections to the MB-HSG housing using standard housing entry-port connectors. Use standard pin-type connectors with a nominal center-conductor diameter of inches. Measure the pin length of the center conductor from the seating plane of the connector. It must be 1.5 inches minimum and 1.65 inches maximum. Longer pins can extend past the center-conductor seizure mechanism and degrade the match. Extremely long pins can result in a short circuit. Tighten the center-conductor seizure screw using a Phillips-head screwdriver. You can also use a socket and a torque wrench as an alternative method. The maximum recommended torque is 12 in-lbs. Figure 4-1 illustrates a typical pin-type connector: Figure 4-1 Pin-type connector 1.65" MAX 1.50" MIN Installing the Unit To install the unit: 1 Re-install the electronics and fasten the module to the housing with the four captive bolts. 2 Apply power to the unit and allow a few minutes for warm-up. 3 Check the ac voltage. When J1 is set in the LO position, the voltage must be greater than 38 Vac when read with a true rms voltmeter or 42 Vac when using a conventional average reading ac voltmeter. When J1 is set in the HI position, the voltage must be greater than 55 Vac when read with a true rms voltmeter or 61 Vac when using a conventional average reading ac voltmeter. 4 Check the dc voltage. The B+ voltagemustbe24vdc± 0.4 volts.