Motorola SG 2000 operation manual N u a l G a i n C o n t r o l

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B e n c h S e t u p

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9Remeasure the output level. It should be within 1 dB of the preferred level. If necessary, adjust the manual gain control. Check the remaining ports and add JXP pads to bring the outputs to the correct level.

10Set the gain reserves using one of the following gain control options. Adjust the selected gain control option using the procedure presented in the appropriate subsection below.

S Manual control only — there is no compensation for changes in amplifier gain due to input level or temperature fluctuations.

T Thermal control — the standard thermal control unit (TCU) is installed at the factory and compensates for gain changes due to temperature fluctuations only.

T Automatic level control — the optional ADU drive unit holds output levels constant despite fluctuations in temperature or input level. The ADU is available as a factory-installed option. You can also install an ADU in place of the standard TCU in the field.

M a n u a l G a i n C o n t r o l

1Connect a signal level meter to the FORWARD TEST POINT and tune it to a channel near 750 MHz.

2Position the drive selector horizontally. Figure 3-2 illustrates the location of the AUTO/MAN drive selector.

3Turn the gain control (MAN ADJ) to maximum (fully clockwise) and then turn it counterclockwise to reduce the output by 4 dB. If the output level is greater than required, change the pad at the receiver output location to obtain the desired level. To calculate the correct pad value, subtract the desired level from the measured level and increase the pad by that amount. Note: Do not install a pad larger than 15 dB at the receiver output. If more attenuation is needed, put the remaining amount at the interstage pad location.

T h e r m a l C o n tr o l , M o d e l T C U

1Perform steps 1 through 3 under Manual Gain Control.

2Position the drive unit selector vertically.

3Turn the level control potentiometer on the TCU to the preferred output level.

A u to m a ti c L e v e l C o n t r o l , Mo d e l A D U

The system must contain a non-scrambled analog channel at the ADU pilot frequency.

1Perform steps 1 through 3 under Manual Gain Control.

2Position the drive unit selector vertically.

3Turn the ADU ADJ control on the main board to the preferred output level.

S G 2 0 0 0 I n s t a l l a t i o n a n d O p e r a t i o n M a n u a l

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Contents A R L I N E Special Symbols that Might Appear on the Equipment Contents Installation E r a t i o nSpecification s Torque Specifications Abbreviations and AcronymsSG2-LR Tables N t e n t s Section SG 2000 closedFeatures include SG 2000 openUsing this Manual Related DocumentationDocument Conventions If You Need HelpBold type Calling for Repairs Housing SG 2000 housing dimensions front and side viewMounting Holes Port Locations Port locationsHousing gaskets GasketsPower Supply SG2-PS2 power supplyConfiguration Network MonitoringTo suit system requirements the RF chassis cover. notation Signal flow diagram Forward PathE r v i e w SG2-LR receiver functional diagram SG2-LR ReceiverModel Description Analog Return PathAnalog Return Transmitters Analog return transmittersSG2 transmitter block diagram JXPDigital Return Path Digital return transmittersDS-SG2-DRT-2X/A Level Control Options and AccessoriesOptions and accessories Model Description FunctionSG2 SG2-SBSG2-PS2 SG2-FEGain Selection Optical input versus 750 MHz gain10 illustrates the gain option selection chart for 870 MHz Optical input versus 870 MHz gainTilt Selection Relative level dB versus 750 MHz slope 77 channelsSG2 870 MHz Slope Chart Analog Channels, 220 MHz Digital Relative level dB versus 870 MHz slope 94 channelsSG2 870 MHz Slope Chart Analog Channels, 120 MHz Digital Relative level dB versus 870 MHz slope 110 channelsN c h S e t u p G u r e 3 2 0 0 0 R F c h a s s i s W e r i n g t h e N o d e Fuse Functi o n Rati ng Ype W e r S u p p l y S e t t i n g s Illustrates the location of the LO-HIjumper Single Power Supply or Commonly Po wered Redundant Supplies I c k C h e c k s F u n c t i o n a l T e s t i n g N u a l G a i n C o n t r o l Analog Retu rn Path R w a r d P a t h P a d d i n g B l e 3 2 0 0 0 p a d c h a r t s t a n d a r d g a i n B l e 3 2 0 0 0 p a d c h a r t h i g h g a i n G u r e 3 N k P e r f o r m a n c e G u r e 3 1 N c h S e t u p Install i n g t h e D S S G 2 D R R B B o a r d O p t i o n G u r e 3 1 S G 2 D R R B b o a r d Install e d G u r e 3 1 C a t i o n o f J X P s o n E p a c k Digital Transmitter Install i n g t h e S t a t u s M o n i t o r O p t i o n 2 0 0 0 a c t i v a t i o n W o r k s h e e t DC powering Service cable connection and compression fitting Splicing FiberInstallation Strand Wire Mounting Mounting bracket-front viewMounting bracket-rear and side views Coaxial Cables Fiber CablesCenter conductor length Housing lid and fiber spool tray Fiber spool tray Installation Forward Path RF Configuration Single Receiver ModeRedundant receiver Redundant Receiver ModeBroadband/Narrowcast Mode Broadband/narrowcastAB Override Functionality OverrideStatus Monitor/Manual Control Operation Status monitor/MCB operationAnalog Return Path RF Configuration Redundant returnSplit return RF chassis and location of the SG2-RPM/C or SG2-RPM/S board Digital Return Path RF Configuration DS-SG2-DRT/A redundant returnDS-SG2-DRT-2X/A split return DS-SG2-DRT-2X/A redundant returnInstalling SG 2000 Optical Modules SG 2000 Optical ModulesRemoving SG 2000 Optical Modules Cleaning the Optical Connector SG2 LR Optical ReceiverFeature Description Test-point voltage versus optical power 0.3Wavelength Selection Jumper Wavelength selection jumperFeatureDescription SG2-IFPT featuresSG2 Ifpt Optical Transmitter Transmitter enable SG2-FPT featuresSG2 FPT Optical Transmitter SG2-DFBT features SG2 Dfbt Optical TransmitterSingle red LED that lights if the hybrid current is outside SG2-DFBT/3 features SG2 DFBT/3 Optical TransmitterSG2-EIFPT features SG2 Eifpt Optical TransmitterDS SG2 DRT/A Digital Return Transmitter DS-SG2-DRT/AFeature DS-SG2-DRT/A featuresDS SG2 DRT 2X/A Digital Return Transmitter DS-SG2-DRT-2X/ADS-SG2-DRT-2X/A features DS-SG2-DRT-2X/A cable connector DS-SG2-DRT-2X/A installed in SGSG2-PS Power Supply SG2-PS power supplyDS-SG2-DRT-2X/A second RF input cable connection Status Monitoring Parameter DescriptionManual Control Board Description FunctionPotentiometers ICS1 Alarm test pointDB test point Through ICS4Ingress Control State DescriptionOff Table A-2 Station RF characteristics Parameter SpecificationTable A-1 SG 2000 optical characteristics Appendix aParameterSpeci fic ation Table A-5 SG2-IFPT RF specifications Table A-6 SG2-FPT RF specificationsParameter Table A-7 SG2-DFBT RF specifications Table A-8 SG2-DFBT/3 RF specificationsTable A-9 SG2-EIFPT RF specifications Table A-10 SG2-DRT/A RF specificationsMinimum Optical Model Output Power DBm Table A-11 SG2-DRT-2X/A RF specificationsOption Watts ac Amps Power @90V @60V @52V @44V Table A-15 SG2-87 performance, with 94 channels Channels Link Launch SystemTable A-14 SG2-75 performance, with 77 channels Table A-16 SG2-87 performance, with 110 channelsTorque Fastener Screw Size Wrench Size In-lbs Ft-lbs DBmV DBcDBm MHzNational Television Standards Committee Return for service authorizationSnap connector Optical modulation indexMgbi