Comtech EF Data PCB-4000A User manual

PCB-4000A
1+1 Phase Combiner
Installation and Operation Manual
Part Number MN-PCB-4000A
Revision 2
IMPORTANT NOTE: The information contained in this document supersedes all previously published
information regarding this product. Product specifications are subject to change without prior notice.

PCB-4000A 1+1 Phase Combiner
Revision 2
MN-PCB-4000A
Copyright © 2018 Comtech EF Data. All rights reserved. Printed in the USA.
Comtech EF Data, 2114 West 7th Street, Tempe, Arizona 85281 USA, 480.333.2200, FAX: [phone]
Revision History
Rev Date Description
- 5-2017 Initial Release.
1 2-2018 Added remote commands STB, STA, STV, TPE, TPS, and RFD to Chapter 5.
Updated Table 6.1,Management Information Base Files, in Chapter 6.
UpdatedAppendixAto add Mounting Bracket Kit, part number KT-0021261 and update cable assembly
in TableA-2 andA-5.
Updated Preface Product Support and Comtech EF Data Headquarters information.
2 2-2018 Added default line for IPA, IPG, and SPAcommands.

PCB-4000A 1+1 Phase Combiner
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Table of Contents TOC-1 MN-PCB-4000A
TABLE OF CONTENTS
PREFACE ...................................................................................................................................................... I
About this Manual........................................................................................................................................i
Conventions and References......................................................................................................................i
Patents and Trademarks............................................................................................................................ i
Warnings, Cautions, and Notes .................................................................................................................ii
Recommended Standard Designations .....................................................................................................ii
Metric Conversion ......................................................................................................................................ii
Safety and Compliance..............................................................................................................................iii
Electrical Safety Notice.............................................................................................................................iii
Product Support ........................................................................................................................................iv
Comtech EF Data Headquarters...............................................................................................................iv
Warranty Policy......................................................................................................................................... v
Limitations of Warranty.............................................................................................................................. v
Exclusive Remedies..................................................................................................................................vi
CHAPTER 1. INTRODUCTION.........................................................................................................1–1
1.1 Overview ......................................................................................................................................1–1
1.2 Functional Description ...............................................................................................................1–2
1.3 Theory of Operation....................................................................................................................1–4
1.3.1 Phase and Gain Equalization ...................................................................................................1–4
1.3.2 System Gain .............................................................................................................................1–5
1.3.3 System Attenuation...................................................................................................................1–5
1.3.4 Soft Fail Protection....................................................................................................................1–5
1.4 Dimensional Envelope................................................................................................................1–6
CHAPTER 2. EXTERNAL CONNECTORS ......................................................................................2–1
2.1 Overview ......................................................................................................................................2–1
2.2 Monitor and Control (M&C) Interface Connectors...................................................................2–2
2.2.1 SYSTEM COM | J1 Connector .................................................................................................2–2
2.2.2 SSPA COM 1 | J2 and SSPA COM 2 | J3 Connectors..............................................................2–3
2.3 SSPA SW OUT | J5 Connector ...................................................................................................2–4
2.3.1 RF INPUT SWITCH | J6 Connector..........................................................................................2–5
2.4 RF Interface Connectors ............................................................................................................2–6
2.4.1 RF IN 1 | J7 and RF IN 2 | J8 Connectors................................................................................2–6
2.4.2 SSPA OUT 1 | J9 Connector.....................................................................................................2–6
2.4.3 SSPA OUT 2 | J10 Connector...................................................................................................2–6
2.5 Power and Ground Interfaces....................................................................................................2–7
2.5.1 AC Power..................................................................................................................................2–7
2.5.2 Ground Connector ....................................................................................................................2–7
CHAPTER 3. OPERATION AND ADJUSTMENT PROCEDURES ..................................................3–1
3.1 Overview ......................................................................................................................................3–1
3.2 System Assembly, Cabling Connections, and Installation.....................................................3–2
3.2.1 1+1 Phase Combiner System Assembly ..................................................................................3–2
3.2.2 PCCB Cabling Connections......................................................................................................3–3

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3.2.3 System Component Installation and Interconnection...............................................................3–4
3.2.4 LED Status Operation...............................................................................................................3–6
3.3 Initial System Setup and Verification........................................................................................3–8
3.4 Gain or Amplitude Balance Verification and Alignment..........................................................3–9
3.5 Amplitude Alignment (as necessary)......................................................................................3–10
3.6 Phase Alignment .......................................................................................................................3–11
3.7 System Online and Transmitting.............................................................................................3–12
CHAPTER 4. UPDATING FIRMWARE .............................................................................................4–1
4.1 Update Firmware via the Internet ..............................................................................................4–1
4.2 Ethernet FTP Upload Procedure................................................................................................4–2
4.2.1 Setup for the Firmware Download ............................................................................................4–2
4.3 Download and Extract the Firmware Update............................................................................4–6
4.4 Firmware Upgrade.......................................................................................................................4–8
CHAPTER 5. SERIAL REMOTE CONTROL....................................................................................5–1
5.1 Overview ......................................................................................................................................5–1
5.1.1 EIA-232.....................................................................................................................................5–1
5.2 Remote Commands and Queries Ovierview ............................................................................5–2
5.2.1 Basic Protocol...........................................................................................................................5–2
5.2.2 Packet Structure........................................................................................................................5–3
5.2.2.1 Start of Packet...............................................................................................................5–3
5.2.2.2 Target (Base) Address...................................................................................................5–4
5.2.2.3 Virtual Address ..............................................................................................................5–4
5.2.2.4 Address Delimiter..........................................................................................................5–5
5.2.2.5 Instruction Code............................................................................................................5–5
5.2.3 Instruction Code Qualifier .........................................................................................................5–5
5.2.4 Optional Message Arguments...................................................................................................5–6
5.2.5 End of Packet............................................................................................................................5–6
5.3 Remote Commands / Queries....................................................................................................5–7
CHAPTER 6. ETHERNET-BASED REMOTE PRODUCT MANAGEMENT.....................................6–1
6.1 Overview ......................................................................................................................................6–1
6.2 Ethernet Management Interface Protocols...............................................................................6–1
6.3 SNMP Interface............................................................................................................................6–1
6.3.1 Management Information Base (MIB) Files..............................................................................6–2
6.3.2 SNMP Community Strings ........................................................................................................6–2
APPENDIX A. ASSEMBLY KITS......................................................................................................A–1
A.1 Overview ..................................................................................................................................... A–1
A.1.1 Summary of Available Assemblies............................................................................................A–3
A.2 C-Band Unit Assemblies............................................................................................................ A–5
A.2.1 C-Band 1+1 Phase Combined HPOD Top Assembly Kit (KT-0000055)...................................A–5
A.2.2 Phase Combiner Box and Bracket Kit (KT-0021171) ...............................................................A–7
A.2.3 C-Band 1:1 Phase Combined Waveguide and Switches, HPOD (KT-0000054)......................A–9
A.2.4 Vertical Mounting Frame Kit (KT-0021179).............................................................................A–11
A.3 Common Kit Subassemblies................................................................................................... A–13

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A.3.1 HPOD 1:1 Redundancy Pole Mount Kit (PL/12319-1)............................................................A–13
A.3.2 1:2 Redundant HPOD Mounting Kit (KT-0000017).................................................................A–15
A.3.3 Uni-Strut Mount HPOD Mounting Bracket Kit (KT/12300-1)...................................................A–17
A.3.4 Vertical Frame Uni-Strut Mount HPOD Mounting Bracket Kit (KT-0021261) .........................A–19

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Table of Contents TOC-4 MN-PCB-4000A
LIST OF FIGURES
Figure 1-1. PCB-4000A 1+1 Phase Combined System............................................................................1–1
Figure 1-2. Combined System Block Diagrams........................................................................................1–2
Figure 1-3. Combining Loss vs. Phase Imbalance Summary of Specifications........................................1–4
Figure 1-4. PCB-4000A Dimensional Envelope........................................................................................1–6
Figure 3-1. PCB-4000A 1+1 Phase Combiner System Assembly Example.............................................3–2
Figure 3-2. PCB-4000A External Connectors - Front ...............................................................................3–3
Figure 3-3. PCB-4000A External Connectors – Right Side ......................................................................3–3
Figure 3-4. PCB-4000A – Left Side...........................................................................................................3–4
Figure 3-5. LED Indicators........................................................................................................................3–6
Figure 4-1. Typical Unit to PC Connection................................................................................................4–2
Figure 4-2. Temporary Folder Setup using Windows Desktop .................................................................4–3
Figure 4-3. Temporary Folder Setup using Windows Explorer .................................................................4–4
Figure 4-4. Temporary Folder Setup using ‘Run’ and ‘Browse’.................................................................4–4
Figure 4-5. Temporary Folder Setup using Windows Command Line......................................................4–5
Figure 4-6. Download Firmware Archive File............................................................................................4–7
Figure A-1. PCB-4000A 1+1 Phase Combined System............................................................................A–2
Figure A-2. C-Band 1+1 Phase Combined HPOD Top Assembly Kit (KT-0000055) ................................A–5
Figure A-3. Phase Combiner Box and Bracket Kit (KT-0021171).............................................................A–7
Figure A-4. C-Band 1:1 Phase Combined Waveguide and Switches, HPOD (KT-0000054) ...................A–9
Figure A-5. Vertical Mounting Frame Kit (KT-0021179) ..........................................................................A–11
Figure A-6. HPOD 1:1 Redundancy Pole Mount Kit (PL/12319-1).........................................................A–13
Figure A-7. 1:2 Redundant HPOD Mounting Kit (KT-0000017)..............................................................A–15
Figure A-8. Uni-Strut Mount HPOD Mounting Bracket Kit (KT/12300-1) ................................................A–17
Figure A-9. Vertical Frame Uni-Strut Mount HPOD Mounting Bracket Kit (KT-0021261).......................A–19

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Table of Contents TOC-5 MN-PCB-4000A
LIST OF TABLES
Table 2-1. External Connectors.................................................................................................................2–1
Table 2-2. Connector J1 Pinouts...............................................................................................................2–2
Table 2-3. Connectors J2 and J3 Pinouts.................................................................................................2–3
Table 2-4. Connector J5 Pinouts...............................................................................................................2–4
Table 2-5. Connector J6 Pinouts...............................................................................................................2–5
Table 3-1. LED Descriptions......................................................................................................................3–7
Table 6-1. Management Information Base Files .......................................................................................6–2
Table A-1. Appendix Figure Quick Reference...........................................................................................A–3
Table A-2. C-Band 1+1 Phase Combined HPOD Top Assembly Kit - BOM (KT-0000055) ......................A–6
Table A-3. Phase Combiner Box and Bracket Kit – BOM (KT-0021171) ..................................................A–8
Table A-4. C-Band 1:1 Phase Combined Waveguide and Switches, HPOD - BOM (KT-0000054) .......A–10
Table A-5. Vertical Mounting Frame Kit – BOM (KT-0021179)................................................................A–12
Table A-6. HPOD 1:1 Redundancy Pole Mount Kit - BOM (PL/12319-1) ...............................................A–14
Table A-7. Hardware Kit (KT-0020905) ...................................................................................................A–14
Table A-8. 1:2 Redundant HPOD Mounting Kit - BOM (KT-0000017) ....................................................A–16
Table A-9. Uni-Strut Mount HPOD Mounting Bracket Kit - BOM (KT/12300-1) ......................................A–18
Table A-10. Vertical Frame Uni-Strut Mount HPOD Mounting Bracket Kit (KT-0021261).......................A–20

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Table of Contents TOC-6 MN-PCB-4000A
Acronym List
Acronym Description
AOF Amplitude Offset
EIA Electronic IndustriesAssociation
GND Ground
HPOD High Powered OutdoorAmplifier
LED Light Emitting Diode
M&C Monitor and Control
NMS Network Management System
OID Object Identifiers
PCB Printed Circuit Board
PCCB Phase Combiner Control Box
RMA Return MarerialAuthorization
RS Recommended Standard
SNMP Simple Network Management System
SSPA Solid State PowerAmplifier
VSWR Voltage Standing Wave Ratio
WG Waveguide

PCB-4000A 1+1 Phase Combiner
Revision 2
Preface i MN-PCB-4000A
PREFACE
About this Manual
This manual provides installation and operation information for the Comtech EF Data PCB-4000A
1+1 Phase Combiner. This is an informational document intended for the persons responsible for
the operation and maintenance of the PCB-4000A.
Comtech EF Data has reviewed this manual thoroughly in order to provide an easy-to-use guide
to your equipment. All statements, technical information, and recommendations in this manual
and in any guides or related documents are believed reliable, but the accuracy and completeness
thereof are not guaranteed or warranted, and they are not intended to be, nor should they be
understood to be, representations or warranties concerning the products described. Further,
Comtech EF Data reserves the right to make changes in the specifications of the products
described in this manual at any time without notice and without obligation to notify any person of
such changes.
This is an informational document intended for the persons responsible for the operation and
maintenance of the modem.
Conventions and References
Patents and Trademarks
See all of Comtech EF Data's Patents and Patents Pending at http://patents.comtechefdata.com.
Comtech EF Data acknowledges that all trademarks are the property of the trademark owners.

PCB-4000A 1+1 Phase Combiner
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Preface ii MN-PCB-4000A
Warnings, Cautions, and Notes
A WARNING indicates a potentially hazardous situation that, if not avoided,
could result in death or serious injury.
A CAUTION indicates a hazardous situation that, if not avoided, may result in
minor or moderate injury. CAUTION may also be used to indicate other unsafe
practices or risks of property damage.
A NOTE: gives you important information about a task or the equipment.
A REFERENCE directs you to important operational information or details
furnished elsewhere, either in the manual or in adjunct Comtech EF Data
publications.
Examples of Multi-Hazard Notices
Recommended Standard Designations
Electronic Industries Association (EIA) designations supersede Recommended Standard (RS)
designations. Reference to the old RS designations (e.g., RS-232) may appear where it might
concern actual text displayed on the unit’s rear panel, Serial Interface, or Web Server Interface
pages. All other references in the manual use the EIA designations.
Metric Conversion
Metric conversion information is provided on the inside back cover of this manual. Comtech EF
Data provides this information to assist the user in cross-referencing non-Metric to Metric
conversions.

PCB-4000A 1+1 Phase Combiner
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Preface iii MN-PCB-4000A
Safety and Compliance
Electrical Safety Notice
Double pole / neutral fusing is used on the prime power supply input.
This equipment is designed to minimize exposure of personnel to hazards. For further
information, contact the Comtech EF Data Customer Support Department. The persons
responsible for the operation and maintenance of the PCB-4000A must:
•Know how to work around, with, and on high voltage equipment.
•Exercise every precaution to ensure personnel safety.
•Exercise extreme care when working near high voltages.
•Be familiar with the warnings presented in this manual.

PCB-4000A 1+1 Phase Combiner
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Preface iv MN-PCB-4000A
Product Support
For all product support, please call:
+1.240.243.1880
+1.866.472.3963 (toll free USA)
By email:
[e-mail]
Comtech EF Data Headquarters
http://www.comtechefdata.com
Comtech EF Data Corp.
2114 West 7th Street
Tempe, Arizona USA 85281
+1.480.333.2200

PCB-4000A 1+1 Phase Combiner
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Preface v MN-PCB-4000A
Warranty Policy
Comtech EF Data products are warranted against defects in material and workmanship for a
specific period from the date of shipment, and this period varies by product. In most cases, the
warranty period is two years. During the warranty period, Comtech EF Data will, at its option,
repair or replace products that prove to be defective. Repairs are warranted for the remainder of
the original warranty or a 90 day extended warranty, whichever is longer. Contact Comtech EF
Data for the warranty period specific to the product purchased.
For equipment under warranty, the owner is responsible for freight to Comtech EF Data and all
related customs, taxes, tariffs, insurance, etc. Comtech EF Data is responsible for the freight
charges only for return of the equipment from the factory to the owner. Comtech EF Data will
return the equipment by the same method (i.e., Air, Express, Surface) as the equipment was sent
to Comtech EF Data.
All equipment returned for warranty repair must have a valid RMA number issued prior to return
and be marked clearly on the return packaging. Comtech EF Data strongly recommends all
equipment be returned in its original packaging.
Comtech EF Data Corporation’s obligations under this warranty are limited to repair or
replacement of failed parts, and the return shipment to the buyer of the repaired or replaced
parts.
Limitations of Warranty
The warranty does not apply to any part of a product that has been installed, altered, repaired, or
misused in any way that, in the opinion of Comtech EF Data Corporation, would affect the
reliability or detracts from the performance of any part of the product, or is damaged as the result
of use in a way or with equipment that had not been previously approved by Comtech EF Data
Corporation.
The warranty does not apply to any product or parts thereof where the serial number or the serial
number of any of its parts has been altered, defaced, or removed.
The warranty does not cover damage or loss incurred in transportation of the product. The
warranty does not cover replacement or repair necessitated by loss or damage from any cause
beyond the control of Comtech EF Data Corporation, such as lightning or other natural and
weather-related events or wartime environments.
The warranty does not cover any labor involved in the removal and or reinstallation of warranted
equipment or parts on site, or any labor required to diagnose the necessity for repair or
replacement.
The warranty excludes any responsibility by Comtech EF Data Corporation for incidental or
consequential damages arising from the use of the equipment or products, or for any inability to
use them either separate from or in combination with any other equipment or products.
A fixed charge established for each product will be imposed for all equipment returned for
warranty repair where Comtech EF Data Corporation cannot identify the cause of the reported
failure.

PCB-4000A 1+1 Phase Combiner
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Preface vi MN-PCB-4000A
Exclusive Remedies
Comtech EF Data Corporation’s warranty, as stated is in lieu of all other warranties, expressed,
implied, or statutory, including those of merchantability and fitness for a particular purpose. The
buyer shall pass on to any purchaser, lessee, or other user of Comtech EF Data Corporation’s
products, the aforementioned warranty, and shall indemnify and hold harmless Comtech EF Data
Corporation from any claims or liability of such purchaser, lessee, or user based upon allegations
that the buyer, its agents, or employees have made additional warranties or representations as to
product preference or use.
The remedies provided herein are the buyer’s sole and exclusive remedies. Comtech EF Data
shall not be liable for any direct, indirect, special, incidental, or consequential damages, whether
based on contract, tort, or any other legal theory.

PCB-4000A 1+1 Phase Combiner
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Introduction 1–1 MN-PCB-4000A
Chapter 1. INTRODUCTION
1.1 Overview
Phase combining is a traditional technique that cost effectively increases the available output
power of an amplifier system. The PCB-4000A 1+1 Phase Combiner (Figure 1-1), together with
two Solid State Power Amplifiers (SSPAs), form a complete 1+1 phase combined system that
doubles the available output power. The PCB-4000A also features a “soft fail” configuration; i.e., if
one SSPA experiences a failure, the total output power will be reduced by only 3 dB, rather than
6 dB.
Figure 1-1. PCB-4000A 1+1 Phase Combined System

PCB-4000A 1+1 Phase Combiner
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Introduction 1–2 MN-PCB-4000A
1.2 Functional Description
The PCB-4000A is available in a C-Band version. Contact Comtech EF Data for X-band and Ku-
band versions. The box may be included in a top-level system assembly or as a subassembly kit.
For application examples, see Appendix A. ASSEMBLY KITS.
Monitor & Control (M&C) System Interconnect
RF System Interconnect
Figure 1-2. Combined System Block Diagrams

PCB-4000A 1+1 Phase Combiner
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Introduction 1–3 MN-PCB-4000A
The block diagrams shown in Figure 1-2 depict the major components of the 1:1 phase combined
system. (These diagrams employ High Powered Outdoor Amplifiers (HPODs) as the designated
SSPAs.)
The Phase Combiner Control Box (PCCB) contains a microprocessor-based Monitor and Control
(M&C) circuit board to control the system. Interconnection is as follows:
•The PCCB communicates with each SSPA via control cables that are attached from the
PCCB “SSPA COM 1 | J2” and “SSPA COM 2 | J3” connectors to each SSPA.
•Through this connection, the PCCB receives its prime power to operate. A +24V signal
from each SSPA is diode OR’ed to provide redundant operating power for the PCCB.
•A “Y” cable connects to the “SSPA SW OUT | J5” connector for control of the waveguide
switches. M&C communication with the PCCB is accomplished via the “SYSTEM COM |
J1” connector.
To avoid ambiguities, all communication to each SSPA is also accomplished via
the PCCB M&C.
The PCCB provides a weatherized housing for the necessary input RF components. System
interconnection is as follows:
•An input RF redundancy switch, controlled via the “RF INPUT SWITCH | J6” connector,
selects which RF path is directed to the output.
•The output RF signal is fed into an in-phase divider, which equally splits the signal in
phase and amplitude to the “SSPA OUT 1 | J9”and “SSPA OUT 2 | J10”
output connectors.
oThe RF path to the “SSPA OUT 1 | J9”output connector contains a manually
adjustable phase shifter. This phase shifter is used to equalize the phase difference
of each SSPA signal path to achieve maximum system output power. It is accessible
via a small cover panel. This critical component is factory set and should only be
adjusted, if needs arise, by carefully following an appropriate alignment procedure.
See Chapter 3. OPERATION and ADJUSTMENT PROCEDURES for
operational and alignment information.
oThe RF path to the “SSPA OUT 2 | J10”output connector contains a length of
coaxial cable that is factory manufactured to provide equal phase length paths from
the RF input to each PCCB output when the adjustable phase shifter is set to its
midpoint. This provides a maximum adjustable phase range.
There are also several isolators inside the PCCB that maintain good system Voltage Standing
Wave Ratio (VSWR). Do not alter any RF cable inside (or outside) of the box that is part of the
RF signal path.
•The RF signals from the PCCB are fed to the RF input of the respective SSPA via a set
of phase-matched cables. Again, the phase length (and matching) of these cables is
essential to system operation and no substitutes should be used. The routing should not
be such to cause extreme bends.
•The output waveguide combining system consists of balanced waveguide lengths, two
waveguide transfer switches, a “Magic-Tee” combiner with termination, and couplers for
test and alignment.

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Introduction 1–4 MN-PCB-4000A
1.3 Theory of Operation
As mentioned previously, phase combining is a common technique to increase the available
output power of an amplifier system. Referring back to Figure 1-2, when two signals of equal
phase and amplitude are fed into the “Magic-Tee” combiner, the individual power of each SSPA is
summed at the output port and cancelled in the termination port.
In real systems, the phase and amplitude of the two signals are never exactly equal, so there is a
small amount of power that is absorbed by the load termination. This terminated port is
sometimes referred to as the “wasted” power port. In practice, however, it is possible to keep
phase and amplitude imbalances at low enough levels such that overall combining losses are
only in the 0.2 to 0.5 dB range.
Figure 1-3 shows the effects of phase imbalance on the power combining efficiency.
Figure 1-3. Combining Loss vs. Phase Imbalance Summary of Specifications
1.3.1 Phase and Gain Equalization
Phase and gain equalization are performed at the factory, and no user
intervention is required unless an amplifier or other critical system component,
such as the phase combiner box, needs to be replaced.
The following paragraphs are provided for informational purposes only.
See Chapter 3. OPERATION and ADJUSTMENT PROCEDURES for
operational and alignment information.
Naturally, two separate amplifiers are likely to have different phase and gain characteristics. The
PCB-4000A 1+1 system is designed such that the phase difference between the two amplifier
paths is compensated by adjusting the phase shifter in the PCCB. This is done at the factory for
the full amplifier bandwidth, and should not normally require further adjustment in the field unless
an amplifier has been replaced.

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Introduction 1–5 MN-PCB-4000A
1.3.2 System Gain
The gains of the amplifiers are calibrated at the factory to provide optimum system performance.
The amplifier gain difference is automatically compensated for by the PCCB M&C System. Upon
power up, the M&C reads the gain of each individual amplifier as calibrated at the factory, and
automatically attenuates the amplifier with the most gain so as to be equal with the lower gain
unit.
For example, if SSPA #1 had a factory-calibrated gain setting of 76 dB, and SSPA #2 had a
factory-calibrated gain setting of 73 dB, the M&C system would automatically set the attenuation
setting of SSPA#1 to 3 dB to equalize the system gain. Although not generally needed or
recommended, a user input gain offset setting is also provided for system fine-tuning.
See Chapter 3. OPERATION and ADJUSTMENT PROCEDURES for
operational and alignment information.
Due to the power divider and cable losses, the overall gain of the system will be less than the
individual gain of each amplifier. Please refer to the system test data sheet for actual system
gain.
1.3.3 System Attenuation
The PCB-4000A makes it easy to adjust the overall system gain. Upon input of the requested
attenuation setting, the PCB-4000A automatically adjusts the gain of each SSPA accordingly,
resulting in the desired attenuation value while maintaining optimum power combining conditions.
The SSPAs included in the system are calibrated over a range 10 dB beyond specification (30 dB
vs. 20 dB). As explained above, a portion of the 30 dB range is required for gain equalization.
Therefore, the maximum allowable attenuation in a 1+1 system is software limited to 24 dB, but
still exceeds system specifications.
1.3.4 Soft Fail Protection
In the event of a failure of one of the SSPAs, the PCB-4000A controls the waveguide switches
such that the good unit’s power is routed around the “Magic-Tee” combiner directly to the output
port. This results in only a 3 dB power loss, or “soft failure”. Without the waveguide switches, a
failure in one unit would result in a 6 dB power loss.

PCB-4000A 1+1 Phase Combiner
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Introduction 1–6 MN-PCB-4000A
1.4 Dimensional Envelope
All dimensions are in English units; metric units are shown in parentheses. This
figure is typical for the C-Band versions of the PCB-4000A.
Figure 1-4. PCB-4000A Dimensional Envelope