Comtech EF Data C, X, Ku Installation And Operation Manual
D
p
HPO
C, X, Ku High-Powered Outdoor Amplifier
Installation and O
eration Manual
Part Number MN/HPOD.IOM
Revision 2
Comtech EF Data is an ISO 9001
Registered Company
HPOD
C, X, Ku High-Powered Outdoor Amplifier
Installation and Operation Manual
Part Number MN/HPOD.IOM
REVISION 2
5/15/2007
HPOD Revision 2
Preface MN/HPOD.IOM
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CUSTOMER SUPPORT
Contact the Comtech EF Data Customer Support Department for:
• Product support or training
• Reporting comments or suggestions concerning manuals
• Information on upgrading or returning a product
A Customer Support representative may be reached at:
Comtech EF Data
Attention: Customer Support Department
2114 West 7th Street
Tempe, Arizona 85281 USA
480.333.2200 (Main Comtech EF Data Number)
480.333.4357 (Customer Support Desk)
480.333.2161 FAX
To return a Comtech EF Data product (in-warranty and out-of-warranty) for repair or replacement:
• Contact the Comtech EF Data Customer Support Department. Be prepared to supply the
Customer Support representative with the model number, serial number, and a description of
the problem.
• Request a Return Material Authorization (RMA) number from the Comtech EF Data
Customer Support representative.
• Pack the product in its original shipping carton/packaging to ensure that the product is not
damaged during shipping.
• Ship the product back to Comtech EF Data. (Shipping charges should be prepaid.)
For Online Customer Support:
An RMA number request can be requested electronically by contacting the Customer Support
Department through the online support page at
Click on the “RMA Request Form” hyperlink, then fill out the form completely before sending.
Click on “Return Material Authorization” for detailed instructions on our return procedures.
www.comtechefdata.com/support.asp.
Send e-mail to the Customer Support Department at
For information regarding this product’s warranty policy, refer to page
service@comtechefdata.com.
xi.
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Table of Contents
CHAPTER 1. INTRODUCTION................................................................................ 1–1
1.1 Introduction.......................................................................................................................................................1–1
1.2 Field Replaceable Power Supply......................................................................................................................1–2
1.3 The Solid-State Advantage................................................................................................................................1–2
1.4 Functional Description......................................................................................................................................1–2
1.5 Built-In Redundancy Controller......................................................................................................................1–2
1.6 Option Free........................................................................................................................................................1–3
1.7 Phase Combining...............................................................................................................................................1–3
1.8 Optional “Smart BUC” Functionality .............................................................................................................1–3
1.9 Featured Packed................................................................................................................................................1–3
1.10 Specifications....................................................................................................................................................1–4
CHAPTER 2. SYSTEM OPERATION...................................................................... 2–1
2.1 Interface Connectors.........................................................................................................................................2–1
2.2 Turning On the SSPA........................................................................................................................................2–6
CHAPTER 3. THEORY OF OPERATION................................................................3–1
3.1 SSPA Block Diagram.........................................................................................................................................3–1
3.2 SSPA Module.....................................................................................................................................................3–3
3.3 Cooling System...................................................................................................................................................3–3
3.4 Monitor and Control (M&C)............................................................................................................................3–3
3.5 Power Supply.....................................................................................................................................................3–4
3.6 Block Up Converter Input Option...................................................................................................................3–4
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CHAPTER 4. CUSTOMER COMMANDS ................................................................4–1
4.1 Introduction.......................................................................................................................................................4–1
4.2 RF Input Level...................................................................................................................................................4–1
4.3 Attenuator Control............................................................................................................................................4–1
4.4 Mute Control......................................................................................................................................................4–1
4.5 Faults ..................................................................................................................................................................4–2
4.6 Power Detector...................................................................................................................................................4–2
4.7 Some Common Commands...............................................................................................................................4–3
4.8 Remote Control Protocol and Structure..........................................................................................................4–3
4.9 RS-485.................................................................................................................................................................4–3
4.10 RS-485 (full duplex) summary:......................................................................................................................4–4
4.11 RS-232...............................................................................................................................................................4–4
4.12 Basic Protocol...................................................................................................................................................4–4
4.13 Packet Structure..............................................................................................................................................4–5
4.7 Remote Commands............................................................................................................................................4–8
CHAPTER 5. MAINTENANCE ................................................................................. 5–1
5.1 Power Supply Removal.....................................................................................................................................5–1
5.2 Fan Removal......................................................................................................................................................5–3
5.3 Scheduled Maintenance.....................................................................................................................................5–5
5.4 Dimensional Envelope.......................................................................................................................................5–5
APPENDIX A. ASSEMBLY KITS.............................................................................A–1
A.1 Redundant Switch Kits....................................................................................................................................A–1
APPENDIX B REDUNDANCY.................................................................................B–1
B.1 Redundancy Operation....................................................................................................................................B–1
B.2 1:1 Mode ...........................................................................................................................................................B–1
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B.3 1:2 Mode ...........................................................................................................................................................B–2
APPENDIX C. 1:1 HPOD SERIES REDUNDANCY TEST.......................................C–1
C.1 Connection........................................................................................................................................................C–1
C.2 Operation..........................................................................................................................................................C–2
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ABOUT THIS MANUAL
This manual provides installation and operation information for the Comtech EF Data
HPOD. This is a technical document intended for earth station engineers, technicians,
and operators responsible for the operation and maintenance of the HPOD.
CONVENTIONS AND REFERENCES
C
AUTIONS AND WARNINGS
CAUTION indicates a hazardous situation that, if not avoided, may
result in minor or moderate injury. CAUTION may also be used to
CAUTION
indicate other unsafe practices or risks of property damage.
WARNING indicates a potentially hazardous situation that, if not
avoided, could result in death or serious injury.
WARNING
IMPORTANT indicates a statement that is associated with the task
IMPORTANT
being performed.
METRIC CONVERSION
Metric conversion information is located on the inside back cover of this manual. This
information is provided to assist the operator in cross-referencing English to Metric conversions.
TRADEMARKS
Other product names mentioned in this manual may be trademarks or registered trademarks of
their respective companies and are hereby acknowledged.
REPORTING COMMENTS OR SUGGESTIONS CONCERNING THIS
MANUAL
Comments and suggestions regarding the content and design of this manual will be appreciated.
To submit comments, please contact:
Comtech EF Data Technical Publications Department: techpub@comtechefdata.com
SAFETY NOTICE
This equipment has been designed to minimize exposure of personnel to hazards.
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The operators and technicians 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.
CAUTION
A Neutral Fusing - Double pole/ neutral fusing used on the prime
power supply input.
INSTALLATION GUIDELINES REGARDING POWER LINE QUALITY
Comtech EF Data has become familiar with the varying quality of the
AC power grid around the world. The following offers some
IMPORTANT
• Surge suppression: High voltage surges can cause failure of the power supply. These
surges are typically caused by circuit switching on the main AC power grid, erratic
generator operation, and also by lightning strikes. While the HPOD does have built in
surge suppression, if the unit will be installed in a location with questionable power grid
quality, Comtech EF Data recommends installation of additional power
conditioning/surge suppression at the power junction box.
• Grounding: The HPOD provides a grounding terminal. This is provided to allow the
user to ground the HPOD to the antenna’s grounding network. All components installed
at the antenna should be grounded to a common grounding point at the antenna.
• Electrical welding: If welding needs to take place at the antenna, disconnect all cables
from the HPOD except for the ground wire. Cap all RF connections with terminations.
This will prevent damage to the input/output circuitry of the HPOD.
• Lightning: Lightning strikes on or around the antenna will generate extremely high
voltages on all cables connected to the HPOD. Depending on the severity of the strike,
the HPOD’s internal surge protection combined with the recommended external
suppression may protect the HPOD’s power supply. However, if the installation will be
in an area with a high probability of lightning strikes, Comtech EF Data recommends the
installation of surge suppression on the RF and IF cables. One source of these
suppressors is PolyPhaser (www.polyphaser.com)
For further information, contact Comtech EF Data, Customer Support Department.
installation guidelines that should help ensure a reliable installation.
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WARRANTY POLICY
Comtech EF Data products are warranted against defects in material and workmanship for a
period of two years from the date of shipment. During the warranty period, Comtech EF Data
will, at its option, repair or replace products that prove to be defective.
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.
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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.
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.
xii
1.1 INTRODUCTION
The High-Power Outdoor (HPOD) Solid-State Power Amplifier (SSPA) shown in Figure
1-1 delivers its rated power, guaranteed, at the 1 dB compression point, to the transmit
waveguide flange. It provides a cost effective, more reliable replacement for TWT
amplifiers in satellite communications.
Chapter 1. INTRODUCTION
Figure 1-1. HPOD SSPA
1–1
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Introduction
1.2 FIELD REPLACEABLE POWER SUPPLY
Recognizing that the MTBF limiting factor for almost all electronic equipment is the
power supply, the HPOD provides for easy field replacement. Simply disconnect the AC
mains, release the captive fasteners, and remove the supply from the SSPA module.
1.3 THE SOLID-STATE ADVANTAGE
Each HPOD SSPA is constructed with highly reliable GaAs FETs. With third order
intermodulation products from 4 to 6 dB better than TWT ratings, the CEFD unit replaces
TWTs with saturated power levels of up to twice the HPOD’s rated output. The HPOD
SSPAs also provide an MTBF that is 4 to 5 times greater than the typical TWT MTBF.
1.4 FUNCTIONAL DESCRIPTION
Each HPOD consists of a CEFD SSPA module with the Monitor/Control Processor
(MCP), a field replaceable power supply, and a field replaceable fan assembly. The
amplifier features a Comtech EF Data low loss combining technique and MCP based
temperature versus gain compensation.
1.5 BUILT-IN REDUNDANCY CONTROLLER
Each Comtech EF Data HPOD has the ability to function as a 1+1 (one backup for one
primary) and 1+2 (one backup for two primary) redundant controller in the backup mode.
The optional redundancy configuration is implemented by attaching a ganged
waveguide/coax transfer switch(es) to the input and output connectors of the amplifiers
with a combination coaxial cable and waveguide kit. When the backup SSPA is
commanded into the controller mode, it monitors the online SSPA(s) for faults. A faulted
online unit may be disconnected and replaced without affecting the online power
amplifier.
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Introduction
1.6 OPTION FREE
Comtech EF Data’s HPOD series of SSPAs come equipped with useful features that
other manufacturers offer as options. Included in the base price are temperature
compensation, sample ports, power monitor, field replaceable power factor corrected
supply, and full remote monitor and control capabilities.
Higher power is available through the use of CEFD 1:1 and 1:2 phase combining kits.
1.7 PHASE COMBINING
Comtech EF Data’s phase-combined systems allow the outputs of two amplifiers to be
summed together. A “normal” 1:1 system using 300W amplifiers provides 300W of
output power (the offline unit’s capabilities are unusable). The same amplifiers in a 1:1
phase-combined system will provide 600W of output power in normal operation, and a
“soft failure” state of 300W. If no degradation on failure can be accommodated, a third
amplifier can be added to form a 1:2 phase-combined system.
1.8 OPTIONAL “SMART BUC” FUNCTIONALITY
Comtech EF Data’s unique approach to L-Band/RF frequency conversions eliminates DC
and 10 MHz from the input coax. This simplifies redundant and multi-carrier operation.
It offers full 13.75 to 14.5 GHz Ku coverage and supports industry standard FSK
modem/BUC communications. The optional BUC can lock to an external or internal
reference oscillator.
1.9 FEATURED PACKED
Comtech EF Data’s HPOD SSPAs come equipped with useful features such as:
temperature compensation, sample ports, power monitor, field-replaceable power factor
corrected supply, and full remote monitor and control capabilities.
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Introduction
1.10 SPECIFICATIONS
SPECIFICATIONS
Output
Frequency C-Band
Available Power: Outputs
P1dB (Psat), Watts
(See Note)
Phase Combined Systems
P1dB (Psat ), Watts
(See Note)
Mute -60 dBc
Impedance 50Ω
VSWR 1.25:1 Maximum
Connector C-Band
5.850 to
6.425 GHz
C-Band
200(250)
250(300)
350(400)
400(500)
500(600)
700(800)
CPR-137G
Waveguide
Gain
Linear C- and X-Band
Adjust 20 dB in 0,25 dB steps
Full Band
with BUC option
Per 40 MHz
with BUC option
-40 to +55°C
with BUC option
70 dB min, 75 dB
typical
± 1.0 dB
± 1.5 dB
± 0.25 dB
± 0.30 dB
± 1.0 dB
± 1.5 dB
Third Order Intermodulation
Products -30 dBc typical, -25 dBc max @
3 dB total back-off from rated P1dB
(two tones, ∆f = 1 MHz)
AM to PM Conversion
2° typical, 3.5° maximum at rated output
Group Delay (per 40 MHz)
Linear ± 0.03 ns/MHz
Parabolic ± 0.003 ns/MHz
Ripple ± 1.0 ns peak to peak
X-Band
7.9 to
8.4 GHz
X-Band
175(200)
200(250)
282(350)
350(400)
400(500)
550(700)
X-Band
CPR-112G
Waveguide
2
Ku-Band
14.0 to
14.5 GHz
13.75 to
14.5 GHz
(Optional)
KU-Band
80(100)
100(125)
160(200)
200(250)
Ku-Band
WR75G
Waveguide
Ku-Band
65 dB min, 70 dB
typical
Spurious
Second Harmonic C- and X-Band
-60 dB dBc max @ 1 dB below rated
Optional BUC
LO Leakage -20 dBm
Note: P1dB over all temp/frequencies, Psat typ.
output
Input
Impedance 50Ω
Noise Figure
with BUC option
VSWR
with BUC option
Connector Type N
8 dB typical, 10 dB maximum @ maximum
gain (15 dB for HPOD Ku-Band)
25 dB
1.25:1 Maximum
1.50:1 Maximum
Sample Ports
Output Sample Type N, 50Ω, -40 dBc nominal
Input Sample Type N, 50Ω, -20 dBc nominal
Remote Control
Com Port RS-485 or RS-232
Alarms
Summary Fault Form C
Environmental
Operating Temp. -40° to +55°C (-40° to 131°F)
Non-Operating Temp. -50° to +75°C (-58° to 167°F)
Operating Humidity 0 to 100% condensing
Altitude 10,000 ft above sea level (derated 2°C/ 1000
ft AMSL)
Power Requirements
C- and X-Band
180 to 264 VAC,
47 to 63 Hz
Physical
Dimensions 26.77L x 17.88W x 11.49H inches
Weight 75 lbs (34 kg) nominal
(67.99L x 45.41W x 29.18H cm)
Available Options
Optional BUC
Ku-Band
180 to 264 VAC,
47 to 63 Hz
1–4
Chapter 2. SYSTEM OPERATION
This section contains instructions for operating the HPOD outdoor SSPA. The primary
customer interface to the HPOD is via the Remote Communications port. This section
defines in detail the customer interface.
2.1 INTERFACE CONNECTORS
2.1.1 CONNECTOR J1: RF IN
The RF Input connector is a type N female. Typical input levels (-30 dBm) depend on
desired output power and unit attenuation. To prevent damage to the SSPA, RF input
levels should not exceed +15 dBm.
Figure 2-1. Interface Connectors
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System Operation
2.1.2 CONNECTOR J2: RF OUT
The RF Output connector is a waveguide interface. The flange is described below
according to the frequency range of the unit.
Table 2-1. Waveguide Output Flange
Unit Frequency Band Waveguide Flange
C CPR112G
X CPR137G
Ku WR75G
For safety reasons, never look directly into the waveguide output..
WARNING
2.1.3 CONNECTOR J10: OPTIONAL -48V DC POWER SUPPLY
Before applying DC power to the unit, make sure the waveguide output of the
amplifier is properly loaded or terminated. Failure to do so could lead to
WARNING
The power connection for the optional –48V DC supply is located on the power supply
itself. A cap (CEFD PN HW/CAP-5015) is provided with the supply that must be
installed on the AC Power Connector(J3) located on the amplifier.
The prime power input requirements are
• -36 to -72 VDC
• Careful consideration must be given to the choice of input wiring
equipment damage and excessive RF radiation levels.
because of the current draw requirements of the HPOD. Wire that is 8
AWG or larger will be required for most installations.
• The total power required from the prime power supply depends on the
model used. Please refer to the respective data sheets.
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System Operation
The DC prime power input connector, J10, is a 4-pin circular connector. A mating
connector (CA3106E2222SB, CEFD PN CN/CA3106E2222SB) is provided. The pin-out
specifications for J10 and its mate are contained in the table below.
Table 2-2. Connector J10 Pinout
Pin Description
A V+
B No Connect
C No Connect
D VMating connector: CA3106E2222SB, CEFD PN CN/CA3106E2222SB
2.1.4 CONNECTOR J3: AC POWER MAINS
Before applying AC power to the unit, make sure the waveguide output of the
amplifier is properly loaded or terminated. Failure to do so could lead to
WARNING
The prime power input requirements are
equipment damage and excessive RF radiation levels.
• 180-264 VAC
• 47 to 63 Hz
• The power supply is power factor corrected. The total power required
from the prime power supply depends on the model used. Please refer
to the respective data sheets.
The AC prime power input connector, J3, is a 3 pin circular connector, type CA3102E2019PB FMLB A. The ground pin A, is of the first make, last break type. A mating
connector (CA3106E20-19SB) is provided. The pin-out specifications for J3 and it’s
mate are contained in the table below.
Table 2-3. Connector J3 Pinout
Pin Description
A Ground
B L2
C L1
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System Operation
2.1.5 CONNECTOR J4: REDUNDANT LOOP
The Redundant Loop Connector J4 is located near the waveguide output and is only
utilized in configurations where the SSPA controls waveguide switching. In alternate
configurations, such as “chain switching”, another system block or external M&C
controls the waveguide switching. In this case, the connector remains unused and the
protective cap should be left attached. The pin-out specification is shown in
Table 2-4. Connector J4 Pinout
Pin Name
A SW_CMD_A1
B SW_CMD_COM
C SW_CMD_A2
D SW_IND_A1
E SW_IND_A2
F SW_CMD_B1
G SW_CMD_B2
H SW_IND_B1
J SW_IND_B2
K ADDR_1
L ADDR_2
M COM
N RED_1_1
P RED_1_2
R SMFLT_1_IN
S SMFLT_2_IN
T SMFLT_OUT
U RED_TXD
V RED_RXD
Table 2-4.
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System Operation
2.1.6 CONNECTOR J6: COM 1, REMOTE COMMUNICATIONS AND DISCRETE
CONTROL PORT
The COM 1/ Discrete Control connector J6 is the primary input for controlling and
monitoring the SSPA. It is a 19-pin circular connector, type MS3112E14-19S. The pinout specification is contained in Table 2-5.
Mating connector: ITT: KPT06J14-19P or MS3116J14-19P.
Pin Name Description
A RS485_+RX
B RS485_-RX
C RS485_+TX
D RS485_-TX
E RS232_RD
F Analog_P wr_Mon Reserved for future use
G RS232_TD
H Aux_In
J Aux_Out Not for customer use
K SumFLT_COM
L SumFLT_NO Open when faulted, else tied to Pin K.
M SumFLT_NC When faulted, tied to Pin K, else open.
N GND
P ONLINE_Status Not for customer use
R +24V Not for customer use
S Mute Control SSPA will be muted if this pin is grounded
T Minor_FLT_COM Reserved for future use
U Minor_FLT_NO Reserved for future use
V Minor_FLT_NC Reserved for future use
.
Table 2-5. Connector J6 Pinout
Auxiliary fault input, software enabled. When enabled, pin must be grounded
to unmute SSPA
2.1.7 CONNECTOR J8: INPUT SAMPLE
The Input sample port connector is a type N female. It provides a nominal –20 dB
sample of the input signal. A calibration label is provided near the connector that shows
the actual coupling values vs. frequency.
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System Operation
2.1.8 CONNECTOR J9: OUTPUT SAMPLE
The Output sample port connector is a type N female. It provides a nominal -40 dB
sample of the output signal. A calibration label is provided near the connector that shows
the actual coupling values vs. frequency.
2.2 TURNING ON THE SSPA
The SSPA does not contain a ‘Power On/Off’ switch. The SSPA is powered ON by
connecting the J3 AC Power connector to the appropriate prime power source. The Mute
or Transmit status of the SSPA will automatically come up in the last stored state (factory
default = Transmit on, not muted).
Never turn the unit ON without proper waveguide termination on the
J2 “RF OUTPUT” port. Individuals can be exposed to dangerously
WARNING
high electromagnetic levels.
Figure 2-2. Outdoor Unit
2–6
Chapter 3. THEORY OF OPERATION
This section provides an overview of the Theory of Operation of the unit. Included are a
basic block diagram and an explanation of the functions of each of the major systems.
3.1 SSPA BLOCK DIAGRAM
A block diagram of the SSPA is shown on the following page in Figure 3-1. The major
components of the unit are:
• SSPA Module
• Cooling System
• Monitor and Control (M&C)
• Power Supply (Power Factor Corrected and Removable/Field Replaceable)
3–1
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Theory of Operation MN/HPOD.IOM
OUTPUT
SAMPLE
INPUT
SAMPLE
RF INPUT
COM/
DISCRETE
CONTROL
BLOCK DIAGRAM
J9
J8
SSPA MODULE
RF
J1
10V A
10V B
CUST.GAIN
CTRL
-5V -5V10V 10V
TEMP
COMP
OUTPUT
POWER
DETECTOR
POWER CONDI TIONING & CONTR OL
CONTROL
& MONITOR
-5V
Interlock
+5.8V
-5.8V 15V
J6
FAN1
MONITOR & CONTROL
FAN2
J2
OUTPUT
(W/G)
REDUNDANT
J4
LOOP
AC IN
10V A
Line
J3
Filter
10V B
-5V
Interlock
POWER SUPPLY
(FIELD REMOVABLE/
REPLACEABLE)
+5.8V 15V-5.8V24V
Figure 3-1. SSPA Block Diagram
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Theory of Operation MN/HPOD.IOM
3.2 SSPA Module
The amplifier module performs the core function of the unit. An isolator is at the RF
input to ensure good VSWR. The RF signal then passes through an input sample port
and on to an electronically controlled attenuator that adjusts the overall attenuation
according to the user input. After some amplification, a second attenuator is
automatically controlled via a look-up table to maintain the amplifier gain at a constant
level over temperature variations.
The RF signal is then amplified by a multi-stage design that utilizes proprietary
combining techniques to meet the rated power requirements. The output circuitry
contains a coupler to provide a sampled signal for monitoring purposes. A power
detector circuit also is included and the reading can be accessed via remote
communication. A high power circulator and load is located at the output to provide
good VSWR and protection from external mismatch.
3.3 Cooling System
The SSPA unit contains a robust heat sink and thermal design to maintain a low operating
temperature. Two temperature controlled fans, which are monitored by the M&C board,
draw cool outside air in across the power supply and specialized heat sink and exhaust
the warmer air out the bottom of the unit. The amplifier module temperature is
monitored, and if for any reason the amplifier temperature exceeds a safe preset limit, the
amplifier module supply is shut down to protect the unit from thermal failure.
3.4 Monitor and Control (M&C)
The unit includes a microprocessor based system that provides monitoring and control of
the essential parameters of the unit. The user interfaces with the unit through the M&C
system via the remote control/discrete communications port. The unit is capable of either
RS-232 or RS-485 remote communication. A discrete mute control and relay status
output is also available. The M&C system monitors the fan speed, unit temperature, all
power supply voltages, power transistor currents, output power, etc. Should a critical
monitored parameter fail, the unit will mute the RF signal and report a fault. The details
of the fault can be accessed via remote communication.
The M&C is also capable of acting as a controller in certain 1:1 or 1:2 redundant systems.
When configured as the back-up SSPA in such a system, it communicates with the other
SSPA(s) and toggles the waveguide switches as necessary.
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Theory of Operation MN/HPOD.IOM
3.5 POWER SUPPLY
The SSPA features a removable power supply which is also power factor corrected. It
connects to the main chassis via a specialized connector capable of the required high
current. It supplies several voltages necessary for the unit to operate. The 10V output is
capable of 2000W and supplies current to the power transistors in the RF amplifier
module via two paths, or cables (10V A and 10V B). The output status of this power
supply is controlled by circuitry within the RF module. If the RF module does not have
the –5V supply for any reason, it will not allow the 10V power supply to turn on. This
protects the power transistors within the RF module from failure due to improper power
supply sequencing. The +24V output powers the cooling fans and is the source of power
for waveguide switching when the SSPA is used in redundant configurations. The +5
and +15 voltages are used to operate the M&C board and other overhead functions.
3.6 BLOCK UP CONVERTER INPUT OPTION
The HPOD amplifier, when delivered from the factory with an internal Block Up
Converter (BUC) translates an L-Band input carrier to the desired output frequency (C-,
X-, or Ku-). LO frequencies are as follows:
BUC-4000 C, X, Ku, Ka
Band Frequency LO Frequency Inverting
C-Band 5850 to 6650 MHz 4900 MHz No
X-Band 7900 to 8400 MHz 6950 MHz No
Ku-Band-W 13.75 to 14.50 GHz 12.800 GHz No
The same Ku-Band BUC is installed independent of amplifier bandwidth. Therefore, the
“standard,” 14.0 to 14.5 GHz HPOD has an L-Band frequency range of 1200 to 1700
MHz which translates up to 14.0 to 14.5 GHz, while the “Extended,” 13.75 to 14.5 GHz
HPOD translates L-Band frequencies from 950 to 1700 MHz up to 13.75 to 14.5 GHz.
Unlike most BUCs, no DC bias voltage should be provided on the center conductor of the
L-Band coax.
In addition, the BUC version of the HPOD is available with an internal 10 MHz
reference. As, such, no 10 MHz reference is required on the center conductor of the LBand coax. If a reference is provided on the coax, the internal reference will detect and
lock to it.
3–4
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