869-894 MHz
Installation & Service Manual
G3S-800-140
Multi-Carrier Amplifier System
869 – 894 MHz
044-05095 Rev. A February 2001
G3S-800-140 Installation & Service Manual
© 2001 Powerwave Technologies Incorporated. All rights reserved.
Powerwave Technologies, and the Powerwave logo are registered trademarks
Powerwave Technologies, Inc. reserves the right to make changes to the documentation and
equipment, including but not limited to component substitution and circuitry changes. Changes
that impact this manual may subsequently be incorporated in a later revision of this manual.
February 2001
Powerwave Technologies, Inc. Tel: (714) 466-1000
1801 E. St. Andrew Place Fax: (714) 466-5800
Santa Ana, CA 92705 Web Site: www.powerwave.com
044-05095 Rev. A ii
G3S-800-140 Installation & Service Manual
Table Of Contents
Par. Section 1 Page
No. General Description No.
1-1 Introduction.........................................................................................................................1-1
1-2 General Description.........................................................................................................1-1
1-3 Functional And Physical Specifications.......................................................................1-1
1-4 Equipment Changes...........................................................................................................1-1
1-5 Ordering Information.........................................................................................................1-2
Section 2
Installation
2-1 Introduction.........................................................................................................................2-1
2-2 Electrical Service Recommendations...........................................................................2-1
2-3 Unpacking and Inspection...............................................................................................2-1
2-4 Installation Instructions...................................................................................................2-2
2-5 Amplifier Module Connectors.........................................................................................2-2
2-5.1 Amplifier Module Status, Alarm, Control, and Power Connector............................2-3
2-5.2 Amplifier Module RF Connector......................................................................................2-4
Section 3
Operating Instructions
3-1 Introduction.........................................................................................................................3-1
3-2 Location and Function of Amplifier Module Controls and Indicators.....................3-1
3-3 Initial Start-Up and Operating Procedures...................................................................3-4
Section 4
Principles of Operation
4-1 Introduction.........................................................................................................................4-1
4-2 RF Input Signal....................................................................................................................4-1
4-3 RF Output Load....................................................................................................................4-1
4-4 G3S-800-140 Amplifier Module........................................................................................4-1
4-4.1 Main Amplifier....................................................................................................................4-2
4-4.2 Error Amplifier....................................................................................................................4-2
4-4.3 Amplifier Monitoring.........................................................................................................4-2
4-4.4 Amplifier Module Cooling................................................................................................4-3
4-4.5 Power Distribution ............................................................................................................4-3
4-4.6 Intermodulation.................................................................................................................. 4-3
4-4.7 Two Tone Intermodulation...............................................................................................4-3
4-4.8 Multitone Intermodulation...............................................................................................4-3
4-4.9 Alarms..................................................................................................................................4-3
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G3S-800-140 Installation & Service Manual
Section 5
Maintenance
5-1 Introduction.........................................................................................................................5-1
5-2 Periodic Maintenance......................................................................................................5-1
5-3 Test Equipment Required For Test..................................................................................5-1
5-4 Clean Air Inlets/Outlets....................................................................................................5-2
5-5 Performance Test...............................................................................................................5-2
5-5.1 Amplifier System Performance Test..............................................................................5-2
5-5.2 Amplifier IMD Test..............................................................................................................5.3
5-5.3 Gain Test..............................................................................................................................5-3
5-5.4 Harmonic Test.....................................................................................................................5-3
5-5.5 Spurious Emissions Test ..................................................................................................5-4
5-5.6 Input Return Loss................................................................................................................5-4
5-6 Field Replacement Parts and Modules.........................................................................5-6
5-6.1 G3S-800-140 Power Amplifier Module...........................................................................5-6
5-6.2 Cooling Fans........................................................................................................................5-6
Section 6
Troubleshooting
6-1 Introduction.........................................................................................................................6-1
6-2 Troubleshooting.................................................................................................................6-1
6-3 Return for Service Procedures........................................................................................6-1
6-3.1 Obtaining an RMA..............................................................................................................6-1
6-3.2 Repackaging for Shipment...............................................................................................6-1
List of Illustrations
Figure
No.
1-1 G3S-800-140 Front and Side View................................................................................... 1-3
2-1 G3S-800-140 Rear View.....................................................................................................2-2
2-2 DC and Logic Connector...................................................................................................2-3
2-3 Amplifier RF Connector.....................................................................................................2-4
3-1 G3S-800-140 Amplifier Module RF Control Indicators................................................3-1
4-1 G3S-800-140 Power Amplifier Module Functional Block Diagram..........................4-2
5-1 Amplifier System Test Setup Diagram...........................................................................5-3
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List Of Tables
Table
No.
1-1 Major Amplifier Components..........................................................................................1-2
1-2 G3S-800-140 MCPA Functional Specifications............................................................1-2
2-1 Amplifier Module DC and Logic Connector Definition...............................................2-3
2-2 Amplifier RF Connector Definition .................................................................................2-4
3-1 Amplifier Module RF Control and Indicators Definition............................................3-2
3-2 Amplifier Module Alarm Indicators Definition............................................................ 3-3
5-1 Periodic Maintenance......................................................................................................5-1
5-2 Test Equipment Required.................................................................................................5-2
5-3 MCPA Test Data Sheet......................................................................................................5-5
6-1 Troubleshooting.................................................................................................................6-1
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G3S-800-140 Installation & Service Manual
Section 1 General Description
1-1 Introduction
This manual contains information and procedures for installation, operation, and maintenance of
Powerwave’s G3S-800-140 multicarrier cellular amplifier. The manual is organized into six sections as follows:
Section 1. General Description
Section 2. Installation
Section 3. Operating Instructions
Section 4. Principles of Operation
Section 5. Maintenance
Section 6. Troubleshooting
1-2 General Description
The G3S-800-140 (see figure 1-1) is a linear, feed-forward power amplifier that operates in the 25
MHz frequency band from 869 MHz to 894 MHz. The amplifier can simultaneously transmit multiple frequencies, with better than -60 dBc third order intermodulation distortion (IMD). It is designed for use in an amplifier system that is modular in design, and is ideally suited for use in
AMPS/TDMA/CDMA/CDPD/W-CDMA base stations. The plug-in Model G3S-800-140 amplifier
modules can each provide 140 watts of power and function completely independently of each
other. The amplifier modules are designed for parallel operation to produce high peak power output and backup redundancy for remote applications. All solid-state, the system is designed to
provide trouble-free operation with minimum maintenance. The system's modular construction
and unique and highly effective LED-based operational status and fault indicators help minimize
downtime. The turn-on and turn-off sequences of voltages are fully automatic, as is overload
protection and recycling. Inadvertent operator damage from front panel manipulation is virtually
impossible.
The amplifier module has a status connector that allows the host system to monitor the amplifier
module performance. The front panel of each amplifier module has unit level status/fault indicators and an RF on/off/reset switch. Primary power for the amplifier is +27 Vdc. Cooling for each
plug-in amplifier module is provided by four fans, two mounted on the front and two on the rear of
the module. The fans draw outside air through the front of the module and exhaust hot air out
through the rear of the module.
1-3 Functional And Physical Specifications
Functional and physical specifications for the amplifier are listed in table 1-2.
1-4 Equipment Changes
Powerwave Technologies, Inc. reserves the right to make minor changes to the equipment, including but not necessarily limited to component substitution and circuitry changes. Changes that
impact this manual may subsequently be incorporated in a later revision of this manual.
044-05095 Rev. A 1-1 February 2001
G3S-800-140 Installation & Service Manual
1-5 Ordering Information
Table 1-1 following gives the part numbers and descriptions to be used when ordering either an
entire amplifier or replacement fans.
Table 1-1 Major Amplifier Components
Model number Description
G3S-800-140 140 W 869-894 MHz
MCPA Module.
800-01075-003 Front fan assembly
800-00972-002 Rear fan assembly.
Table 1-2 G3S-800-140 Multicarrier Cellular Amplifier Functional Specifications
Frequency Range 869-894 MHz (25 MHz Bandwidth)
Total Maximum Input Power -6.0 dBm
Total Output Power 140 W typical (1 Module)
Intermodulation Distortion
and In-Band Spurious:
RF Gain at 880 MHz 58 dB
Gain Flatness:
Gain Variation Over Voltage:
Output Protection: Mismatch Protected
Input Port Return Loss: -16 dB (Min)
Second Harmonics: +5 dBm (Max)
Out of Band Spurious: Better than -60 dBc, +26 to +28 Vdc
Duty Cycle: Continuous
DC Input Power:
Operating Temperature: – 5°C to +50°C
Storage Temperature: -40 ºC. to +85 ºC.
Operating Humidity: 5 % - 95 % Relative Humidity (Noncondensing)
Storage Humidity: 5 % - 95 % Relative Humidity (Noncondensing)
RF Input / Output Connector BMA Coaxial Female, Radiall
Status / Alarm / Control / DC Input
Connectors:
Dimensions: 5.22” High, 17.00” Wide, 20.44” Deep (Including handles, rear
-60 dBc (Max) @ +26 to +28 Vdc @ 140 Watts
-60 dBc (Max) @ +24 to +26 Vdc @ 143 Watts
-60 dBc (Max) @ +21.7 to +24 Vdc @ 100 Watts
± 0.5 dB @ 27 Vdc ±1 Vdc
±0.5 dB from 26 to 28 Vdc
+27 Vdc ± 1 Vdc, 70 Amps Max @ 140 Watts
Operational +21.7 to 30 Vdc
21-Pin D-Subminiature Combo Connector
fans)
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G3S-800-140 Installation & Service Manual
Figure 1-1 G3S-800-140
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G3S-800-140 Installation & Service Manual
Section 2 Installation
2-1 Introduction
This section contains installation recommendations, unpacking, inspection, and installation instructions for the Multicarrier Cellular Amplifier. Carefully read all material in this section prior to
equipment unpacking or installation. Also read and review the operating procedures in Section 3
prior to installing the equipment. It is important that the licensee perform these tasks correctly and
in good faith. If applicable, carefully review the Federal Communications Commission (FCC) rules
as they apply to your installation. DON'T TAKE CHANCES WITH YOUR LICENSE.
2-2 Electrical Service Recommendations
Powerwave Technologies recommends that proper AC line conditioning and surge suppression
be provided on the primary AC input to the +27 Vdc power source. All electrical service should be
installed in accordance with the National Electrical Code, any applicable state or local codes, and
good engineering practice. Special consideration should be given to lightning protection of all
systems in view of the vulnerability of most transmitter sites to lightning. Lightning arrestors are
recommended in the service entrance. Straight, short ground runs are recommended. The electrical service must be well grounded.
Each amplifier system should have its own circuit breaker, so a failure in one does not shut off the
whole installation. Circuit breakers should be capable of handling the anticipated inrush current,
in a load center with a master switch.
2-3 Unpacking And Inspection
This equipment has been operated, tested and calibrated at the factory. Only in the event of severe shocks or other mistreatment should any substantial readjustment be required. Carefully
open the container(s) and remove the amplifier module(s). Retain all packing material that can be
reassembled in the event that the unit must be returned to the factory.
CAUTION
Exercise care in handling equipment during inspection to prevent damage caused by
rough or careless handling.
Visually inspect the amplifier module for damage that may have occurred during shipment. Check
for evidence of water damage, bent or warped chassis, loose screws or nuts, or extraneous
packing material in the connector or fans. Inspect the rear panel connector for bent connector
pins. If the equipment is damaged, a claim should be filed with the carrier once the extent of any
damage is assessed. We cannot stress too strongly the importance of IMMEDIATE careful inspection of the equipment and the subsequent IMMEDIATE filing of the necessary claims against
the carrier if necessary. If possible, inspect the equipment in the presence of the delivery person.
If the equipment is damaged, the carrier is your first area of recourse. If the equipment is damaged and must be returned to the factory, write or phone for a return authorization. Powerwave
may not accept returns without a return authorization. Claims for loss or damage may not be
withheld from any payment to Powerwave, nor may any payment due be withheld pending the
outcome thereof. WE CANNOT GUARANTEE THE FREIGHT CARRIER'S PERFORMANCE.
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G3S-800-140 Installation & Service Manual
2-4 Installation Instructions (refer to figures 1-1 and 2-1)
The G3S-800-140 amplifier module is designed for installation in a subrack that permits access to
the rear of the subrack for connection of DC power, RF, and monitor cables.
To install the amplifier proceed as follows:
1. Install subrack in equipment rack and secure in place.
2. Connect antenna cable to rear of subrack.
3. Connect the transceiver output(s) to rear of subrack.
4. Connect alarms cable(s).
WARNING
Verify that all circuit breaker switches on the rear panel of the subrack are in the OFF
position. Turn off external primary DC power before connecting DC power cables.
5. Connect positive primary power and negative primary power to the subrack. Tighten the
subrack power connections.
6. Install the plug-in amplifier module(s) in the subrack. Tighten left and right thumbscrews.
7. Check your work before applying DC voltage to the system. Make certain all connections are
tight and correct.
8. Measure primary DC input voltage. DC input voltage should be +27 Vdc ±1.0 Vdc. If the DC
input voltage is above or below the limits, call and consult Powerwave before you turn on
your amplifier system.
9. Refer to section 3 for initial turn-on and checkout procedures.
2-5 Amplifier Module Connectors
The amplifier has three connectors on the right rear of the module. The larger is a 21-pin male
D-Sub combo which provides the status, alarm, control, and power connections. The smaller
BMA coaxial female connectors provide the RF connections. Refer to figure 2-1.
Figure 2-1 G3S-800-140 Amplifier, Rear View
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G3S-800-140 Installation & Service Manual
2-5.1 Amplifier Module Status, Alarm, Control, And Power Connector
The amplifier has a separate remote alarm and control connector which may be used by the host
system to monitor and control the individual amplifier modules. The status, alarm, control, and
power connections on the amplifier connector are made through a 21-pin male D-Sub combo
connector (figure 2-2) and are listed and described in table 2-1.
1 2 3 4 5 6 7 8 9
A1
A2
10 11 12 13 14 15 16 17
A3
A4
Figure 2-2 DC and Logic Connector (on Rear of G3S-800-140 Amplifier Module)
Table 2-1 Amplifier Module DC and Logic Connector Definition
Pin Function Description
A1 Power Input +27 Vdc (Power Contact)
A2 Power Input +27 Vdc (Power Contact)
A3 Ground Ground (Power Contact)
A4 Ground Ground (Power Contact)
1 RS485 +TxD Serial Communication Data Out
2 RS485 +RxD Serial Communication Data In
3 Service Loop TTL input to Amp. Gnd. for special test mode (Note 1)
4 MCPA Disabled
(Summary Fault)
5 Mod Addr 0 TTL input to Amp. Gnd. supplied by shelf to identify slot.
6 Mod Addr 1 TTL input to Amp. Gnd. supplied by shelf to identify slot.
7 TP1 TTL output. Future test point.
8 Manual Download GND to download manually
9 DC on stat TTL output. High indicates Amp is powered on.
10 RS485 –TxD Serial Communication Data Out
11 RS485 –RxD Serial Communication Data In
12 SCL7 No connection
13 SDA7 No connection
14 FP Disable Output Output, GND if the front panel switch is in the OFF position; +5 volts
15 FP RST Output, GND if the front panel switch is in the RESET position; +5 volts
16 GND Ground
17 Module Detect Ground potential. Informs the subrack that an MCPA is plugged in.
TTL signal normally low indicates MCPA enabled. A high level indi-
cates that the MCPA has been disabled. Over Power, Over Voltage
takes one second to activate the signal.
indicates the front panel switch is in the ON position.
otherwise.
Note 1: Service loop grounded allows the MCPA to be enabled or disabled by the front panel
switch when not mounted in the shelf.
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G3S-800-140 Installation & Service Manual
2-5.2 Amplifier Module RF Connector
The amplifier has a separate RF connector which is used for the RF signal input and output. The
RF connections on the amplifier connector are made through two BMA female coaxial connectors
(figure 2-3) and are listed and described in table 2-2.
A1
A2
Figure 2-3 Amplifier RF Connector
Table 2-2 Amplifier RF Connector Definition
Pin Function Description
A1 RF Input BMA Coaxial Female, Radiall
A2 RF Output BMA Coaxial Female, Radiall
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G3S-800-140 Installation & Service Manual
Section 3 Operating Instructions
3-1 Introduction
This section contains operating instructions for the Multicarrier Cellular Amplifier System.
3-2 Location And Function Of Amplifier Module Controls And Indicators
Primary +27 Vdc power is applied to the amplifier via a 100-amp circuit breaker (ON-OFF) located
on the left side of the amplifier front panel.
The plug-in amplifier module RF control and indicators, located in the center of the amplifier front
panel between the cooling fans, are shown in figure 3-1. The status and RF control functions are
described in detail in table 3-1. The alarms are described in detail in table 3-2.
Figure 3-1 G3S-800-140 Amplifier Module RF Control and Indicators
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G3S-800-140 Installation & Service Manual
Table 3-1 Amplifier Module RF Control and Indicators Definition
Name Function (Note: MCPA = Multicarrier Power Amplifier)
+27VDC
Indicator
+15VDC
Indicator
+5VDC
Indicator
-5VDC
Indicator
RF ON
Switch
Green LED. When lit, indicates that the +27 Vdc supply is greater than +21 Vdc
and less than +31 Vdc. If the +27 Vdc indicator goes out, the DC FAIL indicator
will illuminate. This indicates that the +27 Vdc voltage dropped below +21 Vdc.
Green LED. When lit, indicates that the +15 Vdc supply is greater than +12 Vdc
and less than +17 Vdc. If the +15 Vdc indicator goes out, the DC FAIL indicator
will illuminate. This indicates that the +15 Vdc voltage dropped below +12 Vdc or
increased above +17 Vdc.
Green LED. When lit, indicates that the +5 Vdc supply is greater than +2 Vdc and
less than +7 Vdc. If the +5 Vdc indicator goes out, the DC FAIL indicator will illuminate. This indicates that the +5 Vdc voltage dropped below +2 Vdc or increased above +7 Vdc.
Green LED. When lit, indicates that the -5 Vdc supply is greater than -7 Vdc and
less than -2 Vdc. If the -5 Vdc indicator goes out, the DC FAIL indicator will illuminate. This indicates that the -5 Vdc voltage dropped below -7 Vdc or increased
above -2 Vdc.
Three position switch:
Off (down position) - Turns off amplifier module.
On (center position) - Normal amplifier on position.
Reset (up position) - When toggled to reset position, all the red LED indicators will
turn on one at a time in sequence followed by all the green indicators one at a
time in sequence; this will also reset the fault latches. If the switch is held in the
reset position, a microcontroller reset will occur. This will be verified by the LEDs
toggling state again. The switch is spring loaded to return to the normal ON position when released. If a fault occurs and the MCPA is disabled, the alarms can be
cleared and the MCPA enabled by this reset position. The functions of the switch
are disabled for five seconds after a power-up condition.
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A ‘Minor Alarm’ will flag a potential fatal problem by the LEDs and the MCPA fault will be in
evaluation. A ‘Critical Alarm’ is indicative of a fatal problem. The fault indicator will latch on and
the MCPA module will be disabled. A ‘Major Alarm’ indicates a major problem but the MCPA
module will not be disabled. Both ‘Major Alarm’ and ‘Critical Alarm’ will be sent to the host system
via the MCPA subrack.
Table 3-2 Amplifier Module Alarm Indicators Definition
Alarm Mode LED
Over Pwr Critical Red Disable High
Over Pwr Critical Red Disable High Input power >-2 dBm
High Temp Minor Red Enable Low High temperature detected
High Temp Critical Red Disable High
VSWR Minor Red Enable Low 14.5 W < Reflected Power < 38W
VSWR Critical Red Disable High
DC Fail Minor Red Enable Low
DC Fail Critical Red Disable High
DC Fail
(Over
voltage)
Fan Fail
(one)
Loop Fail Minor Red Enable Low Loop failure detected
Loop Fail Critical Red Disable High
Low Pwr Minor Red Enable Low
Low Pwr Critical Red Disable High
LPA
DISAB.
NOTES:
1. RS-485 serial alarm will follow LED status.
2. The appropriate status LED shall turn off indicating which voltage is out of its range.
3. When overvoltage is detected:
4. When overpower is detected:
Critical Red Disable High
Major Red Enable Low Any fan failure
Critical Red Disable High
a) MCPA shall shut down (disable)
b) Turn on red DC Fail LED
c) Set flag for DC Fail alarm
a) MCPA shall shut down (disable)
b) Turn on Over Pwr LED
c) Set flag for Over Pwr alarm
d) The MCPA module shall use a peak power detector to determine the overpower fault.
MCPA
Module
MCPA
Disable signal
(pin 4 inTable 2-1)
Condition
MCPA module output power >200
watts (Note 4)
High temperature detected for longer
than two minutes
60W < Reflected power detected at
output longer than approx. two min.
One of the internal DC voltages
dropped below or exceeded the safe
threshold level
Voltage out of range for longer than
approx. two minutes (Note 2)
+27 Vdc input >30 V for longer than
one sec. after initial detection of DC
input >31 V (Note 3)
Loop failure detected longer than 2
minutes
Rack controller detected MCPA output is 3 dB below that of the other
MCPA in the system.
Rack controller detected low power
condition for more than approx. two
minutes
Unit is manually switched off using
the front panel RF ON switch, or disabled by a serial command or auto
shutdown by an alarm condition.
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G3S-800-140 Installation & Service Manual
3-3 Initial Start-Up And Operating Procedures
The amplifier module has two operating controls, both located on the front face of the module: the
power ON - OFF switch and the RF ON - ON/OFF/RESET switch. To perform the initial start-up,
proceed as follows:
1. Double check to ensure that all input and output cables are properly connected.
CAUTION
Before applying power, make sure that the input and output of the amplifier are
properly terminated at 50 ohms. Do not operate the amplifier without a load attached.
Refer to table 1-2 for input power requirements. Excessive input power may damage
the amplifier
NOTE
The output coaxial cable between the amplifier and the antenna must be 50 ohm coaxial
cable. Use of any other cable will distort the output.
2. Verify that the amplifier front panel switches are in the OFF position.
3. Turn on supply that provides +27 Vdc to the amplifier system. Do not apply an RF signal to
the amplifier system
4. Place the ON - OFF circuit breaker on the amplifier in the ON position. Visually check the
indicators on the amplifier module, and verify that the following indicators are on:
A. LPA DISAB. indicator (red) should be on.
B. The +27VDC, +15VDC, +5VDC and -5VDC indicators (green) on the amplifier module
should be on.
5. Set the RF ON switch to the ON (center) position. All red LEDs should turn off after six seconds.
6. Turn on external exciter/transceiver and apply RF input signals.
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Section 4 Principles of Operation
4-1 Introduction
This section contains a functional description of the Multicarrier Cellular Amplifier.
4-2 RF Input Signal
The maximum input power for all carrier frequencies should not exceed the limits specified in table 1-2. For proper amplifier loop balance, the out of band components of the input signals should
not exceed -40 dBc. The input VSWR should be 2:1 maximum (or better).
4-3 RF Output Load
The load impedance should be as good as possible (1.5:1 or better) in the working band for good
power transfer to the load. If the amplifier is operated into a filter, it will maintain its distortion
characteristics outside the signal band even if the VSWR is infinite, provided the reflected power
does not exceed one watt. A parasitic signal of less than one watt incident on the output will not
cause distortion at a higher level than the normal forward distortion (i.e. -60 dBc).
4-4 G3S-800-140 Amplifier Module
The G3S-800-140 amplifier is a linear, feed-forward power amplifier that operates in the 25 MHz
frequency band from 869 MHz to 894 MHz. The amplifier modules are designed for parallel operation to achieve high peak power output, and for redundancy in unmanned remote locations.
The amplifier module, figure 4-1, has an average output of 140 watts power (1400 watts peak
power) with intermodulation products suppressed to better than -60 dBc below carrier levels. The
amplifier provides an amplified output signal with constant gain and phase by adding approximately 30 dB of distortion cancellation on the output signal. Constant gain and phase is maintained by continuously comparing active paths with passive references, and correcting for small
variations through the RF feedback controls. All gain and phase variations, for example those
due to temperature, are reduced to the passive reference variations. Each amplifier module has
an alarm and display board that monitors the amplifier performance. If a failure or fault occurs in
an amplifier module, it is displayed on the individual amplifier front panel.
The amplifier module is comprised of:
Pre-amplifiers
Main amplifier
Error amplifier
Two feed-forward loops with phase-shift and gain controls
DC/DC power regulator
Alarm monitoring, control and display panel
The main amplifier employs class AB amplification for maximum efficiency. The error amplifier
and feed forward loops are employed to correct signal nonlinearities introduced by the class AB
main amplifier. The error amplifier operates in class AB mode. The RF input signals are amplified by a preamp and coupled to an attenuator and phase shifter in the first feed-forward loop.
The main signal is phase shifted by 180 degrees and amplified in the premain amplifier. The output from the premain amplifier is fed to the class AB main amplifier. The output from the main
amplifier is typically 220 watts. The signal is output to several couplers and a delay line.
The signal output from the main amplifier is sampled using a coupler, and the sample signal is
combined with the main input signal and input to the second feed-forward loop. The error signal is
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G3S-800-140 Installation & Service Manual
attenuated, phase shifted 180 degrees, then fed to the error amplifier where it is amplified to a
level identical to the sampled output from the main amplifier. The output from the error amplifier
is then coupled back and added to the output from the main amplifier. The control loops continuously make adjustments to cancel out any distortion in the final output signals.
RF Out
RFL
PWR
Pre
Amp
1st Loop
Phase & Gain
Delay
Feed Forward Loop control
+15 +5 -5
Power Supply
Pre
Main
+27VDC
Smart Rack
Main
Amp
FWD
PWR
2nd Loop
Phase & Gain
Alarms & Display
Error
Amp
-30dB
Front Panel
Delay
-10dB
Figure 4-1 G3S-800-140 Power Amplifier Module Functional Block Diagram
The 2nd loop control section obtains a sample of the distortion added to the output signals by the
main amplifiers, phase shifts the signals by 180 degrees, then feeds it to the error amplifier.
There it is amplified to the same power level as the input sample and coupled on to the main output signal. The final output is monitored by the 2nd loop and adjusted to ensure that the signal
distortion and IMD on the final output is canceled out.
4-4.1 Main Amplifier
The input and output of the amplifier employ two-stage, class AB amplifiers which provide approximately 32 dB of gain in the 25 MHz frequency band from 869 to 894 MHz. The amplifier operates on +27 Vdc, and a bias voltage of +5 Vdc, and is mounted directly on a heat sink which is
temperature monitored by a thermostat. If the heat sink temperature exceeds 85 °C, the thermostat opens and a high temperature fault occurs. The alarm logic controls the +5 Vdc bias voltage
which shuts down the amplifier.
4-4.2 Error Amplifier
The main function of the error amplifier is to sample and amplify the signal distortion level generated by the main amplifier, to a level that cancels out the distortion and IMD when the error signal
is coupled onto the main signal at the amplifier output. The error amplifier is a balanced multistage, class AB amplifier, has 51 dB of gain, and produces up to an 80-watt output. The amplifier
operates on 27 Vdc and a bias voltage of +5 Vdc, and is mounted directly on a heat sink.
4-4.3 Amplifier Monitoring
In the main and error amplifier modules, all normal variations are automatically compensated for
by the feedforward loop control. However, when large variations occur beyond the adjustment
range of the loop control, a loop fault will occur. The alarms are displayed on the front panel indicators and output via a 21-pin connector on the rear of the module to the subrack summary board
for subsequent remote monitoring via the ALARMS connector. Refer to paragraph 2-5 as well as
figure 2-2 and table 2-2 for a description of the ALARMS connector.
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4-4.4 Amplifier Module Cooling
Although each amplifier module contains its own heat sink, it is cooled with forced air. Four fans
are used for forced air cooling and redundancy. The fans, located on the front and rear of the
amplifier module, draw air in through the front of the amplifier and exhaust hot air out the back of
the module. The fans are field replaceable.
4-5 Power Distribution
Primary DC power for the system is provided by the host system to the MCR30830-1-3 Series
subrack. The subrack supplies each amplifier module with +27 Vdc directly and via the RF power
splitter/combiner. The amplifier module has a DC/DC converter that converts the +27 Vdc to +15
Vdc, +5 Vdc and -5 Vdc.
4-6 Intermodulation
The G3S-800-140 amplifier is designed to deliver a 140-watt composite average power, multicarrier signal, occupying a bandwidth less than or equal to 25 MHz, in the bandwidth from 869 to 894
MHz. The maximum average power for linear operation, and thus the amplifier efficiency, will depend on the type of signal amplified.
4-6.1 Two Tone Intermodulation
When measured with two equal CW tones spaced anywhere from 30 kHz to 20 MHz apart, and at
any power level up to the average power, the third order intermodulation products will be below
-60 dBc
4-6.2 Multitone Intermodulation
Adding more tones to the signal will lower individual intermodulation products. If the frequencies
are not equally spaced, the level of intermodulation products gets very low. When the frequencies
are equally spaced, those products fall on top of each other on the same frequency grid. The average power of all intermodulation beats falling on the same frequency is called the composite intermodulation; it is -60 dBc or better.
4-7 Alarms
The presence of several plug-in amplifier alarms can be detected at the DC and logic connector
on the amplifier rear panel. Refer to table 2-1 and figure 2-2 for a description of the connector.
044-05095 Rev. A 4-3 February 2001
G3S-800-140 Installation & Service Manual
Section 5 Maintenance
5-1 Introduction
This section contains periodic maintenance and performance test procedures for the Multicarrier
Cellular Amplifier. It also contains a list of test equipment required to perform the identified tasks.
NOTE
Check your sales order and equipment warranty before attempting to service or repair
the unit. Do not break the seals on equipment under warranty or the warranty will be
null and void. Do not return equipment for warranty or repair service until proper
shipping instructions are received from the factory.
5-2 Periodic Maintenance
Periodic maintenance requirements are listed in table 5-1. Table 5-1 also lists the intervals at
which the tasks should be performed.
WARNING
Wear proper eye protection to avoid eye injury when using compressed air.
Table 5-1 Periodic Maintenance
Task Interval Action
Cleaning
Air Vents 30 Days Inspect and clean per paragraph 5-4
Inspection
Cables and Connec-
tors
Performance Tests
12 Months Inspect signal and power cables for
frayed insulation. Check RF connectors
to be sure that they are tight.
12 Months Perform annual test per paragraph 5-5.
5-3 Test Equipment Required For Test
Test equipment required to test the amplifier system is listed in table 5-2. Equivalent test equipment may be substituted for any item, keeping in mind that a thermistor type power meter is required.
NOTE
All RF test equipment must be calibrated to 0.05 dB resolution. Any deviation from the
nominal attenuation must be accounted for and factored into all output readings.
044-05095 Rev. A 5-1 February 2001
G3S-800-140 Installation & Service Manual
Table 5-2 Test Equipment Required
Nomenclature Manufacturer Model
Signal Generator RDL IMD-801D-03A
30 dB Attenuator, 500 Watt Weinschel Corp. 53-30-34
20 dB Attenuator, 20 Watt
(2 each)
Spectrum Analyzer H.P. 8560E
Coax Directional Coupler H.P. 778D
Power Meter/Sensor H.P. 437B/8481A
Network Analyzer H.P. 8753C
Current Probe
Tenuline
5-4 Cleaning Air Inlets/Outlets
The air inlets and outlets should be cleaned every 30 days. If the equipment is operated in a severe dust environment, they should be cleaned more often as necessary. Turn off DC power
source before removing fans. If dust and dirt are allowed to accumulate, the cooling efficiency
may be diminished. Using either compressed air or a brush with soft bristles, loosen and remove
accumulated dust and dirt from the air inlet panels.
5-5 Performance Test
Performance testing should be conducted every 12 months to ensure that the amplifier system
meets the operational specifications listed in table 5-3. Also verify system performance after any
amplifier module is replaced in the field. The test equipment required to perform the testing is
listed in table 5-2, and the test setup is shown in figure 5-1.
NOTE
The frequencies used in this test are typical for an amplifier with a 25 MHz band from
869 MHz to 894 MHz. Select evenly spaced F1, F2, F3, and F4 frequencies that cover the
instantaneous bandwidth of your system.
5-5.1 Amplifier System Performance Test
This test is applicable to the G3S-800-140 amplifier modules. To perform the test, proceed as
follows:
1. Connect test equipment to the amplifier as shown in figure 5-1.
NOTE
Do not apply any RF signals at this time.
Turn on signal generator and set frequency F1 to 880 MHz, F2 to 883 MHz, F3 to 886 MHz,
and F4 to 889 MHz. Adjust each signal generator output so that the sum power output from
all four signal generators equals -6 dBm at the input.
044-05095 Rev. A 5-2 February 2001
G3S-800-140 Installation & Service Manual
20 dB
Directio nl Coupler
Attenuator
20 dB
20 W
8482A
Attenuator
Spectrum Analyzer
8651E
Power Meter
20 dB
20 W
Power Meter
Sensor Head
8482A
Network Analyzer
8753C
Unit Under Test
+27 Vdc
Gnd RF In
Signal
Generator
G3S-800-140
Plug-in
Amplifier
Module
Filter /
Isotlator
Coupler
10 dB
Variable
Attenuator
RF
Out
Directionl
30 dB
Attenuator
500 W
Sensor Head
Figure 5-1 Amplifier System Test Setup Diagram
5-5.2 Amplifier IMD Test And Current Test
2. Adjust attenuator for an input signal at -10 dBm. Turn on the amplifier by setting RF ON
switch of amplifier. Adjust variable attenuator to set amplifier power output on power meter to
140 watts. Measure IMD on spectrum analyzer. IMD should be -60 dBc max. Record test
data in table 5-3. Set RF ON switch to OFF.
3. With the amplifier module set at 140 watts power output, use the current probe (magnetic
field type) and measure the dc current flow from the +27 Vdc power source. Current should
be 70 amps maximum. Record test data in table 5-3.
5-5.3 Gain Test
4. Disconnect spectrum analyzer from test setup, and connect the network analyzer.
5. Set network analyzer as follows:
Ø Power output to -10 dBm.
Ø Frequency start to 869 MHz.
Ø Frequency stop to 894 MHz.
Ø Normalize the network analyzer for gain and return loss.
6. Check the gain across the band from 869 MHz to 894 MHz. Gain should be between 58 dB.
Record test data in table 5-3.
5-5.4 Harmonics Test
7. 10.With the power set at 140 watts power output, use the spectrum analyzer and check the
frequency band from 869 MHz to 894 MHz for harmonics. Harmonics should be 5 dBm
maximum. Record test data in table 5-3.
044-05095 Rev. A 5-3 February 2001
G3S-800-140 Installation & Service Manual
5-5.5 Spurious Test
8. With the power amplifier set at 140 watts power output, use the spectrum analyzer and check
the frequency band from 869 MHz to 894 MHz for spurious signals. Spurious signals should
be -60 dBc maximum. Record test data in table 5-3.
5-5.6 Input Return Loss Test
9. Reset and turn on amplifier module. Read and record the S
return loss measurement on
11
network analyzer. Input return loss should be –16 dB maximum. Record test data in table
5-3.
044-05095 Rev. A 5-4 February 2001
Table 5-3 Multicarrier Cellular Amplifier Test Data Sheet
DATE _________________________________
AMPLIFIER S/N _________________________
TEST CONDITIONS:
Load and Source Impedance: 50 Ohms
VSWR: < 1.2:1
Supply Voltage: +27 Vdc ±1.0 Vdc
G3S-800-140 Installation & Service Manual
TEST SPECIFICATION MIN
4-TONE IMD
RF Gain
Gain Flatness
Harmonics
Spurious
Input Return
Loss
DC Power
Vcc = 27 Vdc
PO = 140 W
Freq.: 880, 883, 886, and 889
MHz
Vcc = 27 Vdc
PO = 140 W
Freq. = 880 MHz
Vcc = 27 Vdc ±1 Vdc
PO =140 W
869-894 MHz Band
Vcc = 27 Vdc
PO = 140 W
869-894 MHz Band
Vcc = 27 Vdc
PO =140 W
869-894 MHz Band
Vcc = 27 Vdc
PO = 140 W
869-894 MHz Band
Vcc = 27 Vdc
PO = 140 W
4 Tones
57.5 dB 58.5 dB
-0.5 dB +0.5 dB
MAX DAT
A
-60 dBc
5 dBm
-60 dBc
-16 dB
70 Amps
PASS _________________________________ FAIL _______________________________
Tested by ______________________________
044-05095 Rev. A 5-5 February 2001
G3S-800-140 Installation & Service Manual
5-6 Field Replaceable Parts And Modules
The following parts and modules can be replaced in the field on site by a qualified technician with
experience maintaining RF power amplifiers and similar equipment:
1. G3S-800-140 power amplifier modules
2. Cooling fans
5-6.1 G3S-800-140 Power Amplifier Module
To replace a power amplifier module, proceed as follows:
1. Set both the RF ON On/Off/Reset switch and the power ON/OFF switch on the front panel of
the amplifier module to OFF.
2. Loosen two screws that secure amplifier module to subrack.
3. Use handle on front of module, and with a steady even pressure, pull module out of subrack.
CAUTION
When removing the amplifier from the subrack, it is very important to support the
amplifier such that the rear of the module does not suddenly drop when it disengages
from the track. A drop such as this could damage the module.
5-6.2 Cooling Fans
To replace a cooling fan, proceed as follows:
1. Remove amplifier module from subrack; see paragraph 5-6.1 preceding.
2. Loosen four snap fasteners that secure fan to amplifier module. Disconnect fan power connector from amplifier module.
Install replacement in reverse order of steps 1 and 2 above.
044-05095 Rev. A 5-6 February 2001
G3S-800-140 Installation & Service Manual
Section 6 Troubleshooting
6-1 Introduction
This section contains a list of problems which users have encountered and a few suggested actions that may correct the problem. If the suggested corrective action does not eliminate the
problem, please contact your Powerwave field representative or the factory for further instructions.
NOTE
Check your sales order and equipment warranty before attempting to service or repair
the unit. Do not break the seals on equipment under warranty or the warranty will be
null and void. Do not return equipment for warranty or repair service until proper
shipping instructions are received from the factory.
6-2 Troubleshooting
Refer to table 6-1 for troubleshooting suggestions.
Table 6-1 Troubleshooting.
Symptom Suggested Action
1. Check that subrack power connection is secure.
Any voltage indicators (green)
are not lit or blinking
HIGH TEMP alarm (red) is lit
OVER PWR alarm (red) is lit Verify RF input level does not exceed spec – see table 1-2.
VSWR alarm (red) is lit
LOW PWR alarm (red) is lit Contact Powerwave field representative or factory.
2. Check for proper power supply voltage.
3. Check fuses or circuit breakers on amplifier or subrack.
4. Verify that amplifier is fully inserted into subrack.
1. Verify fan(s) are operating properly.
2. Check ambient temperature (not to exceed spec – see ta-
ble 1-2).
Check output connections and cables for integrity and tightness.
6-3 Return for Service Procedures
When returning products to Powerwave, the following procedures will ensure optimum response.
6-3.1 Obtaining an RMA
A Return Material Authorization (RMA) number must be obtained prior to returning equipment to
the factory for service. Please contact our Repair Department at (714) 466-1000 to obtain this
number, or FAX your request to (714) 466-5800. Failure to obtain this RMA number may result in
delays in receiving repair service.
6-3.2 Repackaging for Shipment
To ensure safe shipment of the amplifier, it is recommended that the package designed for the
amplifier be used. The original packaging material is reusable. If it is not available, contact our
Repair Department for packing materials and information.
044-05095 Rev. A 6-1 February 2001
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