Eagle UHF 250 WATT POWER AMPLIFIER User Manual

UHF 250 WATT POWER AMPLIFIER

USER Manual

EAGLE WIRELESS INTERNATIONAL

www.eglw.com [e-mail]

101 Courageous Drive

League City, TX 77573

Telephone: [phone]

Fax: [phone]

Toll Free: 1-800-628-3910

Preface

Preface

Scope

This user manual contains a high level description of the UHF 250 Watt Power
Amplifier as well as a detailed technical description. The scope of this document
is to provide the reader with a general understanding, system description, and
operation of the UHF 250 Watt Power Amplifier.

Section 1 – Presents a general introduction of the UHF 250 Watt Power
Amplifier who are familiarizing themselves with the system for the first time.

Section 2 – Highlights the major features and specifications of the power
amplifier.

Section 3 – Outlines the major system components.

Section 5 – Appendices and Schematics.

Copyright

This document contains proprietary information protected by copyright. All rights
reserved. No part of this document may be photocopied, reproduced,
transmitted, transcribed, stored in a retrieval system, or translated into any
language in any form by any means, electronic, mechanical, magnetic, optical,
chemical, hydraulic, manual or otherwise without prior written consent of EAGLE

WIRELESS INTERNATIONAL, INC.

EAGLE WIRELESS INTERNATIONAL, INC. software and firmware programs

used in the UHF 250 WATT POWER AMPLIFIER is protected by copyright.
Therefore, no software or firmware may be copied or reproduced in any manner
written consent of EAGLE WIRELESS INTERNATIONAL, INC.

Notice

Some EAGLE WIRELESS INTERNATIONAL products may be labeled Eagle
Telecom International. These are simply trade names for certain EAGLE

product lines.

EAGLE WIRELESS INTERNATIONAL, INC. provides this publication as is with
no warranty of any kind, either express or implied including, but not limited to the
implied warranties of merchantability or fitness for a particular purpose. Some
states do not allow disclaimer or express or implied warranties in certain
transactions; therefore, this statement may not apply in all instances.

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Preface

This publication may have technical inaccuracies or typographical errors.
Therefore, the information contained in this manual is subject to change or
revision. Changes or revisions will be incorporated in all new editions of the
publication. EAGLE WIRELESS INTERNATIONAL, INC. may at any time make
improvements and/or changes in product(s) and/or program(s) described in this
publication.

Products are stocked at the address below. Requests for copies of this
publication and for technical information should be directed to EAGLE

WIRELESS INTERNATIONAL, INC.

Customer Service

Eagle Wireless International’s Customer Service Department is dedicated to
provide complete product support to all its customers.

For Technical Assistance only, call the toll-free number 1-800-628-3910,
between the hours of 8:00 A.M. and 5:00 P.M. (CST).

For after hours emergencies, call [phone] for instructions. If you reach
voice mail, please leave a message and your call will be returned promptly.

Customers should maintain a stock of replacement parts or units for emergency
backup.

Eagle Wireless International’s factory trained field service engineers are available
for system installation and optimization. For assistance, write or call:

EAGLE WIRELESS INTERNATIONAL, INC.

101 Courageous Drive, League City, TX 77573

Telephone [phone]

Fax [phone] Toll Free 1-800-628-3910

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Preface

Cautions & Safety Regulations

All RF power transistor and RF termination resistors in this power amplifier
contain the toxic substance beryllium oxide. These assemblies are located on
the combiner, splitter and power amplifier boards. The fumes and dust of
beryllium oxide is also toxic and should only be treated by trained personnel
using proper precautions. Federal law and most state laws strictly prohibit
disposal of beryllium oxide as a public waste.

FCC Requirements

FCC regulations state that:

1. Radio transmitters may be tuned or adjusted only by persons holding a
general class commercial radiotelephone operator’s license, a registered
engineer or by personnel working under their immediate supervision.

2. The RF power output of a radio transmitter shall be no more than that
required for satisfactory technical operation considering the area to be
covered and local conditions.

3. The frequency, deviation, and power of a base station transmitter must be
maintained within specified limits. It is recommended, therefor, that these
three parameters be checked before the station is placed in service.

4. The power input to the final radio frequency stage shall not exceed the
maximum figure specified on the current station authorization. This power
input shall be measured and the results recorded:

a. When the transmitter is initially installed.
b. When any change is made in the transmitter, which may

increase the power input.

c. At intervals not to exceed on year.

FCC Interference Warning

FCC regulations state that:

This equipment generates, uses, and can radiate radio frequency energy and if
not installed and used in accordance with the instructions manual, may cause
interference to radio communications. As temporarily permitted by regulation it
has not been tested for compliance with the limits for Class A computing devices
pursuant to Sub-part J of Part 15 of FCC Rules, which are designed to provide
reasonable protection against such interference. Operation of this equipment in
a residential area is likely to cause interference in which case the user at his own

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Preface

expense will be required to take whatever measures may be required to correct
the interference.

OSHA Safety Standards

The United States Department of Labor, through the provisions of the
Occupational Safety and Health Act, has established an electromagnetic energy
safety standard with applies to the use of this equipment. Proper use of this
radio equipment will result in exposure below the OSHA limit. The following
precautions are recommended:

DO NOT operate the transmitter of a fixed radio (base station, radio paging
transmitter RF equipment) when someone is within two feet (0.6 meters) of the
antenna.

DO NOT operate the transmitter of any radio unless all RF connectors are secure
and any open connectors are properly terminated.

In addition, all equipment must be properly grounded according to National &
Local Electrical Codes.

Lightning Protection Considerations

The Transmitters and Power Amplifiers have protection against high voltages but
for all external connections, added protection against lightning attack should be
considered. For Transmitters used for high power applications with tower
antennas, the following measures will provide sufficient protection against minor
lighting attacks.

− Keep the antenna tower grounding resistance as low as possible.

− The ground rods should be made of copper and be at least eight feet

long. Multiple rods should be used over a single rod, if possible.

− All transmission line bends should be made according to
manufacturer’s exact specifications. All ground line bend should be
made as large as possible.

− Ground the transmission line sheath at every opportunity. Also,
ground the transmission line where it is supported on poles and where
it enters the building.

− Whenever possible, run at least a part of the transmission line through
a length of ground conduit.

− Tie all equipment grounds together to a single point. Then, ground that
point to a grounding rod using as short and as straight a ground wire
as possible.

− The ground wire must never be bundled with other wires in the system.
Also, ground wires must not run along a metal plane.

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Preface

Integrated Circuit Handling Procedure

Care should be taken in handling the circuit boards during installation and
service. A number of IC’s (Integrated Circuits) used in the equipment are from
the MOS (Metal Oxide Semiconductor) family and are vulnerable to damage from
static discharges.

Exercise the following precautions when handling these components.

− Before handling components, ground yourself by touching a ground
rod or the grounded chassis of the equipment momentarily.

− Whenever, either installing or servicing the equipment, take proper
static protection (e.g. wearing a conductive wrist-strap) and stand on a
conductive mat, which is connected to the ground through a 100K ohm
resistor.

− Ground all test equipment and soldering stations that are electrically
powered.

Always connect the ground lead of the test equipment to the Base Station,
Extend-A-Page, and/or Power Amplifier, (which ever is being serviced) first and
then the test probe. While disconnecting, remove the test probe prior to the
ground lead.

Equipment Unpacking and Inspecting

Remove all hardware from the shipping carton and inspect the unit for damage.
If shipping damage has occurred, contact the carrier immediately. Obtain an
RMA number from Eagle Wireless International and return the damaged unit.
Use the original customized package for shipment. All damages must be
reported within 15 days of shipment.

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Warranty

Limited Warranty

1. The product line of paging and mobile equipment, base stations/power
amplifiers, receivers, transmitters, security and transmitter control equipment
sold by EAGLE WIRELESS INTERNATIONAL, INC. is warranted to the
original buyer to meet the then current published specifications, drawings
and/or such modifications thereof as Buyer and Seller have agreed to in
writing and to be free from defects in workmanship and materials. Seller’s
entire warranty obligations are limited to making adjustments by repairing or
replacing any product which fails to meet this warranty and which is returned
to Seller. Replacement, repairs, or adjustment under this warranty shall be

F.O.B. League City, Texas and does not reinstate the warranty set forth
herein. Under all circumstances, the warranty will expire not later than one

(1) year after date of such first shipment.

2. This warranty is void and adjustment will not be allowed for products which
have been subjected to abuse, improper application or installation,
unauthorized alteration, or accidental/negligent damage in use, storage,
transportation or handling.

3. This warranty does not apply to:

a. Incandescent lamps, LEDs, batteries, fuses and other consumable type

goods, operable upon arrival only.

b. Parts and accessories (other than those in the equipment) sold by Eagle

Wireless International, Inc.

c. Service calls and/or shipping charges necessary to transport the equipment

between customer’s location and the factory.

d. Routine checkout and/or tuning equipment.

e. Equipment damaged by an act of God and/or nature, war or terrorism.

f. Equipment that has been sold, rented, or acquired in bankruptcy

proceedings.

g. Equipment where the serial number has been removed, defaced, or

changed.

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Warranty

4. The Seller shall have the right of final determination as to the following: (a) existence
of cause and defect, (b) whether adjustment will be allowed, and (c) if allowed,
whether adjustment will be by repair or replacement. When adjustment is not
allowed, a reasonable charge will be made to the Buyer to cover the Seller’s cost of
inspection and handling. During the first 30 days from the date of original shipment
the seller may elect to accept a returned item for full credit less all shipping charges.
After this thirty day period the buyer will be required to pay a restocking fee of twenty
five percent of the invoice amount if the Seller elects to accept the returned item.

5. In the event the Seller determines that any product claimed to be defective is not
subject to the warranty provisions set forth herein, the Buyer will be notified that the
product is not subject to adjustment. Unless the Buyer furnishes disposition
instructions for the product within thirty (30) days after such notification, Seller may
return product “as is” to Buyer, transportation collect.

6. In returning products under this warranty, Buyer shall comply with terms set forth in
the Warranty Return Procedures. Buyer shall comply with terms set forth in the
Warranty Return Procedures. Buyer in all cases will obtain and comply with Seller’s
packaging and shipping instructions. Buyer will pay for packing, transportation and
transit insurance costs for return of products. Where adjustment is not allowed,
products will be returned to the Buyer, transportation collect.

7. Replacement parts may be secured on an immediate exchange basis, with the
Buyer being billed F.O.B. League City, Texas for parts and shipping. Credit will be
issued for exchange items and shipping upon their receipt, shipping prepaid, at
Eagle Wireless International, Inc.

8. There are no warranties, express or implied, that extend beyond the description on
the face of this contract. Seller shall not be liable for consequential damages. No
change in this warranty shall be binding upon the Seller unless it shall be in writing
and signed by a duly authorized representative of Eagle Wireless International,
Inc.

Version 3 vii 07/18/01

Table of Contents

Page

Preface ………………………………………………………….. i

Limited Warranty ……………………………………………….. vi

Introduction ……………………………………………………… 1-1

Features and Specifications…………………………………… 2-1

Major System Components …………………………………… 3-1

Schematics and Appendices. ………………………………… 4-1

Introduction

Section 1 – Introduction

UHF 250 WATT POWER AMPLIFIER

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Introduction

INTRODUCTION

EAGLE WIRELESS INTERNATIONAL is pleased to introduce its newest state-of­the-art technically advanced UHF 250 WATT POWER AMPLIFIER. The UHF 250
WATT POWER AMPLIFIER is fully solid-state design and built with the most
advanced and rugged LDMOS power transistors. The POWER AMPLIFIER is
designed for continuous duty operation for the paging and link application. The
POWER AMPLIFIER has a modular design approach, thus making it easy to
operate and maintain the unit. The heat sink design is rated well above the
requirement for a 500 watt power amplifier operating on a continuous basis. The
heat sink cooling is provided by three high capacity cooling fans. All adjustments
are factory preset and require no field adjustments. The POWER AMPLIFIER is
fully operationally compatible with the EAGLE and other manufacturer’s made UHF
exciters.

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Features and Specifications

Section 2 – Features and Specifications

UHF 250 WATT POWER AMPLIFIER

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Features and Specifications

Major features of the UHF 250 Watt Power Amplifier:

• Advanced State-of-the-Art Technology

• 100% Solid State Continuous Duty

• Extensive Front Panel Monitoring & Display

• Modular Design

• Multi-channel Capability

Specification of the UHF 250 Watt Power Amplifier:

Frequency Range 450-470 MHz

Power Output 250 Watt
RF Input Impedance 50 Ohm (BNC Female)
RF Output Impedance 50 Ohms (Type N Female)
Emission Designators F1D, F3D, F3E
Duty Cycle 100% at full rated power
Primary Power 26-28 VDC at 25 Amps
Spurious and Harmonics -70 dBc or better
Adjacent Channel Noise -70 dBc or better
Operating Temperature 0ºc to 45ºc (Full Power)
Operating Humidity 0% to 95% relative, non-condensing

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System Components

Section 3 – SYSTEM COMPONENTS

UHF 250 WATT POWER AMPLIFIER

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System Components

Power Amplifier Configuration

The high power amplifier is mounted to the heat sink and is accessible from
the backside of the transmitter. All components of the power amplifier are
contained in an RF tight enclosure such that only the input and output R.F.
coaxial connectors directly penetrate the enclosure. All other penetrations
are by filtered feed through which is designed for the R.F. environment. A
packaging view of the front and rear of the transmitter is shown in Figures 1
and 2. The power amplifier functional bock diagram is shown in Figure 3.

Figure 1 – Power Amplifier Unit Front Packaging View

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FRONT VIEW

System Components

FUSE

BOARD

PREAMP

HIGH

POWER

RF OUTPUT

LOW
PASS
FILTER

FINAL

SPLITTER

REAR VIEW

COMBINER

STAGE

DRIVER

EXCITER

RF INPUT

Figure 2 –Power Amplifier Rear View

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t

System Components

RF

OutPu

Filter &

Coupler

Harminic

Directional

RF Power

Forward & Reflected

Supply

26 VDC

Sensor

Output

Hi Temp

RF Shielded Cage

Final

Stage

12 VDC

Power Bus

Input

1.3 VDC Bias

Board

Power

Sensor

Variable

+12 VDC

Preamp

(Optional)

+12 VDC

Control

DC

Fuse

Board

12 VDC

DC - DC

Converter

Board

Display

Figure 3 – Power Amplifier Functional Block Diagram

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RF

Input

System Components

Power Amplifier – Control Section

The Power Amplifier Control Board provides all of the Power Amplifier
control functions necessary to operate any of the Eagle Power
Amplifier configurations.

Drive Stage

PA Control

Board

DC / DC

Voltage Meter

Calibration

RF Input

Calibration

Converter

FAN

FAN

Notch

P.A. (R19)

Power Adjust

(Clockwise Increases)

RF In LED

Forward Power

Calibration

Reflected Power

Calibration

Supply Voltage

Meter Calibration

Low power LED

Power On LED

High VSWR LED

High Temp LED

Figure 4 – Power Amplifier Control Board

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System Components

Power Amplifier (PA) Control Board

1. The P.A. control board contains all of the hardware and software necessary
to provide the following control functions. See Figure 3 for block diagram.

a. Variable DC control voltage that drives the P.A. pre-amp to control the

output power level of the P.A.

b. Bias supply generation for amplifier configurations requiring external bias.

c. Monitoring of forward power, reflected power, temperature, VSWR

conditions, D.C. power levels, and various alarm conditions.

d. Fan control and sensing.

e. DC power regulation.

f. Input power detection.

g. P.A. keying and deactivation.

h. Front panel Meter display.

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System Components

Power Amplifier Control Functions

The Power Amplifier Control Functions on the Power Amplifier Control
Board are accomplished by the 87C552 master processor located on
this board in conjunction with a variety of support circuitry. All of the
major power amplifier parameters such as forward and reflected
power, heat sink temperature, input drive RF. power, drive stage
voltage, and the master power supply voltage are monitored in this
board by the processor. The 87C552 has a built in A/D converter for
these analog signals and they are sampled after suitable scaling in the
operational amplifier stages of U6 through U8. The gain of most of
these operational amplifiers is controlled by a potentiometer located in
one of the feedback stages as can be observed on the schematic
located in Appendix. Each of these adjustment points can also be
located in Figures 4 and 5. All of these adjustments are factory preset
and should not require field adjustment. However, for convenience,
the following is a summary of these potentiometers and their function.

R24

R33

R43

R18

R19

Driver Voltage Meter Calibration Adjust for proper reading on meter with external voltmeter.

Input RF Threshold Adjustment Sets the input RF level at which the fan circuit is activated.

Forward Output Power Calibration Sets the gain between the forward power sensor and the

input to the microprocessor. Setting depends on frequency
and power options and is factory preset. This input is used
to control the VSWR protection circuit.

Input DC Voltage Meter Calibration This control is used in conjunction with a voltmeter to set

the input DC voltage reading on the display meter.

Output RF Power Level Adjustment This control is used to adjust a control voltage to the pre-

amp stage that ultimately controls the level of the output
forward RF power

The microprocessor, U1, on the Power Amplifier Control Board also provides the
monitoring of the VSWR using the forward and reflected power levels and will
automatically shut the amplifier down if the VSWR exceeds the threshold level set in
the software.

In addition, the microprocessor also continuously monitors the temperature of the
heat sink near the high power final stage and will shut the amplifier down if this
temperature reaches 70 degrees centigrade. Should this event occur, the fan will
continue to run and should the temperature drop to 50 degrees centigrade, the
processor will automatically re-enable the amplifier for full power.

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System Components

R23

R33

R43

R41

R18

R19

Reset

Figure 5 – Transmitter Unit – Power Amplifier Control Board

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System Components

There is, however, a built in delay of two minutes and twenty seconds before
the reset condition can occur to allow adequate cooling for an excessively hot
ambient condition. The microprocessor also has a software threshold to
determine the minimum acceptable output power for a normal transmit
condition. When the output power is below this limit a fault indications
provided (i.e. low power), but otherwise the amplifier operates normally. This
low power threshold is normally set in software to 50% of full rated power
unless the customer makes a special request.

In addition to its normal control functions, the Power Amplifier Control Board
also contains all the drive circuitry for the on-board displays as well as the
circuitry for the front panel display.

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System Components

Power Amplifier – RF Section
General Description

The Power Amplifier circuitry is primarily located in the rear R.F. compartment
that provides R.F. shielding for all of the higher power R.F. circuitry. The
basic configuration of the Power Amplifier RF Section is shown in Figure 6.
This configuration consists of a pre-amp module that drives an intermediate
stage amplifier (the driver stage) followed by the high power amplifier stage.
The high power stage consists of four separate transistors. The particular
transistor configuration is chosen to maximize the performance and reliability
of the products. All power transistors are mounted on special high thermal
performance board material and employ copper heat spreaders. The output
of the power transistor is fed into a low pass harmonic filter to eliminate
unwanted harmonics. The output of this harmonic filter also serves as the RF
output connector mount and support. The individual boards and preamp in
the power amplifier are all fused on an independent basis. This fuse board is
also located in the RF cavity in its own shielded compartment. Each fuse is
also instrumented with a LED indicator to provide easy visibility as to the
health and status of the fuse for that circuit. The back of the RF cavity
enclosure also serves as the mount for an auxiliary cooling fan.

FUSE BOARD

PRE-AMP &
DRIVER SECTION

RF OUTPUT

HARMONIC
FILTER

HIGH POWER
AMPLIFIER SECTION

RF INPUT

Figure 6 – Back View of the Power Amplifier

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System Components

Technical Description

The 250-watt version of the 450 MHz power amplifier utilizes a very
conservative and simplified design. Like all of the EAGLE power amplifier
designs, the exciter output is fed directly through the heat sink and into the
RF. cavity on the back of the transmitter unit as shown in Figure 7 below:

M57729H

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Figure 7

System Components

The block diagram of this configuration is also shown below:

RF Final
4 Stages

C

o
m

b
i

n
e
r

Low Pass
Filter

Forward And Reflected
Power Sensors

RF
Output

Exciter
Input

Resistive
Pad

RF Output Gain
Control And Protection
Circuit

Pre
Amp
Module

RF Input
Power Sensor

S
p
l

i

t

t

e
r

Thermal
Sensor

Figure 8 – Power Amplifier Block Diagram

The input from the exciter (approximately 750 milli-watts and 1.0 Watts) is fed
directly into the Pre-Amp module. The 6dB pad is a resistive pi-attenuator,
which lowers the input power to meet the preamp input requirement as well
as provide optimal input impedance for the amplifier. The pre-amp module is
a high gain amplifier with positive gain control through the use of its bias
voltage. This bias voltage is provided by the PA Control board and is
manually adjustable from the front of the transmitter as well as being
controlled by the PA Control board main processor for VSWR and thermal
shutdown. This information is utilized for a variety of purposes such as fan
control and VSWR validation.

The driver stage is a hybrid module used to provide the required input power
levels to the final stages of the amplifier. It is a self-contained module and is
the final stage of the driver board. Its output is connected to a network of
three hybrid splitters used to provide one to four split. Each output of the
splitter drives the input to a final stage amplifier.

There are four final stage amplifiers used in the amplifier. All four amplifiers
are of equal gain, phase and output power levels. The purpose of these final
stages is again to provide additional gain to the amplifier. The output of each
final stage amplifier is fed to an output combiner, which is used to re-combine
all four signals into one higher power signal.

Each RF. final stage consists of a transistor with a board/copper heat
spreader assembly. This circuit board material is thermally bonded to a
heavy-duty copper heat spreader for added thermal capacity. The heat sink
is instrumented to allow the microprocessor on the Power Amplifier Control
board to continually monitor the thermal performance of the unit.

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System Components

Figure 9 – RF Final Circuit Board Layout

The RF. final Circuit board layout for an individual module is shown in Figure

9. Should the Final Stage ever require replacement, the entire assembly,

including the heat spreader, is easily replaced as a subassembly.

This combined output signal is fed to a low pass filter, which also incorporates
RF detector circuit to determine voltages from the forward and reflected
power levels at the output of PA. These detector outputs are used to provide
an alarm in the event that a high VSWR is present at the output of the power
amplifier.

The output of the low pass filter attenuates high frequency components of the
desired signal, (i.e. harmonics). The output of the low pass filter is connected
to semi-rigid coaxial cable, which is attached to the RF output N connector of
the amplifier.

The pre-amp stage generates about 12-16 Watts. The Pre-amp RF power
then passes through a dual splitter assembly to drive four final stages; each is
capable of generating up to 80 Watts to a total of 320 Watts of RF. power.
This output is then passed through a dual combiner stage and then through a
low pass filter to generate up to 250 watts of RF. power.

The design of the low pass filter utilizes special low loss high dielectric
constant materials with high thermal conductivity. The back of the low pass
board also employs a heat spreader to minimize the board surface
temperature. The inductive elements of the filter are simple half-loop
elements that are soldered directly to the circuit board. The directional
couplers for forward and reflected power measurement are etched into the
filter board design. The final output connector is soldered directly into the
filter assembly. The geometry of the low pas filter board is shown in Figure

10.

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System Components

Figure 10 – Low Pass Filter Board

The final item in the UHF 250 watt power amplifier is the fuse board located in
the fuse compartment as shown in Figure 25. This fuse board is utilized in all
models of EAGLE power amplifiers up to 500 watts. Therefore, in the 250­watt version there are a number of unused fuse locations as shown in Figure
11 below.

LED

Figure 11 – Fuse Board

Each of these fuse locations is instrumented with an LED to provide a quick
visual indication of the health and status of that particular fuse.

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System Components

Backplane Mother Board

The Backplane Mother Board mechanical and electrical details are shown in
Figure 12. The schematic for the Mother Board may be found in the
Appendix of this manual. There are four separate card slots on the mother
board and any of the slots can be used for the PA control board. However,
the PA control board is usually installed in last slot on the left. Also contained
on the mother board is a regulator required to provide the +5 VDC supply to
the PA control board and the display monitor. A 12VDC variable regulator is
also located at the motherboard to provide the drive voltage requirement for
the pre-amp.

Version 3 3-15 07/18/01

Figure 12 – Transmitter Backplane Board

System Components

Power Supply

The power supplies are switch mode type supplies. Depending on the
requirement, it is capable of supplying 40 amps of DC current at 28 VDC from
115 or 220 VAC line voltage. Each supply is made up of four 28 VDC
modules. The modules are assembled in parallels to meet the desired
current rating. Each module is individually fused and contains its own
temperature controlled fan.

The supply is protected against overload and short circuit conditions by fold­back current limiting. The load is protected against over voltage by a
“crowbar circuit” which initiates latched current limiting upon over voltage,
dropping the output voltage to safe levels.

Power Amplifier – Installation

Equipment Required: Wattmeter with RF sample output, Spectrum Analyzer
and Oscilloscope.

Please read and follow instructions carefully before installing the Power
Amplifier.

1. Upon removing the unit from its package, it should be inspected for
any obvious signs of physical damage and loose hardware. If there is
damage, call Eagle to obtain a RMA number to return the unit.

2. Verify that all cabling and DC power connections are in place. If not,
tighten any screw or cables that may have come loose during
shipment.

3. Connect a known good Isolator/Circulator to the RF output of the unit.

4. Connect a known good dummy load to the output of the
Isolator/Circulator with a wattmeter in line between them.

5. Connect the Power Amplifier unit to a correct ampere rated AC outlet.
For most applications 10 amps rated outlet will support a 250 watt
system.

6. Turn power on. The system will perform its internal diagnostic tests,
the HI VSWR and the HI TEMP LED will blink sequentially for about 22
seconds and then stop with both HI VSWR and the HI TEMP LED off
and a “CPU OK” green LED will blink in the PA control board at the
rate once every second. The system is now ready for operation.

7. Check DC voltage at the DC power input terminal located at the rear of
the transmitter unit. This should be at 26 volts.

8. Check that the exciter output is correctly adjusted to meet the input
power requirement (the maximum input power requirement is shown
either at the front or back of the unit) of the PA and the spurious and
harmonics from the exciter should be at 65dBc or better.

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System Components

9. All adjustments are factory preset; no field adjustments are necessary.
Allow the PA to warm up for a period of 5 minutes before taking
measurements. Key the Exciter and check forward Power (factory
adjusted), reflected power (close to zero) at the wattmeter and also at
the Display meter. Also available at the display panel are: DC supply
voltage, Drive voltage and temperature. Rotate the knob on the
display panel to read their values. Check measured data against the
Test Data sheet provided; they should be within 5% of each other.

10. Check forward output power with the desired input power level. Check
results against the Test Data sheet provided. If RF Out power is more
or less than the required output, adjust exciter output.

11. In the Power Amplifier unit itself there are three cooling fans. One at
the rear of the unit, which stays ON as long as the DC power is applied
and the other two fans at the front of the unit turns ON when the Power
Amplifier is keyed and RF Input power is detected. These fans will turn
OFF at about 2 minutes and 20 seconds after the system is unkeyed.

12. Check spurious and harmonics taken from the sampled output of the
wattmeter on a Spectrum Analyzer. These should be at least 65dBc.

13. Un-key the Exciter.

14. Turn Power Off.

15. Remove the dummy load. Leave the Isolator/Circulator and the
wattmeter connected as before.

16. Connect the antenna to the Isolator/Circulator output through the
wattmeter. Before connecting the antenna to the RF Output, have the
antenna and RF cables thoroughly checked by a professional.

17. Apply Power to the system. Wait for the internal diagnostic test time
period to elapse.

18. Manually key the exciter as before. Check reflected power, it should
be no more than 0-3% of the forward power. For reflected power more
than 5% of the forward power, unkey the system and have the antenna
and RF cables checked. Systems running with high reflected power
will cause irreversible damage to RF transistors and/or the
Isolator/Circulator.

19. Check display meter readings as before.

20. Unkey the transmitter. Monitor the system operation with actual
paging data for a short period of time. Check spurious and harmonics
as before.

21. The Power Amplifier is now ready to be put in service.

Version 3 3-17 07/18/01

Appendices

Section 4 – Appendices

UHF 250 Watt Power Amplifier

Version 3 4.1 07/18/01