Glenayre GL-T8541 User manual

Copyright © 1997 Glenayre
GL-T8541 PA 09/10/99
Specifications subject to change without notice
Copyright © 1997 Glenayre
All rights reserved. No part of this work may be reproduced or copied in any form or by
any means -- graphic, electronic, or mechanical, including photocopying, recording,
taping, or information-retrieval system -- without written permission of Glenayre.
GL-T8541 Power Amplifier
USER MANUAL
PN 9110.01002
REV A

GL-T8541 PA Glenayre Document Number: 9110.01002
Document Change Record 09/10/99
Copyright © 1997 Glenayre
Document Change Record
Issue: Revision A
Date: 10/29/97
Changes: none, original

Glenayre Document Number: 9110.01002 GL-T8541 PA
09/10/99 Table of Contents
t8541p1.toc
Copyright © 1997 Glenayre Page: i
Table of Contents
1 GENERAL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1 Manual Scope . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.2 Applicable Documents. . . . . . . . . . . . . . . . . . . . . 1-1
1.3 About Glenayre . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.3.1 Product Warranty Information . . . . . . . . . . . . . . . . . . .1-2
1.3.2 Service Warranty Information . . . . . . . . . . . . . . . . . . .1-2
2 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.2 GL-T8541 PA Specifications . . . . . . . . . . . . . . . . . . 2-1
3 DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1
3.2 Physical Description. . . . . . . . . . . . . . . . . . . . . . 3-1
3.2.1 Electrical Connectors . . . . . . . . . . . . . . . . . . . . . . . .3-1
3.2.2 Chassis Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1
3.2.3 PA Front. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2
3.2.4 PA Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2
3.3 Conceptual Description . . . . . . . . . . . . . . . . . . . . 3-2
3.4 PA Module Interconnection. . . . . . . . . . . . . . . . . . . 3-5
3.4.1 PA Module Dc, Signal, and Control Wiring . . . . . . . . . . . .3-5
3.4.1.1 The Metering Board Location. . . . . . . . . . . . . .3-5
3.4.2 Isolator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6
4 INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.1 Installation . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.1.1 Precautions and Hazards . . . . . . . . . . . . . . . . . . . . . .4-1
4.1.2 Test Equipment and Tools Required . . . . . . . . . . . . . . . .4-1
4.1.3 Component and Adjustment Locations . . . . . . . . . . . . . . .4-1
4.1.4 Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-2
4.1.5 Power Requirement . . . . . . . . . . . . . . . . . . . . . . . . .4-2
4.1.6 PA Module External Connectors . . . . . . . . . . . . . . . . . .4-2
5 OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.2 Controls and Indicators . . . . . . . . . . . . . . . . . . . . 5-1
5.3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.3.1 PA On and Off Control . . . . . . . . . . . . . . . . . . . . . . .5-1

GL-T8541 PA Glenayre Document Number: 9110.01002
Table of Contents 09/10/99
Page: ii Copyright © 1997 Glenayre
5.3.2 Turn Fan On and Off . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.3.3 Key and Unkey PA . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
6 THEORY OF OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
6.1.1 Adding The Optional Isolator . . . . . . . . . . . . . . . . . . . 6-2
6.2 Driver Board . . . . . . . . . . . . . . . . . . . . . . . . 6-2
6.2.1 Q1 Bias and Idle Current Adjustment . . . . . . . . . . . . . . . 6-3
6.2.2 Q2 Bias and Idle Current Adjustment . . . . . . . . . . . . . . . 6-3
6.3 The 1 to 3 Splitter Board . . . . . . . . . . . . . . . . . . . 6-4
6.4 PA Board . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
6.4.1 PA Bias and Idle Current Adjustment . . . . . . . . . . . . . . . 6-5
6.5 3 to 1 Combiner Board . . . . . . . . . . . . . . . . . . . . 6-6
6.5.1 The 3 to 1 Combiner . . . . . . . . . . . . . . . . . . . . . . . . 6-6
6.5.2 Low-Pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
6.5.3 Directional Coupler. . . . . . . . . . . . . . . . . . . . . . . . . 6-6
6.6 PA Module Overall RF Flow . . . . . . . . . . . . . . . . . . 6-8
6.7 Metering Board . . . . . . . . . . . . . . . . . . . . . . . 6-9
6.7.1 Temperature Monitoring Circuit . . . . . . . . . . . . . . . . . . 6-9
6.7.2 Metering Board to Combiner Board to Amplifier Board Interface6-10
6.7.3 Fan Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11
6.7.4 Metering Board Fuses . . . . . . . . . . . . . . . . . . . . . . 6-11
6.7.5 Metering Board Regulators and Test Points . . . . . . . . . . . 6-12
6.7.6 The Analog Signal Multiplexers . . . . . . . . . . . . . . . . . 6-13
6.7.7 PA Current Monitoring Circuit . . . . . . . . . . . . . . . . . . 6-16
6.7.8 AGC Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17
7 CHECKOUT AND MAINTENANCE . . . . . . . . . . . . . . . . . . . . . 7-1
7.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
7.1.1 Test Equipment and Tools Required . . . . . . . . . . . . . . . . 7-1
7.2 Maintenance For Cooling Fans . . . . . . . . . . . . . . . . . 7-1
7.3 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
7.4 Mechanical Integrity . . . . . . . . . . . . . . . . . . . . . 7-2
7.5 Input Voltage Check . . . . . . . . . . . . . . . . . . . . . 7-2
7.5.1 Metering Board Regulators. . . . . . . . . . . . . . . . . . . . . 7-2
7.6 Operational Tests . . . . . . . . . . . . . . . . . . . . . . 7-2
7.6.1 PA Fan and Air Flow Check . . . . . . . . . . . . . . . . . . . . 7-3
7.6.2 PA RF Output Test . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

Glenayre Document Number: 9110.01002 GL-T8541 PA
09/10/99 Table of Contents
t8541p1.toc
Copyright © 1997 Glenayre Page: iii
7.6.3 Calibrating The RF Output of the PA. . . . . . . . . . . . . . . .7-4
7.6.4 Testing the Antenna and its RF Feedline . . . . . . . . . . . . . .7-5
7.6.5 Checking Isolator Loss . . . . . . . . . . . . . . . . . . . . . . .7-6
7.6.5.1 Checking Isolation of Isolator. . . . . . . . . . . . . .7-7
7.7 Setting PA Module Bias and Idle Current . . . . . . . . . . . . . 7-8
7.7.1 Checking Bias Settings . . . . . . . . . . . . . . . . . . . . . . .7-8
7.7.2 Checking Driver Q1 Bias Setting . . . . . . . . . . . . . . . . . .7-8
7.7.3 Setting PA Board RF Transistor Bias. . . . . . . . . . . . . . . .7-9
7.7.4 Setting Driver Board RF Transistor Bias . . . . . . . . . . . . . .7-9
7.8 Resume Paging Operation . . . . . . . . . . . . . . . . . . .7-12
7.9 Maintenance Log . . . . . . . . . . . . . . . . . . . . . . .7-12
7.10 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . .7-12
7.10.1 Troubleshooting Chart . . . . . . . . . . . . . . . . . . . . . . 7-12
7.11 Advanced Troubleshooting . . . . . . . . . . . . . . . . . . .7-15
7.11.1 Checking PA Module Supply Voltage . . . . . . . . . . . . . . 7-15
7.11.1.1 Open Transistor or Blown Fuse. . . . . . . . . . . . 7-15
7.11.1.2 Measuring PA Module Voltages . . . . . . . . . . . 7-15
7.11.2 Driver Board Troubleshooting . . . . . . . . . . . . . . . . . . 7-16
7.11.2.1 Checking the Exciter Output . . . . . . . . . . . . . 7-16
7.11.2.2 Checking Driver Board Q1 . . . . . . . . . . . . . . 7-17
7.11.2.3 Driver Board Output Test. . . . . . . . . . . . . . . 7-19
7.11.3 PA Board Troubleshooting . . . . . . . . . . . . . . . . . . . . 7-21
7.11.3.1 Finding Bad PA board . . . . . . . . . . . . . . . . 7-21
8 REMOVAL AND REINSTALLATION. . . . . . . . . . . . . . . . . . . . . 8-1
8.1 Fan Removal . . . . . . . . . . . . . . . . . . . . . . . . 8-1
8.2 Transmitter Chassis Removal . . . . . . . . . . . . . . . . . . 8-1
8.3 Top Cover Removal. . . . . . . . . . . . . . . . . . . . . . 8-2
8.4 Driver Board. . . . . . . . . . . . . . . . . . . . . . . . . 8-2
8.4.1 Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-2
8.4.2 Reinstallation . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-2
8.5 Splitter Board . . . . . . . . . . . . . . . . . . . . . . . . 8-3
8.5.1 Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-3
8.5.2 Reinstallation . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-3
8.6 PA Board . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
8.6.1 Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-4
8.6.2 Reinstallation . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-4

GL-T8541 PA Glenayre Document Number: 9110.01002
Table of Contents 09/10/99
Page: iv Copyright © 1997 Glenayre
8.7 Combiner Board . . . . . . . . . . . . . . . . . . . . . . . 8-5
8.7.1 Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5
8.7.2 Reinstallation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5
8.8 Metering Board . . . . . . . . . . . . . . . . . . . . . . . 8-6
8.8.1 Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
8.8.2 Reinstallation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6

Glenayre Document Number: 9110.01002 GL-T8541 PA
09/10/99 List of Figures
t8541p1.lof
Copyright © 1997 Glenayre Page: v
List of Figures
Figure 3-1 GL-T8541 PA with DSP Exciter . . . . . . . . . . . . . . . . . . . . . 3-3
Figure 3-2 GL-T8541 PA Module Front and Top View (no cover) . . . . . . . . . 3-4
Figure 3-3 PA Module Circuit Board Connecting Copper Jumper Straps . . . . . . 3-6
Figure 4-1 PA Cabling (external). . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Figure 5-1 GL-T8541 Front View with DSP Exciter. . . . . . . . . . . . . . . . . 5-2
Figure 6-1 GL-T8541 PA Module RF Flow Block Diagram. . . . . . . . . . . . . 6-1
Figure 6-2 Block Diagram Driver and 1 to 3 Splitter Boards . . . . . . . . . . . . 6-3
Figure 6-3 PA Board Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Figure 6-4 The 3 to 1 Combiner Board Block Diagram . . . . . . . . . . . . . . . 6-7
Figure 6-5 PA Module Overall RF Flow . . . . . . . . . . . . . . . . . . . . . . . 6-8
Figure 6-6 Metering Board Block Diagram . . . . . . . . . . . . . . . . . . . . .6-14
Figure 6-7 Metering Board Fuses, Test Points, and Jumpers (2000.00601) . . . . .6-15
Figure 6-8 Metering Board Simplified Current Monitoring Circuits. . . . . . . . .6-16
Figure 6-9 Metering Board Simplified AGC Circuit . . . . . . . . . . . . . . . . .6-17
Figure 6-10 Metering Board Schematic, page 1 or 2 (2000.00601) . . . . . . . . . .6-18
Figure 6-11 Metering Board Schematic, page 2 of 2 (2000.00601) . . . . . . . . . .6-19
Figure 6-12 Driver Board Assembly, Top View (2000.00050) . . . . . . . . . . . .6-20
Figure 6-13 Driver Board Schematic (2000.00050) . . . . . . . . . . . . . . . . . .6-21
Figure 6-14 3 to 1 Splitter Assembly, Top View (2000.00145) . . . . . . . . . . . .6-22
Figure 6-15 3 to 1 Splitter Schematic (2000.00145). . . . . . . . . . . . . . . . . .6-23
Figure 6-16 120 Watt PA Board Assembly, Top View (2000.00027). . . . . . . . .6-24
Figure 6-17 120 Watt PA Board Schematic (2000.00027) . . . . . . . . . . . . . .6-25
Figure 6-18 3 to 1 Combiner Assembly, Top View (2000.00106) . . . . . . . . . .6-26
Figure 6-19 3 to 1 Combiner Schematic (2000.00106) . . . . . . . . . . . . . . . .6-27
Figure 7-1 Chassis Back View . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4
Figure 7-2 Power Amplifier RF Output Power Calibration Setup . . . . . . . . . . 7-4
Figure 7-3 Antenna System Test Setup. . . . . . . . . . . . . . . . . . . . . . . . 7-5
Figure 7-4 Isolator loss Test Setup . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
Figure 7-5 Test Setup to Measure Isolation of the Isolator. . . . . . . . . . . . . . 7-7
Figure 7-6 Driver Board (left) and PA BOARD (right) Layouts. . . . . . . . . . .7-11
Figure 7-7 Exciter Output Test Setup. . . . . . . . . . . . . . . . . . . . . . . . .7-16
Figure 7-8 Driver Board Q1 Test Setup Block Diagram . . . . . . . . . . . . . . .7-17
Figure 7-9 Driver Board Q1 Test Setup . . . . . . . . . . . . . . . . . . . . . . .7-18
Figure 7-10 Driver Board Output Test Setup Block Diagram . . . . . . . . . . . . .7-19
Figure 7-11 Driver Board RF Output Test Setup . . . . . . . . . . . . . . . . . . .7-20

GL-T8541 PA Glenayre Document Number: 9110.01002
List of Figures 09/10/99
Page: vi Copyright © 1997 Glenayre
Figure 7-12 120 Watt PA Board Showing RF Transistor Gate and Drain Pads. . . . 7-22
Figure 8-1 Fan Panel Assembly (exploded) . . . . . . . . . . . . . . . . . . . . . 8-7
Figure 8-2 Top Cover Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8
Figure 8-3 Driver Board Mounting Diagram. . . . . . . . . . . . . . . . . . . . . 8-9
Figure 8-4 3 to 1 Splitter Board Mounting Diagram. . . . . . . . . . . . . . . . . 8-10
Figure 8-5 PA Board Mounting Diagram . . . . . . . . . . . . . . . . . . . . . . 8-11
Figure 8-6 3 to 1 Combiner Board Mounting Diagram . . . . . . . . . . . . . . . 8-12
Figure 8-7 Metering Board Mounting Diagram . . . . . . . . . . . . . . . . . . . 8-13

Glenayre Document Number: 9110.01002 GL-T8541 PA
09/10/99 List of Tables
t8541p1.lot
Copyright © 1997 Glenayre Page: vii
List of Tables
Table 1-1 Applicable Documents . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Table 1-2 Schematic Numbers. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Table 2-1 PA Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Table 3-1 Power Amplifier Assemblies . . . . . . . . . . . . . . . . . . . . . . . 3-2
Table 3-2 Metering Board (J1) to Combiner Board (J8) Connector Pinout . . . . . 3-5
Table 6-1 GL-T8541 PA Optional Isolator RF Power Output. . . . . . . . . . . . 6-2
Table 6-2 Metering Board to Combiner Board Interface . . . . . . . . . . . . . .6-10
Table 6-3 Power Amplifier Metering Board Fuses . . . . . . . . . . . . . . . . .6-11
Table 6-4 Metering Board Test Points. . . . . . . . . . . . . . . . . . . . . . . .6-12
Table 6-5 Metering Board Multiplex Chip Inputs . . . . . . . . . . . . . . . . . .6-13
Table 7-1 Relationship of VSWR to Fwd and Ref Power. . . . . . . . . . . . . . 7-5
Table 7-2 GL-T8541 PA Optional Isolator RF Power Output. . . . . . . . . . . . 7-6
Table 7-3 PA Module Faults. . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-13

GL-T8541 PA Glenayre Document Number: 9110.01002
List of Tables 09/10/99
Page: viii Copyright © 1997 Glenayre

Glenayre Document Number: 9110.01002 GL-T8541 PA
09/10/99 GENERAL
t8541p1.fdk
Copyright © 1997 Glenayre Page: 1-1
1GENERAL
1.1 Manual Scope
This manual presents Glenayre’s 250-watt, 450-MHz power amplifier, and contains infor-
mation concerning installation, operation, and maintenance of the RF PA compartment.
1.2 Applicable Documents
In addition to this manual, other manuals may be required for complete paging-site docu-
mentation. Refer to Table 1-1, Applicable Documents, for a list of applicable documents,
their part numbers, and a brief description of each. Also refer to Table 1-2, Schematic Num-
bers, for relevant schematic numbers.
Table 1-1 Applicable Documents
Document Part Number Description
GL-T 8xx1 series
transmitter system TM 9110.01004 Transmitter manual main binder with typical rackup of typical equipment
Switching power supply
manual 9130.00001 Glenayre 2835 switching power supply
C2000 tx controller
manual 9110.00254 Glenayre C2000 controller hardware and software
Ferroresonant power
supply manual 9110.00257 Glenayre ac-rectifyingferroresonant power supply
Dc breaker/fuse panel
manual 9110.00258 Dc control panel for applications that have external dc
VDT menus user manual 9110.00259 Exciter user-interface software
DSP exciter user manual 9110.00172 Exciter hardware
Table 1-2 Schematic Numbers
Assembly Schematic Number
GL-T8541 PA module assembly 2100.00135-AS
Driver board 2000.00050-SD
Splitter board 2000.00145-SD
PA board 2000.00027-SD
Combiner board 2000.00106-SD
Metering board 2000.00601-SD

GL-T8541 PA Glenayre Document Number: 9110.01002
GENERAL 09/10/99
Page: 1-2 Copyright © 1997 Glenayre
1.3 About Glenayre
Questions regarding the equipment or this manual should be directed to:
U.S.A. CANADA
Glenayre Customer Service - RF Glenayre Customer Service - RF
One Glenayre Way 1570 Kootenay Street
Quincy, Illinois 62301 USA Vancouver, BC V5K 5B8 Canada
Phone: [phone] Phone: [phone]
Fax: [phone] Fax: [phone]
UNITED KINGDOM SINGAPORE
Glenayre Electronics (UK) Ltd. Glenayre Electronics Singapore Pte. Ltd.
Unit 22 Challenge House Block 5012 Ang Mo Kio Avenue 5
Sherwood Drive, Bletchley TechPlace II Unit 0503
Milton Keynes, MK3 6JD UK Singapore 2056
Phone: [phone] Phone: [phone]
Fax: [phone] Fax: [phone]
1.3.1 Product Warranty Information
Glenayre warrants to the original purchaser that Glenayre products are free from defects in
material or workmanship for a period oftwenty-four monthsfrom the original invoice date,
subject to the provisions herein. Glenayre will repair or replace at its option, FOB our
factory, free of charge within one year from the dateof shipment, any component, assembly
or subassembly of our manufacture found to be defective under conditions of normal use.
The unit, if repaired, will be returned to its original specifications. Failures caused by unau-
thorized modifications, force majeure, lightning, physical, environmental, or electrical
damage including use with incompatible equipment are specifically excluded from this
warranty. Glenayre disclaims any and all liability for loss or other damage whether direct,
consequential or of any nature whatsoever, resulting from product failure.
This warranty is in lieu of all other warranties expressed or implied and covers only those
items manufactured by Glenayre. Equipment supplied by, but not manufactured by
Glenayre, is subject only to any warranty offered by the manufacturer of said equipment.
1.3.2 Service Warranty Information
Return of a defective item must be authorized by Glenayre prior to shipment. A Return
Authorization number can be obtained from Glenayre Customer Service. When requesting
a Return Authorization number, give the serial number of the unit. A description of the fault
should accompany the unit on its return and the RA number must be shown on labels
attached to the item(s). The cost of shipping to Glenayre is to be paid by the customer.
Shipping from Glenayre will be prepaid by the customer, and shipped via surface mail. If
express shipping is required, the unit will be shipped collect.
Any repair service performed by Glenayre under this limited warranty is warranted to be
free from defects in material or workmanship for ninety days from the date of repair. All
other terms of this limited warranty apply to the service warranty.

Glenayre Document Number: 9110.01002 GL-T8541 PA
09/10/99 SPECIFICATIONS
t8541p2.fdk
Copyright © 1997 Glenayre Page: 2-1
2 SPECIFICATIONS
2.1 General
Table 2-1, PA Specifications, lists the specifications of the PA. Unless noted, all equipment
tests were performed per the ANSI/EIA-603/1992 standard, “Land Mobile FM or PM
Communications Equipment Measurement and Performance Standards,” approved Octo-
ber 27, 1992, and dated February 1993.
Also refer to the specifications within the transmitter system manual and the exciter man-
ual. Specifications listed here are limited to the characteristics of the power amplifier, not
the transmitter system.
2.2 GL-T8541 PA Specifications
Refer to Table 2-1, PA Specifications, for power amplifier specifications.
Note: the specifications are subject to change without notice.
Table 2-1 PA Specifications
Characteristic (unit of
measurement) Condition Specification
Height Fits inside transmitter
chassis 5.25 in (13.3 cm) : 2 rack units
Width 19 in (48.3 cm)
Depth 13 in (33 cm)
Weight Without exciter 27 lb
RF input power Nominal, supplied by
exciter within tx chassis 250 mW (25 +/-2 dBm)
RF output power range 100-250 W
Duty cycle At full power 100% Continuous
RF bandwidth Band determined by
sales order 395 to 420 MHz 420 to 445 MHz
445 to 470 MHz
470 to 495 MHz
495 to 512 MHz
RF output impedance Nonreactive 50 ohms
RF output connector At rear of PA shelf Type N (female)
Maximum VSWR 1.5:1
Spurious output -90 dBc (or -36dBm if less)

GL-T8541 PA Glenayre Document Number: 9110.01002
SPECIFICATIONS 09/10/99
Page: 2-2 Copyright © 1997 Glenayre
Harmonic output -90 dBc (or -36dBm if less)
RF power stability Over rated temperature ±0.5 dB
Intermodulation of PA With single isolator -40 dBc
With dual isolator -70 dBc
Operating voltage (Vdc) 26.5 - 28
Power consumption (max) At rated RF output 600 W
Ambient temperature (degrees C) See derating factor -30 to +60
Humidity (percent) Noncondensing 0 to 95
Altitude See derating factor To 10,000 ft. (3050 m)
Derating factor Above 5000 ft (1525 m) 2 degrees C per 1000 ft (305 m)
Table 2-1 PA Specifications
Characteristic (unit of
measurement) Condition Specification

Glenayre Document Number: 9110.01002 GL-T8541 PA
09/10/99 DESCRIPTION
t8541p3.fdk
Copyright © 1997 Glenayre Page: 3-1
3 DESCRIPTION
3.1 General
Glenayre’s GL-T8541 power amplifier is designed for FM operation in the 450-MHz band.
RF output is continuously adjustable from 100 to 250 watts; it is driven by a 250 mW (25
+/-2 dBm) source (the DSP exciter). Refer to section 2 for specification-related informa-
tion.
Refer to Figure 3-1, for an overall view of the PA.
3.1.1 Features
The power amplifier exhibits the following features:
• adjustable power output
• continuous operation at rated output
• slide mounts for the power amplifier module and DSP exciter, which allow easy access
and replacement
• current monitoring circuitry (metering board)
• overcurrent protection
• VSWR protection
• modular construction
• status output to exciter
3.2 Physical Description
Refer to Figure 3-2 for board locations in the GL-T8541 PA. Refer to Table 3-1 for pc as-
semblies and part numbers.
3.2.1 Electrical Connectors
The PA module has two type-N connectors for RF input and output and one DB-15 type for
control and monitoring signals. The +dc power cable from the power supply connects to the
metering board. The dc return cable from the power supply as well as the chassis ground
connect to the rear of the PA module.
3.2.2 Chassis Cooling
Forced-air circulation is through the front panel, using a dc fan mounted on the rear panel
of the PA. The air is pulled from front to back over the PA heat sink. The power amplifier
is self-protected against overheating by a temperature sensor which is in contact with the
PA heat sink. The temperature sensor is mounted on the combiner board. Do not operate
the PA in the event the cooling fan should fail.

GL-T8541 PA Glenayre Document Number: 9110.01002
DESCRIPTION 09/10/99
Page: 3-2 Copyright © 1997 Glenayre
3.2.3 PA Front
The PA module and exciter are held in place by front panel screws. Two small handles are
mounted to the front panel of the PA which are used when sliding thePA out of the chassis.
3.2.4 PA Rear
With the fan panel closed, only the fan is visible from the back. With the fan panel open,
the metering board, its dc power distribution, the PA I/O connectors, exciter I/O connec-
tors, and the wiring for the cooling fan are all accessible.
3.3 Conceptual Description
This RF power amplifier unit is functionally located between the exciter and antenna. The
task of RF amplification belongs to the PA unit. Modulated RF is sent from the exciter to
the PA input for amplification. A control voltage from the exciter is used in the metering
board to generate an AGC (automatic gain control) signal. The AGC voltage is applied to
the final amplifier stages in the PA and controls the PA output power. A dc sample propor-
tional to the amount of RF output is sent to the metering board and compared to a reference
level generated by the exciter. The error voltage produced is the AGC signal. Any change
in the output power or AGC reference will produce a corresponding change in the AGC lev-
el. In this way, the AGC circuit maintains control of the RF output power in the presence
of power supply and thermal variations.
Table 3-1 Power Amplifier Assemblies
Assembly Part Number
PA assembly 2100.00135
Driver board 2000.00050
1 to 3 RF splitter 2000.00145
PA board 2000.00027
3 to 1 RF combiner 2000.00106
Metering board 2000.00601

Glenayre Document Number: 9110.01002 GL-T8541 PA
09/10/99 DESCRIPTION
t8541p3.fdk
Copyright © 1997 Glenayre Page: 3-3
v0862.hgl
Figure 3-1 GL-T8541 PA with DSP Exciter

GL-T8541 PA Glenayre Document Number: 9110.01002
DESCRIPTION 09/10/99
Page: 3-4 Copyright © 1997 Glenayre
Figure 3-2 GL-T8541 PA Module Front and Top View (no cover)
Power Amplifier
UHF 3 to 1 Combiner Board
Low Pass Filter and Directional Coupler
(Part of Combiner Board)
UHF Driver Board
UHF 3 to 1 Splitter
120 Watt UHF PA Board
120 Watt UHF PA Board 120 Watt UHF PA Board
PA-1 PA-2 PA-3
RF OUT
RF IN
Metering Board
to PA Interface
Ground
Connection Fuses
1-4 Fuses 6-8 Fuse 5
+dc Input
Connection Metering Board to Exciter
Interface

Glenayre Document Number: 9110.01002 GL-T8541 PA
09/10/99 DESCRIPTION
t8541p3.fdk
Copyright © 1997 Glenayre Page: 3-5
3.4 PA Module Interconnection
3.4.1 PA Module Dc, Signal, and Control Wiring
All PA module dc voltages, monitoring signals, and control signals are routed through the
metering and combiner boards to or from the various PA module circuit boards. The
combiner board to metering board connection is achieved through a D-sub 25 connector.
Refer to Table 3-2, for the PA metering board to combiner board connector pin-out.
The metering board signals are routed from the combiner board to the various PA circuit
boards by copper jumper straps which are soldered between the boards. The RF signals also
travel between the various PA module circuit boards through copper jumper straps.
Figure 3-3 shows the locations of the copper jumper straps in the PA module and the names
of the signals they carry.
3.4.1.1 The Metering Board Location
The metering board is mounted on the outside of the rear panel of the PA module. J1, a
D-sub 25 connector on the metering board provides the interface between the metering
board and the PAmodule. J8 on the PA module combiner board is the mating connector for
this interface.
Table 3-2 Metering Board (J1) to Combiner Board (J8) Connector Pinout
J1 Pin Signal Name J1 Pin Signal Name
1+28Vdc
(not used for this PA)
14
+28 Vdc to PA # 3
215
3
+28 Vdc to PA # 2
16 No connection
4 17 No connection
5 AGC to PAs 1 - 3 18 No PA connection (-15 V from
metering board)
6+28Vdc
(not used for this PA)
19 No connection
7 20 No connection
8
+28 Vdc to PA # 1
21 Temperature Signal
9 22 Forward output power dc sample
10 +28 Vdc
(not used for this PA)
23 Reflected output power dc sample
11 24 Predriver key
12
+28 Vdc to predriver
13
25

GL-T8541 PA Glenayre Document Number: 9110.01002
DESCRIPTION 09/10/99
Page: 3-6 Copyright © 1997 Glenayre
Figure 3-3 PA Module Circuit Board Connecting Copper Jumper Straps
3.4.2 Isolator
The optional isolator (not shown) is connected to the RF output of the PA module. It
prevents intermodulation of the RF signal that may occur from nearby transmissions. A
sample detector circuit in the isolator reject load input monitors the reflected power present
at the isolator output connector. The sample is rectified and filtered, providing a dc voltage
proportional to the reflected power.
UHF 3 to 1 Combiner Board Low Pass Filter and Directional Coupler
(Part of Combiner Board)
UHF Driver Board
UHF 3 to 1 Splitter
Pre amp key Pre amp +28V
PA RF out PA RF Gnd PA +28V PA AGC
PA RF out PA RF Gnd PA +28V PA AGC
PA RF out PA RF Gnd PA +28V PA AGC
Gnd
Splitter RF Input
PA RF Input Gnd PA RF Input Gnd PA RF Input Gnd 120 Watt UHF
PA Board
120 Watt UHF PA Board
120 Watt UHF PA Board
PA-1 PA-2 PA-3
RF OUT
RF IN
Metering Board
to PA Interface
Ground
Connection Fuses
1-4 Fuses 6-8 Fuse 5
+dc Input
Connection Metering Board to Exciter
Interface