Tait T889 User manual

M889-00 1
Copyright TEL 02/10/95
T889 Power Amplifier
UHF FM 800-870MHz
Issue 100 October 1995
M889-00-100

2M889-00
02/10/95 Copyright TEL
Head Office
New Zealand
Tait Electronics Ltd
558 Wairakei Road
P.O. Box 1645
Christchurch
New Zealand
Phone: [phone]
Fax: [phone]
Australia
Tait Electronics (Aust) Pty Ltd
275 Toombul Road
Northgate 4013
P.O. Box 679
Virginia
Queensland 4014
Australia
Phone: [phone]
Toll Free: 1800 077-112
Fax: [phone]
Canada
Tait Mobile Radio Inc.
Unit 5, 158 Anderson Avenue
Markham
Ontario L6E1A9
Canada
Phone: [phone]
Toll Free: 1 800 890-8248
Fax: [phone]
France
Tait France Sarl
2 Avenue de la Cristallerie
92 316 Sèvres, Cedex
France
Phone: [phone]
Fax: [phone]
Germany
Tait Mobilfunk GmbH
Willstätterstraße 50
D-90449 Nürnberg 60
Germany
Phone: [phone]
Fax: [phone]
New Zealand
Tait Communications Ltd
Unit 4, 75 Blenheim Road
P.O. Box 1185
Christchurch
Phone: [phone]
Fax: [phone]
Singapore
Tait Electronics (Far East) Pte Ltd
4 Leng Kee Road
SIS Building #05-11A
Singapore 159088
Phone: [phone]
Fax: [phone]
United Kingdom
Tait Mobile Radio Ltd
Ermine Business Park
Ermine Road
Huntingdon
Cambridgeshire PE18 6YA
United Kingdom
Phone: [phone]
Fax: [phone]
USA
Tait Electronics (USA) Inc.
9434 Old Katy Road
Suite 110
Houston
Texas 77055
USA
Phone: [phone]
Toll Free: 1 800 222-1255
Fax: [phone]

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Copyright TEL 02/10/95
About This Manual
Scope This manual contains general, technical and servicing informa-
tion on the T889 Power Amplifier.
Revision Control Each page in this manual has a date of issue. This is to comply
with various Quality Standards, but will also serve to identify
which pages have been updated and when. Each page and its
publication date is listed in the “List of Effective Pages”.
Any portion of text that has been changed is marked by a verti-
cal line (as shown at left) in the outer margin of the page. Where
the removal of an entire paragraph means there is no text left to
mark, an arrow (as shown at left) will appear in the outer mar-
gin. The number beside the arrow will indicate how many para-
graphs have been deleted.
The manual issue and revision status are indicated by the last
three digits of the manual IPN. These digits start at 100 and will
increment through 200, 300, etc., as the manual is updated and
republished, e.g:
The last two digits are used for manuals published in an updata-
ble ring binder format and do not apply to this manual.
PCB Information PCB information is provided for all current issue PCBs, as well
as all previous issue PCBs manufactured in production quanti-
ties, and is grouped according to PCB. Thus, you will find the
parts list, grid reference index (if necessary), PCB layouts and
circuit diagram(s) for each individual PCB grouped together.
Errors If you find an error in this manual, or have a suggestion on how
it might be improved, please do not hesitate to contact the Tech-
nical Writer, Radio Infrastructure Division, Tait Electronics Ltd,
P.O. Box 1645, Christchurch, New Zealand.
Technical Information
Any enquiries regarding this manual or the equipment it describes should be addressed
in the first instance to your nearest approved Tait Dealer or Service Centre. Further
technical assistance may be obtained from the Customer Support Group, Radio Infra-
structure Division, Tait Electronics Ltd, Christchurch, New Zealand.
Updating Equipment And Manuals
In the interests of improving performance, reliability or servicing, Tait Electronics Ltd
reserve the right to update their equipment and/or manuals without prior notice.
2
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issue status revision status

4M889-00
02/10/95 Copyright TEL
Copyright
All information contained in this manual is the property of Tait Electronics Ltd. All
rights are reserved. This manual may not, in whole or part, be copied, photocopied,
reproduced, translated stored or reduced to any electronic medium or machine readable
form without prior written permission from Tait Electronics Ltd.
Ordering Tait Service Manuals
Service Manuals should be ordered from your nearest Tait Branch or approved Dealer.
When ordering, quote the Tait Internal Part Number (IPN) and, where applicable, the
version.
Date Of Issue
IPN M889-00-100 T889 Power Amplifier Service Manual
Issue 100 published October 1995

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Copyright TEL 02/10/95
Table Of Contents
This manual is divided into seven Sections as listed below. There is a detailed table of
contents at the start of each Section.
Section Title
1 General Information
2 Circuit Operation
3 Introduction To Servicing
4 Initial Tuning & Adjustment
5 Fault Finding
6 Installation
7 PCB Information

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M889-00 General Information 1.1
Copyright TEL 02/10/95
1 General Information
This section provides a brief description of the T889 PA, along with detailed specifica-
tions and a list of variants available.
The following topics are covered in this section.
Section Title Page
1.1 Introduction 1.3
1.2
1.2.1
1.2.2
Specifications
Introduction
General
1.4
1.4
1.4
1.3 Versions 1.6

1.2 General Information M889-00
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M889-00 General Information 1.3
Copyright TEL 02/10/95
1.1 Introduction
The T889 is an FM base station power amplifier designed for single or multichannel
operation within the frequency range 800 to 870MHz. The output power capability is 20
to 100W.
The PA comprises a broad band, two stage drive amplifier whose output is split to drive
four separate output stages. The outputs from these final stages are then recombined
and filtered before being fed to the output socket. This type of balanced output stage
offers two advantages over single ended types:
- improved intermodulation performance in the presence of high signal levels
from adjacent transmitters;
- enhanced reliability: if one of the four output stages fails, the transmitter can
still produce half its rated power.
VSWR and thermal protection is incorporated into the basic design, while monitoring
and alarm signals are available for both forward and reverse power. The output power
is adjustable from the front panel.
The main PCB is mounted directly on a die-cast chassis/heatsink. For long-term relia-
bility, four high quality, low loss Teflon PCBs are sweated to the main PCB in areas of
high RF current. Extensive use is also made of the latest surface mount technology.
Forced air cooling for the heatsink is provided on the T889 by a fan, which is activated
whenever the transmitter is keyed. Thermal sensors will also activate the fan automati-
cally if the internal temperature reaches an unacceptable level.
The T889 has a width of 120mm, occupying a double module in a Tait rack shelf
(T99-770) which will accommodate up to seven standard modules to give an attractive
and convenient installation.

1.4 General Information M889-00
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1.2 Specifications
1.2.1 Introduction
The performance figures given are minimum figures, unless otherwise indicated, for
equipment tuned with the maximum switching band and operating at standard room
temperature (+22°C to +28°C).
Where applicable, the test methods used to obtain the following performance figures are
those described in the EIA specification. However, there are several parameters for
which performance according to the CEPT specification is given.
Details of test methods and the conditions which apply for Type Approval testing in all
countries can be obtained from Tait Electronics Ltd.
1.2.2 General
Power Output:
Rated Power .. 90W
Range Of Adjustment .. 20 to 100W (typical)
Duty Cycle Rating: .. 90W continuous to +60°C
Intermodulation .. -70dBc or -40dBi1with 25dB isolation
(PA with output isolator) & interfering signal of -30dBc
Mismatch Capability:
Ruggedness .. infinite VSWR
Stability .. 5:1 VSWR (all phase angles)
Supply Voltage:
Operating Voltage .. 10.8 to 16V DC
Standard Test Voltage .. 13.8V DC
Polarity .. negative earth only
Polarity Protection .. diode
Supply Current:
Standby .. 50mA
Transmit .. 27A (20A typical @ 850MHz)
1. dBi denotes the level of the intermodulation product relative to the interfering signal.