Tait TB8100 User manual

TB8100 base station
Installation and
Operation Manual
MBA-00005-06
Issue 6
June 2005

2TB8100 Installation and Operation Manual
© Tait Electronics Limited June 2005
Tait Contact Information
Tait Radio Communications
Corporate Head Office
Tait Electronics Ltd
P.O. Box 1645
Christchurch
New Zealand
For the address and telephone number of
regional offices, refer to the TaitWorld
website:
We b si t e: http://www.taitworld.com
Technical Support
For assistance with specific technical issues,
contact Technical Support:
E-mail: [e-mail]
Web si te: http://support.taitworld.com
To our European customers:
Tait Electronics Limited is an environmentally responsible company which
supports waste minimization and material recovery. The European Union's
Waste and Electrical and Electronic Equipment Directive requires that this
product be disposed of separately from the general waste stream when its
service life is over. Please be environmentally responsible and dispose
through the original supplier, your local municipal waste “separate
collection” service, or contact Tait Electronics Limited.

TB8100 Installation and Operation Manual 3
© Tait Electronics Limited June 2005
Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Scope of Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Enquiries and Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Updates of Manual and Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Copyright . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Document Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Associated Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Publication Record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.1 The TB8100 BSS Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.2 Mechanical Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2 Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.1 Reciter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.2 PA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3 PMU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.4 Control Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3 Operating Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.1 Control Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.1.1 Standard Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.1.2 Dual Base Station Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.1.3 Power Save Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.2 Reciter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.3 PA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.4 PMU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.1 Base Station System Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.1.1 Single Base Station System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.1.2 Dual Base Station System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.1.3 Single and Dual 12V PA Base Station Systems . . . . . . . . . . . . . . . . . . 41
4.2 System Control Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.3 Signal Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.4 Power Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.5 PMU Operation on DC Input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4.6 Data, Control and Monitoring Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

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© Tait Electronics Limited June 2005
4.7 Fan Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.8 Power Saving. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
4.8.1 Power Saving Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
4.8.2 Power Saving Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
4.8.3 Overview of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4.8.4 Using the Service Kit with Power Save Base Stations . . . . . . . . . . . . . 63
4.8.5 Configuring Receiver Gating for Base Stations with Power Save. . . . . 65
5 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
5.1 Personal Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
5.1.1 Lethal Voltages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
5.1.2 Explosive Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
5.1.3 Proximity to RF Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
5.1.4 High Temperatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
5.2 Equipment Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
5.2.1 ESD Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
5.2.2 Antenna Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.2.3 Equipment Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.2.4 Installation and Servicing Personnel . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.3 Regulatory Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.3.1 Distress Frequencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.3.2 FCC Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.3.3 Unauthorised Modifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.3.4 Health, Safety and Electromagnetic Compatibility in Europe. . . . . . . . 76
5.4 Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
5.4.1 Operating Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
5.4.2 Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
5.4.3 Dust and Dirt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
5.5 Grounding and Lightning Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.5.1 Electrical Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.5.2 Lightning Ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.6 Recommended Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.7 Ventilation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
5.7.1 Ambient Air Temperature Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
5.7.2 Cabinet and Rack Ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
5.8 Installing the Base Station System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
5.8.1 Unpacking the Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
5.8.2 Mounting the Subrack. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
5.8.3 Auxiliary Support Bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
5.8.4 Optional Slide Mounting Rails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.8.5 Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
6 Replacing Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
6.1 Saving the Base Station’s Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
6.2 Preliminary Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
6.3 Replacing the Control Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

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© Tait Electronics Limited June 2005
6.4 Replacing the Reciter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
6.5 Replacing the Power Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
6.6 Replacing the Power Management Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
6.7 Replacing the Front Panel Fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
6.8 Replacing the Module Guide Rails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
6.9 Replacing the Subrack Interconnect Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
6.10 Final Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
7 Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103
7.1 Overview of Inputs and Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
7.2 Power Supply Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
7.2.1 AC Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
7.2.2 DC Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
7.2.3 Auxiliary DC Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
7.3 RF Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
7.4 System Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
7.4.1 Digital Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
7.4.2 System Interface Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
7.5 Service Kit Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
7.6 Microphone Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
7.7 12V PA Power Saving Control Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . 124
8 Preparation for Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127
8.1 Tuning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
8.2 Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
8.3 Applying Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
8.4 Test Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
9 Maintenance Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .131
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133
Tait General Software Licence Agreement . . . . . . . . . . . . . . . . . . . . . . . . . . . .141
Directive 1999/5/EC Declaration of Conformity . . . . . . . . . . . . . . . . . . . . . . . .143

6TB8100 Installation and Operation Manual
© Tait Electronics Limited June 2005
Preface
Scope of Manual
Welcome to the TB8100 base station system Installation and Operation
Manual. This manual provides information on installing and operating the
TB8100 hardware. Also included in this manual are a high level circuit
description, a functional description and a maintenance guide.
The 100W PA is not available in all markets. A lower power level is also
available if required. Consult your nearest Tait Dealer or Customer Service
Organisation for more information.
Enquiries and Comments
If you have any enquiries regarding this manual, or any comments,
suggestions and notifications of errors, please contact Technical Support
(refer to “Tait Contact Information” on page 2).
Updates of Manual and Equipment
In the interests of improving the performance, reliability or servicing of the
equipment, Tait Electronics Ltd reserves the right to update the equipment
or this manual or both without prior notice.
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 in 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. All trade names referenced are the
service mark, trademark or registered trademark of the respective
manufacturers.
Disclaimer
There are no warranties extended or granted by this manual. Tait
Electronics Ltd accepts no responsibility for damage arising from use of the
information contained in the manual or of the equipment and software it
describes. It is the responsibility of the user to ensure that use of such

TB8100 Installation and Operation Manual 7
© Tait Electronics Limited June 2005
information, equipment and software complies with the laws, rules and
regulations of the applicable jurisdictions.
Document Conventions
“File > Open” means “click File on the menu bar, then click Open on the
list of commands that pops up”. “Monitor > Module Details > Reciter”
means “click the Monitor icon on the toolbar, then in the navigation pane
find the Module Details group, and select Reciter from it”.
Within this manual, four types of alerts are given to the reader: Warning,
Caution, Important and Note. The following paragraphs illustrate each type
of alert and its associated symbol.
Warning!! This alert is used when there is a potential risk
of death or serious injury.
Caution This alert is used when there is a risk of minor or
moderate injury to people.
Important This alert is used to warn about the risk of equipment dam-
age or malfunction.
Note This alert is used to highlight information that is required to
ensure procedures are performed correctly.
Associated Documentation
TB8100 Installation Guide (a subset of this manual).
TB8100 Service Manual.
TB8100 Specifications Manual.
TB8100 Service Kit and Alarm Center User’s Manuals and online Help.
TB8100 Calibration Kit User’s Manual and online Help.
Technical notes are published from time to time to describe applications for
Tait products, to provide technical details not included in manuals, and to
offer solutions for any problems that arise.
All available TB8100 product documentation is provided on the Product
CD supplied with the base station. Updates may also be published on the
Tait Technical Support website (http://support.taitworld.com).

8TB8100 Installation and Operation Manual
© Tait Electronics Limited June 2005
Publication Record
Issue Publication Date Description
1 June 2003 First release
2 March 2004 Chapter 4 “Functional Description” added
3 September 2004
(MBA-00005-03)
information added for 24VDC and 48VDC
PMU, TaitNet RS-232 system interface board,
and B-band & C-band equipment
4 December 2004 information added for K-band equipment;
improved description of PMU auxiliary DC
power supply, and system interface inputs and
outputs
5 March 2005 information added for 12V PA, and L-band
equipment (850MHz to 960MHz); improved
description of dual base station systems
6 June 2005 ■information added about PMU operation
on DC input
■corrections to K-band and L-band
frequenciesa
■minor corrections and additions
a. Refer to “Frequency Bands and Sub-bands” on page 16 for the actual frequency cov-
erage in these bands.

TB8100 Installation and Operation Manual Description 9
© Tait Electronics Limited June 2005
1 Description
The TB8100 is a software-controlled base station system (BSS) which is
designed for operation on most standard frequency ranges1. It makes
extensive use of digital and DSP technology. Many operating parameters
such as channel spacing, audio bandwidth, signalling, etc. are controlled by
software. It is also capable of generating alarms for remote monitoring.
The TB8100 BSS comprises a number of separate modules. Each module
is inserted into the TB8100 4U subrack from the front and is secured at the
front with a metal clamp. Both clamp and module are easily removed for
rapid module replacement. The modules are secured laterally with plastic
guides which clip into the top and bottom of the subrack. These guides can
be easily repositioned to change the configuration of a subrack. The heavier
modules are also secured laterally by metal tabs at the rear of the subrack.
All modules are interconnected at the front of the subrack. The only
connections at the rear of the subrack are:
■RF input from and output to the antenna
■external frequency reference input
■AC and/or DC power supply input
■auxiliary DC output (optional)
■system inputs and outputs (via the optional system interface board fitted
to the reciter).
The TB8100 BSS features rugged construction with generous heatsinks and
fan-forced cooling for continuous operation from –30°C to +60°C (–22°F
to +140°F). Several different configurations are possible. The most
common are:
■one 5W or 50W base station plus accessory modules or extra receivers
■two 5W or 50W base stations
■one 100W base station plus accessory modules or extra receivers.
1. Consult your nearest Tait Dealer or Customer Service Organisation for
information on the most suitable equipment for your area and application.

10 Description TB8100 Installation and Operation Manual
© Tait Electronics Limited June 2005
1.1 The TB8100 BSS Modules
The modules which make up the TB8100 BSS are described briefly below.
You can find more detailed information on these modules in the other
chapters in this manual, and also in the service manual.
Reciter The receiver, exciter and digital
control circuitry is located in the
reciter module. It also incorporates an
optional system interface board which
provides standard system inputs and
outputs.
Power Amplifier The power amplifier (PA) amplifies the RF output from the reciter and is
available in 5W, 50W and 100W models.
The 5W and 50W models mount vertically in the subrack, while the 100W
model mounts horizontally as it has a wider heatsink. The 100W PA is also
fitted with an airflow duct.
All three models of PA are designed to operate on the 28VDC output
provided by the TB8100 power management unit. In addition, 5W and
50W models are available for operation on 12VDC. These two 12V PAs
are fitted with an internal boost regulator board, which converts the 12V
nominal DC input to a 28VDC output to power the PA circuit boards. The
boost regulator board also provides a 12VDC output to power the reciter.
5/50W PA 100W PA

TB8100 Installation and Operation Manual Description 11
© Tait Electronics Limited June 2005
Power
Management Unit The power management unit (PMU)
provides the 28VDC power supply for
the modules in the TB8100 BSS. The
input voltage can be AC, DC or both
AC and DC, depending on the
model. An auxiliary DC output is
also available when the optional
power supply board is fitted. This
board is available with an output of
13.65VDC, 27.3VDC, or 54.6VDC.
Front Panel The TB8100 front panel is mounted onto the subrack with two quick-
release fasteners. It incorporates the cooling fans for the PA and PMU.
Control Panel The TB8100 control panel is
mounted onto the subrack and is
accessible through an opening in the
front panel. The control panel
provides the user with hardware
controls and connections for direct
control of the BSS. Three models are
available: standard, dual base station,
and Power Save.
Subrack The TB8100 4U subrack is made of passivated steel and is designed to fit
into a standard 19 inch rack or cabinet.
AC and DC PMU shown
standard control panel shown

12 Description TB8100 Installation and Operation Manual
© Tait Electronics Limited June 2005
Calibration Test Unit The TB8100 calibration test unit
(CTU) provides a selection of inputs
and outputs which allows the TB8100
BSS to be connected to standard test
equipment, and also to a PC running
the Service Kit or Calibration Kit
software. Refer to TN-778 for more
details.
1.2 Mechanical Assembly
The main mechanical components of the TB8100 BSS are shown in the
following illustrations.
The front panel can be easily removed from the subrack by undoing two
quick-release fasteners. Once the front panel is removed, the control panel
Figure 1.1 Mechanical assembly - front panel, fans and control panel
bfront panel iairflow separator
cPMU fan jcable retaining clip
dPA fan 1) subrack
ePMU fan duct 1! reciter
fPA fan duct 1@ plastic guide rail
gPMU 1# module retaining clamp
hPA 1$ control panel
b
c
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1)
1!
1@
1#
1$
single 5W or 50W base station shown

TB8100 Installation and Operation Manual Description 13
© Tait Electronics Limited June 2005
can also be removed from the subrack by undoing a single screw. Refer to
“Replacing Modules” on page 87 for more details.
Note Figure 1.1 shows the cooling fans and their ducts detached from
the front panel only for the clarity of the illustration. The cooling
fans and ducts are normally screwed to the rear of the front panel.
Figure 1.1 also shows the configuration for a typical single 5W or 50W base
station. The PMU occupies the slot at the left end of the subrack, with the
PA directly beside it. The single reciter normally occupies the second slot
from the right of the subrack.
The single PA is mounted vertically with the heatsink facing the centre of
the subrack. This positions the cooling fins directly behind the PA fan. The
airflow separator is fitted directly beside the PA to help direct the cooling
airflow through the heatsink.
Figure 1.2 above shows the configuration for a typical dual 5W or 50W base
station. The PMU occupies its normal slot at the left end of the subrack,
with the reciters in the two right-hand slots.
The two PAs are mounted vertically in the middle of the subrack with the
heatsinks facing each other. This positions the cooling fins directly behind
Figure 1.2 Mechanical assembly - dual 5W or 50W base station
bPMU freciter for base station 1
cPA for base station 1 greciter for base station 2
dairflow separator hsubrack
ePA for base station 2
bcdef
h
g

14 Description TB8100 Installation and Operation Manual
© Tait Electronics Limited June 2005
the PA fan. The airflow separator between the PAs helps to direct the
cooling airflow evenly through each heatsink.
Note The configuration for single and dual 12V PA base stations is the
same as shown in Figure 1.1 and Figure 1.2, but the PMU and its
cooling fan are not fitted.
Figure 1.3 above shows the configuration for a typical single 100W base
station. The PMU occupies its normal slot at the left end of the subrack,
with the PA directly beside it. The single reciter occupies the slot
immediately to the right of the PA.
Unlike the 5W and 50W PAs, the 100W PA is mounted horizontally with
the heatsink facing upwards. It is also fitted with an airflow duct to channel
the airflow from the cooling fan through the heatsink fins.
Figure 1.3 Mechanical assembly - single 100W base station
bPMU fmodule retaining clamp
cPA gplastic guide rail
dairflow duct hsubrack
ereciter icable retaining clip
bcdef
g
h
i

TB8100 Installation and Operation Manual Circuit Description 15
© Tait Electronics Limited June 2005
2 Circuit Description
Figure 2.1 below shows a typical TB8100 dual base station system of 5W or
50W. It illustrates the main inputs and outputs for power, RF and control
signals, as well as the interconnection between modules. The circuitry of
the individual modules that make up the BSS is described in more detail in
the following sections.
Figure 2.1 Dual base station system high level block diagram
Reciter 2
Reciter 1
PMU
PA 2
PA 1
System Control Bus
RF From
Antenna
Base Station 2 *located on subrack
interconnect board
Base Station 1
RF To
Antenna
RF To
Antenna
System I/O
External Reference
Frequency
(if used)
(if used)
RF From
Antenna
System I/O
External Reference
Frequency
AC I/P
DC I/P
28VDC
(low current)
Control
Panel
Cooling
Fans
Microphone I/P
Rotation
Sensor
RS-232
DC
RF +
PA Key
RF +
PA Key
Auxiliary
DC O/P
(Optional)
28VDC
(high current)
28VDC
(high current)
I C Current
Source
2
I C Current
Source*
2

16 Circuit Description TB8100 Installation and Operation Manual
© Tait Electronics Limited June 2005
Frequency Bands
and Sub-bands Much of the circuitry in the TB8100 base station modules is common to
both VHF and UHF frequency bands, and is therefore covered by a single
description in this manual. Where the circuitry differs between VHF and
UHF, separate descriptions are provided for each frequency band. In some
cases the descriptions refer to specific VHF or UHF bands or sub-bands, and
these are identified with the letters listed in the following table.
2.1 Reciter
The reciter comprises three boards: an RF, a digital, and an optional system
interface board. These boards are mounted on a central chassis/heatsink.
Figure 2.2 on page 18 shows the configuration of the main circuit blocks,
and the main inputs and outputs for power, RF and control signals.
Receiver RF -
VHF Reciter The incoming RF signal is fed through a low pass filter, then through a
band-pass “doublet” filter, and finally through a high-pass filter. The signal
is then amplified and passed through another band-pass “doublet” filter
before being passed to the mixer, where it is converted down to the
16.9MHz IF (intermediate frequency). A VCO (voltage controlled
oscillator) provides a +17dBm input to the mixer, and a diplexer terminates
the mixer IF port in 50 Ω.. The signal from the mixer is fed through a 2-pole
crystal filter to the IF amplifier which provides enough gain to drive the
digital receiver. Note that there are two 2-pole crystal filters, one for narrow
bandwidth and one for wide bandwidth. The appropriate filter is selected
by software-controlled PIN switches, according to the bandwidth selected
Frequency
Identification Frequency Band and Sub-band
VHF
B band B1 = 136MHz to 174MHz
B2 = 136MHz to 156MHz
B3 = 148MHz to 174MHz
C band C0 = 174MHz to 225MHz
C1 = 174MHz to 193MHz
C2 = 193MHz to 225MHz
UHF
H band H0 = 400MHz to 520MHz
H1 = 400MHz to 440MHz
H2 = 440MHz to 480MHz
H3 = 470MHz to 520MHz
K band K4 = 762MHz to 870MHza
a. The actual frequency coverage in this band is:
Transmit: 762MHz to 776MHz, and 850MHz to 870MHz
Receive: 792MHz to 824MHz
L Band L0 = 850MHz to 960MHz
L1 = 852MHz to 854MHz, and 928MHz to 930MHz
L2 = 896MHz to 902MHz (receive only)
L2 = 927MHz to 941MHz (transmit only)

TB8100 Installation and Operation Manual Circuit Description 17
© Tait Electronics Limited June 2005
in the Service Kit software. The signal is finally passed to the ADC
(analogue-to-digital converter) in the digital receiver via an anti-alias filter.
Receiver RF -
UHF Reciter The incoming RF signal is fed through a band-pass filter, followed by a
simple low-pass network. It then passes through further stages of filtering,
amplification and AGC1(automatic gain control) before being fed to the
mixer where it is converted down to the 70.1MHz IF (intermediate
frequency). A VCO (voltage controlled oscillator) provides a +17dBm
input to the mixer, and a diplexer terminates the mixer IF port in 50Ω.. The
signal from the mixer is fed through a 4-pole crystal filter to the IF amplifier
which provides enough gain to drive the digital receiver. The signal is finally
passed to the ADC (analogue-to-digital converter) in the digital receiver via
an anti-alias filter.
Exciter RF Audio signals from the line or microphone input are fed to the exciter RF
circuitry via the DSP (digital signal processor) and CODECs (encoder/
decoder). These modulating signals are applied to the exciter at two points
(dual point modulation): low frequency modulation is via the FCL
(frequency control loop), which modulates the exciter synthesizer’s
frequency reference, and speech band modulation is supplied directly to the
VCO.
The VCO is phase-locked to the frequency reference via the synthesizer.
The output from the VCO passes through the VCO buffer to the exciter
amplifier, which increases the RF signal to +20dBm. This signal is then
attenuated through a pad to +11dBm. An 8VDC PA Key signal is mixed
in with the RF signal which is then fed to the PA.
The K-band and L-band reciters use two VCOs, with the appropriate VCO
stage being selected for operation according to the frequency of the channel
in use. Only one VCO can be operational at any one time.
Digital Circuitry The IF from the receiver RF circuitry is passed through an ADC and a DDC
(digital downconverter) to the DSP. The DSP provides demodulation, RSSI
calculation, SINAD calculations, muting, and decoding of subaudible
signals. Audio and RSSI from the DSP is passed via CODECs to the system
interface board.
Incoming audio from the system interface board or microphone is passed to
the exciter RF circuitry via the DSP and CODECs. The DSP provides the
audio characteristics, generates subaudible signals (e.g. DCS, CTCSS), and
controls the CODECs for line audio input.
1. AGC is available in H-band reciters only. It can be disabled using the Serv-
ice Kit software.

18 Circuit Description TB8100 Installation and Operation Manual
© Tait Electronics Limited June 2005
Control Circuitry The RISC controls the operating functions of the reciter and provides the
interface to the outside world. Some of the functions it controls are:
■Tx key and Rx gate
■communications to the system interface board
■digital input from the system interface board
■communication with the other modules in the TB8100 BSS via the I2C
bus
■communications with the Service Kit software.
Figure 2.2 Reciter high level block diagram
DSP
CODEC
CODEC
CODEC
40MHz
Clock
Receiver
Exciter
Synthesizer
Subsystem
Reference
Frequency
Subsystem
Digital
Receiver
Power
Supply
Power
Supply
RISC
DSP/RISC
CODECs
IF
12.8MHz
Ref.
RF I/P
28VDC I/P
28V
28V 5V
3.3V
8.5V
RF O/P +
PA Key Audio
System
Control Bus System I/O
Digital
Receiver
Audio &
RSSI
Control &
Communications
Control &
Communications
Modulation
& Frequency
Control
Control &
Communications
External
Reference
Frequency
(if used)
RF Board Digital Board
System
Interface
Board

TB8100 Installation and Operation Manual Circuit Description 19
© Tait Electronics Limited June 2005
System Interface
Board The reciter can be fitted with an optional system interface board which
provides the links between the reciter’s internal circuitry and external
equipment. The circuitry on the system interface board provides additional
signal processing so that the outputs meet standard system requirements.
Several different types of system interface board are available, although only
one board can be fitted to a reciter at any one time. Each system interface
board can identify itself to the reciter control circuitry.
Power Supply The reciter operates off a +28 VDC (nominal) supply. The supply is fed to
two separate power supplies, one on the RF board and a second on the
digital board. The power supply on the RF board also powers some of the
circuitry on the system interface board.
The power supply on the RF board provides 5.3V and 8.5V regulated
supplies. This 5.3V supply is boosted to 23V and also provides a 3.3V
regulated supply. The power supply on the digital board provides 3.3V and
5.3V regulated supplies. It is also fed through to provide a 2.5V supply.
2.2 PA
The TB8100 PA is a modular design with the circuitry divided among
separate boards which are assembled in different configurations in different
models. Interconnect boards are used in certain models to connect boards
that are physically separated on the heatsink. The 5W, 50W and 100W PAs
are available for operation on 28VDC, while the 5W and 50W PAs are also
available for operation on 12VDC. Figure 2.3 on page 21 shows the
configurations of a 100W 28V PA and a 50W 12V PA, along with the main
inputs and outputs for power, RF and control signals.
RF Circuitry The RF output from the reciter is fed first to the 6W board. In the 100W
model shown in Figure 2.3, the output from the 6W board is fed into a
–3dB hybrid coupler on a separate splitter board and then to two 60W
boards in quadrature. The outputs from these two boards are then combined
by another –3dB hybrid coupler on a separate combiner board before being
fed to the low-pass filter (LPF)/directional coupler board.
In the 50W model, the output from the 6W board is fed to one 60W board
and then to the LPF/directional coupler board. In the 5W model, the
output from the 6W board is fed directly to the LPF/directional coupler
board.
Control Circuitry The microprocessor located on the control board monitors and controls the
operation of the PA. There are no manual adjustments in the PA because
all the calibration voltages and currents required to control and protect the
PA are monitored by the microprocessor. The software also automatically
detects the PA configuration and controls the PA accordingly.

20 Circuit Description TB8100 Installation and Operation Manual
© Tait Electronics Limited June 2005
If any of the monitored conditions exceeds its normal range of values, the
microprocessor will generate an alarm and reduce the output power to a
preset level (foldback). If the measured values do not return within the
normal range after foldback, the PA will be shut down.
The alarms and diagnostic functions are accessed through I2C bus messages
on the system control bus via the reciter, control panel and Service Kit
software. Some measurements are logged by the microprocessor and this
information can also be accessed through the system control bus.
The operation of the cooling fan mounted on the front panel is determined
by the temperature limits set in the PA software. If two PAs are fitted in a
TB8100 subrack, either PA will turn on the fan when required.
Power Supply The 100W PA operates off a 28VDC external power supply only, while the
5W and 50W PAs can operate off a 28VDC or 12VDC external power
supply, depending on the model. The 12V PAs are fitted with an internal
boost regulator board (refer to “Boost Regulator” below).
The PA also has four internal power supplies which produce –3, +2.5, +5
and +10VDC.
Boost Regulator 5W and 50W 12V PAs are fitted with a boost regulator board. Figure 2.3
on page 21 shows the configuration for a 50W PA, along with the main
inputs and outputs for power, RF and control signals. Note that the 60W
board is only fitted to the 50W PA.
The boost regulator board accepts an input of 12VDC nominal. The input
is firstly fed through the DC input filter, and then through an output filter
and switch which is controlled by a battery control circuit. This output is
fed to the reciter, which operates from 12VDC instead of the standard
28VDC provided when a PMU is used. The output from the DC input
filter is also fed to the power stage where the voltage is boosted to 28VDC,
and is then fed through an output filter to provide the 28VDC output for
the PA circuit boards.
The battery control circuitry monitors the DC input voltage from the
battery. Protection is provided against the wrong input voltage being
supplied. Reverse polarity protection is provided by a diode between
positive and ground, and requires a user-provided fuse or circuit breaker in
series with the DC input line. The fuse or circuit breaker should be rated
at 15A to 18A at 30VDC.
The startup voltage is 12VDC or higher. Once started, the boost regulator
will operate down to 10.25VDC ±0.25V before it shuts down to prevent
deep discharge of the battery.