Trimble TRIMMARK III Operation Manual

TRIMMARK III

Operation Manual

Part Number: XXXXX-00
Revision: A
Date: November 1999

Trimble Navigation Limited
Surveying & Mapping Division
645 North Mary Avenue
Post Office Box 3642
Sunnyvale, CA 94088-3642
U.S.A.

1-800-827-8000 in North Americ a
[phone] International
Fax: [phone]

www.trimble.com

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Trimble Navigation Europe Limited
Trimble House, Meridian Office Park
Osborn Way, Hook
Hampshire RG27 9HX
ENGLAND
[phone]
Fax: [phone]
Voicemail: [phone]

Trimble Navigation Singapore PTE Limited
79 Anson Road
# 05-02
Singapore 079906
SINGAPORE
[phone]
Fax: [phone]
Voicemail: [phone]

Trimble Japan K.K.
Sumitomo Hamamatsu-cho, Building 10F
1-18-16 Hamamatsu-cho Minato-ku
Tokyo 105
JAPAN
[phone]
Fax: [phone]

Trimble Navigation New Zealand Limited
11 Birmingha m Dr i ve
P.O. Box 8729 Riccarton
Christchurch
NEW ZEALAND
[phone]
Fax: [phone]

Copyright

© 1999 Trimble Navigation Limited. All rights reserved. No part of this manual may be
copied, photocopied, reproduced, translated, or reduced to any electronic medium or machine­readable form without prior written consent from Trimble Navigation Limited.

Printed in the United States of America. Printed on recycled paper.

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Revision Notice

This is the November 1999 release (Revision A) of the TRIMMARK III Operation Manual,
part number XXXXX-00.

Trademarks

TRIMTALK 450S, TRIMTALK 900, RTK, OSM2, 4000Si, 4000SSi, 4600LS, 4700, 4800,
7400MSi, and GPS Total Station are trademarks of Trimble Navigation Limited. IBM is a
registered trademark of International Business Machines, Inc. MS-DOS and Windows are
trademarks of Microsoft Corporation. Intel is a trademark of Intel Corporation. All other brand
names are trademarks of their respective holders.

Notices

Safety. Exposure to RF energy is an important safety consideration. The FCC has adopted a
safety standard for human exposure to radio frequency electromagnetic energy emitted by FCC
regulated equipm ent as a result of its actions in General Docket 79-144 on March 13, 1986.
Proper use of this radio modem results in exposur e below government limits. The following
precautions are recommended:

DO NOT operate the transmitter when someone is within two feet (0.6 meter) of the antenna.
DO NOT operate the transmitter unless all RF connectors are secure and any open connectors

are properly terminated.
DO NOT operate the equipment near electrical blasting caps or in an explosive atmosphere.
All equipment must be properly grounded according to Trimble installation instructions for

safe operatio n.
All equipment should be serviced only by a qualified technician.
Class A Computing Device—Information to User. This equipment has been tested and

found to comply with the limits for a Class A digital d evice, pursuant to part 15 of the FCC
Rules. These limits are designed to provide reasonable protection against harmful interference
when the equipment is operated in a commercial environ ment. This equipment generates, uses,
and can radiate radio frequency energy and, if not installed and used in accordance with the
instruction manual, may cause harmful interference to radio communications. Operation of this
equipment in a residential area is likely to cause harmful interference in which case the user
will be required to correct the interference at his own expense.

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Disclaimer of Warranty

XCEPT AS INDICATED IN “LIMITED WARRANTY” HEREIN, TRIMBLE HARDWARE, SOFTWARE,

E

IRMWARE AND DOCUMENTATION IS PROVIDED “AS IS” AND WITHOUT EXPRESS OR LIMITED

F

WARRANTY OF ANY KIND BY EITHER TRIMBLE NAVIGATION LIMITED OR ANYONE WHO HAS
BEEN INVOLVED IN ITS CREATION, PRODUCTION, OR DISTRIBUTION INCLUDING BUT NOT
LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. THE ENTIRE RISK, AS TO THE QUALITY AND PERFORMANCE OF THE TRIMBLE

ARDWARE, SOFTWARE, FIRMWARE AND DOCUMENTATION, IS WITH YOU. SOME STATES DO

H

NOT ALLOW THE EXCLUSION OF IMPLIED WARRANTIES, SO THE ABOVE EXCLUSION MAY NOT
APPLY TO YOU.

Limitation of Liability

IN NO EVENT WILL TRIMBLE OR ANY PERSON INVOLVED IN THE CREATION, PRODUCTION, OR
DISTRIBUTION OF THE TRIMBLE PRODUCT BE LIABLE TO YOU ON ACCOUNT OF ANY CLAIM FOR
ANY DAMAGES, INCLUDING ANY LOST PROFITS, LOST SAVINGS, OR OTHER SPECIAL,
INCIDENTAL, CONSEQUENTIAL, OR EXEMPLARY DAMAGES, INCLUDING BUT NOT LIMITED TO
ANY DAMAGES ASSESSED AGAINST OR PAID BY YOU TO ANY THIRD PARTY, RISING OUT OF THE
USE, LIABILITY TO USE, QUALITY OR PERFORMANCE OF SUCH TRIMBLE PRODUCT INCLUDING
HARDWARE, SOFTWARE, FIRMWARE AND DOCUMENTATION, EVEN IF TRIMBLE OR ANY SUCH
PERSON OR ENTITY HAS BEEN ADVISED OF THE POSSIBILITY OF DAMAGES, OR FOR ANY CLAIM
BY ANY OTHER PARTY. SOME STATES DO NOT ALLOW THE LIMITATION OR EXCLUSION OF
LIABILITY FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATIONS MAY
NOT APPLY TO YOU.

Software and Firmware Limited Warranty

Trimble Navigation Limited warrants that Software and Firmware products will substantially
conform to the published specifications provided it is used with the Trimble products,
computer products, and oper ating s ystem for which it was designed. For a peri od of ninety (9 0)
days, commencing thirty (30) days after shipment from Trimble, Trimble also warrants that the
magnetic media on which Software and Firmware are distributed and the documentation are
free from defects in materials and workmanship. During the ninety (90) day warranty period,
Trimble will replace defectiv e media or documentation, or correct substantial program errors at
no charge. If Trimble is unable to replace defective media or documentation, or correct
program errors, Trimble will refund the price paid for The Software. These are your sole
remedies for any breach in warranty.

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Hardware Limited Warranty

Trimble Navigation Limited products are warranted against defects in material and
workmanship for a period of one year. The warranty period shall commence thirty (30) days

after shipment from Trimble’s factory. Warranty service will be provided at a designated
Trimble Service Center . T rimble will at its option either repair or replace products that prove to
be defective. The Customer shall pay all shipping charges for products return ed to Trimble for
warranty service. Trimble shall pay all shipping charges for the return of products to the
Customer.

The above warranty shall not apply to defects resulting from:

1. Improper or inadequate maintenance by the buyer

2. Buyer-supplied software or interfacing

3. Unauthorized modification or misuse

4. Operation outside of the environmental specifications of the product

5. Improper installation, where applicable

6. Lightning or other electrical discharge

7. Fresh or salt water immersion or spray

8. Normal wear and tear on consumable parts (for example, batteries)
No other warranty is expressed or implied. Trimble Navigation Limited specifically disclaims

the implied warranties of fitness for a particular purpose and merchantability.

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Table of Contents

Preface

Scope and Audience . . . . . . . . . . . . . . . . . . . . . . . . .xv

Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xv

Related Information . . . . . . . . . . . . . . . . . . . . . . . . .xvi

Update Notes . . . . . . . . . . . . . . . . . . . . . . .xvi

Other Information . . . . . . . . . . . . . . . . . . . . . . . . . .xvi

World Wide Web (WWW) Site . . . . . . . . . . . . . .xvi

File Transfer Protocol (FTP) Site . . . . . . . . . . . . .xvii

Technical Assistance . . . . . . . . . . . . . . . . . . . . . . . . .xvii

Reader Comment Form. . . . . . . . . . . . . . . . . . . . . . . .xvii

Document Conventions. . . . . . . . . . . . . . . . . . . . . . . .x viii

Warnings, Cautions, Notes, and Tips. . . . . . . . . . . . . . . . .xix

1 Overview

1.1 TRIMMARK III . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1.1.1 TRIMMARK III Features . . . . . . . . . . . . . . . . .1-2

1.1.2 Equipment Sets and Accessories . . . . . . . . . . . . .1-3

TRIMMARK III Base Equipment Set. . . . . . . . . . .1-3

TRIMMARK III Repeater Equipment . . . . . . . . . .1-4

1.1.3 Accessories . . . . . . . . . . . . . . . . . . . . . . . .1-4

4000, 4400 and 4600 GPS Receiver Accessories . . . . .1-4

1.1.4 Typical Broadcast Network . . . . . . . . . . . . . . . .1-5

1.2 TRIMMARK III Description. . . . . . . . . . . . . . . . . . . . .1 -6

TRIMMARK III Operation Manual vii

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1.2.1 Controls and Indicators . . . . . . . . . . . . . . . . . .1-6

1.2.2 Power and I/O Cables . . . . . . . . . . . . . . . . . . .1-7

1.2.3 Defaults . . . . . . . . . . . . . . . . . . . . . . . . . .1-7

1.3 Standard Omnidirectional Antennas . . . . . . . . . . . . . . . . .1-8

1.4 Directional Antennas . . . . . . . . . . . . . . . . . . . . . . . . .1-8

2 Operation

2.1 Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1

2.1.1 Configuring the Radio Modem . . . . . . . . . . . . . .2-2

2.1.2 Getting Started with CommSet . . . . . . . . . . . . . .2-3

2.1.3 Frequency Updates . . . . . . . . . . . . . . . . . . . .2-3

2.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-4

2.2.1 TRIMMARK III . . . . . . . . . . . . . . . . . . . . . .2-4

Connecting to a Computer. . . . . . . . . . . . . . . . .2-2

Using CommSet . . . . . . . . . . . . . . . . . . . . . .2-3

Installation as a Base . . . . . . . . . . . . . . . . . . .2-5

Installation as a Repeater . . . . . . . . . . . . . . . . .2-6

2.2.2 Antenna Installation . . . . . . . . . . . . . . . . . . . .2-8

Line of Sight Obstruction . . . . . . . . . . . . . . . . .2-9

Cable Losses. . . . . . . . . . . . . . . . . . . . . . . .2-9

Antennas. . . . . . . . . . . . . . . . . . . . . . . . . .2-10

2.3 Verifying Operation. . . . . . . . . . . . . . . . . . . . . . . . . .2-12

2.3.1 TRIMMARK III . . . . . . . . . . . . . . . . . . . . . .2-12

Base Operation . . . . . . . . . . . . . . . . . . . . . .2-12

Repeater Operation . . . . . . . . . . . . . . . . . . . .2-12

3 Characteristics and Specifications

3.1 Antenna Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1

3.1.1 Omnidirectional Antennas . . . . . . . . . . . . . . . . .3-1

3.2 Broadcast Network . . . . . . . . . . . . . . . . . . . . . . . . . .3-3

viii TRIMMARK III Operation Manual

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3.2.1 Frequency Band and Channel Selection. . . . . . . . . .3-3

3.2.2 Wireless Data Rate. . . . . . . . . . . . . . . . . . . . .3-4

3.2.3 Transmit Power . . . . . . . . . . . . . . . . . . . . . .3-4

3.2.4 TRIMMARK III Electrical Interface . . . . . . . . . . .3-5

3.3 General Specifications . . . . . . . . . . . . . . . . . . . . . . . .3-6

3.4 General Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7

3.5 Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7

4 Regulations and Safety

4.1 Type Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-2

4.2 Licensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-2

4.3 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-3

A Using Radio Communication Systems with GPS Sur veyi ng

Receivers

A.1 Selecting Communications Radios . . . . . . . . . . . . . . . . . .A-2

A.2 Useful Field Procedures . . . . . . . . . . . . . . . . . . . . . . .A-5

A.3 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-6

Index

TRIMMARK III Operation Manual ix

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x TRIMMARK III Operation Manual

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List of Figures

Figure 2-1 Standard UHF Omnidirectional Antennas . . . . . . . . . 2-11

Figure 3-1 Omnidirectional Antenna Gain Patterns . . . . . . . . . . 3-2

TRIMMARK III Operation Manual xi

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xii TRIMMARK III Operation Manual

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List of Tables

Table 2-1 Repeater Use in Networks . . . . . . . . . . . . . . . 2-7

Table 2-2 Cable Losses . . . . . . . . . . . . . . . . . . . . 2-9

Table 3-1 TRIMMARK III Physical Specifications . . . . . . . . . 3-6

Table 3-2 Antenna Physical Specifications . . . . . . . . . . . . 3-6

Table 3-3 Performance Specifications (Typical) . . . . . . . . . . 3-7

Table A-1 RF Bands to Avoid When Using GPS Surveying Receivers . . A-3

TRIMMARK III Operation Manual xiii

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xiv TRIMMARK III Operation Manual

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Preface

Welcome to the TRIMMARK™ III Operation Manual. This manual
describes the TRIMMARK III radio modem for use in real-time
differential and real-time kinematic GPS applications. The
TRIMMARK III, when used with a Trimble 4700 or 4800 rover with
an internal radio modem, provides a high-speed wireless data link
between base and rover GPS receivers.

Scope and Audience

We recommend that you spend some time reading this manual. The
following s ecti on pro vide s you wit h a g uide t o this manual, a s well a s
to other documentation you have received with this product.

Organization

This manual contains the following chapters and appendices:

• Chapter 1, Overvie w - pro vides a br ief ov ervi ew and physic al

• Chapter 2, Operation - contains complete installation and

• Chapter 3, Characteristics and Specifications - summarizes

TRIMMARK III Operation Manual xv

description of the TRIMMARK III radio modem.

configuration instructions for the TRIMMARK III radi o
modem.

performance characteristics and specifications that can be
expected from a TRIMMARK III radio modem.

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Preface

• Chapter 4, Regulations and Safety - contains regulation and

safety information.

• Appendix A, Using Radio Communications Sy stems with

GPS Surveying Receivers - discusses the special problems
encountered when using radio communication systems with
GPS receivers.

Related Information

This manual contains system-wide, general information on the
TRIMMARK III radio modem. Other sources of information are
discussed in the following sections.

Update Notes

You will find a Warranty Activat ion Sheet with your TRIMMARK III
radio modem. By sending in your Warranty Activation Sheet, you are
automatically sent update notes as they become available. When you
receive these packages, read them. They contain important
information about sof twa re and h ardwa re cha nges. Contact your l ocal
Trimble Dealer for more information about support agreement
contracts for software and firmware, and extended warranty programs
for hardware.

Other Information

This section lists sources that provide other useful information.

World Wide Web (WWW) Site

For more information about Trimble, visit our site on the
World Wide Web:

• www.trimble.com

xvi TRIMMARK III Operation Manual

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File Transfer Protocol (FTP) Site

Use the Trimble FTP site to send files or to receive files such as
software patches, utilities, and answers to Frequently Asked
Questions (FAQs):

• ftp://ftp.trimble.com

You can also access the FTP site from the Trimble World Wide Web
site at:

• www.trimble.com/support/support.htm

Technical Assistance

If you ha ve a p roblem and cannot f ind the informati on you n eed in th e
product documentati on, contact your local dealer. Alternatively,
request technical support using the Trimble World Wide Web site
(http://www.trimble.com/support/support.htm).

Preface

Reader Comment Form

Thank you for purchasing this product. We would appreciate
feedback about the documentation. Use the reader comment form at
the back of this manual or, if this is not avai labl e, send comment s and
suggestions to t he addr ess i n the front . All c omments an d s uggesti ons
become the property of Trimble Navigation Limited.

TRIMMARK III Operation Manual xvii

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Preface

Document Conventions

Italics identify software menus, menu commands, dialog boxes, and
the dialog box fields.

MALL CAPITALS identify DOS commands, directories, filenames,

S
and filename extensions.

Courier represents messages printed on the screen.
Courier Bold represents information that you must type in a

software screen or window.

Helvetica Bold identifies a software command button.

[Ctrl] is an example of a hardware function key that you must press on
a personal computer (PC) . If you must press more t han one of thes e at
the same time, this is represented by a plus sign, for example, [Ctrl] +
[C].

xviii TRIMMARK III Operation Manual

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W arnings, Cautions, Notes, and Tips

Warnings, cautions, notes, and tips draw attention to important
information and indicate its nature and purpose.

Preface

M

I

*

P

Warning – W arnings alert you to situations that could cause personal
injury or unrecoverable data loss.

Caution – Cautions alert you to situations that could cause hardware
damage or software error.

Note – Notes give additional significant information about the subject
to increase your knowledge, or guide your actions.

Tip – Tips indicate a shortcut or other time- or labor-saving hint that
can help you make better use of the product.

TRIMMARK III Operation Manual xix

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Preface

xx TRIMMARK III Operation Manual

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1 Overview

The rugged TRIMMARK III radio modem is designed for harsh
environments, such as those associated with seismic and mining
surveys. Used with a Trimble 4700 or 4800 rover GPS receiver with
an internal rad io modem, the TRIMMARK III pro vides a conveni ent ,
versatile means of establishing a robust wireless data broadcast
network for real-time differential and real-time kinematic GPS
applications.

1.1 TRIMMARK III

The TRIMMARK III unit can be used as a base or a repeater. The

function of a part icular unit—base or repeater—is determined by its
configurat io n. Units used as a base can be connected to most Trimble
surve y-grade GPS rec ei v ers throug h a single cab le for serial I/ O and a
separate cable for power. When used as a repeater the TRIMMARK
III unit operates autonomously and does not require anything
connected to the serial port.

To achieve l ine -of- sight (LOS) coverage to all point s in a s urv e y a rea,
a TRIMMARK III radio modem network can include up to two
repeaters. The repeat ers r etra nsmit data pack ets ac cor ding t o a simpl e
time-sharing scheme to avoid mutual interference. The operation of
the repeater is transparent to the rovers. The rovers can b e moved
while continually receiving data packets from the base or any one of
the repeaters, whichever the rover detects first.

TRIMMARK III Operation Manual 1-1

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Overview

1.1.1 TRIMMARK III Features

The TRIMMARK III has the following standard featur es:

• Selectable, 20 channel capability through an external channel

selector

• Built-in channel monitor capability

• Station ID selectable through the CommSet utility.

• Selectable 2W/25W transmit power

• Narrowband UHF technology

• Up to 15 km line-of-sight range under optimal conditions

• Selectable wireless data rate of 4800, 9600, or 19200 bps

• Interfaces with all Trimble survey-grade GPS receivers

• Operating mode selectable through the CommSet utility

1

*

• Supports up to two repeaters in a single network

• Rugged, weatherproof constructi on

• Two line, 16-character VFD display

• Trimble CMR and RTCM SC-104 Version 2.1 compatible

Note – As used in this manual, CMR as well as CMR Plus formats are
both represented by CMR.

• Carrier detect mode selectable through the CommSet

™

Windows

utility program

1-2 TRIMMARK III Operation Manual

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1 Overview

1.1.2 Equipment Sets and Accessories

The TRIMMARK III is av ailable as a stand-alone produ ct or in one of

two convenient, standard equipment sets—the base or repeater set.
These standard equipment sets are designed for use with GPS
receivers such as the Trimble 4700 and 4800. The equipment sets
contain many of the accessori es requir ed to operat e the radio mo dems
including cables, mounts, and antennas.

TRIMMARK III Base Equipment Set

The standard TRIMMARK III Base Equipment Set consists of these
components:

• TRIMMARK III radio modem

(410–420 MHz, 430–450 MHz, or 450–470 MHz)

• Standard antenna (0 dB, 5 dB UHF)

• 15-foot antenna cable with integrated antenna mount

*

• 2-foot antenna mounting poles, 3 each

• Tripod mounting plate

• Configuration cable (PC to radio modem)

• 50-foot data cable (0 shell to 0 shell)

• 6-foot power cable

• CommSet comm unication setup software diskette

• Oper ation manual

Note – The standard base equipment set is designed for use with
GPS receivers such as the Trimble 4700 and 4800. Contact Trimble
for information about connecting other GPS receivers.

TRIMMARK III Operation Manual 1-3

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Overview

1

TRIMMARK III Repeater Equipment

The standa rd TRIMMARK III Repeate r Equipment Set consists of
these components:

• TRIMMARK III Radio Modem (410–420 MHz, 430–450

MHz, or 450–470 MHz)

• Standard antenna (0 dB, 5 dB UHF)

• 15-foot antenna cable with integrated antenna mount

• 2-foot antenna mounting poles, 3 each

• Tripod mounting plate

• Configuration cable (PC to radio modem)

• 6-foot power cable

• CommSet communication setup soft ware Diskette

• Oper ation manual

1.1.3 Accessories

The standard equi pment sets for th e TRIMMARK III ar e design ed for
use with GPS receivers such as Trimble 4700 and 4800. Additional
accessories must be purchased to use the TRIMMARK III with GPS
receivers such as Trimble series 4000, Site Surveyor 4400, and
4600LS.

4000, 4400 and 4600 GPS Receiver Accessories

The data cable provi ded as par t of the sta ndard Base equipment s ets is
designed for use with Trimble 4700 and 4800 GPS receivers. The
following additional cable must be purchased for the use of GPS
receivers such as Trimble Series 4000, Site Surveyor 4400, and the
4600LS with the TRIMMARK III radio modem.

• 50-foot data cable (0-shell to 1-shell) for base use

1-4 TRIMMARK III Operation Manual

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1 Overview

*

Note – The 0-shell to 1-shell data cable will not connect directly

to the Trimble 4600LS GPS receiver. Use this data cable along
with the appropriate cable supplied with the 4600 to connect
the TRIMMARK III to the 4600LS.

1.1.4 Typical Broadcast Network

The TRIMMARK III radio modem is pri marily des igned to br oadcast
and repeat RT K (Real-Time Kinematic) data for use in GPS

surveying. It is compatible with Trimble’s CMR RTK data format as
well as the RTCM SC-104 Ver. 2.1 RTK da ta format. It is also
compatible with RTCM SC-104 Ver. 1.0, Ver. 2.0 and Ver. 2.1 for
DGPS broadcasts.

At UHF frequencies, wireless data links are line-of-sight (LOS). LOS
links are attenu ate d b y te rrai n feat ures su ch a s b uildi ngs and tr ees. As
a result, it is easier to bring survey control into the local work area
than to stretch the wire less data link to the limit of its usability.

With a LOS wireless data link, antenna height at the radio modem
becomes critical. Doubling the antenna height increases radio range
approximately 40%. In comparison, doubling broadcast power only
provides a 10% increase in LOS range.

The TRIMMARK III radio modems operate in one these frequency
bands:

• 410–420 MHz

• 430–450 MHz

• 450–470 MHz

Each unit operates in one of these bands, not across bands.

TRIMMARK III Operation Manual 1-5

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Overview

1.2 TRIMMARK III Description

The TRIMMARK III radio modem is packaged in a weatherproof
housing. The front panel has a VFD display to indicate channel
frequency, status, and errors. There are four buttons on the front
panel:

• SPEAKER

• UP

• DOWN

• NEXT

The rear panel has three electrical connectors:

• POWER connector (two-pin LEMO)

• DATA connector (seven-pin female LEMO)

• ANTE NNA connector (female TNC)

1

1.2.1 Controls and Indicators

The NEXT button is used to browse through the various menu
screens. The UP and DO WN b uttons are use d to change the displayed
parameters in the menu screens. The selected parameters appear on
the display. For example, while in the Main screen which displays
channel number and frequency, the UP and DOWN buttons control
channel/frequency selection. When the UP or DOWN button is
pressed, the selected channel/frequency will change. The radio
display shows the selected channel and freque ncy. Channels can on ly
be changed when the radio is not transmitting.

The SPEAKER button in t he upper-left corner of the radio panel
controls the volume of the received audio signal from the currently
selected channel. If traffic is present, you will hear the traffic if the
volume is turned on.

1-6 TRIMMARK III Operation Manual

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1 Overview

1.2.2 Power and I/O Cables

The TRIMMARK III equipment set comes with a data cable (not
provided in the repeater equipment set), an antenna cable with
integrated antenna mount, and a power cable. In addition a
configuration cable (PC to radio modem) is provided. The
configuration cable allows you to modify the radio modem
configuration using the Windows-based CommSet utility, includin g
the channel frequency, serial port settings, over-the-air baud rate,
carrier detect ON/OFF setting, station ID, and the operating mode.

When configured as a base, the radio modem receives data at the
DATA connector through a single LEMO-to-LEMO cable that plugs
into a Trimble 4700 or 4800 GPS receiver. When the unit is
configured as a repeater, no data connection is required.

Power is connected to the unit at the POWER connector from a
suitable power source.

1.2.3 Defaults

The TRIMMARK III radio modem is shipped from the factory with
the serial I/O port configured for 38400 bps, 8 data bits, odd parity
and 1 stop bit. The wirele ss data link is conf igu red to commun icate at
9600 bps and Carrier Detect is ON. If the base equipment set is
ordered, the unit is preconfigured for Base without a Repeater
operating mode, and transmit power is set to 25W. If the repeater
equipment set is ordered, the unit is preconfigured for Repeater 1
operating mode, and transmit power is set to 2W.

TRIMMARK III Operation Manual 1-7

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Overview

1.3 Standard Omnidirectional Antennas

Each radio modem, when purchased as part of a base or repeater
equipment set, is supplied with a standard omnidirectional antenna.
The omnidirectional antenna is a 5 dB gain UHF antenna with an
interchangeable 0 dB tip. Either of these antennas can be used with a
unit configured as a base or repeater. The antenna threads onto an
integrated antenna mount and cable. The integrated antenna mount
attaches to the antenna mounting poles on the top of a tripod using a
tripod mounting plate.

1.4 Directional Antennas

Two directional antenna options are available. The directional
antennas should be bolted to an extended mast for ma xi mum range at
the base or repeater. Each antenna comes with an integral antenna
cable for the radio modem. The integral antenna cable is not long
enough to connect directly to the TRIMMARK III. An additional
coaxial cable is required for most installations. The integral cable
terminates in a male TNC connector.

1

*

1-8 TRIMMARK III Operation Manual

Note – Always use the shortest, highest-quality coax cable possible
between the radio modem and the antenna. Cable attenuation at the

unit’s operating frequency can severely limit the radio's operational
range.

Additional antenna options are possible for special applications. The
major trade-offs are size, weight, cost, gain, and cou ntry-of-use
regulations. Characteristics and Specifications, page 3-1, describes
the trade-offs involved in selecting antenna types.

– DRAFT –

2 Operation

The TRIMMARK III radio modem contains both a data modem and a
radio. It can be used in a variety of configurations with appropriate
rover radio modems to form a complete wireless data network. One
configurat ion is as a TRIMMARK III base radio modem broadcasti ng
directly to a Trimble 4700 or 4800 rover GPS receiver equipped with
an internal radio modem. TRIMMARK III units may also operat e as
repeaters in this network.

Each TRIMMARK III radio modem can be used as soon as it is
hooked up. At power-up, the configuration parameters stored in non­volatile memory initialize the unit for operation. Some of these
parameters must be set to match the same values used in all units
operating on a network.

2.1 Configuration

Each TRIMMARK III radio modem comes fr om the factory with its
serial I/O port con f igure d for 38,4 00 bps, 8 dat a bits , odd pari ty and 1
stop bit. The wireless data link is set to 9600 bps and carrier detect is
set to ON at the factory. In addition, the TRIMMARK III is
preconfigured for either the Base without a Repeater or Repeater 1
operating mode, dependent on which equipment set is ordered.

TRIMMARK III Operation Manual 2-1

– DRAFT –

Operation

The factory default parameters are stored in nonvolatile memory and
serve as the initial power-up settings for the radio modems. The units
retrieve the parameters stored in non -volatile memory at each power­up. The power-up settings can be changed as often as necess ary usi ng
the CommSet utility (COMMSET.EXE) provided on the CommSet
diskette.

2.1.1 Configuring the Radio Modem

Using the CommSet utility, you can set up the serial I/O parameters,
operating mode, select the appropriate channel frequency, enable
carrier detect, and select the Station ID. Some of these parameters

also can be changed from the unit’s front panel.

2

*

*

Note – The BAUD RATE, FORMAT, and CTS parameters for the GPS
receiver must be configured to properly transfer data between the
receiver and the radio modem. BAUD RATE must be set to match the
maximum serial I/O rate of the radio modem (38400 bps) and
FORMAT is always set to 8-ODD-1. CTS flow control is disabled.

The radio modem must be connected to a computer running
Microsoft W ind o ws 95/98 o r W ind o ws NT to run the Co mmSet utility

COMMSET.EXE) and its associated help file (COMMSET.HLP).

(
Perform the following procedures to connect the unit to your
computer, install the CommSet utility under Windows, and set up the
desired radio modem parameters.

Note – Your computer must be able to support a 38400 bps serial
port data rate.

Connecting to a Computer

Connect the radio modem’s DATA connector to a COM port on the
computer with the Conf iguration cab le (DB9-LEMO). Connect po wer
between the POWER connector on the unit and a suitable power
source.

2-2 TRIMMARK III Operation Manual

– DRAFT –

2 Operation

2.1.2 Getting Started with CommSet

CommSet is a communications setup utility used for configuring
TRIMMARK III parameters. You need Microsoft Windows 95,
Windows 98, or Window s NT to run CommSet on your computer.
Read the README.TXT file provided on the CommSet diskette or
read the Microsoft Windows documentation for installation
instructions. The setup program adds a CommSet command to your
Windows Start menu and places and CommSet icon on the desktop.

Using CommSet

To use CommSet, follow the instructions on the screen to setup the
TRIMMARK III unit. For more i nformati on, ref er t o Commset online
help.

2.1.3 Frequency Updates

Each TRIMMARK III radio modem contains a list of up to 20
preprogrammed frequencies stored in non-volatile memory. This list
is preconfigured based on the frequencies requested when the unit
was ordered.

Governmental regulations prevent you from programming new
frequencies. Only manuf acturers or authorized deal ers can update thi s
frequency list. All frequencies programmed into a TRIMMARK III
radio modem must comply with the host country regulations.

When you want to change the frequency list (add, delete, or replace
frequencies) , t he internal frequency list must be updated. To facilita te
field updates, contact your Trimble dealer and provide the

TRIMMARK III radio modem’s serial number and a complete,
updated frequency list in order to obtain this update. There is a
nominal charge for this service.

TRIMMARK III Operation Manual 2-3

– DRAFT –

Operation

2.2 Installation

Before setting up the equipment in the field, verify that each radio
modem is set to the same frequency and wireless data rate. Also use

the Commset utility to ver ify th at the radi o modem’s GPS Port (serial
port) settin gs a re 3 8400 Ba ud Rate and Odd Parit y. Set the serial port
settings for both the base and rover GPS rece ivers to 38400 bps, 8
bits, odd parity and 1 stop bit. Refer to the GPS receiver manual for
general GPS receiver setup information. If these settings are not
available, use the CommSet utility to set th e radio modem’s serial port
settings to those of the GPS receiver.

2

*

Note – High-power signals from a near-by high-power radio station or
radar transmitter can overwhelm the radio modem circuits. This does
not harm the instruments, but can prevent them from functioning
correctly. To avoid problems, try not to use the radio modems within
400 meters of powerful radar, television, or other transmitters. Low­power transmitters such as the ones in portable phones and walkie­talkies normally do not interfere with TRIMMARK III radio modem
operations unless they are tuned to the same channel as your radio
modem units. Always monitor any frequency before and during
operation. Only transmit on a clear channel.

Also, to avoid possible interference with GPS reception, keep the
base radio modem antenna as far a s possibl e from t he GPS an tenna. A
minimum of 10 feet is recommended.

Refer to Using Radio Communication Systems with GPS Surveying
Receivers, page A-1, which is a copy of Trimble publication 1-612­0082-2/94 Using Radio Communication systems with GPS Surveying
Receivers, for precautions in using certain frequencies that can
interfere with GPS operation.

2.2.1 TRIMMARK III

The TRIMMARK III radio modem can be installed in a network as
the base station or as a repeater.

2-4 TRIMMARK III Operation Manual

– DRAFT –

2 Operation

Installation as a Base

To use a TRIMMARK III radio modem as a base, do the following:

1. If necessary, reconfi gure the unit ’ s seria l port setti ngs to thos e

of the GPS receiver using either the unit’s front panel or the
CommSet utility. Depending on whether or not repeaters are
to be used in the ra dio modem netw ork, sel ect the ap propriat e
operating mode on the unit. This step is very important to
ensure proper operation of the radio modem network.

2. Before connecting the power cable, thread the base antenna
onto its mount. Assemble the 3 antenna mounting poles
together and attac h the antenna mount and ant enna. The 5 dB
antenna tips are recommended for most applications.

3. Mount the entire antenna assembly on a tripod using the
tripod mounting plate and connect the antenna cable to the
TRIMMARK III radio modem.

I

4. Attach the antenna cable to the ANTENNA port on the unit.

5. Connect the power cable between the TRIMMARK III unit’s
POWER port and an appropriate 12V DC power source.

Caution – Be careful to connect the power cable with the correct
polarity. Reversing polarity does not damage the base radio modem,
but the protective 10 Amp fuse in the power cable will blow.

6. The front panel di spl ay s hould display the channel frequency
and status. Listen to the channel you are planning to operate
on using the built-in speaker or an external scanner. Change
the channel if you hear other users.

7. Connect the 50-foot data cable between the base radio
modem DATA port and the GPS receiver data port. For the
Trimble 4700 and 4800 GPS rece ivers, this is Port 3 (the 7­pin connector).

TRIMMARK III Operation Manual 2-5

– DRAFT –

Operation

2

If the GPS receiver is outputting data, the base should now be in
operation. Check the display on the front panel of the base unit to
verify operation when transmitting. A blinking TX indicates normal
transmission is in progress.

The TRIMMARK III radio modem at the base location broadcasts all
data it recei v es from the base GPS rece i ver to th e ro vers and repeaters
in the net work.

*

Note – To avoid possible interference with GPS reception, keep the
radio modem antenna as far as possible from any GPS antenna. A
minimum of 10 feet is recommended.

Installation as a Repeater

To achieve coverage to all points in a survey area, a TRIMMARK III
network may include up to two repeaters under certain conditions.
The repeaters retransmit data packets in a way that avoids mutual
interference with the base. The operation of the repeaters is
transpar ent to the rovers. A rover can be m oved and collec t data
packets fro m the base or repeaters, whichever the rover receives first.

The option to include repeaters in a TRIMMARK III network
depends on the selected wireless data rate and the broadcast
information content and rate (that is, CMR vs. RTCM 2.1 RTK
packets at 1Hz vs. 2Hz RTK epoch rates). Table 2-1 illustrates when
and how many repeaters may be used in a network for various
wireless data rates, RTK formats and RTK epoch rates.

2-6 TRIMMARK III Operation Manual

– DRAFT –

2 Operation

Table 2-1 Repeater Use in Networks

Wireless
Data Rate
(bps)

4800 1 1 X X
9600 2 2 0 0
19200 2 2 1 1

X Wireless dat a lin k is ino p er a ble.
0 No repeaters may be used.
1 One repeater possible.
2 Two repeaters possible.

RTCM 2.0
DGPS @ 1Hz CMR @ 1 Hz CMR @ 5 Hz

To install a TRIMMARK III radio modem as a repeater, do the
following:

1. Verify that the TRIMMARK III is configured to operate in

Repeater 1 or Repeater 2 r adi o mode us ing the fro nt pa nel or
CommSet utility, see page 2-3.

2. Also using CommSet, verify that the Base is set to be used as
Base with Repeater 1 or as a Base with 2 Re peaters. It is very

important to change the Operating Mode of the Base as well
as the repeat ers; otherwise, the radio modem n etwork will not
operate properly.

RTCM 2.1
DGPS & RTK
@ 1 Hz

3. Before connecting the power cable, thread the repeater

4. Mount the entire antenna assembly on a tripod using the

5. Attach the antenna cable to the ANTENNA port on the unit.

TRIMMARK III Operation Manual 2-7

antenna onto its mount. Assemble the 3 antenna mounting
poles together and attach the ant enna mount and ant enna. The
5 dB antenna tips are recommended for most applications.

tripod mounting plate, and connect the antenna cable to the
TRIMMARK III radio modem.

– DRAFT –

Operation

2

6. Connect the power cable between the TRIMMARK III unit’s

POWER port and an appropriate 12V DC power source. The
front panel should display the channel frequency as well as
status.

I

Caution – Be careful to connect the power cable with the correct
polarity. Reversing polarity does not damage the base radio modem,
but the protective 10 Amp fuse in the power cable will blow.

7. Set the repeater’s channel frequency to match the base radio
modem’s channel frequency. Radio modem channels are
changed by using the UP and DOWN arrow keys from the
Main screen. Channels can be chan ged only when the r adio is
not transmitting. The channel number/frequency in use is
displayed on the front panel.

8. Verify that the channel assignments are the same for all bas e,
repeater, and rover units.

The repeater should now be in operation. The display on the front
panel will blink "RPT", indicating proper operation of the repeater.

2.2.2 Antenna Installation

Several factors should be considered when installing and locating
antennas. Place antennas as high as possible above the ground and
surrounding obstructions such as trees, vehicles, buildings, and hills.

*

2-8 TRIMMARK III Operation Manual

Note – Antenna height is the most important factor in achieving
maximum range with radio modems. Doubling the antenna height
results in a 40% increase in line-of-sight range.

– DRAFT –

2 Operation

Line of Sight Obstruction

Objects placed near the antennas, especially metal objects, can
severely limit their efficiency. I f an antenna is to be mounted on an
antenna mast, make sure the antenna is mounted so that its radiating
element is completely above the top of any obstructing source if
possible.

P

Tip – Keep the radio modem unit near its antenna. Mount the unit as
close as possible to the antenna, rather than running a long length of
cable from the unit to an antenna, see Table 2-2.

Cable Losses

The cable length between the TRIMMARK III radio modem and its
antenna affects antenna range. Cabl e introduces loss in overall power
transmitted by your TRIMMARK III radio modem.

Table 2-2 lists typical loss characteristics for three popular types of
coaxial cable. The losses are expressed in dB/100 feet of cable.
Remember that connectors add an additional 0.25 to 0.5 dB loss per
connector.

Table 2-2 Cable Losses

Cable Type Cable Loss at 150

MHz (dB/100 Feet)

RG-58 6 dB 12 dB

Cable Loss at 450

MHz (dB/100 Feet)

RG-214 3 dB 5 dB
5/8" Heliax

*

TRIMMARK III Operation Manual 2-9

Note – Typically 3 dB signal loss = 50% power loss = 30% range
reduction.

®

0.5 dB 1 dB

– DRAFT –

Operation

2

Antennas

Three different omnidirectional UHF antennas, see Figure 2-4, are
available with both a 0dB tip and a 5dB tip. One antenna is used with

410–420 MHz radio modems, one is used with 430–450 MHz radio
modems, and a separate antenna is used with 450–470 MHz radio
modems.

The base of all standard antennas have a spring tab that must make
good contact with the b utton i n the cent er top of th e anten na mount. If
range seems limited to a few hundred feet, verify that this tab is
properly aligned.

2-10 TRIMMARK III Operation Manual

– DRAFT –

2 Operation

Frequency

Band

(cm)

L1

(in) (cm) (in)

L2

(MHZ)

410-420 20.3 8 15.0 5.9

430-450 17.4 6.8 12.3 4.8
450-470 16.9 6.6 13.3 5.2

IMPORTANT

Check these lengths and
adjust if necessary by

5 dB gain tip

0 dB gain tip

L1

loosening Allen screw

L2

Hand tighten desired antenna

tip onto antenna feed.

IMPORTANT

Check that the contact tab in
the base of the antenna feed
is at a 45 ˚ angle.

0.5 to 0.6 cm

(0.2 to 0.25 in.)

Figure 2-1 Standard UHF Omnidirectional Antennas

TRIMMARK III Operation Manual 2-11

– DRAFT –

Operation

2.3 Verifying Operation

Test the TRIMMARK III radio modem for proper operation. Always
monitor any f re quency before and during opera ti on. Only transmit on
a clear channel. Turn Carrier Detect ON to automatically monito r a
channel. If Carrier Detect is ON, the unit will only transmit when it
cannot hear an yone el se on t he chan nel. U.S. u sers s hould a lso ena ble
Station ID and enter the appropriate call sign to comply with FCC
regulations.

2.3.1 TRIMMARK III

The following sections describe how to verify the operation of the
TRIMMARK III radio modem.

Base Operation

Verify the operation of the TRIMMARK III radio modem by
watching the TX icon in the display on the front panel. In units
configured for b ase use, the TX icon blin ks to ind icate s uccess ful data
transmission.

2

Radio modem channels are changed by pressing the UP or DOWN
buttons on the radio from the Main screen. Channels can be changed
only when the radi o is not transmitting. The channel number/
frequency in use is displayed on the radio display.

To avoid possible interference with GPS reception, keep the radio
modem antenna as far as possible from th e GPS ant enna. A min imum
of 10 feet is recommended.

Repeater Operation

Depending on the configuration, the repeater can receive data
broadcast by either the base or another repeater. When such data is
received and successfully transmitted by the repeater, RPT will blink
on the front panel display.

2-12 TRIMMARK III Operation Manual

– DRAFT –

3 Characteristics and

Specifications

This chapter briefly summarizes performance characteristics and
specifications that can be expected from a TRIMMARK III radio
modem.

3.1 Antenna Gain

The antennas supplied with the TRIMMARK III do not increase the
energy radia ted by the radio modem. They concentrate the energy
from the radio modem in a particular direction. The degree to which
they concentrate radio frequency energy in any particular direction is
called directivity and is measured in dB, or decibels. The greater the
antenna gain in dB, the higher the directivity and the more the
radiated energy from the antenna is concentrated in some direction.

3.1.1 Omnidirectional Antennas

An antenna that radiates energy equally in all directions in the
horizontal plane is called omnidirectional. Omnidirectional antennas
radiate an equal amount of energy at every azimuth. However, they
are not omnidirectional in the vertical plane.

TRIMMARK III Operation Manual 3-1

– DRAFT –

Characteristics and Specifications

Figure 3-1 shows the radiated energy patterns of the omnidirectional
antennas used with the radio modems. All omnidirectional antennas
must be oriented vertically when used.

top view

3

Azimuth

0 dB

5 dB

ground level

view

Elevation

45˚

12˚

Figure 3-1 Omnidirectional Antenna Gain Patterns

The top view shows radiated energy patterns in the horizontal, or
azimuth plane of the antennas, the plane that perpendicularly bisects
the length of the antenna. For omnidirectional antennas, all azimuths
receive equal energy, but the 5 dB antenna radiates almost four times
more power in the horizontal plane than does the 0 dB antenna. In an
open field, four times more power approximately doubles the range.

3-2 TRIMMARK III Operation Manual

– DRAFT –

3 Characteristics and Specifications

The bottom view shows radiated energy patterns in the vertical, or
elevation, plane of the antennas. Much of the energy from the 5 dB

antenna is concentrated in elevation to within ±12° of horizontal. A
rover antenna within this sector receives stronger signals from a 5 dB
antenna. However, at angles greater than 12° from horizontal, the 0
dB gain antenna radiates more energy.

Antenna gain has exactly the same effect on signal reception as it
does on signal transmission. A high gain rover antenna can increase
range performance as long as it is oriented correctly w ith respect to
the transm it antenna. For high gain antennas, this means keepin g the
antenna element vertical and at the same elevation as the transmitting
antenna. Otherwise, it may be better to use an antenna with less gain.

3.2 Broadcast Network

The following sections describe the frequency bands, channel
spacings and wireless data rates available with the TRIMMARK III
radio modem.

3.2.1 Frequency Band and Channel Selection

The TRIMMARK III radio mod em operates in one the following
frequency bands:

• 410 to 420 MHz

• 430 to 450 MHz

• 450 to 470 MHz

Each unit operates in one of these bands, not across bands. The
TRIMMARK III radio modem stores up to 20 factory pre­programmed frequencies, and operates on one of these frequencies,
depending on which is selec ted. All 20 frequenci es must reside with in
one of the abo ve frequency bands. These freque nci es a re pre set at t he
factory.

TRIMMARK III Operation Manual 3-3

– DRAFT –

Characteristics and Specifications

3

*

Note – Each radio modem in a network must be tuned to the same
frequency in order for the network to operate.

In addition, the TRIMMARK III radio modem is available in two
different channel spacing configurations: 12.5 kHz and 25 kHz.
Channel spacing refers to the minimum separation, in Hz, between
two adjacent frequencies and can be viewed as the tuning resolution
of the radio modem. Channel spacing is dependent on local
government regulations.

3.2.2 Wireless Data Rate

The wireless data rate is the sp eed, in bits per second (bps), at which
the base unit transmits data to the rover unit. The TRIMMARK III
can be used only at 4800, 9600, or 19,200 bps.

*

Note – Each radio modem in a wireless data network must have the
same wireless data rate and chann el spa ci ng .

3.2.3 Transmit Power

The TRIMMARK III can be used as a base transmitter or as a
repeater.

Each unit can be configured to transmit 2W or 25W of power. The
transmit power can be configured from the front panel of the unit or
by using the CommSet utility. Units shipped as part of the base
equipment set are set to 25W at the factory. Units shipped as part of
the repeater set are set to 2W at the factory.

3-4 TRIMMARK III Operation Manual

– DRAFT –

3 Characteristics and Specifications

3.2.4 TRIMMARK III Electrical Interface

The TRIMMARK III rear panel has a grounding stud and three
connectors:

• POWER

• DAT A

• ANTENNA

The POWER connector is a 2-pin LEMO connector (+VDC, GND).
Be careful to connect the power cable with the correct polarity.
Reversing polarity does not damage the base radio modem, but the
protective 10 Amp fuse in the power cable will blow.

The DATA connector is a 7-pin LEMO connector.
The antenna connector on the TRIMMARK III radio modem is a

female TNC. The antenna should be connected to this port with the
shortest, highest-quality coax cable possible.

*

Note – Long antenna cables seriously degrade the range of the
wireless data network.

TRIMMARK III Operation Manual 3-5

– DRAFT –

Characteristics and Specifications

3.3 General Specifications

The following tables contain information on the TRIMMARK III
radio modems and antennas.

Table 3-1 TRIMMARK III Physical Specifications

Size 12.5 cm (4.9 in.) Wide

22.9 cm (9.0 in.) Deep

7.9 cm (3.1 in.) High

Weight 1.59 kg (3.5 lbs)
Power Input 10 VDC to 16 VDC, nominal
Connectors Power 2-pin LEMO (+VDC, GND)

Data 7-pin female LEMO (supports

Antenna TNC female

Temperature Operating –40 ° to +65° C (–40° to +149° F)

3

RXD, TXD and SGND)

Storage –55 ° to +75 ° C (–67 ° to +167° F)

Humidity 100%, fully sealed, weatherproof

Table 3-2 Antenna Physical Specifications

Type Length (typical) Weight

Standard 0 dB UHF
omni whip

Standard 5 dB UHF
omni whip

47 cm (18.5 in.) 0.5 kg (1.0 lb.)

99 cm (39 in.) 0.5 kg (1.1 lb.)

3-6 TRIMMARK III Operation Manual

– DRAFT –

3 Characteristics and Specifications

Table 3-3 Performance Specifications (Typical)

Transmit Power Selectable 2W / 25W
Wireless Data Rate 4800, 9600, or 19,200 bps
Frequency Bands 410–420 MHz, 430–450 MHz, or 450–470 MHz. Only

one band per radio modem

Channel Spacing 12.5 kHz or 25 kHz. Only one per radio modem
Number of Channels Up to 20 factory preprogrammed frequencies,

internally stored

RF Modulation Format Gaussian Minimum Shift Keying (GMSK)
Serial Port One set of RS-232 signals available. Data is 8 bits with

selectable parity and 1 stop bit. Supported data rates
are 9600 and 38400 bps.

1. Use the same frequency for all radio modems in the same wireless data network.

1

3.4 General Care

The TRIMMARK III radio modem is design ed to t ole rate the normal
rough treatment th at equipment can suf fer in the f iel d. Howe v er , these
units are high-precision electronic instruments, and should be treated
with reasonabl e care. The ra dio modems ope rate in temperatures from

–40° to +65° Celsius (–40°F to +149°F). The enclosures are sealed
and buoyant.

M

Warning – Operating or storing your TRIMMARK III radio modem
outside the specified temperature range can destroy or limit the
longevity of the instruments.

3.5 Service

There are no us er serv iceable parts with the TRIMMARK III. Con tact
your Tr imble dealer for information about obtaining service for your
product. Refer to the Preface at the front of this manual for
information about getting technical assistance.

TRIMMARK III Operation Manual 3-7

– DRAFT –

Characteristics and Specifications

3

3-8 TRIMMARK III Operation Manual

– DRAFT –

4 Regulations and Safety

Regulations regarding the use of the radio m odems vary greatly from
country to country. In some countries, the unit can be used without
obtaining an end-user license. However, most countries require end­user licensing. Consult your local communications governing agency
for licensing info rmation.

Before operating a TRIMMARK III radio modem, determine if
authorization or a license to operate the unit is required in your
country. Obtaining an operator’s permit or license for the

TRIMMARK III for the location or country-of-use is the
responsibility of the end user.

*

TRIMMARK III Operation Manual 4-1

Note – This device complies with Part 15 of the FCC Rules.
Operation is subject to the condition that this device does not cause
harmful interference.

– DRAFT –

Regulations and Safety

4.1 Type Approval

Type Approval, or acceptance, covers technical parameters of the
equipment related to emissions that can cause interference. Type
Approval is granted to the manufacturer of the transmission
equipment, independent from the operation or licensing of the units.
(Licensing or application for operation is the responsibility of the
user.) Some countries have unique technical requirements for
operation in certain radio modem frequency bands. To comply with
those requirements, Trimble may have modified your equipment in
order to be granted Type Approval. Unauthorized modification to the
units voids the Type Approval, the warranty and the operational
license of the equipment.

4

I

Caution – Changes or modifications to this equipment not approved,
in writing, by Trimble Navigation Limited voids your authority to
operate the equipment.

4.2 Licensing

Many countries require that the operator of a radio, or radio modem,
obtain a license prior to operating the radio, or radio modem. Some
do not. Consult your local communications governing agency for
licensin g informat ion. Obtaining an operator’s permit or license

for the TRIMMARK III for the location or country-of-use is the
responsibility of the end user.

Before operatin g t hi s ra dio modem, you are legally req uir ed to obtain
frequency licenses as required by the country-of-use. Please contact
your local communications governing agency for the licensing
requirements for each of these radio modems.

4-2 TRIMMARK III Operation Manual

– DRAFT –

4 Regulations and Safety

4.3 Safety

Exposure to RF ener gy is an important s afety con siderati on. The FCC
has adopted a safety standard for human exposure to radio frequency
electromagnetic energy emitted by FCC regulated equipment as a
result of its actions in General Docket 79-144 on March 13, 1986.
Proper use of this radio modem result s in exposure bel ow gov ernment
limits. The following precautions are recommended:

• DO NOT operate the transmitter when someone is within
two feet (0.6 meter) of the antenna.

• DO NOT operate th e transmit ter unle ss all RF c onnect ors are
secure and any open connectors are properly terminated.

• DO NOT operate the equip ment near electrical blasting caps
or in an explosive atmosphere.

• All equipment must be properly grounded according to
Trimble installation instructions for safe operation.

• All equipment should be serviced only by a qualified
technician.

TRIMMARK III Operation Manual 4-3

– DRAFT –

Regulations and Safety

4

4-4 TRIMMARK III Operation Manual

– DRAFT –

A Using Radio

Communication
Systems with GPS
Surveying Receivers

Trimble Publication 1-612-0082-2/94

"GPS receiver, antenna, tripod, tribrach, tape, cones, flagging,
radio...", such is the checklist of most GPS surveyors preparing for a
day of observations. But a truly successful survey is not just a matter
of making sure that you have all of the equipment, you must also
ensure that you optimize the usage of these new tools for the highest
productivity.

The GPS receiver is trying to measure very faint radio signals from
satellites orbiting at 22,000 kilometers in space. There are many

factors that can hinder the receiver’s ability to perform. For example,
placing your hand over the antenna or setting up the antenna under a
tree are factors that have already proven to interfere with GPS signal
reception.

TRIMMARK III Operation Manual A-1

– DRAFT –

Using Radio Communication Systems with GPS Surveying Receivers

As GPS receivers developed, their processors have become more
sensiti ve t o incoming d ata flo w. This provide s an increas e in accurac y
by extracting more information out of the GPS radio signal. But with
this gain i n accura cy, there is a n increa sed sus ceptibi lity to other ra dio
signals. The receiver is now more sensitive to the incoming GPS
signal, and consequently it is also more sensitive to other incoming
radio signals. This means that communications radios, such as ones
commonl y used by surveyor s, can sometimes crea te difficulty with
the GPS signal reception.

There are some very simple steps you can follow to remove the
effects of rad io i nte rf erence on the GPS receiver. First, you should be

aware of the type of communications equipment you’re buying and
understand its characteristics. Secondly, a little care in using
communications radio can greatly decrease your chances of
experiencing any interference with satellite tracking.

A

A.1 Selecting Communications Radios

If you do not alre ady hav e communicati ons radios, a nd are thinking of
buying them to supplement your survey activities, there are a couple
of factors to keep in mind before purchasing: (a) some frequencies
can cause interruptions or GPS tracking; (b) certain communications
equipment creates spurious signals not related to their frequency that
can interfer e with satelli te tracking ; and (c) po werful communi cations
transmitters can create such a strong radio signal that the GPS signal
cannot be identi fied.

Most communication transmitters emit overtones of their assigned
frequency. If these overtones line up with the GPS frequency, it can
filter i n t o th e GPS equipment and interfere with t he sat ellite tracking.
Some communication transm itters emit more of these overtones than
others. But the number of overtones can be difficult to determine and
is not the most important factor when considering this nuisance
parameter. To avoid being affected by transmitter overtones, simply
avoid those frequencies that lie within the GPS frequency range.

A-2 TRIMMARK III Operation Manual

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A Using Radi o Communication Systems with GPS Surveyin g Receivers

Table A-1 shows frequency bands that you should avoid.

Table A-1 RF Bands to Avoid When Using GPS

Surveying Receivers

From this Frequency To this Frequency

781.210 794.210

607.300 620.300

520.806 529.473

404.866 413.533

390.605 397.105

312.484 317.684

303.650 310.150

260.403 264.736

242.920 248.120

223.202 226.917

202.433 206.766

195.302 198.552

173.602 177.228

156.242 158.842

151.825 155.075

142.038 144.401

134.955 137.844

130.201 132.368

120.186 124.060

110.418 113.458

TRIMMARK III Operation Manual A-3

– DRAFT –

Using Radio Communication Systems with GPS Surveying Receivers

Some communication transmitters and receivers also emit spurious
signals. These are extremely difficult to predict. So, the only way to
know if y our recei ver is being hampered b y spuriou sly emitted s ignals
is to test the communication equipment with the GPS receiver. If you
plan to buy a ne w rad io, the best cour se of actio n is to test it with your
existing GPS equipment, to determine any problems exist.

Communications equipment that uses more power is more likely to
create signals from which the GPS signal cannot be extracted. This
case typically occurs from signals emitted from the radio transmitter
box and not its antenna. Non-GPS signals enter the GPS system
through the GPS antenna and not through the receiver. Therefore,
most of the effe cts of non-GPS signals can be minimized by
physically separating your radio and GPS equipment.

A

A-4 TRIMMARK III Operation Manual

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A Using Radi o Communication Systems with GPS Surveyin g Receivers

A.2 Useful Field Procedures

There are a few useful field procedures that you can follow to
minimize the effects of your radio. Since most of the radio signal in
the GPS band is emitted directly from the radio transmitter box and
received via the GPS antenna, make sure the GPS antenna is
separated from the radio transmitter by 2-3 meters . If you are still
experiencing difficulties at this distance the GPS signal may be
getting o ve r -p o wer ed b y the ra dio tr ansm issi ons. In thi s cas e, you ca n
either separate the equipment even more or shield the radio
transmitter.

Radio signal strengt h drops as you mov e further a way from the source

of the transmission – dropping as a square of the distance. Therefore,
if there is a problem, se parate the GPS ant enna and radio e ve n more to
lessen the strength of the radio signal received at the GPS antenna.

If you are using a geodetic ant enna, you ca n use the ante nna’s ground
plane to shield the radio waves. In fact, you can shield the antenna
from the radio signal by moving behind nearby objects such as a car
or tree. If you cannot move away from the GPS antenna, move th e
radio below the level of the GPS antenna ground plane. This is not
ideal, but may help in those cases where you are left with no
alternative.

TRIMMARK III Operation Manual A-5

– DRAFT –

Using Radio Communication Systems with GPS Surveying Receivers

A.3 Summ a ry

Using communications radios with GPS receivers requires some
special c onsiderations. By striving to extract the utmost accuracy
from the GPS system, receiver designs have made greater use of the
radio spectrum. However, the methods used to increase performance
and accuracy also make GPS receivers more susceptible to receiving
other radio signals.

Radio signals in the GPS band arise from a few different sources.
Some radio transmitters produce overtones of their frequency, which
lie within the GPS P-code frequ ency range. Others crea te random,
spurious signals, which affect GPS signal reception. Still other radio
systems use high power levels to boost communication range and
create noise that limits the GPS signal tracking. These are all
characteristics to avoid when purchasing or using communications
equipment in conjunction with GPS.

Before using radios on full-fledged survey job, it is a good idea to test
the communications equipment to determine if it affects the GPS
signal recepti on in an y wa y. T estin g radios with the GPS equi pment is
especially importa nt if you are consideri ng purchasing ne w radios. Be
sure to always:

A

• Choose the communication frequency of your radios
carefully so t hey do not transmit on or create h armonics in the
frequency r ange of GP S.

• Prior to buying radios , make sure that you test them with yo ur
GPS receivers.

• If problems arise, put some distance between the radio
transmitter case and the GPS antenna. Also, shielding the
radio transmitt er shoul d mi ni mize the effe ct s of radio signals
on the GPS signal reception.

Radio signal strength drops as a function of distance. The greater the
separation betwee n the GPS anten na and the rad io transmit ter , the les s
likely you are to experience the interruptions in satellite tracking.

A-6 TRIMMARK III Operation Manual

– DRAFT –

Index

Numerics

1 stop bit 2-1
38,400 bps 2-1
8 data bits 2-1

A

accessories 1-3
ANTENNA

cable 2-5
connector 1-6, 3-5
electrical interface 3-5
installation 2-5
port 2-7
specifications 3-6

antenna 2-9

0 dB 3-2
5 dB 3-2
cable

attenuation 1-8
cable losses 2-9
directional 1-8
doubling broadcast power 1-5
doubling height 1-5
gain 3-1

omnidirectional

height 2-8

antennas 3-1

installation 2-8
obstructions 2-8
omnidirectional 1-8, 3-1
physical specifications 3-6

attenuation

antenna cable 1-8

audience xv

B

base

equipment set 1-3
operation 2-12

Base without a repe ater

operating mode 2-1

Base without repeater

operating mode 1-7

baud rate

serial port 2-2

broadca st network

electrical interface 3-5
frequency band and channel

selection 3-3
overview 3-3
transmit p ower 3-4
wireless data rate 3-4

button

DOWN 1-6

TRIMMARK III Operation Manual Index-1

– DRAFT –

Index

NEXT 1-6
SPEAKER 1-6
UP 1-6

C

cable

ANTENNA 2-5
DA T A 2-5
directional antenna 1-8
I/O 1-7
omnidirectional ant enna 1-8
POWER 2-5
power 1-7
power losses 2-9

carrier detect

default 1-7
cautions xix
channel

spacing 3-7
characteristics 3-1
COM port 2-2
CommSet utility

configuring

radio modem 2-2
getting started 2-3
help 2-2
radio modem configuration 1-7,

2-2

using 2-3

configuration

computer connection 2-2
overview 2-1
radio modem 2-2
serial DATA port 2-2
TRIMMARK III 2-1

rover 2-1

connecting

PC 2-2

connector

ANTENNA 1-6, 3-5
DATA 1-6, 3-5
POWER 3-5
POWER & I/O 3-5

controls and indicators

TRIMMARK III 1-6

copyright ii

D

DA T A

connector 1-6, 3-5
electrical interface 3-5
port 2-5

specifications 3-6
data modem 2-1
defaults

carrier detect 1-7

serial communication

parameters 1-7
transmit p ower 1-7
TRIMMARK III 1-7

directional antenna 1-8
disclaimer of warranty iv
document conventions xviii

E

electrical interface

broadca st network 3-5

equipment sets 1-3

repeater 1-4
TRIMMARK III 1-3

Index-2 TRIMMARK III Operation Manual

– DRAFT –

Index

F

FCC

call sign 2-12
compliance 4-1
safety standard 4-3
type approval 4-2

field procedures

TRIMMARK III A-5
File Transfer Protocol (FTP) site xvii
format

serial I/O port 2-2
frequencies

preprogrammed 3-7
frequency

bands 1-5, 3-7

operating 1-8

updates 2-3
ftp.trimble.com xvii

G

overview 2-4
POWER cable 2-5
repeater 2-6
TRIMMARK III 2-4

L

licensing

TRIMMARK III 4-2
limitation o f liability iv
limited warranty

firmware iv

software iv
line-of-sight (LOS)

achieving coverage 1-1

obstructions 2-9

wireless data links 1-5
LOS (line-of-sight)

achieving coverage 1-1

wireless data links 1-5

general

care 3-7
specifications 3-6

GMSK

RF modulation format 3-7

I

I/O cable

TRIMMARK III 1-7

installation

antenna 2-8
ANTENNA cable 2-5
base 2-5
DATA cable 2- 5

TRIMMARK III Operation Manual Index-3

– DRAFT –

N

network

repeater usage 2-7
NEXT button 1-6
notes xix
notices iii
number

of channels 3-7

O

obstructions

line-of-sight 2-9
odd parity 2-1

Index

omnidirectional ant enna 1-8
omnidirectional ant enna s

gain 3-1
gain patterns 3-2
operation 2-10

operating mode

Base without a repeater 2-1
Base without repeater 1-7
Repeater 1 1-7, 2-1

operation

base 2-12
repeater 2-12
TRIMMARK III 2-1

TRIMMARK Rover 2-1
organization xv
overview

TRIMMARK III 1-1

P

performance

specifications 3-7

TRIMMARK III 3-7

physical specifications

TRIMMARK III 3-6
port

ANTENNA 2-5

DA T A 2-5

POWER 2-5
POWER

connector 1-6, 3-5

electrical interface 3-5

port 2-5

specifications 3-6
preface xv

R

radio 2-1

frequency bands to avoid when

using GPS surveying
receivers A-3

using A-1

radio mode

Repeater 1 2-7
Repeater 2 2-7

range

operational limitations 1-8
reader comment form xvii
regulati ons 4-1

affecting TRIMMARK III 4-1
repeater 1-1

installation 2-6

operation 2-12

use in networks 2-7
Repeater 1

operating mode 1-7, 2-1

radio mode 2-7
Repeater 2

radio mode 2-7
revisi on not ice iii
RF

bands to avoid A-3

energy iii, 4-3

modulation format 3-7
rover 1-1

S

safety 4-1

overview 4-3

TRIMMARK III 4-1
scope xv

Index-4 TRIMMARK III Operation Manual

– DRAFT –

Index

selecting

communications ra dios A-2

serial

DATA port

configuration 2-2
format 2-2

port 3-7

baud rate 2-2

service

TRIMMARK III 3-7

setup

CommSet utility 2-3
SPEAKER button 1-6
specifications 3-1

antenna 3-6

ANTENNA port 3-6

DATA port 3-6

general 3-6

performance 3-7

physical 3-6

POWER port 3-6

TRIMMARK III 3-1

T

technical assistance xvii
temperature

operating 3-6

storage 3-6
tips xix
trademarks iii
transmit

power 3-7

broadcast network 3-4

power default 1-7
Trimble

publication 1-612-0082-2/94 A-1

TRIMMARK III 1-3

accessories 1-3
antenna physical

characteris ti cs 3-6

base

equipment set 1-3

operation 2-12
buttons 1-6
characteris ti cs and

specifi ca ti ons 3-1
configur at ion 2-1
connector

ANTENNA 1-6
DA T A 1-6
POWER 1-6

specifi ca ti ons 3-6
controls and indicators 1-6
DA T A

cable 1-7

connector 1-7
defaults 1-7
description 1-6
directional antenna 1-8
equipment sets 1-3

repeater 1-4
FCC

compliance 4-1

type approval 4-2
features 1-2
field procedures A-5
frequency update s 2-3
general care 3-7
general s pecifications 3-6
installation 2-4

base 2-5

repeater 2-6
licensing 4-2

TRIMMARK III Operation Manual Index-5

– DRAFT –

Index

omnidirectional ant enna 1-8
operating temperatur e 3-6
operation 2-1
overview 1-1
physical specifications 3-6
POWER

cable 1-7

connector 1-7
power 3-6
radio modem

network 3-1
regulations and safety 4-1
repeater

equipment 1-4

operation 2-12

usage 2-7
RF bands to avoid A-3
rover configurat ion 2-1
safety 4-1, 4-3
service 3-7
size 3-6
specifications

performance 3-7
storage temperature 3-6
supported frequency bands 1-5
typical broadcast network 1-5
verifying operation 2-12
weight 3-6

type approval

FCC 4-2

typical broadcast network

TRIMMARK III 1-5

radio communication sy stems with

GPS surveying receivers A-1

V

verifying

base operation 2-12
repeater operation 2-12

W

warnings xix
wireless

data link

default 1-7
data links 1-5
data rate 3-4, 3-7

broadca st network 3-4

World Wide Web ( W WW) site xvi
www.trimble.com xvi
www.trimble.com/support/

support.htm xvii

U

update notes xvi
using

Index-6 TRIMMARK III Operation Manual

– DRAFT –

Reader Comment Form

TRIMMARK III Operation Manual November 1999
P/N: XXXXX-00 Revision A

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– DRAFT –