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Wattcher® monitor/alarm
Models 3026A, 3127A, and 3128A
©
Copyright 2010
Instruction Book Part Number 920-3126/27/28A Rev. B
by Bird Electronic Corporation
Wattcher is a registered trademark
of Bird Electronic Corporation
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Safety Precautions
The following are general safety precautions that are not necessarily related to any specific
part or procedure, and do not necessarily appear elsewhere in this publication. These precautions must be thoroughly understood and apply to all phases of operation and maintenance.
WARNING
Keep Away From Live Circuits
Operating Personnel must at all times observe general safety precautions. Do not replace
components or make adjustments to the inside of the test equipment with the high voltage
supply turned on. To avoid casualties, always remove power.
WARNING
Shock Hazard
Do not attempt to remove the RF transmission line while RF power is present.
WARNING
Do Not Service Or Adjust Alone
Under no circumstances should any person reach into an enclosure for the purpose of
service or adjustment of equipment except in the presence of someone who is capable of
rendering aid.
WARNING
Safety Earth Ground
An uniterruptible earth safety ground must be supplied from the main power source to test
instruments. Grounding one conductor of a two conductor power cable is not sufficient
protection. Serious injury or death can occur if this grounding is not properly supplied.
WARNING
Resuscitation
Personnel working with or near high voltages should be familiar with modern methods of
resuscitation.
WARNIN G
Remove Power
Observe general safety precautions. Do not open the instrument with the power on.
Safety Symbols
WARNING
Warning notes call attention to a procedure, which if not correctly performed could result in
personal injury.
CAUTION
Caution notes call attention to a procedure, which if not correctly performed could result in
damage to the instrument.
This symbol indicates that a shock hazard exists if the precautions in the
instruction manual are not followed.
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The caution symbol appears on the equipment indicating there is important information in the instruction manual regarding that particular area.
This symbol indicates that the unit radiates heat and should not be touched
while hot.
Note: Calls attention to supplemental information.
Warning Statements
The following safety warnings appear in the text where there is danger to operating and maintenance personnel and are repeated here for emphasis.
WARNING
When using dry cleaning solvents, provide adequate ventilation and observe normal safety
precautions. Many dry cleaning agents emit toxic fumes that may be harmful to your health,
if inhaled.
See page 18.
WARNING
Never attempt to disconnect the transmission line while RF power is being applied. Leaking
RF energy is a potential health hazard..
See page 18.
Caution Statements
The following equipment cautions appear in the text whenever the equipment is in danger of
damage and are repeated here for emphasis.
CAUTION
The Wattcher, elements and line section have been calibrated together. Replacing any
component without recalibrating all the components as a unit may affect accuracy.
See page 7.
CAUTION
Be sure voltage selector switch is in the appropriate position before applying ac power.
Failure to do so will damage the unit.
See page 10.
CAUTION
Do not remove RF center conductor. Placement is critical for proper calibration and
obtaining specified accuracy.
See page 18.
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CAUTION
Do not attempt to check the microammeters with an ohmmeter. Damage to the movement or
pointer will result.
See page 19.
CAUTION
Replace with only the same type and rating fuse. T, 125 mA, 250VAC.
See page 19.
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Safety Statements
USAGE
ANY USE OF THIS INSTRUMENT IN A MANNER NOT SPECIFIED BY THE
MANUFACTURER MAY IMPAIR THE INSTRUMENT’S SAFETY PROTECTION.
USO
EL USO DE ESTE INSTRUMENTO DE MANERA NO ESPECIFICADA POR EL
FABRICANTE, PUEDE ANULAR LA PROTECCIÓN DE SEGURIDAD DEL
INSTRUMENTO.
BENUTZUNG
WIRD DAS GERÄT AUF ANDERE WEISE VERWENDET ALS VOM HERSTELLER
BESCHRIEBEN, KANN DIE GERÄTESICHERHEIT BEEINTRÄCHTIGT WERDEN.
UTILISATION
TOUTE UTILISATION DE CET INSTRUMENT QUI N’EST PAS EXPLICITEMENT
PRÉVUE PAR LE FABRICANT PEUT ENDOMMAGER LE DISPOSITIF DE
PROTECTION DE L’INSTRUMENT.
IMPIEGO
QUALORA QUESTO STRUMENTO VENISSE UTILIZZATO IN MODO DIVERSO DA
COME SPECIFICATO DAL PRODUTTORE LA PROZIONE DI SICUREZZA
POTREBBE VENIRNE COMPROMESSA.
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SERVICE
SERVICING INSTRUCTIONS ARE FOR USE BY SERVICE - TRAINED
PERSONNEL ONLY. TO AVOID DANGEROUS ELECTRIC SHOCK, DO NOT
PERFORM ANY SERVICING UNLESS QUALIFIED TO DO SO.
SERVICIO
LAS INSTRUCCIONES DE SERVICIO SON PARA USO EXCLUSIVO DEL
PERSONAL DE SERVICIO CAPACITADO. PARA EVITAR EL PELIGRO DE
DESCARGAS ELÉCTRICAS, NO REALICE NINGÚN SERVICIO A MENOS QUE
ESTÉ CAPACITADO PARA HACERIO.
WARTUNG
ANWEISUNGEN FÜR DIE WARTUNG DES GERÄTES GELTEN NUR FÜR
GESCHULTES FACHPERSONAL.
ZUR VERMEIDUNG GEFÄHRLICHE, ELEKTRISCHE SCHOCKS, SIND
WARTUNGSARBEITEN AUSSCHLIEßLICH VON QUALIFIZIERTEM
SERVICEPERSONAL DURCHZUFÜHREN.
ENTRENTIEN
L’EMPLOI DES INSTRUCTIONS D’ENTRETIEN DOIT ÊTRE RÉSERVÉ AU
PERSONNEL FORMÉ AUX OPÉRATIONS D’ENTRETIEN. POUR PRÉVENIR UN
CHOC ÉLECTRIQUE DANGEREUX, NE PAS EFFECTUER D’ENTRETIEN SI L’ON
N’A PAS ÉTÉ QUALIFIÉ POUR CE FAIRE.
ASSISTENZA TECNICA
LE ISTRUZIONI RELATIVE ALL’ASSISTENZA SONO PREVISTE ESCLUSIVAMENTE
PER IL PERSONALE OPPORTUNAMENTE ADDESTRATO. PER EVITARE
PERICOLOSE SCOSSE ELETTRICHE NON EFFETTUARRE ALCUNA RIPARAZIONE
A MENO CHE QUALIFICATI A FARLA.
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CONNECT INTERLOCK TO TRANSMITTER BEFORE OPERATING.
BRANCHER LE VERROUILLAGE À L'ÉMETTEUR AVANT EMPLOI.
CONECTE EL INTERBLOQUEO AL TRANSMISOR ANTES DE LA OPERACION.
VOR INBETRIEBNAHME VERRIEGELUNG AM SENDER ANSCHLIESSEN.
PRIMA DI METTERE IN FUNZIONE L'APPARECCHIO, COLLEGARE IL
DISPOSITIVO DI BLOCCO AL TRASMETTITORE.
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About This Manual
This manual covers the operating and maintenance instructions for the following models:
3126A 3127A 3128A
Changes to this Manual
We have made every effort to ensure this manual is accurate. If you discover any errors, or if you
have suggestions for improving this manual, please send your comments to our Solon, Ohio factory. This manual may be periodically updated. When inquiring about updates to this manual
refer to the part number and revision on the title page.
Terminology
There are some unique terms used throughout this literature. They are defined here to clarify
any misunderstanding.
Introduction — Describes the features of the load resistor, lists equipment supplied and
optional equipment, and provides power-up instructions.
Theory of Operation — Describes how the load resistor works.
Installation — Describes the power supply and load connection instructions.
Operating Instructions — Describes the base level operation instructions.
Maintenance — Lists routine maintenance tasks as well as troubleshooting for common prob-
lems. Specifications and parts information are also included.
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Table of Contents
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Warning Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ii
Caution Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ii
Safety Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii
Changes to this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii
Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii
Chapter 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Purpose and Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Items Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Line Sections & Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Cable Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Enclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Chapter 2 Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Alarm Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Fail-Safe/Non Fail-Safe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Element Socket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Matching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Load Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
r vs. f and its Significance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Measurement and Monitoring of Transmitter Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 3 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Items Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Line Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Wattcher RFMonitor/Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Chapter 4 Operating Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Zero Adjust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Alarm Enable/Disable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Fail-Safe / Non Fail-Safe Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Adjusting Reflected Power Trip Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Connecting the Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Using Remote Reset & Auxiliary DC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Meter Scales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Alarm Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Determining VSWR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
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Chapter 5 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Preparation for Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Line Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
DC Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Line Section Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Meter Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Contact Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Fuse Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Models 3126A and 3127A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Model 3128A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Common Specifications and Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Replacement Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Coupling Kits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Available QC Type Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Limited Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
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Chapter 1 Introduction
This publication refers to the Wattcher RF Monitor/Alarm models 3126A, 3127A, and 3128A. The differences between models are listed in the specifications. All models will generally be referred as a Wattcher Unit throughout this manual.
The information in this instruction book pertains to all models except noted differences referred to in the text.
The Bird Wattcher RF Monitor/Alarm—when installed with a dual port Thruline Line Section and two elements—is
designed for the protection and monitoring of radio frequency transmission systems. The line section is selected to
be compatible with the RF coaxial line used in the transmission system. The elements are selected by the user to
cover the desired power levels and frequency ranges.
Purpose and Function
Abnormal loading conditions cause the transmitter to quickly shutdown, a user selectable audible alarm to sound,
and an alarm LED to flash.
Remote access is available for resetting audible and visual alarms. Fail-safe or non fail-safe modes are user selectable and the reflected power trip level is adjustable. "Operating Instructions" on page 11 detail these features.
Figure 1 Outline Drawing
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Items Supplied
• Wattcher Monitor/Alarm
• 115/230 VAC Power Cord
• DC Cable (2)—25’ Standard Other Lengths Optional
• Interlock Connector—Six-Terminal, Screw-Clamp Plug Connector
• Remote Reset / Auxiliary DC Connector—Four-Terminal Screw-Clamp Plug Connector
Options
Line Sections & Elements
Frequency and power range are governed by the line section and elements selected. Refer to sales catalog for available models.
Cable Assemblies
DC Cable Assemblies are available for remote rigid line installation. The assemblies are various length of RG-58/U
cable with a DC plug, P/N 7500-076 on one end and a BNC(m) connector installed on the opposite end. See
“Replacement Parts List” on page 21 for cable lengths and part numbers.
Functional Description
Enclosure
The Wattcher RF Monitor/Alarm is enclosed in an aluminum housing intended for a standard 19" rack mount.
Figure 2 Front Panel
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Table 1-1 Front Panel
1 Forward Power Meter Analog Meter Indicating forward power.
2 Reflected Meter Analog Meter indicating reflected power.
3 Alarm Active LED Green LED, when illuminated the alarm is active, power
is on.
4 RFL Alarm LED Red LED, flashes when the reflected power trip level has
been exceeded for more than 50ms.
5 Reset Push-button Resets the Wattcher to normal operation after the error
condition is corrected
6 View Push-button Allows for viewing the reflected power trip level during
adjustment.
7 Adjust Potentiometer providing for adjustment of reflected
power trip level.
Figure 3 Rear Panel
Table 1-2 Rear Panel
1 Forward Sensor
Input Connector
2 Reflected Sensor
Input Connector
39-16 VDC Auxiliary positive (+) DC power connection.
4Ground Auxiliary negative (-) power connection.
5Ground Remote reset ground connection.
6 Remote Reset Remote reset connection.
7NO1 Normally open connection for interlock one.
8COM1 Common Connection for interlock one.
9NC1 Normally closed connection for interlock one.
10 NO2 Normally open connection for interlock two.
11 COM2 Common Connection for interlock two.
12 NC2 Normally closed connection for interlock two.
13 Non Fail / Fail Safe Select switch for non fail-safe or fail-safe mode.
14 Alarm Alarm enable/disable switch.
15 Fuse Fuse receptacles for 0.125A, 250v fuses.
16 AC Receptacle Provides a means of supplying AC line power to
17 Line Voltage Selector
Switch
Input connector for forward power sensor cable from
port A of line section.
Input connector for reflected power sensor cable from
port B of line section.
Wattcher.
Determines line voltage operation.
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Chapter 2 Theory of Operation
General
The forward power meter acts as a continuous monitor of forward power output. This provides a reference against
the reflected power value enabling determination of power ratios and VSWR.
Alarm Condition
An alarm condition occurs as the result of the reflected power being greater than the reflected power set point for
longer than 50ms. If enabled, an audible alarm will sound.
An alarm condition will also activate the interlock. An active interlock will cause the normally open terminals to
close and the normally closed terminals to open.
Fail-Safe/Non Fail-Safe
In the fail-safe mode an alarm condition will also occur if the Wattcher is not powered. The non fail-safe mode
requires power for an alarm condition.
Element
The function of the element is to detect (sense) the forward or reflected RF power in the line section at any given
time. The direction in which the “arrow” on the element cap is oriented indicates the direction in which it is sensing
the RF power flow in the system.
Figure 4 Element Schematic
The forward wave travels and its power flows from the source to the load. It has an RF voltage E
phase, with E
f / If = Zo.
f and current If in
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The reflected wave originates by reflection at the load, travels, and its power flows from the load back to the source.
WfWattsForward E
f
2
ZoI
f
2
=⁄ ZoEfIf===
WfWattsReflected E
r
2
ZoI
r
2
=⁄ ZoErIr===
WLLoadinWatts WfWr–==
It has an RF voltage E
r and current Ir in phase, with Er / Ir = Zo.
Note that each component wave is mathematically simple and is completely described by a single figure for power,
for instance:
Z
o is the characteristic impedance of the uniform line, and simplifies matters by being a pure resistance, usually 50
ohms for useful lines. The main RF line circuit of the Thruline Wattmeter is a short piece of uniform air line section,
whose Z
o is 50 ohms, in which accurate measurements may be made.
The electrical values of the element circuits are carefully balanced and so designed that the inductive current produced from the reverse direction wave will cancel its portion of the capacitive current almost completely. The result
is a directivity always higher than 25 dB, which means that the element is highly insensitive (nulled) to the reverse
direction wave. By being highly directional, the Thruline Wattmeter is sensitive at either one of its settings, but to
only one of the two traveling waves which produce standing waves by interference. Thruline Wattmeter measurements are also independent of their position along the standing waves.
Element Socket
An accurately positioned socket for inserting a radio frequency coupling device, called a Thruline Plug-In Element, is
mounted on the outer conductor. The socket is precision bored to hold the rotatable element in its calibrated position, with a spring-loaded clasp to keep the element firmly seated. The machined step on the top face of the socket
engages a stop-pin on the element. Rotary movement of the element is thereby restricted to 180 degrees and is
stopped on the axial center line.
The measuring socket has a hole bored through the wall through which an insulated phosphor bronze contact finger
projects. The Plug-In Element has terminals on diametrically opposite sides of its body, so that pickup can be made
from either side. A small silvered button tip can contact the element only in the precise forward and reflected measuring positions, against the end stops. A specially designed jack mounted on the side of the socket mates with the
plug on the DC cable furnished with the read-out meter. The DC jack assembly has a built-in filter capacitor shunted
across the meter circuit. This more fully protects meter readings against the adverse effects of any stray RF energy
generated in the Plug-In Element. The line section is bright silver plated over practically all of its metal parts.
Matching
CAUTION
The Wattcher, elements and line section have been calibrated together. Replacing any
component without recalibrating all the components as a unit may affect accuracy.
The scale on the read-out meter reads full scale for the power rating stamped on the cap of the Plug-In Element. The
Wattcher, the Plug-In Element, and the Thruline Section are all stamped with matching serial numbers. The equipment is supplied as a matched and calibrated set and the parts, particularly the elements, should not be interchanged with any other like equipment. Such an interchange of the measuring elements could produce readings
with an error greater than the stated 5 percent of full scale accuracy.
Load Power
Power delivered to and dissipated in a load is given by:
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Where appreciable power is reflected, as with an antenna, it is necessary to subtract the reflected power from the
Φ
ρ 1–
ρ 1+
------------
2
=ρ
1 Φ+
1 Φ–
------------------=
and
where
ρ VSWR=
and
Φ
W
r
W
f
-------=
forward power to get the effective power. This correction is negligible, less than 1 percent, if the loading device has
a VSWR of 1.2 to 1 or less.
VSWR scales, and their attendant controls for setting the reference point, have been intentionally omitted from the
Thruline Wattmeter for two reasons.
a. Why make something similar to a hypothetical DC volt ohmmeter with con-
trol potentiometers for the voltmeter multipliers? Even more complications
arise when diodes at RF are involved.
b. Experience using the Thruline Wattmeter on operating problems, such as
transmitter tuneup, antenna matching etc., shows that the power ratio φ is
no mean competitor, in practical usefulness, to the standing wave ratio ρ =
VSWR.
A trial is suggested for a few days - forget VSWR and try thinking in terms of f = Wr / Wf when the Thruline Wattmeter is used. It will be noted that even without bothering to calculate the ratio exactly the two meter readings, Wr and
Wf, give an automatic mental impression which pictures the situation. Thus, in an antenna matching problem the
main objective usually is to minimize Wr, and anything done experimentally to this end is noted directly when the
Thruline Element is turned to the reflected position. Furthermore, the ratio of readings, even if only mentally evaluated, is a reliable guide to the significance of the remaining reflected power.
ρ vs. φ and its Significance
Since there are definite simple relationships between standing wave ratio ρ and the reflected/forward power ratio φ
indicated by the Thruline Wattmeter, the latter may be conveniently used to measure VSWR.
Note that around φ = 10 percent, below which W
r will appear insignificant and may be hard to read, you are close to
the commonly accepted lower limit ρ = 2. Trying to adjust to an even lower value of φ, in order to improve antenna
match still further, becomes less and less worthwhile in many systems. Experimentally by using the Thruline Wattmeter it can be readily shown that reducing φ below 10 percent produces little in the way of increased W
L. TV trans-
mitter antenna lines and VHF omnirange transmitters are among those systems that require much lower levels of
reflected power but for reasons other than simple power transmission. A very small level of reflected power, e.g., φ
= .06 percent, corresponds to ρ = 1.05. With just a single element subitable for measuring W
power is possible down to about φ = 1 percent (ρ = 1.2), providing W
f approaches full scale. However, measurement
f, detection of reflected
is possible only down to about φ = 5 percent (ρ = 1.5).
Measurement and Monitoring of Transmitter Power
Little more need be said about this in view of the preceding load power discussion. The Thruline Wattmeter is useful
for the continuous monitoring of transmitter output and is also helpful for the continuous monitoring of reflected
power, for instance in checking intermittent antenna or line faults.
Like diode devices in general, the Thruline meter indicates the carrier component on amplitude modulation, with
very little response to side band components added by modulation.
7
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8
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Chapter 3 Installation
Items Required
• Wattcher RF Monitor Alarm
• Thruline Line Section
Note: Ordered separately, p/n depends on transmission line type.
• Elements
Note: Ordered separately, p/n depends on Wattcher model, power level and frequency ranges.
• Coupling Kit
Note: Ordered separately, p/n depends on transmission line type.
• 2 DC Cables - Length as required
General
The Wattcher Unit model and serial numbers are located on the back panel. Before proceeding with the installation
record these numbers in the space provided on the last page of this manual. The model and serials numbers will be
required when obtaining information from the Factory or Bird’s customer service department.
Line Section
A coupling kit is required for connecting the line section to the transmission line. The coupling kit will be similar to
one of the coupling kits shown below. Review the following and refer to the diagram to install the line section.
1. Locate the line section so that element sockets are oriented for easy access.
2. Be sure center conductor anchor bullets have been positioned with insulators properly seated in the counterbores.
3. For flanged connectors, tighten evenly around flange to obtain a firm uniform contact.
4. For unflanged connectors, bullets should firmly seated in the center conductor. The
ends of the line section should be butted snugly against the ends of the transmission
line.
5. Position clamp bands approximately 3/4" from ends of sleeve and tighten securely.
6. The coaxial line should be continuous with no bends or offsets in its axial line.
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Figure 5 Coupling Connections
Wattcher RFMonitor/Alarm
The Wattcher is designed to mount in an EIA standard 19" relay rack. Wire lengths are not critical, the unit may be
installed where convenient for monitoring and operation. The following connections and switch settings should be
made before installation. See “Operating Instructions” on page 11 for descriptions of various modes.
• Auxiliary DC
• Remote reset
• Interlock
• Alarm enable/disable mode selected
• Fail-safe / non fail-safe mode selected
• Forward and reflected power sensor cables
• Forward power sensor cable from port A of the line section
• Reflected power sensor cable from port B of the line section
Note: AC line voltage selector switch is in the appropriate position. Voltage visible in the switch window is
selected voltage.
CAUTION
Be sure voltage selector switch is in the appropriate position before applying AC power.
Failure to do so will damage the unit.
• AC power cable connected
Elements
The element port designator is stamped on the line section ports and after the serial numbers on the elements. Be
sure to match these designators to achieve stated accuracy. Refer to Figure 5.
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Chapter 4 Operating Instructions
General
This section contains information about the various operating modes and features of the Wattcher RF Monitor/Alarm.
Zero Adjust
The two panel meters should be checked for zero set under no power conditions. With no power applied the meter
pointers should set exactly on zero. If adjustment is required, turn the adjustment screw until the pointer is set at zero.
Figure 6 Zero Adjust
Alarm Enable/Disable
The audible alarm will be enabled when the push-button is not depressed, and disabled when it is depressed.
Fail-Safe / Non Fail-Safe Mode
Non fail-safe mode is selected when the push-button is not depressed, and fail-safe is selected when it is depressed.
Non fail-safe mode—An interlock active condition is caused only by exceeding reflected power trip value. Fail-safe
mode—An interlock active condition can be caused by exceeding reflected power trip value or if the Wattcher Unit is
not operating.
Adjusting Reflected Power Trip Level
Ensure that the plug-in elements in the line section of transmission line are properly positioned and directed. Make
sure that the fail-safe/non fail-safe switch is in the desired mode.
While depressing the view push-button, rotate alarm level adjust screw until the pointer indicates the desired trip
level.
Connecting the Interlock
There are two sets of interlocks provided. Wire the interlocks based on transmitter requirements. During an alarm
condition the interlocks become active. An active interlock—in the non-fail safe mode—causes the normally closed
terminals to open and the normally open terminals to close. Connection to the interlocks is achieved through a sixterminal Screw-Clamp plug connector.
Note: The opposite is true for fail safe mode.
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Figure 7 Interlock Connector
Using Remote Reset & Auxiliary DC
Remote reset can be used to wire a reset switch in a convenient location. Actuating the switch will reset the alarm condition after the error has been corrected.
The reset input can be jumpered to ground so that the alarm will clear automatically when the reflected power
drops below the set point.
Auxiliary DC, (9-16 VDC @ 1A), can be used to power the Wattcher Unit.
Connection to these features is achieved through a four-terminal Screw-Clamp plug connector.
Figure 8 Remote Reset Auxiliary DC Connector
Meter Scales
Both the forward and reflected meter faces have triple-range scales. The full scale value shown on the element cap
determines the power scale to be read.
Alarm Condition
If the reflected power reading reaches the trip level, (for longer than 50ms) the buzzer will sound if enabled, the
alarm LED will flash, and the interlocks will be active. This condition will continue until the condition has been corrected and the reset button is pushed.
Determining VSWR
The forward/reverse RF power ratio is readily calculated from the readings, and VSWRs may be determined from the
following figures. Following the vertical and horizontal grid, determine intersection of forward and reverse power
values. Slanted lines passing closest to this point indicate VSWR.
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Figure 9 VSWR Conversion Nomograph
13
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Figure 10 VSWR Conversion Nomograph
14
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Chapter 5 Maintenance
Preparation for Shipment
Elements
The elements can be left in the sockets of the line section with their ARROWS turned midway between the measuring positions. Any additional elements should be well padded and wrapped before being put in the shipping container.
Line Section
Wrap the connectors on the flanged models with padding and tape them securely in place. Cover both ends of the
line section and the socket to keep out dust and foreign material. Place the line section in a sturdy shipping container such as a corrugated paper box.
DC Cables
Pad and wrap the DC connector plugs and then coil the cables tightly.
Meter
Cover the meter face with padding to protect the glass window, then wrap the housing and place it in the same box
as the line section.
Storage
No special preparations for storage are necessary other than to cover the equipment to keep out dust and dirt. For
an extra precaution, leave an element in the socket with the arrow turned midway between the measuring positions.
Troubleshooting
The following table contains troubleshooting information for problems which can occur during normal operation.
Locate the problem, review the possible cause, and perform the corrective action listed.
Only those functions within the scope of normal maintenance are listed. This manual cannot list all malfunctions
that may occur, or all corrective actions. If a malfunction is not listed or not corrected by the listed corrective
actions, notify a qualified service center.
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Table 1-3 Troubleshooting
PROBLEM CAUSE AREAS TO CHECK / CORRECTION
No meter indication No RF power Check RF source.
Intermittent or
inconsistent meter
readings
Alarm Active LED
does not Illuminate
Arrow on plug-in
element pointing in
wrong direction
No pickup from DC
contact finger
Open or short circuit
in DC cable
Meter burned out or
damaged
Faulty transmission
line
Dirty DC contact on
elements
Sticky or defective
meter
No Line Power Check power source, restore
Fuses Opened Check fuses, replace if needed. See
Change position of element.
Adjust the contacts. See “Contact
Adjustment” on page 19.
Replace defective DC meter cable (RG58/U). See “Meter Replacement” on
page 19.
Return Wattcher, line section, and
elements to the factory for meter
replacement and calibration. See
“Preparation for Shipment” on page 15.
Inspect line. See “Inspection” on page 18.
Clean DC contacts. See “Cleaning” on
page 18.
Return Wattmeter line section, and
elements to the factory for meter
replacement and calibration. See
“Preparation for Shipment” on page 15.
“Fuse Replacement” on page 19.
16
High VSWR or
reflected power
Defective LED Replace LED
Bad load or poor
connectors
Shorted or open
transmission line
Foreign material in
the section or in RF
connector bodies
Replace load or connectors.
Have line serviced. See “Line Section
Care” on page 18.
Remove foreign material. See “Line
Section Care” on page 18.
Page 29
Customer Service
Any maintenance or service procedure beyond the scope of those in this chapter should be referred to a qualified
service center.
If the unit needs to be returned for any reason, request an RMA through the Bird Technologies website. All instruments returned must be shipped prepaid and to the attention of the RMA number.
Bird Service Center
30303 Aurora Road
Cleveland (Solon), Ohio 44139-2794
Fax: (440) 248-5426
E-mail: bsc@bird-technologies.com
For the location of the Sales Office nearest you, visit our Web site at:
http://www.bird-technologies.com
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Page 30
Cleaning
WARNING
When using dry cleaning solvents, provide adequate ventilation and observe normal
safety precautions. Many dry cleaning agents emit toxic fumes that may be harmful to
your health, if inhaled.
If any of the contacts or line connectors become dirty, they should be wiped off with a clean cloth and a dry cleaning
solvent. Use an aerosol contact cleaner that is self-drying, but forms no residue, on the inaccessible internal parts.
Clean all contact areas and especially the exposed faces of the Teflon insulators.
It is important to keep the following surfaces clean:
• Socket bore
• Element body circumference
• Bottom rim of element body
• Seat at the base of the socket in the line section
• DC contacts on the element
The outside surface of the Wattcher can be cleaned with a soft cloth dampened with a mild detergent solution. Do
not wipe the meter glass with a dry cloth, if a static charge could develop causing an erroneous indication on the
meter.
WARNING
Never attempt to disconnect the transmission line while RF power is being applied.
Leaking RF energy is a potential health hazard..
Inspection
Inspect the Wattcher Unit cleanliness, proper adjustment, and with the RF power removed, check the ZERO setting
and adjust if necessary.
Preventive Maintenance
The element socket should be kept plugged as much as possible to prevent the intrusion of dust. If a Plug-In Element
is to be used for this purpose, use the highest power element available. The element should be positioned so that
the ARROW is pointing midway between the FWD and RFL measuring positions. This will not only protect the meter
by shunting the movement, but will also avoid exposing the element’s crystal to dangerous potentials if the RF line
section should be energized.
Line Section Care
CAUTION
Do not remove RF center conductor. Placement is critical for proper calibration and
obtaining specified accuracy.
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Page 31
If there is any evidence of contamination inside the RF line section, the accessible portions should be cleaned and
the interior carefully blown out. Keep all connections tight, and keep the nut of the meter cord plug turned tight on
the line section DC jack. This connection may often be serviced by simply loosening the nut of the DC plug, rotating
the body several times through a fraction of a turn and retightening the knurled nut securely.
Meter Replacement
CAUTION
Do not attempt to check the microammeters with an ohmmeter. Damage to the
movement or pointer will result.
Disassembly
1. Remove four screws securing the front panel.
2. Pull front panel forward until it clears the lamps and switches.
3. Lay the front panel face down so that the meter terminals are accessible.
4. Remove leads taking note of wire locations, red to positive, black to negative.
5. Remove nuts securing the meter bezel.
6. Remove meter.
7. Reassemble by reversing steps 6 to 1.
Note: When installing the four meter mounting screws, torque the to 10 in/lbs.
Contact Adjustment
In cleaning the socket bore the operator should be careful not to disturb the spring finger of the DC contact. It is
important that the operating position of this part be properly maintained. If the spring finger of the DC contact
requires adjustment, it may be done manually if carried out with care. The tip must be positioned far enough out to
maintain good contact with the element but not so far as to interfere with easy entry of the element body. The DC
jack, with attached spring finger, may be detached for service by removing the two 4-40 fillister head machine
screws which fasten it to the side of the RF line section. Then lift off the jack assembly carefully to avoid losing the
small Teflon insulating bead that straddles the base of the phosphor bronze spring and nests in a counterbore on the
side of the RF body. When replacing the assembly, be sure that the bead is again properly inserted.
Fuse Replacement
CAUTION
Replace with only the same type and rating fuse. T, 125 mA, 250VAC.
Use a screwdriver to remove fuse receptacle, insert new fuse and replace.
19
Page 32
Specifications
Models 3126A and 3127A
Model 3128A
Power Range
6 100W to 250 kW using Bird plug-in
elements
Frequency Range
2 to 1000 MHz
Accuracy ±5% of full scale (for elements
calibrated with the Wattcher)
Meter Scales
3126A
3126A
3127A
3127A
Power Range
6
FWD 15/30/60 kW
RFL 1.5/3/6 kW
FWD 5/10/25 kW
RFL 1/2.5/5 kW
100mW to 10kW using Bird plug-in
elements
Frequency Range
0.45 to 2700MHz
Accuracy ±5% of full scale (for elements
calibrated with the Wattcher)
Meter Scales
FWD and RFL 25/50/100W
Common Specifications and Features
Front Panel Controls Reset push button and reflected power limit set
Rear Panel Controls Fail-safe/Non fail-safe mode selector switch,
Alarms Audible buzzer and visual front panel LED
Alarm Actuation Time 50ms (typical)
Finish Light navy gray powder coat
Nominal Size 19" X 5-7/32" X 3-3/4" (483 X 133 X 95 mm)
Weight 5 lb. (2.28kg)
Power 115/230Vac, 50/60 Hz, 0.125A or 9-16 VDC, 1A
20
(screwdriver adj.)
normally open/normally closed alarm contacts (5A @
230 Vac Resistive), remote reset and DC power
connections, audible alarm disable switch
Page 33
Replacement Parts List
Qty. Description Part Number
1 BR1, Rectifier, full wave silicone bridge 5-1661
1 LS1, Buzzer, alarm 5-1714
2 F1 - F2, Fuse .125A at 250 Vac 5A2257-7
1 LS1, Fuse holder, alarm 5A2295-1
2 K1, Power relay, 3pdt 5A2116-1
1 M2, Meter, triple scale, incident power
- Model 3126, 100uA 15/30/60kW scale
- Model 3127, 100uA 5/10/25kW scale
- Model 3128, 30uA 25/50/100W scale
1 M1, Meter, triple scale, reflected power
Model 3126, 100uA 1.5/3.0/6.0kW scale
Model 3127, 100uA 1.0/2.5/5.0kW scale
Model 3128, 30uA 25/50/100W scale
1 S1, Alarm, enable/disable switch 5-1899-42N
1 S2, Alarm level adjust switch 5-1899-42N
1 S3, Alarm reset switch 5A2292-21-CN
1 S4, Mode selector switch 5-1899-42N
1 T1, Power transformer 5A2309-8
1 AC power input receptacle 5A2297
1 J4, Remote terminal plug connector (4 contacts) 5A2075-4
1 J5, Interlock terminal plug connector (6
contacts)
2 J1 - J2, BNC connectors 5A2319-1
2150-259
2150-230
2150-256
2150-257
2150-259
2150-258
5A2075-6
Coupling Kits
Line Type Impedance Kit Part Number
7/8“ EIA flanged 50Ω 4240-220
1&” EIA flanged 50Ω 4712-020
3@“ EIA flanged 50Ω 4600-020
3@” EIA flanged 50Ω 5-726
6@“ EIA flanged 50Ω 5-1322
6@” EIA flanged 50Ω 4902-020
21
Page 34
Available QC Type Connectors
For 7/8“ line section equipped with quick change “qc” connectors.
Note: When selecting “QC” connectors, consideration must be given to frequency and power range capability of size of connector.
N-Female 4240-062
BNC-Male 4240-132
N-Male 4240-063
LT-Female 4240-018
HN-Female 4240-268
LT-Male 4240-012
HN-Male 4240-278
C-Female 4240-100
LC-Female 4240-031
C-Male 4240-110
LC-Male 4240-025
UHF-Female (So-239) 4240-050
BNC-Female 4240-125
UHF-Male (PL-259) 4240-179
7/8" EIA Air Line 4240-002
22
Page 35
Limited Warranty
All products manufactured by Seller are warranted to be free from defects in material and workmanship
for a period of one (1) year, unless otherwise specified, from date of shipment and to conform to applicable specifications, drawings, blueprints and/or samples. Seller’s sole obligation under these warranties shall be to issue credit, repair or replace any item or part thereof which is proved to be other than as
warranted; no allowance shall be made for any labor charges of Buyer for replacement of parts, adjustment or repairs, or any other work, unless such charges are authorized in advance by Seller.
If Seller’s products are claimed to be defective in material or workmanship or not to conform to specifications, drawings, blueprints and/or samples, Seller shall, upon prompt notice thereof, either examine the products where they are located or issue shipping instructions for return to Seller
(transportation-charges prepaid by Buyer). In the event any of our products are proved to be other
than as warranted, transportation costs (cheapest way) to and from Seller’s plant, will be borne by
Seller and reimbursement or credit will be made for amounts so expended by Buyer. Every such claim
for breach of these warranties shall be deemed to be waived by Buyer unless made in writing within
ten (10) days from the date of discovery of the defect.
The above warranties shall not extend to any products or parts thereof which have been subjected to
any misuse or neglect, damaged by accident, rendered defective by reason of improper installation or
by the performance of repairs or alterations outside of our plant, and shall not apply to any goods or
parts thereof furnished by Buyer or acquired from others at Buyer’s request and/or to Buyer’s specifications. Routine (regularly required) calibration is not covered under this limited warranty. In addition,
Seller’s warranties do not extend to the failure of tubes, transistors, fuses and batteries, or to other
equipment and parts manufactured by others except to the extent of the original manufacturer’s warranty to Seller.
The obligations under the foregoing warranties are limited to the precise terms thereof. These warranties provide exclusive remedies, expressly in lieu of all other remedies including claims for special or
consequential damages. SELLER NEITHER MAKES NOR ASSUMES ANY OTHER WARRANTY WHATSOEVER, WHETHER EXPRESS, STATUTORY, OR IMPLIED, INCLUDING WARRANTIES OF MERCHANTABILITY AND FITNESS, AND NO PERSON IS AUTHORIZED TO ASSUME FOR SELLER ANY OBLIGATION OR LIABILITY NOT STRICTLY IN ACCORDANCE WITH THE FOREGOING.
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