BIRD Wattcher 3127A User manual

Wattcher® Monitor/Alarm
Models
3126A, 3127A, and 3128A
Operation Manual
©Copyright 2017 by Bird Technologies, Inc.
Instruction Book Part Number 920-3126/27/28A Rev. C
Wattcher is a registered trademark
of Bird Electronic Corporation

i
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.
WARNING
Remove Power
Observe general safety precautions. Do not open the instrument with the power on.

Safety Precautions
ii
Safety Symbols
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.
See page 16.
See page 16.
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.
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.
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.
WARNING
Never attempt to disconnect the transmission line while RF power is being applied. Leaking
RF energy is a potential health hazard.

Wattcher® Monitor/Alarm
iii
Caution Statements
The following equipment cautions appear in the text whenever the equipment is in danger of damage and are
repeated here for emphasis.
See page 5.
See page 8.
See page 16.
See page 17.
See page 17.
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.
CAUTION
Be sure voltage selector switch is in the appropriate position before applying ac power.
Failure to do so will damage the unit.
CAUTION
Do not remove RF center conductor. Placement is critical for proper calibration and
obtaining specified accuracy.
CAUTION
Do not attempt to check the microammeters with an ohmmeter. Damage to the movement or
pointer will result.
CAUTION
Replace with only the same type and rating fuse. T, 125 mA, 250VAC.

Safety Precautions
iv
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.

Wattcher® Monitor/Alarm
v
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.

Safety Precautions
vi
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.

Wattcher® Monitor/Alarm
vii
About This Manual
This manual covers the operating and maintenance instructions for the following models:
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.
Chapter Layout
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 problems. Specifications
and parts information are also included.
3126A 3127A 3128A

viii
Table of Contents
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i
Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Warning Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Caution Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Safety Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Changes to this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Chapter Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Alarm Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Fail-Safe/Non Fail-Safe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Element Socket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Matching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Load Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
r vs. f and its Significance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Measurement and Monitoring of Transmitter Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Chapter 3 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Items Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Line Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Wattcher RF Monitor/Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Chapter 4 Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Zero Adjust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Alarm Enable/Disable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Fail-Safe / Non Fail-Safe Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Adjusting Reflected Power Trip Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Connecting the Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Using Remote Reset & Auxiliary DC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Meter Scales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Wattcher® Monitor/Alarm
ix
Alarm Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Determining VSWR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Chapter 5 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Preparation for Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Line Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
DC Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Line Section Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Meter Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Contact Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Fuse Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Models 3126A and 3127A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Model 3128A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Common Specifications and Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Replacement Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Coupling Kits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Available QC Type Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Limited Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

1
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 9 detail these features.
Figure 1 Outline Drawing

Wattcher® Monitor/Alarm
2
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 19 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

Introduction
3
Table 1 Front Panel
Figure 3 Rear Panel
Table 2 Rear Panel
1 Forward Power Meter Analog Meter Indicating forward power.
2 Reflected Meter Analog Meter indicating reflected power.
3 Adjust Potentiometer providing for adjustment of reflected
power trip level.
4 View Push-button Allows for viewing the reflected power trip level during
adjustment.
5 Reset Push-button Resets the Wattcher to normal operation after the
error condition is corrected
6 RFL Alarm LED Red LED, flashes when the reflected power trip level
has been exceeded for more than 50ms.
7 Alarm Active LED Green LED, when illuminated the alarm is active,
power is on.
1 Forward Sensor Input
Connector
Input connector for forward power sensor cable from port A of
line section.
2 Reflected Sensor Input
Connector
Input connector for reflected power sensor cable from port B
of line section.
3 9-16 VDC Auxiliary positive (+) DC power connection.
4 Ground Auxiliary negative (-) power connection.
5 Ground Remote reset ground connection.
6 Remote Reset Remote reset connection.
7 NO1 Normally open connection for interlock one.
8 COM1 Common Connection for interlock one.
9 NC1 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 Wattcher.
17 Line Voltage Selector
Switch
Determines line voltage operation.

4
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 Ef and current If in
phase, with Ef / If = Zo.

Theory of Operation
5
The reflected wave originates by reflection at the load, travels, and its power flows from the load back to the
source. It has an RF voltage Er 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:
Zo 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 Zo 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
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:
WLLoadinWatts W fWr –==
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.
WfWattsForward E f2ZoIf2 =ZoEfIf ===
WfWattsReflected Er2ZoIr2
=ZoErIr ===

Wattcher® Monitor/Alarm
6
Where appreciable power is reflected, as with an antenna, it is necessary to subtract the reflected power from the
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 control 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 is no mean competitor, in practical usefulness, to the
standing wave ratio = 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.
vs. and its Significance
Since there are definite simple relationships between standing wave ratio and the reflected/forward power ratio
indicated by the Thruline Wattmeter, the latter may be conveniently used to measure VSWR.
Note that around = 10 percent, below which Wr will appear insignificant and may be hard to read, you are close to
the commonly accepted lower limit = 2. Trying to adjust to an even lower value of 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 below 10 percent produces little in the way of increased WL. TV
transmitter 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.,
= .06 percent, corresponds to = 1.05. With just a single element suitable for measuring Wf, detection of
reflected power is possible down to about = 1 percent (= 1.2), providing Wf approaches full scale. However,
measurement is possible only down to about = 5 percent (= 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.
1–
1+
------------
2
=1+
1–
------------------= and
where VSWR=
and
Wr
Wf
--------=

7
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.

Wattcher® Monitor/Alarm
8
Figure 5 Coupling Connections
Wattcher RF Monitor/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. "Operating Instructions" on page 9 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 win-
dow is selected voltage.
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.
CAUTION
Be sure voltage selector switch is in the appropriate position before applying AC
power. Failure to do so will damage the unit.

9
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 six-
terminal Screw-Clamp plug connector.
Note: The opposite is true for fail safe mode.

Wattcher® Monitor/Alarm
10
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.