BIRD 4314B User manual

INSTRUCTION BOOK
OPERATING INSTRUCTIONS
RF DIRECTIONAL
THRULINE WATTMETER
MODEL 4314B
ÓCopyright 2000 by Bird Electronic Corporation
Instruction Book Part Number 920-4314B Rev. C
Thruline ® is a Registered Trademark of Bird Electronic Corporation
Electronic Corporation
Cleveland (Solon) Ohio US
A

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.
Keep Away From Live Circuits
Operating personnel must at all times observe normal safety precautions. Do
not replace components inside equipment with the high voltage supply
turned on. To avoid casualties, always remove power.
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 some-
one who is capable of rendering aid.
Safety Earth Ground
An uninterruptible earth safety ground must be supplied from the main
power source to test instruments. Grounding one conductor of a two conduc-
tor power cable is not sufficient protection. Serious injury or death can occur
if this grounding is not properly supplied.
Shock Hazard
Do not attempt to remove a RF transmission line while power is present. Ra-
diated RF power is a potential health hazard.
Resuscitation
Personnel working with or near high voltages should be familiar with modern
methods of resuscitation.
i

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 appears on the equipment indicating there is
important information in the instruction manual regard-
ing that particular area.
+Note: Calls attention to supplemental information.
4314B Warning Statements
The following warnings appear in the text where there is danger to operating
and maintenance personnel, and are repeated here for emphasis.
WARNING
Exposure to RF power radiation and the possibility of RF shock or
burns exists with some operating conditions. Always be sure to turn off
the transmitter when connecting or disconnecting a wattmeter. Be sure
the transmission line is terminated into a load or antenna. When a
Plug-In Element is removed from the RF line socket, the line section
center conductor is exposed. Do not put fingers or other objects into the
Plug-In Element socket while RF power is applied.
WARNING
Always be sure transmitter power is off before disconnecting the unit
from the transmission line.
ii

4314B Caution Statements
The following cautions appear in the text whenever a procedure, if not prop-
erly followed, could put the equipment in danger of damage and are repeated
here for emphasis.
CAUTION
Do not drop the Thruline Wattmeter or its elements or subject them to
hard blows. The microammeter is shock mounted in the wattmeter
housing, but its delicate mechanism may be damaged by severe impact.
CAUTION
Severe damage to the Plug-In Element or wattmeter can result from
exposure to excessive RF power. Make sure the Plug-In Element
installed in the wattmeter has a sufficiently high wattage rating to
handle the line load when it is first applied to the RF line.
CAUTION
Use reasonable care in handling. Do not drop or subject the wattmeter
or elements to hard blows as accuracy may be impaired or other
damage may result.
CAUTION
Do not apply RF power to the wattmeter in excess of the full scale
range of the element.
CAUTION
When making low reflection readings using a more sensitive element,
take care to insert the element so that it senses reflected power only.
Do not rotate the element in the socket so that it is subjected to
forward power. This can result in damage to the Plug-In Element, the
microammeter, or both.
CAUTION
If other than Female N type connectors are used, limit power and
frequency to the capabilities of the RF coaxial cable or connectors used.
Damage to connectors or errors in reading could result.
Model 4314B Safety Statements
USAGE
ANY USE OF THIS INSTRUMENT IN A MANNER NOT
SPECIFIED BY THE MANUFACTURER MAY IMPAIR
THE INSTRUMENT’S SAFETY PROTECTION.
iii

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 FABRI-
CANT PEUT ENDOMMAGER LE DISPOSITIF DE PRO-
TECTION DE L’INSTRUMENT.
IMPRIEGO
QUALORA QUESTO STRUMENTO VENISSE
UTILIZZATO IN MODO DIVERSO DA COME
SPECIFICATO DAL PRODUTTORE LA PROZIONE DI
SICUREZZA POTREBBE VENIRNE COMPROMESSA.
SERVICE
SERVICING INSTRUCTIONS ARE FOR USE BY SER-
VICE -TRAINED PERSONNEL ONLY. TO AVOID DAN-
GEROUS 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 NINGÉN
SERVICIO A MENOS QUE ESTÉ CAPACITADO PARA
HACERIO.
WARTUNG
ANWEISUNGEN FÜR DIE WARTUNG DES GERÄTES
GELTEN NUR FÜR GESCHULTES FACHPERSONAL.
iv

ZUR VERMEIDUNG GEFÄHRLICHE, ELEKTRISCHE
SCHOCKS, SID 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.
RF VOLTAGE MAY BE PRESENT IN RF ELEMENT
SOCKET - KEEP ELEMENT IN SOCKET DURING OP-
ERATION.
DE LA TENSION H.F. PEAT ÊTRE PRÉSENTE DANS
LA PRISE DE L’ÉLÉMENT H.F. -CONSERVER
L’ÉLÉMENT DANS LA PRISE LORS DE L’EMPLOI.
HF-SPANNUNG KANN IN DER
HF-ELEMENT-BUCHSE ANSTEHEN -ELEMENT
WÄHREND DES BETRIEBS EINGESTÖPSELT
LASSEN.
PUEDE HABER VOLTAJE RF EN EL ENCHUFE DEL
ELEMENTO RF -MANTENGA EL ELEMENTO EN EL
ENCHUFE DURANTE LA OPERACION.
IL PORTAELEMENTO RF PUÒ PRESENTARE
VOLTAGGIO RF - TENERE L’ELEMENTO NELLA
PRESA DURANTE IL FUNZIONAMENTO.
v

About This Manual
This instruction book guides the user through the operation and maintenance
of the Bird Model 4314B RF Directional Thruline Wattmeter.
This instruction book is arranged so that the essential information about
safety is in the front of the book. Reading the Safety Precautions section be-
fore operating the equipment is strongly advised.
The remainder of this manual is divided into chapters and sections. At the
beginning of each chapter, a general overview describes the contents of that
chapter.
Operation
First time users should read Chapter 1 - Introduction, Chapter 2 -
Installation, and Chapter 3 - Theory of Operation, to get an overview of
equipment capabilities. An experienced operator can refer to Chapter 4 - Op-
erating Instructions. All instructions necessary to operate the equipment are
in this chapter.
Maintenance
All personnel should be familiar with preventive maintenance found in Chap-
ter 5 - Maintenance. If a failure should occur, the troubleshooting section will
aid in isolating and repairing the failure.
Parts
For the location of major assemblies or parts, refer to the parts list in Chap-
ter 5 - Maintenance.
Changes To This Manual
We have made every effort to ensure this manual is accurate. If you should
discover any errors, or if you have suggestions for improving this manual,
please send your comments to our factory. This manual may be periodically
updated. When inquiring about updates to this manual refer to the part num-
ber and revision level on the title page.
vi

vii
Table of Contents
Safety Precautions ......................i
Warning Statements ....................ii
Caution Statements ....................iii
About This Manual .....................vi
Introduction .........................1
Purpose and Function ...................1
Description ........................1
Performance Characteristics and Capabilities .........1
Power Requirements ....................2
Additional Equipment ...................2
Standard Plug-In Elements .................2
Specifications .......................3
Installation .........................5
Portability ........................5
Connections........................5
Theory of Operation .....................9
Traveling Wave Viewpoint .................9
Coupling Circuit......................9
Peak Power Operation...................10
Component Description ..................14
Operating Instructions ...................17
Zero Adjust Meter ....................17
Plug-In Element Selection and Insertion ...........17
CW Power Measurements .................18
Peak Power Measurements.................18
Load power .......................18
Determining VSWR ....................19
Making Low Reflection Readings ..............22
Testing Lines, Connectors, Filters and Related Components. . . 22
Attenuation By Open Or Short Circuit............23
Measuring Percentage Of Positive Modulation ........23
Performance Notes ....................25
Shutdown ........................26
Maintenance ........................29
Cleaning ........................29
Preventative Maintenance .................29
Line Section Care ....................29
Inspection ........................30

viii
Bird Model 4314B RF Directional Thruline Wattmeter
Trouble Shooting .....................30
Troubleshooting Guide...................31
Battery Test .......................33
Battery Replacement ...................33
Meter Replacement ....................34
Instrumentation Module Replacement............36
RF Connector Replacement.................38
Calibration .......................38
Customer Service .....................40
Replacement Parts ....................41
Available QC Type Connectors ...............41

Chapter 1
Introduction
Purpose
and
Function
The Model 4314B Thruline Wattmeter is an inser-
tion-type RF wattmeter designed to measure power flow
and load match in 50 ohm coaxial transmission lines. It
is intended for use on CW, AM, FM, SSB, TV, and pulse
signals only.
Description The Model 4314B Thruline Wattmeter is a portable unit
contained in a die cast aluminum housing. The unit is
equipped with a plastic strap for carrying, four rubber
shock feet on the base, and four rubber bumpers on the
back which allow the unit to stand vertical or lie flat in a
horizontal position when used. For additional protection,
the microammeter is specially shock mounted. A slotted
screw is provided on the lower front face of the meter for
zeroing the pointer. The RF line section face below the
meter protrudes slightly from the wattmeter housing with
the Plug-In Element socket in the center. The circuit
module is mounted on the line section inside the housing.
It has an attached phosphor bronze spring contact finger,
which protrudes through a lateral hole and into the
Plug-In Element socket on the RF line section. The finger
has a button on its end which makes connection with the
contacts of the Plug-in Element. The silver-plated brass
RF line section is precision made to provide the best pos-
sible impedance match to the coaxial RF transmission
line in which the wattmeter is inserted. At each end of
the line section are Bird Quick-Change type RF connec-
tors, which may be quickly interchanged with any other
Bird “QC” connectors.
Performance
Character-
istics and
Capabilities
To make measurements, insert a Plug-In Element into
the line section socket and rotate it to either stop. Point
the element arow in the source to load direction of power
flow and the meter will display a reading of forward
power. Rotate the element so that the arrow is pointed in
the opposite direction to obtain a reflected power reading.
With known values of forward and reflected power the
load match can now be determined by calculating the
VSWR or by using the graphs supplied in this manual
(pages 20-21).
1

Setting the front panel toggle switch to peak mode gives
the wattmeter the capability of indicating peak pulse or
envelope power.
Power
Require-
ments
The Model 4314B can operate from two different power
sources. The wattmeter comes supplied with two 9 V al-
kaline batteries which typically provide 20 hours of oper-
ation. AC adapters are also available for use with either
a 115 or 230 Vac line.
Additional
Equipment
The only additional equipment required by the Model
4314B is a Plug-In Element (see table below). Most of
them are designed to read both average and peak power.
Some are designed exclusively for peak reading applica-
tion.
Standard Plug-In Elements
Bird Model 4314B RF Directional Thruline Wattmeter
2
Use Frequency (MHz) Power Ranges (Watts)
Average of
Peak
0.45-2.5
2-30
25-60, 50-125, 100-250,
200-500, 400-1000
60-80, 80-95 95-125,
110-160, 150-250, 200-300,
275-450, 425-850, 800-950
60-80, 80-95, 95-150,
150-250, 200-300, 250-450,
400-850, 800-950
950-1260, 1100-1800,
1700-200, 2200-2300
1000, 2.5 kW, 10 kW
50, 100, 250, 500, 1000,
2500, 5000
5, 10, 25, 50, 100, 250, 500,
1000
1 Watt
2.5 Watts
1, 2.5, 5, 10, 25
Peak Only 25-60, 50-125, 100-250,
200-500, 400-1000
950-1260
2.5 kW, 5 kW, 10 kW
50, 100, 250, 500, 2.5 kW,
5kW

Specifications
Impedance 50 ohms nominal
Insertion VSWR
With “N” Connectors
1.05 Max. to 1000 MHz, 1.1 Max.
to 2300 MHz
Connectors Bird Quick Change “QC” Female N
normally supplied
RF Power Ranges
Average (CW) Mode
100 mW to 10 kilowatts (±5% of
full scale)
Peak-pulse or envelope-power
mode
100 mW to 10 kilowatts (±8% of
full scale)
Frequency Range 0.45 to 2300 MHz (either mode)
Pulse Parameters
Minimum duty factor 1.0 x 10-4
Minimum repetition rate 30 pps
Minimum pulse width 0.4 microseconds at 100-2300 MHz
1.5 microseconds at 26-99 MHz
15 microseconds at 2-25 MHz
Weight 3 lb. (1.4 kg)
Dimensions 3-5/8”L x 4”W x 7”H
(92.1 x 102 x 178 mm)
AC Power requirements (using
adapter)1115 Vac. ±10%, 60 Hz
220 Vac, ±10%, 50Hz
Batteries Two 9 V alkaline
Battery Life 20 hours of operation, typically
1 Use only adapter supplied by Bird Electronic Corporation
Introduction
3

4

Chapter 2
Installation
Portability The Model 4314B is a portable instrument; the housing is
not designed for fixed mounting. A strap is provided for
carrying purposes.
CAUTION
Do not drop the Thruline Wattmeter or its elements or
subject them to hard blows. The microammeter is shock
mounted in the wattmeter housing, but its delicate
mechanism may be damaged by severe impact.
When transporting the Thruline Wattmeter, it is best to
insert the original dust plug, or a Plug-In Element with
the arrow pointed down, in the measuring socket, and se-
cure it with the catch. This will shunt the meter circuit
and serve to protect it by dampening the pointer action
during handling or shipping. Also, set the wattmeter con-
trols to ON and CW modes. In this position, any unneces-
sary battery drain will be avoided. Handle the Plug-In
Elements with care at all times as their calibration could
be disturbed if they are dropped.
WARNING
Exposure to RF power radiation and the possibility of
RF shock or burns exists with some operating
conditions. Always be sure to turn off the transmitter
when connecting or disconnecting a wattmeter. Be sure
the transmission line is terminated into a load or
antenna. When a Plug-In Element is removed from the
RF line socket, the line section center conductor is
exposed. Do not put fingers or other objects into the
Plug-In Element socket while RF power is applied.
Connec-
tions
The Model 4314B Wattmeter is normally supplied with
two Female N type connectors which are of the Bird
Quick-Change “QC” design. Other “QC” connectors are
available as listed in the Replacement Parts list at the
back of this manual.
Quick-Change connectors can be replaced by removing the
four 8-32 screws from each corner of the square flange of
5

Bird Model 4314B RF Directional Thruline Wattmeter
6
1-5/16"
(33.3mm)
3-3/8"
3-5/8”
(
92.1mm
)
(85.7mm)
6-7/8"
(174.6mm)
4"
(101.6mm)
1-3/4"
(44.5mm)
Female "N" Q.C.
Connectors (2)
(Normally
Supplied)
ON
BATTERY
CW
PEAK
15
80
F.S.= 30 UA.PN 2080- 002
W
ELECTRONIC
20
0
BIRD
10
5
30
40
TTA
THRULINE
60
S
CORP.
R
20
10
40
50
100
20
Figure 1
Model 4314B
Outline
Drawing

the connector and then pulling it straight outward. In-
stall the new connector by reversing this procedure.
Insert the Model 4314B Thruline Wattmeter in coaxial
transmission lines of 50 ohms nominal impedance. The
signal source and load connections can be made to either
side of the wattmeter with no difference in effect. Use a
coaxial transmission line fitted with suitable matching RF
connectors. If cables of other than 50 ohms impedance are
used, a mismatch will occur which could cause serious in-
accuracies in the readings.
CAUTION
Severe damage to the Plug-In Element or wattmeter
can result from exposure to excessive RF power. Make
sure the Plug-In Element installed in the wattmeter
has a sufficiently high wattage rating to handle the
line load when it is first applied to the RF line.
Installation
7

8

Chapter 3
Theory of Operation
Traveling
Wave
Viewpoint
The operation of this wattmeter is based on the travelling
wave concept of RF transmission. As RF power is applied
to a transmission line, there is a forward wave travelling
from the transmitter to the load, and a reflected wave
travelling from the load to the transmitter. The closer the
load is matched to the transmission line, the smaller the
reflected wave will be. To determine the amount of power
dissipated in a load resistor, it is necessary to determine
the wattage of the forward wave and the wattage of the
reflected wave. The difference between the two indicates
load power.
VSWR (Voltage Standing Wave Ratio) has become a
widely used tool in the travelling wave concept. The
standing waves which are produced by transmission line
mismatch cannot be read directly. However, the VSWR
can be easily determined by the use of the VSWR Con-
version Nemographs (figures 5-6, pages 20-21), without
requiring the use of unwieldy and expensive slotted line
equipment. Many users find that the ratio of
watts reflected
watts forward is more useful than VSWR.
Coupling
Circuit
When the wattmeter is connected into the system, the RF
power is directed through the unit’s line section. The air
line is a short, uniform section which does not impair the
impedance of the RF coaxial line into which it is inserted.
When the Plug-In Element is installed in the socket of
the line section, the RF waves travelling through the line
produce energy in the coupling circuit of the Plug-In Ele-
ment by both inductance and capacitance (figure 2). The
inductive currents will flow according to the direction of
the travelling waves producing them. Therefore, assuming
that the Plug-In Element remains stationary, the coupling
currents produced from the waves of one direction add in
phase, while those produced from the waves of the oppo-
site direction subtract in phase. The additive or “arrow”
direction is assigned to the forward wave. The element is
designed so that the wave components travelling in the
opposite direction of the arrow will nearly cancel each
other out, making the element highly insensitive to the
reverse wave direction. Because of the highly directional
characteristics of the element, the resultant direct current
9

sensed by the microammeter indicates the power level of
only the RF waves travelling in the arrow direction.
The Plug-In Element is designed so that it can be rotated
180 degrees in its socket in the line section. When it is
rotated, the meter indicates the power in a direction op-
posite that of the initial reading. If the forward direction
power is read first, the reflected direction power will be
read after the Plug-In Element is rotated. The energy re-
sulting from the inductively coupled component of the for-
ward wave will bring about cancellation as described
above.
Peak Power
Operation
The Model 4314B is designed to measure peak power in
addition to average power. When the toggle switch is
placed in peak mode, battery power energizes the ampli-
fier system. If the ac adapter is being used, it energizes
relay (K1) and disengages the batteries (figure 3).
The battery test circuit is energized when the pushbutton
of switch S2 is depressed. If the voltages of the two 9 V
batteries are within the limits necessary to properly oper-
ate the amplifier circuit, the pointer of the meter deflects
beyond the battery test mark on the meter scale. If the
pointer fails to reach the mark, the batteries need re-
placed. Replacement of both batteries simultaneously will
assure that sufficient battery power will be available for
extended periods of time (see Chapter 5, Maintenance).
The amplifier circuit is designed to provide current to the
meter which indicates at a steady state the peak of the
power applied to resistor R5. Resistor R5 exactly matches
the resistance of meter M so that the existing circuit in
the Plug-In Element is loaded exactly the same as during
the average reading mode (figure 2).
When switch S1 is pressed, the dc input which is nor-
mally applied to the meter is interrupted and is applied
instead to resistor R5 and differential amplifier Q1. This
results in a current gain ratio of approximately 100:1.
This output is applied to a resistance bridge consisting of
resistors R6, R7, R8, R9, and R10. Variable resistor R8 of
this bridge permits zero calibration of the amplifier cir-
cuit. Bridge output is applied to differential amplifier U1
which provides a voltage gain of about 1000:1. This ratio
represents the surge of voltage from the amplifier which
charges capacitor C3 and indicates the minimum pulse
duration. Capacitor C3 applies a potential to differential
amplifiers Q2 and Q3 as long as the capacitor remains
Bird Model 4314B RF Directional Thruline Wattmeter
10