Bird Technologies 4308 User Manual

INSTRUCTION BOOK

C

A

OPERATING INSTRUCTIONS

THRULINE®WATTMETER

MODEL 4308

Electronic Corporation

leveland (Solon) Ohio US

Copyright 2007 by Bird Electronic Corporation

Instruction Book Part Number 920-4308 Revision D

Thrulineis a Registered Trademark

of Bird Electronic Corporation

Bird Model 4308 Thruline Wattmeter

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 general safety precautions. Do not replace
components or make adjustments inside equipment with the high voltage supply turned
on. To avoid casualties, always disconnect 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 someone 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 conductor 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 disconnect an RF transmission line while RF power is present. Radiated
RF power is a potential health hazard.

Resuscitation

Personnel working with or near high voltages should be familiar with modern methods
of resuscitation.

E

Bird Model 4308 Thruline Wattmeter

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 regarding that particular area.

+ Note: Calls attention to supplemental information.

4308 Warning Statement

The following safety warning appears in the text where there is danger to operating and
maintenance personnel and is repeated here for emphasis.

WARNING

Leaking RF energy is a potential health hazard. Never attempt to connect or

disconnect equipment from the transmission line while RF power is being applied.

Severe burns, electrical shock, or death can occur.

4308 Caution Statement

The following equipment caution appears in the text whenever the equipment is in danger
of damage and is repeated here for emphasis.

CAUTION

Do not drop the Thruline Wattmeter equipment or submit it to hard blows. The

voltmeter circuitry or microammeter, even though it is shock mounted, may be

damaged by severe impact.

EE

4308 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 DELINSTRU­MENTO.

BENUTZUNG
WIRD DAS GERÄT AUF ANDERE WEISE VERWEN-

DET 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 UTILIZ-

ZATO IN MODO DIVERSO DA COME SPECIFICATO
DAL PRODUTTORE LA PROZIONE DI SICUREZZA
POTREBBE VENIRNE COMPROMESSA.

EEE

Bird Model 4308 Thruline Wattmeter

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

EL

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 OP­ERATION.

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 H F-ELEMENT­BUCHSE 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.

L

Bird Model 4308 Thruline Wattmeter

LE

About This Manual

This instruction book covers the model 4308 Thruline Wattmeter.
This instruction book is arranged so that essential information on safety is contained in

the front of the book. Reading the Safety Precautions Section before operating the
equipment is strongly advised.

The remainder of this instruction book is divided into Chapters and Sections. At the
beginning of each chapter a general overview will be given, describing the contents of
that chapter.

Operation

First time operators should read Chapter 1 - Introduction, and Chapter 3 - Installation,
to get an overview of equipment capabilities and how to install it. An experienced
operator can refer to Chapter 4 - Operating Instructions. All instructions necessary to
operate the equipment, are contained in this section.

Maintenance

All personnel should be familiar with preventative maintenance found in Chapter 5 ­Maintenance. If a failure should occur, the troubleshooting section will aid in isolating
and repairing the failure.

Parts

For location of major assemblies or parts refer to the part lists in Chapter 5.

Changes To This Manual

We have made every effort to ensure this manual is accurate at the time of publication.
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 number and revision level
on the title page.

LEE

Bird Model 4308 Thruline Wattmeter

LEEE

Table Of Contents

Safety Precautions. ............................i

Warning Statement. ...................... ii

Caution Statement. ...................... ii

4308 Safety Statements. ................... iii

About This Manual. ......................vii

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Purpose and Function. .................... 1

Performance Characteristics and Capabilities. ........ 1

Specifications. ......................... 2

Accessory Item. ........................ 2

Theory Of Operation. . . . . . . . . . . . . . . . . . . . . . 3

Travelling Wave Viewpoint. .................. 3

Travelling Wave vs Standing Wave . ............. 3

Power. ............................ 5

Coupling Circuit. ........................ 5

Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Portability. ........................... 7

Connections. .......................... 7

EN

Bird Model 4308 Thruline Wattmeter

Operating Instructions. . . . . . . . . . . . . . . . . . . . . 9

Zero Adjust. .......................... 9

Range Switch and Power Measurement. ........... 9

VSWR Calculations. ......................10

Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . 13

Troubleshooting. ........................13

Cleaning. ............................14

Repair and Replacement. ...................14

Calibration Checks . ......................17

Customer Service. .......................19

Replacement Parts List. ....................20

N

Chapter 1

Introduction

This chapter contains introductory information including product specifications, items
supplied, and accessory items.

Purpose and Function

The Model 4308 Thruline Wattmeter is a portable multi-range RF wattmeter. It is a
device which requires no external power source or batteries for operation. It is used to
measure RF power when inserted into a transmission line of 50 ohms impedance. When
operated in this manner, it is used to determine power flow and load mismatch in coaxial
transmission lines. It may be used to make measurements of CW, FM, or PM (Plane
Modulated) RF Power.

Performance Characteristics and Capabilities

On the front face of the unit, there are four power ranges which are controlled by a
selector switch. Each position of the selector switch corresponds to a power range on
the read-out meter, refer to the Specifications. There is also a “TRANSIT” position to
be used when transporting the unit. This position effectively shunts the delicate meter
movement to avoid damage from harsh blows.

The meter, line section, and related circuitry of the instrument are contained in a rugged
aluminum housing. This housing is equipped with a carrying strap, four rubber bumper
feet on the bottom, and four rubber bumper feet on the back. These bumper feet allow
the unit to be used in a standing (vertical) or flat (horizontal) position.



Bird Model 4308 Thruline Wattmeter

Specifications

Impedance: 50 ohms nominal
Full Scale Power Range: 1.5, 5, 15, 50 Watts

Insertion VSWR:
Female “TNC” Connector

1.05 max. from 440-512 MHz

1.07 max. from 512 to 960 MHz

Female “UHF” Connector

Insertion Loss:

With Female “UHF” Connectors

Accuracy: 440-960 MHz ± 5% Full Scale
Weight, Nominal: 3 lb.. (1.36 kg)
Dimensions, Nominal:

Without Connectors:
With Female “TNC” Connectors:

Connectors: Bird Quick Change “QC” type,

Finish: Grey Powder Coat

Meets European EMC Standards: EN55011 and EN50082-1, which are in
accordance with council directives 89/336/EEC and 92/31/EEC.
Meets European Safety Standard EN 61010-1, Which is in accordance with
council directive 73/23/EEC and 93/68/EEC.

1.08 max. from 440-512 MHz

1.12 max. from 512 to 960 MHz

0.1 dB max. 440 to 512 MHz

0.13 dB 512 to 960 MHz

0.1 dB 440-512 MHz

0.15 dB 512-960 MHz

3-29/32" L x 4" W x 6-7/8" H
(99 mm x 102 mm x 175 mm)

3-29/32" L x 5" W x 6-7/8" H
(99 mm x 127 mm x 175 mm)

Female TNC normally supplied.

Accessory Item

Case — Model CC-1, Vinyl case holds Wattmeter and accessories.

Chapter 2

V

Theory Of Operation

Travelling Wave Viewpoint

The operation of the Model 4308 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
back to the transmitter. The closer the line termination, or load, is matched to the line
impedance, the smaller the reflected wave will be. To determine the number of watts
dissipated in the load, it is necessary to determine both the power of the forward wave
and the power of the reflected wave. The difference between the two will indicate
effective power dissipation.

Travelling Wave vs Standing Wave

The interference between the forward and reflected waves, produces a standing wave in
a coaxial system. In the standing wave concept, VSWR (voltage standing wave ratio) is
a widely used tool. There is a simple relationship between forward power, reflected
power, and VSWR.

W

r

+−1

W

SWR

=

1

W
W

f

r

f

Where Wf= forward power; and Wr= reflected

!

R

Bird Model 4308 Thruline Wattmeter

Model 4308 Outline Drawing

RUBBER FEET (4)

Figure 1

Q.C. CONNECTO

3-3/8

(86mm)

3-5/8

(92mm)

3-29/32

(99mm)

ELECTRONIC

4240-156

1-5/16

(33mm)

6-7/8

(175mm)

1-3/4

(44mm)

RUBBER FEET(4)

TRANSIT

50W

440-960MHz

(101mm)

1.5

5

15

50

4308-1

4"

"

X
o
L

Theory Of Operation

Power

Since there is a definite relationship between the standing wave ratio and the forward­reflected power ratio, the forward and reflected powers may be read from the Thruline
Wattmeter and converted to VSWR. The charts are furnished in this Instruction Book.

Coupling Circuit

The coupling circuit which samples the travelling waves is in the Plug-In Element. The
circuitry of the element and its relationship to the other components of the Thruline
Wattmeter are illustrated in the schematic diagram, see figure 2.

Energy will be produced in the coupling circuit of the element by both mutual inductance
and capacitance from the two travelling RF waves in the line section. The inductive

Figure

2

Schematic

Diagram

RF Coaxial Line

MTR
r
OAD

Directional Coupling

Detector Element

Diode

DC Contact

Circuit Board

Meter

LOAD
or
XMTR

#

Bird Model 4308 Thruline Wattmeter

currents will flow according to the direction of the travelling waves producing them,
whereas the capacitive portion of these currents is independent of the direction. Therefore,
in either position of the Plug-In Element, the coupling currents produced from the waves
of one direction will add in phase, and those produced from waves of the opposite
direction will accordingly subtract in phase. The additive direction is indicated by the
arrow.

The electrical values of the element circuits are carefully balanced and designed so that
the inductive current produced from the reverse wave will cancel its portion of the
capacitive current almost completely. The result is a directivity greater than 25 dB, which
means that the element is highly insensitive (i.e. produces little or no signal) from the
reverse direction wave. By being so highly directional, the Detector element is sensitive
at either one of its settings, but to only one of the two travelling waves. Thruline
Wattmeter measurements are also independent of their position along the standing waves.

$

Chapter 3

Installation

Portability

CAUTION

Do not drop the Thruline Wattmeter equipment or submit it to hard blows. The

voltmeter circuitry or microammeter, even though it is shock mounted, may be

damaged by severe impact.

The Model 4308 is a portable instrument, and the housing is not designed for fixed
mounting. A strap is provided for carrying purposes. To protect the meter movement
during periods of transit, put the range switch in the “TRANSIT” position. This
effectively shunts the meter movement and dampens the pointer action.

Connections

WARNING

Leaking RF energy is a potential health hazard. Never attempt to connect or

disconnect equipment from the transmission line while RF power is being applied.

Severe burns, electrical shock, or death can occur.

Install the wattmeter in the 50 ohm transmission line as follows:

1. Attach the transmission line to the connectors on either side of the
wattmeter housing. It makes no difference which sides the RF
power source and the load are connected.

+ Note: Use of a short length of 50 ohm cable fitted

with the appropriate mating connectors may be useful
when inserting the wattmeter in the transmission line.

%

Bird Model 4308 Thruline Wattmeter

2. Rotate the element so that the arrow points in the direction of
power flow.

If coaxial cables other than 50 ohm impedance are used, a mismatch will occur which
may cause serious inaccuracies in the readings.

Figure

3

Element

Direction

To Load To Transmitter

Forward Power Measurement

To Load To Transmitter

Reflected Power Measurement

&

Operating Instructions

Chapter 4

Operating Instructions

A description of the features of the Thruline Wattmeter have been discussed in the
previous sections. Read and become familiar with the following instructions before
operating the Model 4308. As mentioned, no batteries or external power sources are
required to operate the meter. A small but sufficient amount of power is obtained from
the transmission line into which the unit is connected.

Zero Adjust

Before applying any RF power, check to see that the meter pointer is set at zero. If
adjustment is required, it will be necessary to zero adjust the meter under power off
conditions. Refer to figure 4.

Turn the zero-adjust screw on the bezel of the meter, using a small screwdriver, clockwise
or counterclockwise as necessary. Turn until the pointer exactly aligns with the zero of
the meter scale.

Figure 4

Zero Adjust

Zero Adjust Screw

Range Switch and Power Measurement

The range switch should be placed at the highest power setting, (i.e., 50 Watts). This is
especially true when the amount of power being applied is unknown. After the RF power
is applied the range switch may be switched down so that a power indication is given
in the upper one-third of the scale.

'

Bird Model 4308 Thruline Wattmeter

The Model 4308 is supplied with a special broadband 50 W element with a frequency
range of 440-960 MHz. This element is capable of operating at lower power levels and
up to 50 watts equally as well. At lower power levels, the range switch should be turned
to a lower setting for better resolution. Do not select a range lower than necessary or
damage to the meter may result.

Forward power (i.e., the forward direction of power flow) is indicated when the element’s
arrow is pointing towards the load. Reflected power can be indicated by rotating the
element in the line section so that the arrow points in the direction of the reflected power
flow, i.e., towards the source of power. Refer to figure 4. When the reflected power is
decisively lower, switching the range switch to a lower level, if possible, will give better
resolution.

Where appreciable power is reflected, as with an antenna, it is necessary to subtract the
reflected from the forward power to get load power. Power delivered to, and dissipated
in a load is given by:

Wl= Watts into load = Wf-W

r

This correction is negligible (less than one percent) if the load is such as to have a
VSWR of 1.2 or less. Good load resistors, such as Bird Termaline Load Resistors, will
produce a negligible or unreadable reflected power.

VSWR Calculations

After obtaining the forward and reverse power, the VSWR may be found by calculation,
as described in Theory of Operations - Chapter 2 , or by using the VSWR Nomographs
in figures 5 and 6 to simplify finding VSWR. Simply apply the obtained forward and
reflected power readings to the chart, following the cross lines to their intersection and
taking the VSWR from the nearest sloping line.



0

REFLECTED POWER - WATTS

2.0

1.8

1.6

1.4

1.2

1.0

20
18
16

14

12

10

8

6

4

.8

.6

.4

.2

VSWR=

0.5

Reflected Power

1+

Forward Power
Reflected Power

1

Forward Power

1.0 1.5

VSWR Conversion Nomograph

Figure 5

VSWR

10

4.0

3.0

3.0

2.5

4.0

2.0

5.0

10

FORWARD POWER - WATTS

2.5

2.0

1.8

1.6

1.5

1.4

1.3

1.25

1.20

1.16

1.14

1.12

1.10

1.09

1.08

1.07

1.06

1.05

20

30 40

15

25

100 150 200

50

300 400

50



0

REFLECTED POWER - WA TTS

Bird Model 4308 Thruline Wattmeter

VSWR Conversion Nomograph

Figure 6

1.0
.9
.8

VSWR

.7

.6

.5

.4

.3

.2

.1

.09
.08
.07

.06

.05

.04

.03

.02

10

4.0

3.0

2.5

2.0

1.8

1.6

1.5

1.4

1.3

1.25

1.20

1.16

1.14

1.12

1.10

1.09

1.08

1.07

1.06

1.05

1.04

1.03



.01

1.0 1.5

0.5

3.0

2.5

4.0

2.0

5.0 25

10 15

20

30 40

50

100 150 200

300 400

50

FORWARD POWER - WATTS

Chapter 5

Maintenance

This chapter includes cleaning, inspection, troubleshooting, and performance information.

Troubleshooting

Use the following table to aid in isolating problems, their possible cause, and corrections.

Cleaning

Problem Possible Cause Correction

No meter in­dication

No RF power applied to unit. Check RF source and check

cables.

“Arrow” on Plug-In Element
pointed in the wrong
direction.

No pick-up from dc contact
finger

Open or short circuit in dc
circuit.

Meter burned out or
damaged

Reposition element

Adjust contact finger

Check switch connections,
circuit board, and meter
leads.

Replace or return wattmeter
to the factory for meter
replacement and recalibration

!

Bird Model 4308 Thruline Wattmeter

Problem Possible Cause Correction

Intermittent
or Inconsis­tent Meter
Readings

High VSWR
or Reflected
power

Care and cleanliness is a main factor in maintenance. If any of the contacts or line
connectors become dirty, they should be cleaned with a dry cleaning solvent that does
not leave a residue.

It is important to keep these areas clean:

I

All contact surfaces and especially the exposed faces of the Teflon insula­tors.

I

The meter face and the housing, clean with a soft cloth dampened with a
mild detergent solution.

Faulty transmission line or
antenna

Sticky or defective meter Replace or return wattmeter

Dirty dc contact on element Clean contact
Bad load or poor connectors Replace load, antenna or

Shorted or open
transmission line

Inspect line

to the factory for meter
replacement and calibration

connectors.
Service or replace line

Repair and Replacement

Although the Model 4308 is designed to for long term, trouble free operation. In the
case of malfunction of the unit, the repair or replacement procedures in this section
should be followed.

+ Note: Do not perform unauthorized maintenance work

during the first year. It could be cause to void the
warranty.

"

Maintenance

Line Section or Element Coupling Circuit

If a problem should occur in the line section or element coupling circuit, it is advised
that the unit be returned to Bird Electronic Corporation for repair and recalibration.

Meter Housing

For access to the inside of the meter housing, the back cover must be taken off. To do
this:

1. Remove the four screws located near the back at the top and bot­tom of the sides.

2. Pull the cover straight off.

Line Section and Circuit Board

1. Loosen the nuts on the meter terminals using a 5/16 inch wrench.

2. Remove the connecting wires on the meter terminals.

3. Remove the range switch knob. Use a 1/16 inch hex wrench to
loosen the set screw.

4 . Remove the two 10-32 Phillips head screws located on the front

of the meter housing on either side of the detector element. Sup­port the line section while removing the 10-32 screws. The line
section with the attached circuit board will fall straight out the
back.

5. Detach the circuit board by removing the two screws that secure it
to the line section.

Be careful not to distort the spring finger of the dc contact that protrudes into the line
section. Also be careful not to lose either; the Teflon insulator on the spring contact
finger or the small spacers on the circuit board mounting screws. It is important that the
operating position of this part be properly maintained for correct contact with the dc
contact on the element body. Also take special care not to disturb the setting of the
potentiometers on the circuit board. These potentiometers are for calibration purposes
and the accuracy of the unit will be altered if the setting of these potentiometers is
changed.

#

Bird Model 4308 Thruline Wattmeter

These parts are not subject to further disassembly and must be replaced in their entirety
if defective. The circuit board is only replaceable at the factory.

6. Reassemble the unit by reversing the above procedures.

Connector Replacement

The Model 4308 is normally supplied with two Female TNC Bird Quick-Change
Connectors. Other “QC” connectors are available. These connectors may be obtained
from Bird Electronic Corporation. Refer to the Available Connector List.

These “QC” connectors are quickly changed by:

1. Remove the four 8-32 round head machine screws from the cor­ners of the connector flange.

2. Pull the connector straight out.

3. Install connectors by reversing the above procedure. Making sure
the center contact pin aligns properly with the socket.

Element Removal

1. Remove the screw and sleeve on the lower left corner of the ele­ment port flange.

2. Grasp the knurled part of the element knob in your fingers and
gently pull up while turning slightly in a clockwise direction. The
element will easily pull right out.

Element Installation

When reassembling the element in the line section, be sure the retaining clip on the front
face of the line section is repositioned. It must be on the shoulder of the element, before
replacing the retaining clip, stop-sleeve, and screw.

+ Note: If a defective element must be replaced, the unit

must be returned to the factory for element replace­ment and recalibration.

$

Meter Replacement

To replace the meter in the unit follow these steps:

1. Disconnect the meter leads from the terminals on the back of the
meter.

2. Remove the screws securing the meter in place. The screws are lo­cated on each side of the housing.

3. Pull the meter, with the shock mount assembly, straight out of the
unit.

4. Reinstall the meter, be sure the bumper feet, shock mount strip,
and shock mount ring are in place on the meter.

5. Position the mounting ring on the meter so that the side mounting
holes are parallel to the meter lugs.

6. Place the wattmeter housing on a flat surface with its front face
down.

7. Position the meter with the shock ring in place and press down on
the shock ring, manipulating it until its side holes are aligned
with those in the housing and the fastening screws can be inserted.

8. Insert the fastening screws into the housing and shock ring.

9. Be sure the meter is correctly positioned and tighten the fastening
screws.

Maintenance

Calibration Checks

If a calibration check of the Model 4308 is necessary, set-up the Model 4308 Wattmeter
in series with a standard wattmeter of a known accuracy.

For example, a Bird Model 43 Thruline Wattmeter could be used. Refer to figure 7 for
a sample set-up. Follow the guidelines outlined below.

I

Use a suitable low pass filter between the wattmeters and the RF power
source.

I

Terminate the set-up in a suitable 50 ohm load, similar to the Bird Model

8201.

%

Bird Model 4308 Thruline Wattmeter

I

Make all connections as short as possible to avoid mismatches and addi­tional insertion losses.

I

Make all calibration checks on each range at the upper one-third of the
scales.

I

If the unit is found to be outside the stated accuracy, the unit must be re­turned to the factory for recalibration.

Customer Service

Any maintenance or service procedure beyond scope of those provided in this section
should be referred to a qualified service center. Bird Electronic Corporation maintains
complete repair and calibration facilities at the following address:

Figure 7

Calibration Check Set-up

RF PowerSource

&

Power Meter

Power Head

Load

1.5

5

15

50

TRANSIT

4308-1

440-960 MHz

50W

Model 4308
(Wattmeter
Under Test)

50E

400-1000 MHz

50W

Model 43

Standard

Element

Coaxial

Cable

Filter

Sales / Repair Facilities

U.S.A. Sales and Manufacturing

Bird Electronic Corporation
30303 Aurora Road Cleveland (Solon), Ohio 44139-2794
Phone: [phone] Fax: [phone]

Sales Facilities

European Sales Office

Bird Electronic Corporation
Berkhamsted House
121 High Street
Berhamsted Hertfordshire
HP4 2DJ England
Phone: [phone] Fax: [phone]

Pan Asian Sales Office

Bird Electronic Ltd.
3A Unit 6 Tyrwhitt Road
Singapore 0820
Phone: [phone] Fax: [phone]

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Bird Model 4308 Thruline Wattmeter

Replacement Parts List

Item Qty. Description Part Number

1 1 Micrometer Meter 2120-017
2 1 Housing Assembly 4410-003
3 1 Cover Assembly 4210-005-1
4 1 Line Section Assembly 4308-003
5 1 Carrying Strap 8580-003
6 1 RF Connectors *See table
7 3 Meter Bumper Feet 4220-098
8 1 Range Switch Knob 5-1852
9 1 Range Switch Label 4308-006
10 1 Cushion Strip, Shock Mount 5-1066
11 4 Rubber Feet 5-1388
12 1 Meter Shock Mount Ring 4220-087

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*Available “QC” Type Connectors

Connector Part Number Connector Part Number

N-Female 4240-062 LT-Female 4240-018
N-Male 4240-063 LT-Male 4240-012
HN-Female 4240-268 C-Female 4240-100
HN-Male 4240-278 C-Male 4240-110
LC-Female 4240-031 UHF-Female 4240-050
LC-Male 4240-025 UHF-Male 4240-179
BNC-Female 4240-125 TNC-Female 4240-156
BNC-Male 4240-132 TNC-Male 4240-160
SMA-Female 4240-336 SC-Female 4240-090
SMA-Male 4240-334 Mini UHF-Female 4240-346
7/8" EIA 4240-002 7/16" IEC (Plug)

Type 169-4
1-5/8" EIA Fixed 4240-096 1-5/8" EIA Swivel 4240-208
7/16" IEC (Jack)

Type 169-4

4240-344 Open Term.

#10-32 Nut

4240-363

4240-080

Maintenance

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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. 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.

QUALITY INSTRUMENTS

FOR RF POWER MEASUREMENTS

From 2 to 4000 MHz and from 25 milliwatts

to 250 kilowatts in 50 ohm coaxial line systems

TERMALINE

ABSORPTION

WATTMETERS

LOAD RESISTORS

CALORIMETERS

THRULINE

DIRECTIONAL

MONITORING

WATTMETERS

TENULINE

ATTENUATORS

COAXWITCH

SELECTOR

SWITCHES

COAXIAL RF FILTERS

SENTRILINE

FILTER-COUPLERS

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30303 Aurora Road Cleveland, (Solon) Ohio 44139-2794

ELECTRONIC CORPORATION