INSTRUCTION BOOK
OPERATING INSTRUCTIONS
MULTI-PURPOSE
THRULINE® WATTMETER
RF POWER ANALYST®
MODEL 4391A
©Copyright 2008 by Bird Electronic Corporation
Instruction Book Part Number 920-4391A Rev. H
Thruline® and Power Analyst® are Registered Trademark of
Bird Electronic Corporation
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.
Keep Away From Live Circuits
Operating personnel must at all times observe normal safety regulations.
Do not replace components or make adjustments inside the equipment
with high voltage turned on. To avoid casualties, always remove power.
Shock Hazard
Do not attempt to remove the RF transmission line while RF power is
present. Radiated RF power is a potential health hazard. Observe general
safety precautions for handling high voltage equipment. Always
disconnect power before attempting any repairs.
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.
Chemical Hazard
Dry cleaning solvents for cleaning parts may be potentially dangerous.
Avoid inhalation of fumes or prolonged contact with skin.
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.
Resuscitation
Personnel working with or near high voltages should be familiar with
modern methods of resuscitation.
Safety Symbols
WARNING
Warning notes call attention to a procedure which, if not correctly
performed, could result in personal injury.
i
Bird Model 4391M Power Analyst
CAUTION
Caution notes call attention to a procedure which, if not correctly
performed, could result in damage to the instrument.
The caution symbol appears on the equipment
indicating there is important information in the
instruction manual regarding that particular area.
ꢀ NOTE: Calls attention to supplemental information
Fuse Replacement
Always use the same type and rating of fuse when replacing the fuse.
Fuse information can be found in the parts list on page 30.
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
Use only NIckel Metal Hydride (NiMH) batteries that have a minimum
capacity of 4600 milliamper hours (mAh). Do not install batteries that are
not Nickel Metal Hydride. Do not install NiMH batteries that have less
than 4600 mAh capacity. Failure to comply may result in damage to the
batteries, damage to the instrument, and injury to personnel from battery
chemicals.
WARNING
Use dry cleaning solvents in a well ventilated area. Avoid excessive
inhalation of solvent fumes, since they can be toxic in heavy concentrations.
Always wear eye protection and avoid skin contact with the solvent.
WARNING
Be sure that the power cable is unplugged before opening the wattmeter
case. The power supply capacitor, C1, can retain a dangerous charge that
must be removed before touching. Always have another person standing by
who is trained in electric shock first aid.
ii
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
Long-term storage of this instrument can affect battery performance and
reduce battery life. Do not store the instrument for long periods of time
result in reduced battery charge and shortened battery life.
CAUTION
If the element cannot be fully inserted into the socket, do not force
it. You might damage the element.
CAUTION
Internal batteries are connected. Remove one of the battery tubes before
unsoldering wires connected to the Main PCB. Failure to comply may result
in permanent equipment damage and severe shock to individuals.
CAUTION
Never apply RF power to the Model 4391A Wattmeter unless both line
section sockets are filled with either an element or a dust plug. If an
element is used it is advisable to place the element with the arrow at a 90°
angle to the coaxial line.
CAUTION
Always be certain the 115/230 voltage selector is set to the proper voltage
before ac power is applied.
CAUTION
Always disconnect AC power before opening the Model 4391 enclosure.
Removal of at least one battery cell is also recommended when servicing the
instrument.
CAUTION
This instrument contains static sensitive electronic components. Before
opening or servicing the unit, make sure that you understand and practice
electrostatic discharge component handling. Failure to comply may result
in permanent damage to sensitive components.
iii
Bird Model 4391M Power Analyst
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.
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
iv
PRÉVENIR UN CHOC ÉLECTRIQUE DANGEREUX, NE PAS EFFECTUER
D’ENTRETIEN SI L’ON N’A PAS ÉTÉ QUALIFIÉ POUR CE FAIRE.
UNITS ARE EQUIPPED WITH RECHAREABLE BATTERIES.
THESE ARE TO BE REPLACED BY AUTHORIZED SERVICE
PERSONNEL ONLY!!!
LAS UNIDADES VIENEN EQUIPADAS CON BATERIAS
RECARGABLES. ¡¡¡Y SOLAMENTE EL PERSONAL DE SERVICIO
AUTORIZADO PUEDE REEMPLAZARLAS!!!
GERÄTE SIND MIT WIEDER AUFLADBAREN BATTERIEN BESTÜCKT.
BATTERIEN SIND NUR VON QUALIFIZIERTEM SERICE PERSONAL
AUSZUWECHSELN!!!
CES DISPOSITIFS SONT ÉQUIPÉS DE BATTERIES RECHARGEABLES.
SEUL LE PERSONNEL D’ENTRETIEN AUTORISÉ EST HABILITÉ À LES
REMPLACER!
LE UNITÀ SONO DOTATE DI BATTERIE RICARICABILI, CHE DEVONO
DA COME SPECIFICATO DAL PRODUTTORE LA PROTEZIONE DI
SICUREZZA POTREBBE VENIRNE COMPROMESSA.
USE CORRECT VOLTAGE SETTING AND FUSE - SEE
MANUAL.
UTILISER UNE TENSION ET UN FUSIBLE CORRECTS -
CONSULTER LE MODE D’EMPLOI.
USE LA INSTALACION Y FUSIBLE DE VOLTAJE CORRECTO - VEA EL
MANUAL.
AUSSCHLIESSLICH VORSCHRIFTSMÄSSIGE WECHSELSPANNUNGS-
EINSTELLUNG UND SICHERUNG BENUTZEN - SIEHE DAZU
HANDBUCH.
UTILLIZZARE TENSIONE E FUSIBLE ADATTI - FARE RIFERIMENTO AL
MANUALE.
BE SURE THE 115/230V AC VOLTAGE SELECTOR IS SET TO
THE PROPER LINE VOLTAGE, AND THE CORRECT AC LINE
FUSE IS INSTALLED BEFORE AC POWER IS APPLIED.
S’ASSURER QUE LE SÉLECTEUR DE TENSION 115/230V C.A.
EST BIEN RÉGLÉ POUR LA TENSION DU RÉSEAU ET QUE LE FUSIBLE
DE LIGNE C.A. CORRECT EST EN PLACE AVANT DE METTRE SOUS
TENSION C.A.
CERCIORESE QUE EL SELECTOR DE VOLTAJE DE 115/230V CA ESTE
COLOCADO A LA LINEA DE VOLTAJE APROPIADA Y QUE EL FUSIBLE
ESTE INSTALADO A LA LINEA CA ANTES DE APLICAR LA CORRIENTE
ALTERNA.
VOR EINSCHALTEN DER WECHSELSTROMZUFUHR SICHERSTELLEN,
DASS DER 115/230V WECHSELSPANNUNGS-SELEKTOR AUF DIE
VORSCHRIFTSMÄSSIGE LEITUNGSSPANNUNG EINGESTELLT UND
DIE RICHTIGE WECHSELSTROM-HAUPTSICHERUNG EINGESETZT
IST.
v
Bird Model 4391M Power Analyst
PRIMA DI EROGARE CORRENTE, ASSICURARSI CHE IL SELETTORE DI
VOLTAGGIO 115/230 V.C.A. SIA REGOLATO CORRETTAMENTE E CHE
IL FUSIBLE ADATTO ALLA LINEA DI ALIMENTAZIONE C.A. SIA
INSTALLATO.
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 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.
vi
About This Manual
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 manual is divided into Chapters and Sections.
Figures and tables are numbered sequentially within each chapter.
Chapter Layout
Introduction
Introduces the external features and and functions of the unit, equipment
provided, and optons available.
Theory of Operation
Describes the overall operation of the circuitry and the instrument
functions.
Installation
Provides information about connecting the instrument to your equipment.
Operation
Theory of Operation, and Chapter 3 - Installation, to get an overview of
equipment capabilities and how to install it. Experienced operators can
operate the equipment, are contained in this section.
Maintenance
All personnel should be familiar with calibration and repair information
troubleshooting section will aid in isolating and repairing the failure.
Parts
For location of major assemblies or parts refer to the part lists and
associated drawings.
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.
vii
Bird Model 4391M Power Analyst
viii
Table of Contents
ix
x
Chapter 1
Introduction
The Model 4391A is a multi-purpose Radio Frequency
wattmeter designed around a microcomputer. A program
stored in permanent memory controls the operation of the
instrument at all times, permitting the detection and
correction of various error sources and the refinement of the
raw data produced by the directional detectors. The
instrument can compute VSWR, amplitude modulation, and
various decibel variables reducing the odds of error and
making such measurements consistent or repeatable
regardless of who makes the measurement.
Other benefits include extended range using standard
elements in some modes of operation, continuous monitoring
of maximum and minimum readings, a peaking aid, and
error messages.
Because of its complexity, the proper use of the 4391A is not
always obvious. For this reason it is strongly advised that
this manual be read in its entirety before using the device.
Purpose and
Function
The 4391A RF Power Analyst is an insertion type digital RF
Directional Thruline® Wattmeter designed to measure peak
or average power flow, load match, and amplitude
modulation in 50 ohm coaxial transmission lines. It is
intended for use with CW, AM, FM, SSB, TV, and Pulse
modulation envelopes. The instrument directly reads PEP or
CW power in watts, milliwatts, or kilowatts in 9 ranges from
2.5 to 1000 full scale forward power and 0.25 to 100 full scale
reflected power depending on the Plug-in Element. In
addition it reads SWR directly over the range of 1.00 to
99.99, percent modulation directly over the range of 0.0 to
99.9, and return loss over the range of 0 to 36.1 dB. For
convenience, forward and reflected CW power can be
displayed in dBm (dB above 1 milliwatt) from 6 dB above to
24 dB below nominal element range.
Power range and frequency band are determined by the
Plug-in Elements used. Two switches on the front panel of
the instrument are set by the user to correspond to the
nominal power range of the forward element. The reflected
element is assumed to have a nominal range one tenth that
of the forward element.
In any mode of operation, the instrument can recall from
memory the lowest or highest reading taken or tell the
operator whether the newest reading is less than, equal to,
or greater than the previous reading.
1
Bird Model 4391A Power Analyst
Description
The instrument is housed in an aluminum case
approximately 4-3/8 inches high by 9-5/8 inches deep by 6-1/
4 inches wide (111 mm x 244 mm x 159 mm) including
connections, see Figure 1. At each end of the line section are
Bird Quick-Change type RF connectors which may be easily
interchanged with any other Bird QC connector. See Bird
Catalog for types available.
Operating power is derived from rechargeable nickel metal
hydride batteries inside the unit or from a 115/230 VAC
power source connected to the unit through the power cord
supplied with the unit.
Figure 1
Outline
Drawing
2
Chapter 2
Theory of Operation
Description of
Operation
Figure 2 is a block diagram of the major functional parts of
the Model 4391A RF Wattmeter. The Microcomputer
integrated circuit shown, controls all the other portions of
the instrument, which fall into two major groups.
Figure 2
Circuit Block
Diagram
Keyboard,
Range
Switches, and
Display
The keyboard and range switches serve only to pass
information to the computer. The display, of course, returns
information from the computer to the operator. The display,
which is comprised of four seven-segment LED digits, is
strobed digit by digit left to right at a rate of approximately
one digit per millisecond. This serves to conserve battery
power and drive circuitry while providing scanning for the
columns of the keyboard. Each time a digit is strobed, the
corresponding column of the keyboard is read and if a key is
pressed, the computer puts the code for that key into a
memory cell. The nine mode keys select which parameter is
to be measured. The three modifier keys simply modify the
way in which the result is displayed. The range selector
switches identify to the computer the nominal full scale
values of the elements used. They have no effect on input
sensitivity, which is determined by the elements.
Group
Elements,
Analog
Circuitry, and
A/D Converter
These components are controlled by the computer. The Plug-
in Elements in the line section provide low level positive
voltages related to the instantaneous value of power (see
Figure 3). The first group of solid state switches selects the
forward element, the reflected element, or ground as the
input to the preamplifier which boosts these signals to 0.1 to
2.0 volt range. The remaining switches shown as two groups
direct the output of the preamp to the analog-to-digital
converter either directly or through a peak or negative peak
detector. The analog-to-digital converter converts the voltage
to a 15 digit binary number.
3
Bird Model 4391A Power Analyst
Each reading output by the display is derived from up to
three voltage readings using the circuitry described above.
Once these voltages are measured, all remaining operations
are performed within the computer chip as follows:
The voltages are corrected for error due to dc drift in the
analog circuitry. Each voltage is converted to square root of
power using stored data tables. These values are then
combined mathematically to arrive at the final result in
binary. This is used to update the registers containing the
last value, the maximum value, or the minimum value as
required. Finally, the result is converted to a decimal
number and placed into a register from which the display
driving routine operates.
Figure 3
Plug-In
Element
Schematic
Diagram
The coupling circuit that 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 Watt-
meter are illustrated in the schematic diagram. Energy will
be produced in the coupling circuit of the element by both
mutual inductance and capacitance from the travelling RF
waves of the line section. The inductive currents will flow
according to the direction of the travelling waves producing
them. The capacitive portion of these currents is
independent of the direction of the travelling waves.
Therefore, assuming that the Plug-in Element remains
stationary, 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 or “arrow” direction is assigned to the
forward wave.
4
Theory of Operation
The electrical values of the element circuits are carefully
balanced and designed so that current from the reverse wave
will cancel the other almost completely. The result is
directivity always higher than 25 dB, which means that the
element is highly insensitive (nulled) to the REVERSE
direction wave. Being highly directional, the Thruline
element is sensitive (at one setting) only to one of the
travelling waves that produce standing waves by
interference. Thruline Wattmeter measurements are,
therefore, independent of position along standing waves.
Figure 4
Readings with
Various
Envelopes
5
Bird Model 4391A Power Analyst
6
Chapter 3
Installation
The Model 4391A RF Power Analyst is completely portable
and very suitable for field or laboratory use. Its power is
derived from rechargeable nickel metal hydride batteries
inside the unit or from an AC outlet via the power cord
supplied with the device.
The batteries are shipped in a low charge state. It is,
therefore, recommended that you charge the instrument for
16 hours before using it for continuous operation.
CAUTION
Long-term storage of this instrument can affect battery
performance and reduce battery life. Do not store the
instrument for long periods of time without recharging the
in reduced battery charge and shortened battery life.
Operating on
AC Power
For ac power operation, the Model 4391A is simply
connected to an AC receptacle using the line cord provided.
The correct AC voltage is selected via a rear panel switch
(Figure 5). The meter may be operated in this manner with
the batteries removed if desired.
CAUTION
Always be certain the 115/230 voltage selector is set to the
proper voltage before ac power is applied.
Figure 5
Rear Panel
Item No.
Description
1
2
3
AC input voltage selector switch
Fuse holder
AC power cable connector
7
Bird Model 4391A Power Analyst
Connections
The Model 4391A contains a short section of rigid 50 ohm
coaxial air dielectric transmission line. To make
measurements relating to the travelling waves in a coaxial
line, that line must be disconnected at some convenient point
to permit the Model 4391A air line to be inserted.
Although the Model 4391A is normally supplied with two
Female N-type connectors, a variety of easily
interchangeable connectors are available to facilitate
connecting to the user’s system.
Once the Model 4391A is installed in the coaxial line, a Plug-
in Element or a pair of Plug-in Elements must be selected
which correspond to the frequency and power levels to be
measured.
ꢀ NOTE: The instrument is shipped with dust plugs
installed in the element sockets. Remove the dust plugs
to insert elements.
In order to take full advantage of the Model 4391A’s
capabilities, two elements in a 10:1 ratio of power range
should be used. If only one element is used, the other socket
should be filled with a dust plug or a higher power element.
Also, for greatest accuracy, the element(s) should be chosen
having the lowest possible power range that will not result
mode of operation.
Table 1
Plug-In
Elements
Required
Mode
Forward
Reflected
FWD CW
RFL CW
SWR
ꢁ
ꢁ
ꢁ *
ꢁ
ꢁ
FWD PEP
RFL PEP
% MOD
ꢁ
ꢁ
ꢁ
FWD dBm
RFL dBm
RTN Loss
ꢁ
ꢁ *
ꢁ
*
The reflected element must have a nominal power range
one tenth that of the forward element.
The higher power element is placed in the socket marked
“FORWARD” and its arrow pointed in the direction of
forward power flow (toward antenna or load). The lower
power element is placed in the socket marked
“REFLECTED” and is normally pointed in the direction
opposite to forward power flow. The elements are clamped in
place by the hold-down catches on the face of the line section.
These catches must be used to avoid error due to the element
not contacting the bottom or seating plate of the socket. With
the element(s) in place, set the range switches to correspond
8
Installation
with the nominal power range of the elements. For example,
if the forward element is a 5 watt element, the switches are
set at 5 and x1. For a 250 watt element they are set at 2.5
and x100. Sometimes it is necessary to use milliwatts or
kilowatts as the unit of measure. In other words, 1 watt
becomes 10 x 100 milliwatts and 2500 watts becomes 2.5 x 1
kilowatts.
9
Bird Model 4391A Power Analyst
10
Chapter 4
Operating Instructions
Operating
Modes
The Model 4391A has nine modes of operation which are
selected by pressing the mode keys momentarily. In
addition, each mode has three output options selected by
pressing the modifier keys. Detailed descriptions of the
modes and output options follow.
Reading
Forward CW
Power
For this measurement only a forward element is needed.
Install the meter and element according to the preceding
paragraphs and move the power switch to LINE or BAT
depending on the power source desired. When powered up,
the Model 4391A always goes into the forward CW power
mode. If the unit is already operating, the forward CW power
mode is selected by pressing the FWD CW key momentarily.
If the applied power exceeds 120 percent of the range, two
right-facing arrow heads (i.e., “greater-than” symbols) will
be displayed. The operation of this error message does not
depend on the correct setting of the range switches by the
operator, nor will the meter or its elements be damaged if
the switches are incorrectly set.
CAUTION
Never apply RF power to the Model 4391A Wattmeter
unless both line section sockets are filled with either an
element or a dust plug. If an element is used it is
advisable to place the element with the arrow at a 90°
angle to the coaxial line.
CAUTION
Always disconnect ac power before opening the Model
4391A enclosure. Removal of at least one battery cell is
also recommended when servicing the instrument.
Figure 6
Forward
Power (CW)
The Model 4391A arrives at values of CW power by a method
quite different from analog meters such as the Model 43, also
manufactured by Bird Electronic. While the two instruments
will agree when the measured wave is of constant amplitude,
AM or SSB waves will result in different indications (in the
CW mode). This is because the analog instrument uses the
inertia of the microammeter to “time-average” the varying
11
Bird Model 4391A Power Analyst
signal coming from the element, whereas the Model 4391A
uses peak and negative peak detector circuits to measure
peak and minimum square root of power and combines them
using the equation:
2
Peak Power + Minimum Power
⎛
⎝
⎞
⎠
-----------------------------------------------------------------------------------
CW POWER =
2
With this technique, operation of CW mode is predictable
regardless of envelope shape (see Figure 4).
Reading
Reflected CW
Power
Operation of the reflected CW power mode is identical to
that for forward CW power described above with two
exceptions: the readings are taken from the element in the
socket marked “REFLECTED” and the range of the element
is assumed to be 1/10 the range indicated by the range
switches.
Figure 7
Reflected
Power (CW)
Reading SWR
Two elements with a 10 to 1 power range ratio are required
for this mode. Press the SWR key momentarily. If average
forward power is between 10% and 120% of the scale and the
average reflected power is less than 120% of the reflected
element range, SWR will be displayed. If any of the above
conditions are not met, an error message will be displayed.
Two arrows pointing to the right — or “greater-than”
symbols — indicate over-range, while two left-pointing
arrows — or “less-than” symbols — indicate under-range or
Figure 8
Standing
Wave Ratio
(SWR)
12
Operating Instructions
Table 2
Voltage
Standing
Wave Ratio
(VSWR)
VSWR Return
Loss
Reflected VSWR Return Reflected
Power %
Loss
(dB)
Power %
(dB)
1.01
1.02
1.03
1.04
1.05
1.06
1.07
1.08
1.09
1.10
1.15
1.20
1.25
1.30
1.35
1.40
46.1
40.1
36.6
34.2
32.3
30.7
29.4
28.3
27.3
26.4
23.1
20.8
19.1
17.7
16.5
15.6
0.00
0.01
0.02
0.04
0.06
0.08
0.11
0.15
0.19
0.23
0.49
0.83
1.23
1.70
2.22
2.78
1.45
1.50
1.75
2.00
2.25
2.50
2.75
3.00
3.25
3.50
3.75
4.00
4.25
4.50
4.75
5.00
14.7
3.37
4.00
14.0
11.3
9.50
8.30
7.40
6.60
6.00
5.50
5.10
4.70
4.40
4.20
3.90
3.70
3.50
7.44
11.11
14.79
18.37
21.78
25.00
28.03
30.86
33.52
36.00
38.32
40.50
42.53
44.44
Measuring
Peak
Envelope
Power
PEP power measurements are made in the same manner as
CW power readings described above, except that the FWD
PEP and RFL PEP buttons are pressed and the readings are
displayed directly as peak power.
ꢀ NOTE: The accuracy of measurements made with
modulation having a frequency, duty cycle, pulse width,
or repetition rate outside the instrument range cannot
be assured in any mode of operation.
Figure 9
Peak
Envelope
Power (PEP)
13
Bird Model 4391A Power Analyst
Measuring
Amplitude
Modulation
Only a forward element is required for this mode. Point the
element in the direction of forward power and press % MOD.
Modulation is displayed directly in percent, provided the
average signal is above 10% and the PEP of the signal is
below 400% of the element’s nominal full scale. For specified
accuracy, the average CW power levels must be greater than
one-third of full scale. Modulation is calculated as follows:
⎛
⎜
⎝
⎞
⎟
⎠
Peak Power – Minimum Power
------------------------------------------------------------------------------------
Peak Power + Minumum Power
MODULATION =
× 100
and is therefore limited to the range of 0 to 99.9 percent.
Over-modulation will be indicated as 99.9 percent. Refer to
Table 3
Amplitude
Modulation
Peak /
% Modulation Peak /
CW Power
% Modulation
CW Power
1.00
1.10
1.21
1.32
1.44
1.56
1.69
1.82
1.96
2.10
2.25
0
2.40
2.56
2.72
2.89
3.06
3.24
3.42
3.61
3.80
4.00
55
60
65
70
75
80
85
90
95
100
5
10
15
20
25
30
35
40
45
50
Because of the threshold of the RF diode, a modulated signal
which has a minimum power level below 0.3 percent of full
scale will result in high modulation reading with uncertain
accuracy.
Figure 10
Amplitude
Modulation
(%)
14
Operating Instructions
Measuring
Power in dBm
Operation of the forward and reflected dBm modes is
identical to the forward and reflected CW power modes,
except that the resulting reading is converted to dB above 1
milliwatt before it is displayed. It should be noted that in
doing this conversion, the range set on the slide switches is
assumed to be watts rather than kilowatts or milliwatts. If it
is not, 30.0 must be added to all dBm readings when the
range is in kilowatts, or subtracted from all readings when it
is in milliwatts. An error message is displayed if CW power
is more than 24 dB below, or peak power is more than 6 dB
Figure 11
CW Power in
dBm
Table 4
Watts/dBm
Equivalents
Power
1 milliwatt
dBm
Power
4 watts
dBm
36
0
10 milliwatts
100 milliwatts
1 watt
10
20
30
33
10 watts
20 watts
40 watts
100 watts
40
43
46
50
2 watts
Measuring
Return Loss
The measurement of return loss is the same as that of SWR
except that the result is displayed in dB. In other words a
reading of 21.65 indicates that reflected power is 21.6 dB
down from forward power.
Figure 12
Return Loss,
Insertion
Loss, or
Attenuation
15
Bird Model 4391A Power Analyst
Insertion
Loss or
Attenuation
Attenuation or insertion loss can be measured directly using
an external single port line section (P/N 4230-006-1), a dc
feed-in adapter (P/N 4381-050), and a dc cable (P/N 3170-
058-6). The Model 4391A is inserted at the source end of the
device being measured. The second line section is inserted at
the load end and its dc output is routed by the dc cable to the
adapter inserted in the REFLECTED socket of the Model
4391A. Both elements are in this case pointed in the
direction of forward power flow. If the two elements do not
have a ten to one ratio, a correction factor must be added to
depending on the ratio of the elements.
Table 5
Correction
Factors
Table 6 Correction Factors
Ratio of
Elements
Added dB Ratio of
Elements
Added dB
1:1
–10
–7
–6
–4
–3
0
3
4
6
7
100:1
200:1
250:1
400:1
500:1
1000:1
2000:1
2500:1
4000:1
5000:1
10
13
14
16
17
20
23
24
26
27
2:1
2.5:1
4:1
5:1
10:1
20:1
25:1
40:1
50:1
Monitoring
Maximum and
Minimum
While operating in any of the modes described, the Model
4391A will continuously keep track of the highest and lowest
reading obtained. This action begins after ten reading cycles
to allow time for the peak detectors to settle from the
previous mode. To recall the maximum or minimum reading,
depress and hold the MAX or MIN key. When these keys are
released, the meter goes back to displaying the current value
of the parameter being measured. Recalling max or min does
not stop the meter from continuing to monitor the current
value and updating the minimum and maximum registers.
To clear the minimum and maximum register, the mode key
must be pressed again or a new mode selected. For example,
if CW power deviations are monitored, the Model 4391A is
installed as described at the beginning of this section and
turned on, then the power source is turned on and allowed to
stabilize. Once the system has stabilized, press FWD CW to
clear the MAX and MIN registers. At any time during test
the MAX and MIN keys can be used to recall the maximum
and minimum values without affecting the test. However,
pressing the FWD CW key or changing modes will clear the
registers.
Readings
16
Operating Instructions
Figure 13
Maximum or
Minimum
Readings
Using the
Peaking Aid
The peaking aid is useful for making adjustments to
optimize any of the parameters which the Model 4391A
measures. After the mode is selected, press the delta (∆) key
momentarily. This blanks the least significant digit of the
display, and replaces it with a right-facing arrow head if the
measured quantity is increasing or a left-facing arrow head
if it is decreasing. If there is no change, the digit is left
blank. To find a peak, begin making the adjustment in
whichever direction produces a right-facing arrow and
continue slowly in that direction until the arrow head turns
around. At this point the peak has been reached. To check to
make sure the peak has not been passed, press the MAX key
to read the highest value read and release it to read the
current value. The two should be the same. Desired
minimum levels (e.g. of reflected power or of SWR) are found
in a similar manner.
Figure 14
Peaking Aid
(∆)
17
Bird Model 4391A Power Analyst
Battery Care
With average use, the nickel metal hydride batteries in the
4391A will power the unit for 12 hours before needing
recharged. The 4391A will maintain rated accuracy until all
the decimal points light, indicating that recharging is
required. To recharge, connect AC power to the unit. To fully
charge the batteries requires approximately 16 hours. To
prolong the life of the batteries, it is recommended that you
periodically allow the batteries to discharge until the
decimal points light before recharging. If the batteries lose
the ability to hold a charge they should be replaced. See
Chapter 5 - Maintenance for important precautions
regarding static electricity when opening the housing.
WARNING
Use only NIckel Metal Hydride (NiMH) batteries that
have a minimum capacity of 4600 milliamper hours
(mAh). Do not install batteries that are not Nickel Metal
Hydride. Do not install NiMH batteries that have less
than 4600 mAh capacity. Failure to comply may result in
damage to the batteries, damage to the instrument, and
injury to personnel from battery chemicals.
CAUTION
Long-term storage of this instrument can affect battery
performance and reduce battery life. Do not store the
instrument for long periods of time without recharging the
in reduced battery charge and shortened battery life.
18
Chapter 5
Maintenance
The 4391A RF Power Analyst was designed and built to
provide many years of trouble free service. This section
provides the information needed to prevent and correct
equipment failure.
Preventive Maintenance
To avoid unnecessary damage, always observe the following
cautions:
1. The RF Power Analyst is a rugged and portable instru-
ment intended for field use. However, it should not be
unnecessarily exposed to extreme environmental condi-
tions.
2. When not in use, store the RF Power Analyst with the
LINE/OFF/BATT switch is in the off position.
3. Charge the batteries for 16 hours prior to extended use
of the RF Power Analyst. Refer to “Battery Care” on
Cleaning and
Inspection
Perform a periodic inspection to ensure that the RF power
analyst is always operational. Any damage noticed during
inspection should be listed and repaired before use.
1. Visually inspect the equipment for loose or damaged
parts.
2. Wipe dust and dirt from the front panel and lower hous-
ing. Remove stubborn dirt with mild detergent and a
soft cloth.
WARNING
Use dry cleaning solvents in a well ventilated area.
Avoid excessive inhalation of solvent fumes, since they
can be toxic in heavy concentrations. Always wear eye
protection and avoid skin contact with the solvent.
3. Clean the inside of the line section bores using cotton
swab stick dampened with alcohol.
4. Visually inspect the RF connectors for any sign of wear
or damage and replace if necessary. Clean the connec-
tors with alcohol or any acceptable dry cleaning fluid.
Long-term
Storage
Do not store the instrument for long periods of time without
recharging the batteries. When the instrument is stored for
long periods of time without use, the batteries will loose
their charge and also loose the ability to reach full charge
when put into service. To restore the battery charge, perform
a full charge for 16 hours. If the batteries are not fully
charged after 16 hours, completely discharge the batteries
19
Bird Model 4391A Power Analyst
then perform a full charge again. If necessary, repeat this
discharge and charge cycle up to three times. If the batteries
do not remain charged after three discharge-charge cycles,
replace the batteries.
WARNING
Use only NIckel Metal Hydride (NiMH) batteries that
have a minimum capacity of 4600 milliamper hours
(mAh). Do not install batteries that are not Nickel Metal
Hydride. Do not install NiMH batteries that have less
than 4600 mAh capacity. Failure to comply may result in
damage to the batteries, damage to the instrument, and
injury to personnel from battery chemicals.
Calibration
The RF Power Analyst should be calibrated once each year
or after any repair.
Required
Equipment
Refer to Table 7 for test equipment needed to calibrate the
RF Power Analyst.
Table 7
Required
Equipment
Recommended Model
Calibrator/Source
Keithly Model 263 or
equivalent
Calibration
Equipment
Cable Assembly (1 Required)
BNC to BNC (1 meter long)
DC Feed-in Element (1 required) Bird Electronic 4381-050
Initial Setup
On a clean flat workspace perform the following setup
procedure:
2. Insert a DC feed-in adapter into the FWD element of the
socket. Insert a metal dust plug (supplied with the
instrument) into the RFL element socket.
3. Connect a BNC to BNC cable assembly from the output
of calibrator/source to the DC feed-in adapter.
4. Set the RF Power Analyst range switches to the 10 and
x100 positions. Connect AC power and place the LINE/
OFF/BATT switch to the LINE setting.
20
Maintenance
5. Switch on the Calibrator/Source and let it warm up for
at least one hour.
6. Set the Calibrator/Source to output 30 ±0.05 microamps.
the RF Power Analyst Displays 1000 ±5.
Figure 15
Calibration
Potentiometer
Element Wiper Contact Adjustment
CAUTION
If the element cannot be fully inserted into the
socket, do not force it. You might damage the
element.
Continuous insertion or rotation of the element might
cause a slight change in the position of the contact
spring in the element socket. If the contact spring
changes position, you might experience erratic power
readings.
You can use a small screwdriver to adjust the position
of the contact spring. Be careful not to bend the spring
out so far that it interferes with insertion of the
elements.
21
Bird Model 4391A Power Analyst
Perform the following steps to adjust the contact
spring.
1. Using a small flat head screwdriver, place the
flat side of the screwdriver behind the contact
bar as indicated and bend the contact bar so
that the contact rests in the center of the slot
adjacent to the element socket (Figure 16).
Figure 16
Adjust Element
Contact Up
and Down
2. After centering the contact, bend it slightly
toward the center of the element socket bore,
so that the profile of the element contact is
visible when viewing the element socket from
Figure 17
Adjust Element
Contact In and
Out
3. If the contact is accidently moved too far into
the element bore, the element will not slide
into the socket. Move the contact back into the
recessed area and repeat the process.
22
Maintenance
Troubleshooting
General
The troubleshooting instructions are intended to aid in fault
isolation. This is accomplished through the use of a
troubleshooting table.
First, locate the symptom(s) in the problem column of
Table 8. In some cases the same fault can have more than
one symptom and more than one possible remedy. Compare
the possible causes until you arrive at a suspected fault.
Once a fault has been isolated, repair or replace the defective
components.
ꢀ NOTE: Always recalibrate the RF Power Analyst after
repairing the fault.
Table 8
Trouble-
shooting
PROBLEM
POSSIBLE CAUSE
REMEDY
Inaccurate
RF Power Analyst
Recalibrate.
power readings uncalibrated
Defective Plug-in
Elements
Replace defective elements.
Intermittent connection
at the element wiper
Adjust the element wiper
contact. Refer to page 21.
Loose hold down catch
Readjust catch to hold element
securely in place.
Worn line section
Replace line section. Refer to
Defect on Data
Acquisition PC board
assembly
Replace the PC board
assembly (attached to line
High standing
waves
Dirty Connectors
Worn or damaged
connectors
Clean the connectors.
Replace the connectors Refer
Foreign objects in line
section
Remove object from the line
section.
Short battery
life
115/230V switch in
wrong position
Set 115/230V switch to correct
position.
Damaged/worn batteries Replace the batteries.
Will not operate 115/230V switch in
Set 115/230V switch to correct
position.
Replace blown fuse (Figure 5,
from AC line
wrong position
Blown fuse
Defective line cord
Repair or replace.
23
Bird Model 4391A Power Analyst
PROBLEM
POSSIBLE CAUSE
REMEDY
Display
indicates “0”
Power
Element wiper not
Readjust the element wiper to
make good contact (page 21).
Replace Plug-In Element.
contacting the element
Defective Plug-in
Element
Defect on Data
Acquisition PC board
assembly
Replace the PC board
assembly (attached to line
One segment of Defective Display
a display doesn’t
light
Replace the display.
All decimal
points stay lit
Low charge on the
batteries
Recharge the batteries.
Defective circuit
component
Replace the Main circuit board
assembly. Refer to page 25.
Same segment
on all displays
doesn’t light
Defective circuit
component
Replace the Main circuit board
assembly. Refer to page 25.
One or more
keys do not
function
Defect on Main PC board Replace the Main circuit board
assembly.
Disassembly
WARNING
Be sure that the power cable is unplugged before opening
the wattmeter case. The power supply capacitor, C1, can
retain a dangerous charge that must be removed before
touching. Always have another person standing by who is
trained in electric shock first aid.
CAUTION
This instrument contains static sensitive electronic
components. Before opening or servicing the unit, make
sure that you understand and practice electrostatic
discharge component handling. Failure to comply may
result in permanent damage to sensitive components.
Front Panel
Removal
1. Disconnect AC power from the instrument.
2. Remove the six screws that secure the front panel to the
3. Remove the two screws and lock washers that secure the
front panel at the bottom of the housing (item 2).
4. Remove the two screws and lock washers that secure the
front panel at the back of the housing (item 3).
24
Maintenance
5. Lift the front panel from the housing. Be careful to clear
the line section blocks.
6. Remove pads from the three toggle switches.
Figure 18
Removing
Front Panel
Main Printed
Circuit (PC)
Board
page 26, item 1).
Removal
3. Remove the six screws and washers that secure the cir-
cuit board supports to the housing (item 2).
CAUTION
Internal batteries are connected. Remove one of the battery
tubes before unsoldering wires connected to the Main PCB.
Failure to comply may result in permanent equipment
damage and severe shock to individuals.
4. Lift the Main PC board and remove one battery tube.
5. On the Main PC board, unsolder and remove the red and
orange wires that come from the power supply circuit
board.
25
Maintenance
Line Section
Removal
2. Remove the four screws and lock washers that secure
line section assembly to the housing (item 3).
3. Using minimum pressure, spread apart the sides of the
lower housing assembly just far enough to allow the line
section assembly to be removed.
Figure 20
Removing QC
Connectors
and Line
Section
To remove the line section PCB, continue with the next
steps.
CAUTION
This instrument contains static sensitive electronic
components. Before opening or servicing the unit, make
sure that you understand and practice electrostatic
discharge component handling. Failure to comply may
result in permanent damage to sensitive components.
4. Remove the two screws (units with serial numbers 1723
and below) or the two hex nuts (units with serial
the PCB cover then remove the cover (item 6) and
spacers (item 7).
5. Disconnect the ribbon cable assembly from the PC board
header (J1).
27
Bird Model 4391A Power Analyst
6. Remove the two screws (item 4) that secure the PCB to
the line section then pull the PC board assembly (item 3)
away from the line section subassembly. Remove the
spacers (item 2).
7. Remove keying beads (item 1) from the element wiper
contacts on the PC board assembly.
Figure 21
Removing Line
Section PCB
Battery
Replacement
item 1) that secure the Main PCB.
3. Loosen, but do not remove the remaining two screws
that secure the Main PCB (item 2).
4. Tilt the Main PC board assembly up to expose the bat-
teries then tighten the two screws to secure the PCB.
5. Unfasten the velcro strap and remove it from the D-ring.
6. Note the polarity orientation of the batteries. Remove
the three battery tubes from the battery clips then
remove two batteries from each tube.
7. Install new batteries into the tubes then secure the
tubes in the battery clips. Be sure to observe proper
polarity.
28
Bird Model 4391A Power Analyst
Parts List
This section contains an illustrated list of all authorized
replacement parts for the 4391A RF power Analyst. Parts
are grouped into major assemblies and subassemblies.
Figure 24
Parts
Drawing
Item No. Description
Part No.
Qty
1
Connector, QC F-N
4240-062
5-1337
2
4
1
1
1
1
1
6
2
1
2
LED display, (DS1 - DS4)
Keyboard legend
3
4386-012
4391B007
5-1958
4
PC board, Main, assembly
Velcro strap
5
6
PC board assy (includes rectifier circuit)
Fuse, Slo-Blo, IEC 1/8 amp
Battery (rechargeable) “C” cell
Dust plug
4391A041
5A2257-7
5A1230
7
N/S
N/S
N/S
3610-031
4421-055
Cable, power cord, 115V / 230V
N/S = not shown in figure
30
Maintenance
Figure 25
Line Section
Assembly
(S/N 1723
and below)
Item No.
Description
Part No.
Qty
1
2
3
4
5
Line Section, Subassembly
PC Board, Data Acquisition Assy
Bead, Keying
4381-005
4391A006
4391-026
4391-027
COML
1
1
2
2
2
Spacer
Screw, Machine, filister head,
No. 4-40, 1/4 in. lg, sst
6
7
Support
4381-029
COML
2
4
Screw, Machine, filister head,
No. 8-32, 1/2 in. lg, sst
8
Screw, Machine, filister head,
No. 4-40, 7/8 in. lg, sst
COML
2
9
Spacer
4391-035-1
4391-034
COML
2
1
2
1
10
11
N/A
Cover, PC Board
Lock Washer, No. 4 internal sst
Line Section Complete
4391-014
31
Bird Model 4391A Power Analyst
Figure 26
Line Section
Assembly
(S/N 1724
and above)
Part No.
Description
Part No.
Qty
1
2
3
4
5
Line Section, Subassembly
PC Board, Data Acquisition Assy
Bead, Keying
4381-005
4391A006
4391-026
4391-027
COML
1
1
2
2
2
Spacer
Screw, Machine, filister head,
No. 4-40, 1/4 in. lg, sst
6
7
Support
4381-029
COML
2
4
Screw, Machine, filister head,
No. 8-32, 1/2 in. lg, sst
8
Hex Nut, with nylon insert, No. 4-40
Spacer
1131-1013-00
4391-035-1
4391-034
COML
2
2
1
2
2
9
10
11
12
Cover, PC Board
Lock Washer, No. 4 internal sst
Standoff, Threaded
4391-038
32
Maintenance
Customer Service
Any maintenance or service procedure beyond the scope of
those in this chapter should be referred to a qualified service
center.
If you need to return the unit for any reason, contact the
Bird Service Center for a return authorization. All
instruments returned must be shipped prepaid and to the
attention of Bird Service Center.
Bird Service Center
30303 Aurora Road
Cleveland (Solon), Ohio 44139-2794
Phone: (440) 519-2298
Fax: (440) 519-2326
E-mail: [email protected]
For the location of the Sales Office nearest you, give us a call
or visit our Web site at:
33
Bird Model 4391A Power Analyst
Specifications
Measuring Medium
RF Power Range*
RF Transmission in 50 ohm lines
100 mW to 10 kW full scale using Bird Plug-in Elements.
Accuracy not guaranteed with components not supplied by
Bird
Usable Over-Range*
To 120% of scale on CW, PEP, SWR, and Return loss functions.
To 400% of scale (PEP) on dBm and 0% modulation.
450 kHz to 2.7 GHz
Frequency Range*
Sampling Range
Settling Time
2-3 readings per second
10 seconds (worst case)†
Accuracy
Power Readings
CW
PEP
SWR
% Modulation
Return Loss
±5% of full scale
±8% of full scale
±10% of reading
±5%‡
±0.3 dB to corresponding SWR value
Impedance
50 ohms
Insertion SWR
1.05 max to 1000 MHz
Pulse Parameters (square pulses)
0.8 µsec. min.**
25 pps min.
0.01% min.
Pulse Width
Repetition Rate
Duty Cycle
RF Line Connections
Standard
Optional
Bird Quick Change “QC” Female N
Any Standard AN “QC” type
Temperature Range
Operating
Storage
10ºC to 45ºC (50ºF to 113º F)
-20ºC to 45ºC (-4ºF to 113º F)
Input Power Requirements
Voltage
100-130 or 200-230 VAC (Switch Selectable) or 7.2 Vdc
(internal battery)
50-60 Hz
6 Watts
Frequency
Power
Batteries
Battery Life
Weight
6-1.2 V NiMH C size (Rechargeable)
12 hours approx.
5-3/4 lb (2.6 kg)
*
Frequency band and power range is determined by the Plug-in Elements select-
ed. See Bird Catalog for availability. Some modes require two elements in a 10:1
power ratio.
†
‡
VSWR and return loss functions settle in less than 1 second.
For CW power levels greater than one-third of full scale, accuracy of the percent
modulation mode is 5% from 0 to 90% and +10% from 90 to 100%. Modulation fre-
quency is 25 to 100,000 Hz; except for “A” and “B” elements: 25 to 20,000 Hz; and
“H” elements: 25-10,000 Hz.
** For “A” and “B” elements the minimum pulse width is 1.5 microseconds. For “H”
elements the minimum pulse width is 15 microseconds.
34
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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