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TERMALINE® LOAD RESISTOR
SERIES 8920
MODELS:
8921
8922
8926
8927
8928
8922D
8926D
8927D
©Copyright 2008
Instruction Book Part Number 920-8920S Rev. H
Termaline® and Thruline® are Registered Trademarks
by Bird Electronic Corporation
of Bird Electronic Corporation
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I am not blank
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Safety Precautions
The following are general safety precautions that are not necessarily related to any specific
part or procedure, and do not necessarily appear elsewhere in this publication. These precautions must be thoroughly understood and apply to all phases of operation and maintenance.
WARNING
Keep Away From Live Circuits
Operating Personnel must at all times observe general safety precautions. Do not replace
components or make adjustments to the inside of the test equipment with the high voltage
supply turned on. To avoid casualties, always remove power.
WARNING
Shock Hazard
Do not attempt to remove the RF transmission line while RF power is present.
WARNING
Do Not Service Or Adjust Alone
Under no circumstances should any person reach into an enclosure for the purpose of
service or adjustment of equipment except in the presence of someone who is capable of
rendering aid.
WARNING
Safety Earth Ground
An 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.
WARNING
Resuscitation
Personnel working with or near high voltages should be familiar with modern methods of
resuscitation.
WARNING
Remove Power
Observe general safety precautions. Do not open the instrument with the power on.
Safety 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.
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This symbol indicates that a shock hazard exists if the precautions in the
instruction manual are not follwed.
The caution symbol appears on the equipment indicating there is important information in the instruction manual regarding that particular area.
This symbol indicates that the unit radiates heat and should not be touched
while hot.
Note: Calls attention to supplemental information.
Warning Statements
The following safety warnings appear in the text where there is danger to operating and maintenance personnel, and are repeated here for emphasis.
Caution Statements
The following equipment cautions appear in the text and are repeated here for emphasis.
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Safety Statements
USAGE
ANY USE OF THIS INSTRUMENT IN A MANNER NOT SPECIFIED BY THE
MANUFACTURER MAY IMPAIR THE INSTRUMENT’S SAFETY
PROTECTION.
USO
EL USO DE ESTE INSTRUMENTO DE MANERA NO ESPECIFICADA POR EL
FABRICANTE, PUEDE ANULAR LA PROTECCIÓN DE SEGURIDAD DEL
INSTRUMENTO.
BENUTZUNG
WIRD DAS GERÄT AUF ANDERE WEISE VERWENDET ALS VOM
HERSTELLER BESCHRIEBEN, KANN DIE GERÄTESICHERHEIT
BEEINTRÄCHTIGT WERDEN.
UTILISATION
TOUTE UTILISATION DE CET INSTRUMENT QUI N’EST PAS
EXPLICITEMENT PRÉVUE PAR LE FABRICANT PEUT ENDOMMAGER LE
DISPOSITIF DE PROTECTION DE L’INSTRUMENT.
IMPIEGO
QUALORA QUESTO STRUMENTO VENISSE UTILIZZATO IN MODO
DIVERSO DA COME SPECIFICATO DAL PRODUTTORE LA PROZIONE DI
SICUREZZA POTREBBE VENIRNE COMPROMESSA.
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SERVICE
SERVICING INSTRUCTIONS ARE FOR USE BY SERVICE - TRAINED
PERSONNEL ONLY. TO AVOID DANGEROUS ELECTRIC SHOCK, DO NOT
PERFORM ANY SERVICING UNLESS QUALIFIED TO DO SO.
SERVICIO
LAS INSTRUCCIONES DE SERVICIO SON PARA USO EXCLUSIVO DEL
PERSONAL DE SERVICIO CAPACITADO. PARA EVITAR EL PELIGRO DE
DESCARGAS ELÉCTRICAS, NO REALICE NINGÚN SERVICIO A MENOS
QUE ESTÉ CAPACITADO PARA HACERIO.
WARTUNG
ANWEISUNGEN FÜR DIE WARTUNG DES GERÄTES GELTEN NUR FÜR
GESCHULTES FACHPERSONAL.
ZUR VERMEIDUNG GEFÄHRLICHE, ELEKTRISCHE SCHOCKS, SIND
WARTUNGSARBEITEN AUSSCHLIEßLICH VON QUALIFIZIERTEM
SERVICEPERSONAL DURCHZUFÜHREN.
ENTRENTIEN
L’EMPLOI DES INSTRUCTIONS D’ENTRETIEN DOIT ÊTRE RÉSERVÉ AU
PERSONNEL FORMÉ AUX OPÉRATIONS D’ENTRETIEN. POUR PRÉVENIR
UN CHOC ÉLECTRIQUE DANGEREUX, NE PAS EFFECTUER D’ENTRETIEN
SI L’ON N’A PAS ÉTÉ QUALIFIÉ POUR CE FAIRE.
ASSISTENZA TECNICA
LE ISTRUZIONI RELATIVE ALL’ASSISTENZA SONO PREVISTE
ESCLUSIVAMENTE PER IL PERSONALE OPPORTUNAMENTE
ADDESTRATO. PER EVITARE PERICOLOSE SCOSSE ELETTRICHE NON
EFFETTUARRE ALCUNA RIPARAZIONE A MENO CHE QUALIFICATI A
FARLA.
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CONNECT INTERLOCK TO TRANSMITTER/GENERATOR/AMPLIFIER BEFORE
OPERATING.
BRANCHER LE VERROUILLAGE À L’ÉMETTEUR/GÉNÉRATEUR/
AMPLIFICATEUR AVANT EMPLOI.
CONECTE EL INTERBLOQUEO AL TRANSMISOR/GENERADOR/
AMPLIFICADOR ANTES DE LA OPERACION.
VOR INBETRIEBNAHME VERRIEGELUNG AM SENDER/GENERATOR/
VERSTÄRKER ANSCHLIESSEN.
PRIMA DI METTERE IN FUNZIONE L’APPARECCHIO, COLLEGARE IL
DISPOSITIVO DI BLOCCO AL TRASMETTITORE/GENERATORE/
AMPLIFICATORE.
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About This Manual
This manual covers the operating and maintenance instructions for the following models:
8921 8922 8926 8927
8928 8922D 8926D 8927D
Changes to this Manual
We have made every effort to ensure this manual is accurate. If you discover any errors, or if
you have suggestions for improving this manual, please send your comments to our Solon,
Ohio factory. This manual may be periodically updated. When inquiring about updates to this
manual refer to the part number and revision on the title page.
Definitions
Measure Match Mode - The Match Measurement mode shows the resonant frequencies
for an antenna or filter. It also confirms that there are no impedance problems in the nonresonant components such as cables, connectors, lightning protectors, and jumpers.
Fault Location Mode - The Fault Location mode shows the location of any problems in the
antenna system. This is shown in either feet or meters from the cable end connected to the
Site Analyzer.
Cable Loss Mode - The Cable Loss mode shows the insertion loss of a coaxial cable. By
comparing this with the manufacturer’s specs, it confirms that there are no problems with the
cable.
VSWR - VSWR units used to be the preferred way to measure an antenna system. A good
antenna has a VSWR of less than 1.5:1 at its operating frequency.
Return Loss - Return Loss measures, in dB, how much of a wave is reflected back to the source. It is
now the preferred method for measuring antenna systems. A good antenna will have a return loss of –14
dB or less at the operating frequency. The more negative the reading, the better the antenna.
Markers - Markers are used to show the exact value at one point on the graph. In Measure
Match and Cable Loss modes, the marker displays the frequency and loss (or VSWR). In Fault
Location mode, the marker displays the distance and loss.
Run / Hold - When HOLD is displayed, the unit makes a new sweep every few seconds, and
displays the latest sweep. When RUN is displayed, the unit will only make a single sweep. The
display will not update if the Site Analyzer is disconnected or if the cable is jiggled. This is usually preferred.
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Table of Contents
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Warning Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ii
Caution Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ii
Safety Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
Changes to this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
Chapter 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Items Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Items Required but not Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chapter 2 Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Load Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Thermal Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Chapter 3 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Unpacking and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Installing Thermoswitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Interlock Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Connecting RF Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
“QC” Connector Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Swivel Flanged Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Unflanged Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Chapter 4 Operating Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Operation Under Abnormal Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Emergency Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Chapter 5 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
DC Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Coolant Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
RF Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Load Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Storage and Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Available “QC” Type Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Limited Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Chapter 1 Introduction
VENT PLUG
INTERLOCK
THERMOSWITCH
(OPTIONAL)
26-7/8”
(681mm)
28-1/4”
(718mm)
8-3/8”
(212mm)
DEPENDS ON
CONNECTOR
7”
(178mm)
9-1/8”
(241mm)
(4) MTG. HOLES
3/8” (10 mm)
Bird 8920 Series Loads are portable, 50 ohm, coaxial RF transmission line terminations, designed for frequency
ranges of DC – 1 GHz. Bird 8920D Series Loads are identical, except that they are designed for the UHF (470 – 860
MHz) band. They provide accurate, dependable, and low reflection line terminations. Up to 5000 watts of RF power
can be dissipated.
The load has a coolant chamber surrounded by radiator fins. The front and rear fins form mounting flanges which can be
used as supports for freestanding use or as brackets for fixed mounting. A vent plug at the top of the unit relieves internal
pressure from coolant expansion. The load’s simple and rugged design minimizes maintenance requirements.
Items Supplied
• Load Resistor: Pre-filled with coolant at the factory
• One Shipping Plug
• One Vent Plug
• Instruction Manual
Items Required but not Supplied
• Coupling Kit: Connects the load to the RF line
Optional Accessories
• Interlock Thermoswitch: Automatically shuts off the transmitter to prevent over-
heating of the load
Figure 1 Bird 8920 Series Outline Drawing
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Chapter 2 Theory of Operation
O-ring seal
O-ring seal
Load Resistor
Bird 8920 series loads consist of a thin-film-on-ceramic resistor immersed in a dielectric coolant. The resistor, individually selected for its accuracy, is enclosed in a special housing. When surrounded by the coolant, this produces a
uniform, practically reflectionless line termination over the specified frequencies.
Coolant
The load is cooled by natural fluid and air convection currents. The coolant, chosen for its dielectric and thermal
characteristics, carries heat from the resistor to the walls of the cooling tank, where radiator fins surrounding the
tank transfer the heat to the air.
When the coolant is heated, thermal expansion causes an increase in the internal pressure. The vent plug relieves
this pressure while protecting the opening from dirt or other contaminants.
Thermal Interlock
Loads can be supplied with an optional passive overtemperature thermoswitch. Normally closed, it opens at the
maximum safe load temperature of 236 °C (457 °F), turning off transmitter power. The interlock system will not permit use of the transmitter until the load has reached a safe temperature.
Figure 2 Shipping Plug
Figure 3 Vent Pl
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Chapter 3 Installation
This chapter provides information for on-site requirements, unpacking, inspection, and preparing the load for use.
Unpacking and Inspection
1. Carefully inspect shipping container for signs of damage.
2. Do one of the following:
• If the shipping container is damaged, do not unpack the unit. Immediately notify
the shipping carrier and Bird Electronic Corporation.
• If the shipping container is not damaged, unpack the unit. Save shipping materi-
als for repackaging.
3. Inspect unit for visual signs of damage.
Note: If there is damage, immediately notify the shipping carrier and Bird Electronic Corporation.
Mounting
Place the load in a dry, dust and vibration free environment. Do not use outdoors or in areas of condensing humidity.
Allow at least 12" (30 cm) of clearance on all sides of the load.
CAUTION
This load is designed for operation in a horizontal position only, with the vent plug up. Do not use in any other
manner.
The load is equipped for either portable use or fixed installation. The mounting brackets on the front and rear faces
have four mounting slots arranged in a 4
mm) diameter max.
The vent plug must be used at all times when the unit is operating or cooling. Failure to do so could result in an
1
⁄2" x 147⁄32" rectangle (114.3 x 361.2 mm). Use a screw with a 3⁄8" (9.53
WARNING
explosion or severe burns.
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Setup
Note: Before first using the load, get a resistance baseline for future maintenance. Refer to "DC Resistance"
on page 12 for details.
1. Remove the shipping plug.
2. Install the vent plug. Refer to Figure 2 and Figure 3.
Installing Thermoswitch
Bird 8920 series loads can be equipped with an optional interlock thermoswitch, P/N 8890-008. It is normally closed,
opening at 236 °C (457 °F), with a rating of 10A @ 120 VAC and 5A @ 230 VAC.
WARNING
The vent plug must be used at all times when the unit is operating or cooling. Failure to
do so could result in an explosion or severe burns.
1. Stand the unit on its front, supporting it so that the connector is not damaged.
Note: In this position there is no danger of the coolant pouring out through
the socket plug hole.
2. Remove the socket plug just above the connector assembly, using a
3. Replace the plug with the thermoswitch.
4. Apply pipe sealing compound, sparingly, to the external threads, only, of the thermoswitch.
CAUTION
Do not contaminate the coolant with pipe sealant.
9
⁄16" hex wrench.
Interlock Connection
Note: Connect the thermoswitch to the interlock as follows (see Figure 4):
5. Check for coolant leaks upon completion.
6. Remove the shipping plug. Install the vent plug.
CAUTION
If installed, connect optional interlock before applying RF power.
1. Unscrew the large knurled ring-nut (A) at the lower end of the coupling jack assembly.
2. Pull it off the thermoswitch jack (B).
3. Unscrew the small knurled cover fitting from the base plug (D) of the connector to
release the base.
4. Thread the control switch wires through the clamp (E) with the washers (F) inside
and with its threaded fitting in place.
5. Service the control switch wire with short tips and put spaghetti sleeves over the
wire ends if necessary.
6. Securely solder the control switch leads to the lugs (G) of the connector base.
Note: The ring-nut (A) must be in place over the base plug (D) with the knurled
end facing out.
7. Screw on the cover ring, then fasten the cable clamp (E) in place and tighten both
yoke screws (H).
8. Put the plug back on the thermoswitch and tighten the nut (A).
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Figure 4 Thermoswitch Assembly
BOLT BULLET LOADRF COAXIAL LINE
Connecting RF Power
After installing the load, the RF transmission line can be attached using standard coaxial line coupling kits.
WARNING
Never attempt to connect or disconnect RF equipment from the transmission line while RF power is being
applied. Leaking RF energy is a potential health hazard.
“QC” Connector Coupling
Swivel Flanged Coupling
Note: To couple the swivel flange with a flanged RF transmission line, use an appropriate coupling kit.
1. Insert the center bullet.
2. Push it in until it is fully seated.
3. Connect the coaxial input in a straight line.
4. Push carefully on the center conductor to close.
5. Insert the bolt sets and tighten evenly all around to transmission line manufacturer’s
6. Use all of the bolts.
Figure 5 Swivel Flanged Coupling
• Use 50 ohm coaxial cable such as RG-218/U or -220/U (-17A or -19A), appropri-
ate for the frequency and power level of operation.
• Use a cable connector which will mate with the one on the load.
Note: The swivel flange on the load makes connection independent of the orientation of the fixed flange on the coaxial input outer conductor.
recommended torque.
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Unflanged Coupling
RF COAXIAL
LINE
CLAMPING
BANDS
CONNECTOR
SLEEVE
BULLET
LOAD
Note: To couple the unflanged connector with an unflanged RF line, use an appropriate coupling kit. Refer
to Figure 6 while following the instructions below:
1. Insert the center bullet and bottom it on the midpoint nibs.
2. Position the outer sleeve, with clamping bands, over the input connector.
3. Set the transmission line snugly against the coupling stops.
4. Position the clamping bands evenly about 3/4” from the ends of the sleeve.
5. Tighten the clamping bands.
Figure 6 Unflanged Coupling
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Chapter 4 Operating Instructions
WARNING
The vent plug must be used at all times when the unit is operating or cooling. Failure to do so could result in an
explosion or severe burns.
Normal Operation
Bird 8920 series loads have no indicators or operating controls. They require no special operating procedures or surveillance when their performance limits are not exceeded. Follow the instructions for the specific transmitter equipment.
Operation Under Abnormal Conditions
The load can be subjected to moderate overloads for short periods. If this is likely, make sure the interlock is properly connected to prevent damage to the load.
Shutdown
These loads are passive devices, so have no way of being turned off. Turn off RF power at the source.
WARNING
Never attempt to connect or disconnect RF equipment from the transmission line while RF power is being
applied. Leaking RF energy is a potential health hazard.
Emergency Shutdown
Turn off RF power at the source.
If the interlock thermoswitch is properly connected, RF power will be automatically turned off when the coolant
temperature reaches an unsafe level.
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Chapter 5 Maintenance
This chapter covers cleaning, inspection, trouble-shooting, and specifications for the Bird 8920 series loads.
WARNING
Never attempt to connect or disconnect RF equipment from the transmission line while RF power is being
applied. Leaking RF energy is a potential health hazard.
WARNING
Disconnect the unit from all power sources before servicing.
The unit may be energized from multiple sources.
The potential for electric shock exists.
WARNING
Oil is slippery. If a leak occurs, be careful not to fall.
Troubleshooting
The table below contains troubleshooting information for problems which can occur during normal operation. This
manual cannot list all malfunctions that may occur, or their corrective actions. If a problem is not listed or is not corrected by the listed actions, notify a qualified service center.
Problem Possible Cause Correction
Leaking coolant Loose clamping band Tighten the clamping band
Defective or improperly installed
O-ring
High or low DC
resistance
Overheating radiator RF power too high Lower RF power
Loose RF input connector Tighten connector
Faulty RF input connector Model 8921: Replace connector
Faulty resistor Replace the resistor
Coolant level too low Check the coolant level. Add coolant if necessary
Coolant degraded Replace the coolant
Faulty resistor Replace the resistor
Replace the O-ring
(See “Load Resistor” on page 14)
(See “RF Connector” on page 13)
All other models: Return the unit for service
(See “Load Resistor” on page 14)
(See “Coolant Level” on page 13)
(See “Coolant Level” on page 13)
(See “Load Resistor” on page 14)
11
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Maintenance
Cleaning
The outside surface of the instrument should be wiped free of dust and dirt when necessary. Excessive dust on the
cooling fins will interfere with heat dissipation. Clean the RF connector, both metallic and insulating surfaces, with a
dry, non-residue forming solvent.
WARNING
Oil is slippery. If a leak occurs, be careful not to fall.
Inspection
Inspect the unit every six months. Check for coolant leakage around the clamping band and the thermoswitch. Also
check for corrosion.
DC Resistance
Measuring the DC resistance between the inner and outer conductors of the RF connector provides a good check of
the condition of the load resistor. This simply measures changes in the resistor’s condition over time. Under normal
operating conditions, the resistor should provide at least 5,000 hours of operation before requiring any additional
service. DC resistance tracking must start before the resistor is put into service, and should be measured annually.
Perform the following steps and record the value for future comparison. Make sure that you have an ohmmeter with
an accuracy of ±1% at 50 ohms and that the load temperature is between 20 and 25 °C (68 to 77 °F) before starting.
WARNING
Never attempt to connect or disconnect RF equipment from the transmission line while RF power is being
applied. Leaking RF energy is a potential health hazard.
1. Turn off the RF power and interlock circuitry.
2. Disconnect the RF line.
3. Connect the multimeter test leads to the center and outer conductor of the load
resistor. Refer to Figure 7.
4. Compare the measured value with the previous measurement and with the baseline
resistance, measured when the load was put into service.
Note: If the new value differs from either of these by more than 2 ohms this
could indicate a failing resistor.
Figure 7 Measuring Resistance
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Coolant Level
Coolant lifetime will vary greatly depending on operating conditions. For heavy use (full RF power for long times,
high ambient temperature), check the coolant every 500 hours. If the load has only had light duty (fraction of full
power, low ambient temperature), then coolant inspection may only be necessary every 2,000 hours.
WARNING
Disconnect the unit from all power sources before servicing. The unit may be energized from multiple sources.
The potential for electric shock exists.
WARNING
Oil is slippery. If a leak occurs, be careful not to fall.
CAUTION
Use only Bird coolant, P/N 5-1070, to prevent damage to the load.
Note: Correct any coolant leakage before inspection. (See "Troubleshooting" on page 11)
1. Remove the load resistor (Refer to “Load Resistor” on page 18).
2. Ensure the coolant should be clear, with a faint yellow tinge, and have a slightly
sweet smell.
3. Do the following ff the coolant is black with a burnt or acrid smell:
a. Drain it
b. Add about 6.7 gal (25.2 L) of coolant.
Note: With the load still on end, the coolant level should be 4
3
⁄4" (125 mm) below
the top surface of the resistor assembly mounting ring, at ambient temperature.
4. Add coolant if necessary.
Repair
WARNING
Disconnect the unit from all power sources before servicing. The unit may be energized from multiple sources.
The potential for electric shock exists.
WARNING
The vent plug must be used at all times when the unit is operating or cooling. Failure to do so could result in an
explosion or severe burns.
RF Connector
The Model 8921, only, has a special Bird “QC” connector which allows easy changing of the RF connector. This does not
disturb the coolant seal or affect the electrical continuity of the load. To change the connector, proceed as follows:
1. Remove the four screws at the corners of the RF connector.
2. Pull the connector straight out.
3. Push the new connector in.
4. Ensure that the center pin on the connector is properly seated in the mating socket
on the load.
5. Replace the screws.
Note: If not using the connector normally supplied, frequency and power must
be limited to the capabilities of the connector.
13
Page 24
Load Resistor
WARNING
Oil is slippery. If a leak occurs, be careful not to fall.
1. Remove the vent plug.
2. Install the shipping plug.
3. Stand the unit on its back with the connector end up.
Note: Support the unit to prevent damage to the interlock
Note: In this position there is no danger of the coolant pouring out through
the resistor hole.
4. Unscrew and remove the clamping band.
5. Lift the load resistor assembly out of the tank.
6. Allow any coolant to drip back into the tank.
Note: The O-Ring should be free of twists and positioned evenly around the
flange of the resistor housing. If it shows signs of deterioration (e.g. is no longer
pliable or has surface cracks) replace it.
7. Replace the entire load resistor assembly.
Note: It cannot be further disassembled.
8. Put the clamping band in place and tighten it.
9. Remove the shipping plug. Install the vent plug.
Storage and Shipment
Cover the load before storing to keep out dust and dirt. It is not necessary to install the shipping plug. Store in a dry,
dust-free environment where the ambient temperature will remain between
–40 and +45 °C (–40 to +113 °F).
To ship the load, take the following precautions:
1. Remove the vent plug and replace it with the shipping plug.
2. Wrap the vent plug with padding.
3. Tape it to the side of the load for protection.
Note: With the shipping plug installed, it is not necessary to empty out the
coolant.
4. Wrap the connector in padding.
5. Pack and brace the load in a sturdy wooden crate for shipment.
14
Page 25
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, request an RMA through the Bird Technologies website (link shown
below). All instruments returned must be shipped prepaid and to the attention of the RMA number.
Bird Service Center
30303 Aurora Road
Cleveland (Solon), Ohio 44139-2794
Fax: (440) 248-5426
E-mail: [email protected]
For the location of the Sales Office nearest you, visit our website at:
http://www.bird-technologies.com
15
Page 26
Specifications
Frequency Range
Power Rating 5000 W continuous duty
Peak Power for Pulse Width
10 µs
100 µs
1000 µs
5000 µs
Mode CW, AM, FM, SSB, TV, & Pulsed Digital Systems
Impedance, Nominal
VSWR
Connectors
Interlock Thermoswitch Normally closed. Opens at 236 °C (457 °F)
Thermoswitch Rating
Ambient Temperature
Altitude
Humidity 95% noncondensing max
Cooling Method Oil dielectric and convection currents
Dimensions 29”L x 9-1/2”W x 26-53/64”H
Weight, Nominal 119 lb. (54 kg)
Finish
8921-MM-3-150
8922D, 8926D, 8927D
All other models
1 µs
8921-MM-3-150
All other models
†
8921-MM-3-150
8922D, 8926D, 8927D
All other models
‡
8921
8922, 8922D
8926, 8926D
8927, 8927D
8928
115 VA C
230 VAC
8921-MM--3-150
All other models
**
8921-MM-3-150
All other models
100 - 200 MHz
470 – 860 MHz
DC – 1 GHz
*
150 kW
115 k W
80 kW
54 kW
22 kW
150 ohms
50 ohms
3:1 ± 0.5
1.065
1.10
Female LC
1-5/8" EIA Flanged
3-1/8" EIA Flanged
3-1/8" EIA Unflanged
3-1/8" EIA Unflanged, Recessed Center
10 A
5 A
-40 to +50 ºC (-40 to +122º F) (storage temp)
0 to + 50 º C (32 to +122 º F) (operating temp)
–40 to +45 °C (–40 to +113 °F)
1520 m (5000 ft.)
(737 x 241 x 681 mm)
Black
Grey Powder Coat
16
* Set the duty factor so that load’s average power rating is not exceeded.
† VSWR measured using a female N connector.
‡ For model 9821 VSWR Measured using a female N connector.
** Derate RF power by 2.5% for every 305m (1,000 ft.) above 1,520m (5,000 ft.).
Page 27
Replacement Parts
Description Qty Part Number
RF Load Resistor:
8921
8922, 8922D
8926
8926D
8927
8927D
8928
Resistor O-Ring 1 5-230
Clamping Band Assembly 1 2430-055
Plug
Vent
Shipping
Interlock Thermoswitch
Thermoswitch Body
Thermoswitch Jack
Radiator Assembly 1 8921-002
Access Plug, 3/4"-14 Hex Socket 1 5020-103
Coolant, 6.7 gal (23 liters) 1 5-1070-3
1
8890A050
8892-015
8891-050
8891-071
8897-003
8897-006
8898-006
1
2450-094
2450-049
1 8890-008
8890-005
2450-018
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Page 28
Available “QC” Type Connectors
Connector Part Number
BNC-Female 4240-125
BNC-Male 4240-132
C-Female 4240-100
C-Male 4240-110
HN-Female 4240-268
HN-Male 4240-278
LC-Female
LC-Male 4240-025
*
4240-031
Open Term.
# 10-32 Nut
LT-Female 4240-018
LT-Male 4240-012
N-Female 4240-062
N-Male 4240-063
SC-Female 4240-090
SMA-Female 4240-336
SMA-Male 4240-334
7/16 Jack, IEC
Type 169-4
7/16 Plug, IEC
Type 169-4
Mini UHF-Female 4240-346
UHF-Female 4240-050
UHF-Male 4240-179
1-5/8” EIA Fixed 4240-096
4240-080
4240-344
4240-363
18
1-5/8” EIA Swivel 4240-208
7/8” EIA 4240-002
TNC-Female 4240-156
TNC-Male 4240-160
* Normally supplied on the 8921
Page 29
Limited Warranty
All products manufactured by Seller are warranted to be free from defects in material and workmanship for a period
of one 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 WHAT-SOEVER, 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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