BIRD Termaline Series User manual

Termaline®Load Resistor
SERIES 8720
Operation Manual
©Copyright 2017 by Bird Technologies Inc.
Instruction Book P/N 920-8720 Rev. B
Termaline are Registered
Trademarks of Bird Electronic Corporation

i
Safety Precautions
The following are general safety precautions that are not necessarily related to any specific part or procedure, and
do not necessarily appear elsewhere in this publication. These precautions must be thoroughly understood and
apply to all phases of operation and maintenance.
WARNING
Keep Away From Live Circuits
Operating Personnel must at all times observe general safety precautions. Do not replace
components or make adjustments to the inside of the test equipment with the high
voltage supply turned on. To avoid casualties, always remove power.
WARNING
Shock Hazard
Do not attempt to remove the RF transmission line while RF power is present.
WARNING
Do Not Service Or Adjust Alone
Under no circumstances should any person reach into an enclosure for the purpose of
service or adjustment of equipment except in the presence of someone who is capable of
rendering aid.
WARNING
Safety Earth Ground
An uniterruptible earth safety ground must be supplied from the main power source to
test instruments. Grounding one conductor of a two conductor power cable is not
sufficient protection. Serious injury or death can occur if this grounding is not properly
supplied.
WARNING
Resuscitation
Personnel working with or near high voltages should be familiar with modern methods of
resuscitation.
WARNING
Remove Power
Observe general safety precautions. Do not open the instrument with the power on.

Safety Precautions
ii
Safety Symbols
Note: Calls attention to supplemental information.
Warning Statements
The following safety warnings appear in the text where there is danger to operating and maintenance personnel,
and are repeated here for emphasis.
On pages 6.
On page 7.
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.
The caution symbol appears on the equipment indicating there is
important information in the instruction manual regarding that particular
area.
This symbol indicates that the unit radiates heat and should not be
touched while hot.
WARNING
When using dry cleaning solvents, provide adequate ventilation and observe normal safety
precautions. Many dry cleaning agents emit toxic fumes that could be harmful to your
health, if inhaled.
WARNING
Never attempt to disconnect RF equipment from the transmission line while RF power is
being applied. Leaking RF energy is a potential health hazard.

Termaline® Load Resistor
iii
Caution Statements
The following equipment cautions appear in the text and are repeated here for emphasis.
On page 3.
On page 5.
On pages 5.
On page 6.
CAUTION
Never reverse the cooling water connections. It is very important for the safety of the load
resistor to observe proper flow direction. Also, when the load is first installed or is
reconnected, run the water for approximately a minute to fill the system and remove all
bubbles before turning on the RF power.
CAUTION
Do not excessively overload these units above the rated 5 kilowatts of power. Overload for
any length of time will cause resistor failure.
CAUTION
Any more than 5 W of power applied to the load resistor without water cooling will quickly
damage the equipment. The new sealed system effectively protects the resistive film from
possible moisture damage by any condensate formation. Flow of cooling water through
the system without applied power represents no danger.
CAUTION
Do not submerge the device during the cleaning process. The fluid could enter the inside of
the system and cause the failure of the device when power is applied.

Safety Precautions
iv
Safety Statements
USAGE
ANY USE OF THIS INSTRUMENT IN A MANNER NOT SPECIFIED BY THE MANUFACTURER MAY
IMPAIR THE INSTRUMENT’S SAFETY PROTECTION.
USO
EL USO DE ESTE INSTRUMENTO DE MANERA NO ESPECIFICADA POR EL FABRICANTE, PUEDE
ANULAR LA PROTECCIÓN DE SEGURIDAD DEL INSTRUMENTO.
BENUTZUNG
WIRD DAS GERÄT AUF ANDERE WEISE VERWENDET ALS VOM HERSTELLER BESCHRIEBEN,
KANN DIE GERÄTESICHERHEIT BEEINTRÄCHTIGT WERDEN.
UTILISATION
TOUTE UTILISATION DE CET INSTRUMENT QUI N’EST PAS EXPLICITEMENT PRÉVUE PAR LE
FABRICANT PEUT ENDOMMAGER LE DISPOSITIF DE PROTECTION DE L’INSTRUMENT.
IMPIEGO
QUALORA QUESTO STRUMENTO VENISSE UTILIZZATO IN MODO DIVERSO DA COME
SPECIFICATO DAL PRODUTTORE LA PROZIONE DI SICUREZZA POTREBBE VENIRNE
COMPROMESSA.

Termaline® Load Resistor
v
SERVICE
SERVICING INSTRUCTIONS ARE FOR USE BY SERVICE - TRAINED PERSONNEL ONLY. TO AVOID
DANGEROUS ELECTRIC SHOCK, DO NOT PERFORM ANY SERVICING UNLESS QUALIFIED TO DO
SO.
SERVICIO
LAS INSTRUCCIONES DE SERVICIO SON PARA USO EXCLUSIVO DEL PERSONAL DE SERVICIO
CAPACITADO. PARA EVITAR EL PELIGRO DE DESCARGAS ELÉCTRICAS, NO REALICE NINGÚN
SERVICIO A MENOS QUE ESTÉ CAPACITADO PARA HACERIO.
WARTUNG
ANWEISUNGEN FÜR DIE WARTUNG DES GERÄTES GELTEN NUR FÜR GESCHULTES
FACHPERSONAL.
ZUR VERMEIDUNG GEFÄHRLICHE, ELEKTRISCHE SCHOCKS, SIND WARTUNGSARBEITEN
AUSSCHLIEßLICH VON QUALIFIZIERTEM SERVICEPERSONAL DURCHZUFÜHREN.
ENTRENTIEN
L’EMPLOI DES INSTRUCTIONS D’ENTRETIEN DOIT ÊTRE RÉSERVÉ AU PERSONNEL FORMÉ AUX
OPÉRATIONS D’ENTRETIEN. POUR PRÉVENIR UN CHOC ÉLECTRIQUE DANGEREUX, NE PAS
EFFECTUER D’ENTRETIEN SI L’ON N’A PAS ÉTÉ QUALIFIÉ POUR CE FAIRE.
ASSISTENZA TECNICA
LE ISTRUZIONI RELATIVE ALL’ASSISTENZA SONO PREVISTE ESCLUSIVAMENTE PER IL
PERSONALE OPPORTUNAMENTE ADDESTRATO. PER EVITARE PERICOLOSE SCOSSE
ELETTRICHE NON EFFETTUARRE ALCUNA RIPARAZIONE A MENO CHE QUALIFICATI A FARLA.

About This Manual
vi
About This Manual
This manual covers the operating and maintenance instructions for the following models:
Changes to this Manual
We have made every effort to ensure this manual is accurate. If you discover any errors, or if you have suggestions
for improving this manual, please send your comments to our Solon, Ohio factory. This manual may be periodically
updated. When inquiring about updates to this manual refer to the part number and revision on the title page.
Terminology
The following terms will be used throughout this manual to refer to certain components of the Econoload:
Econoload or Load — The entire unit. It contains the RESISTOR.
Resistor — A subcomponent of the LOAD. This is the ceramic resistor which actually absorbs the RF power.
Chapter Layout
Introduction — Describes the features of the Econoload RF Load, lists equipment supplied and optional
equipment, and provides power-up instructions.
Installation — Describes how to install the Econoload.
Theory of Operation — Describes how the load works on a fundamental level.
Operating Instructions — Describes the features of the Econoload RF Load and its process of operation.
Maintenance — Lists routine maintenance.
Specifications — List the specification for the 8720 Econoload.
8720

vii
Table of Contents
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i
Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Warning Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Caution Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Safety Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vi
Changes to this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
Chapter Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
Chapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Purpose and Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Performance Characteristics and Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Utility Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Environmental Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Items Furnished . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Items Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Tools and Test Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Chapter 2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Chapter 3 Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Heat Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Chapter 4 Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Use and Function of Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Initial Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Start-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Cooling Water for the Model 8720 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Emergency Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Chapter 5 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
RF Assembly Resistance Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
DC Resistance Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Preparation for Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Replacement Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Chapter 6 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Limited Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

1
Chapter 1 Introduction
Purpose and Function
The Model 8720 Load Resistor is designed as a compact, low reflection and nonradiating termination of coaxial
transmission lines. Cooled by internal water flow, it generates almost no ambient heat, making installation space
minimal and convenient.
This sub-miniature unit may be carried easily and installed anywhere, for use in whatever position desired.
Performance Characteristics and Capabilities
A Model 8720 can absorb up to 5000 Watts continuously and dissipate it harmlessly as heat over a frequency range
of DC to 2000 MHz. It will show a maximum VSWR of 1.1 to 1.0 from DC to 500 MHz, 1.15 to 1.0 for 500 to 900 MHz
and 1.25 to 1.0 from 900 to 2000 MHz.
Power input is through a Bird 50 ohm 1-5/8 inch EIA flanged connector. The RF power is converted to heat in the
load resistor, and directly dissipated by means of the water cooling system. Water flow through the inside of the
resistor directly absorbs the dissipated power of the resistive film.
Dimensions
This load has a body length of 8-1/32 inch (204 mm). A pair of water supply tubes adds another 8 inches (203 mm)
to the overall length. The major body diameter is 1-5/8 inch (41 mm), however, the 1-5/8 inch EIA swivel flange
connector diameter is 3-1/2 inch (89 mm). The weight is only 2lb, 2 oz (96 kg) and the shipping weight is 5 lbs (2.27
kg).
Figure 1 8720 Water Load
Utility Requirements
The Model 8720 is a passive device that is self-contained and does not need any external source of power or utilities
to function. It does need a source of running water, however, to provide for its cooling. The water must flow from a
rate of one gallon (3.8 liter) per minute at a water temperature of +5C (+41F) to a rate of four gallons (15.2 liter
per minute at +80C (+176F) in order to provide adequate heat dissipation.

Termaline® Load Resistor
2
Environmental Requirements
The load should be operated in a dust and vibration free environment. The ambient temperature range should
remain between +5C and +80C (+41F and +176F) for proper operation. However, this is not critical for cooling.
Items Furnished
The Model 8720 is equipped with a 1-5/8 inch EIA swivel flanged RF connector and 1/4 inch female pipe threaded
nuts for the water supply lines. This operation manual is the only additional item furnished.
Items Required
The only items required are a 1-5/8 inch EIA flanged coupling kit for the RF transmission line and 1/4 inch male pipe
thread fittings on the ends of the water lines.
Tools and Test Equipment
An adjustable wrench is the only tool that would be useful for mounting this load. A resistance bridge or an
ohmmeter with an accuracy of one percent or better at 50 ohm is recommended for checking the resistance value
of the load resistor (see "RF Assembly Resistance Test" on page 7 ).

3
Chapter 2 Installation
General
The Model 8720 Termaline Load Resistor unit may be installed in any position or attitude required. Its relatively
small size permits mounting in a very limited space since cooling is by water flow rather than air convection. No
clearance for airflow is needed. It is also comparatively easy to carry and to relocate as necessary.
The input and output water conducting tubes are made of copper and can be easily bent as required for connection.
However, care should be exercised not to pinch the tubes in bending as this would restrict the flow and cause the
device to operate improperly. The fitting at the center of the water chamber is the water input and outer is the
water output tube. Water connections on the load are 1/4 inch female pipe thread fittings.
Check the resistance of the RF Assembly, see
"RF Assembly Resistance Test" on page 7 .
Attach the RF coaxial transmission line with a 1-518 inch EIA coupling kit, P/N 4712-O2O. The center conductor
bullet should be clean. Bottom it firmly and tighten the four screw and nut sets evenly and securely.
Note: Always handle the load with care to prevent subjecting the load to unnecessary shock or
impact.
CAUTION
Never reverse the cooling water connections. It is very important for the safety of the
load resistor to observe proper flow direction. Also, when the load is first installed or is
reconnected, run the water for approximately a minute to fill the system and remove
all bubbles before turning on the RF power.

4
Chapter 3 Theory of Operation
General
The Model 8720 RF Load Resistor is unique in that it uses primarily an external water supply for the cooling of the
resistor element. By using this technique, the need for an intermediate dielectric fluid to transfer the heat
generated in the resistive element has been eliminated, reducing the physical size of the load to a virtual minimum.
This simplified system allows use of the load in more varied environments and attachment at any attitude (see
"Specifications" on page 9 ).
For the direct reading of power measurements up to 5 kW, these loads may be used in conjunction with any Bird
Series 4700 Thruline Wattmeter.
Heat Transfer
Cold water enters the unit by the center pipe and is directed by a center flow tube to the RF input end of the load
resistor where it passes through peripheral holes in the wall. This flow tube, supported at both ends, is constructed
of dielectric material so that it will not affect the electrical properties of the device. The water is then directed
backwards over the inside surface of the ceramic resistor tube. This tube has a resistive film of very uniform
thickness deposited on its outside surface. The resistor substrate is manufactured from high thermal conductivity
ceramic that is very strong. The heat generated by the RF energy absorbed is readily conducted through its
comparatively thin wall. This ceramic also essentially isolates the water electrically from fields inherent to the
coaxial line. The heat is carried off by the water passing over the inner surface, and the RF power absorbed by the
load is translated into an increased temperature of the water flowing out of the load. The value of this power may
be easily calculated, if the water flow is known, by using the following formula:
Where: P = Power in kilowatts
T1= Outlet water temperature in C
T2= lnlet water temperature in C
GPM = Water flow in gallons per minute
In °F the formula is:
P0.263 T1T2 –GPM=
P0.146 T1T2
–GPM=

5
Chapter 4 Operating Instructions
Use and Function of Controls
The load, being a passive device, has no indicators or operating controls.
Initial Adjustments
No initial adjustments are required other than to connect the load to the RF source by means of a coaxial line with a
suitable coupling.
Start-Up
Turn on the water flow and wait a moment for all the air to be purged out of the lines before turning on the RF
power.
Cooling Water for the Model 8720
The electrical performance of these RF loads will be affected by impurities or other chemical additives in the cooling
water. The presence of salts in the water definitely make the device unusable because they cause a rapid increase in
VSWR. Therefore, sea water or silty water should not be used for cooling the loads.
The thermal performance of these loads can be also affected by impurities, particularly those impurities that
accumulate in the form of scale on the exposed surfaces of the fluid paths of the load assembly. These deposits may
result in an increase ¡n the thermal and/or fluid resistance(s) of the load and may in turn cause the load to overheat
and fail.
The following types of water are considered safe for the cooling of the Model 8720 Load Resistor filtered city or soft
water. In general, any potable water is suitable for cooling the load.
Normal Operation
Operation of this equipment is rather simple. First, turn on the water supply, before applying any RF power. Set the
flow between 1 gpm (3.8 liter) for +5C (+41F) water temperature and 4 gpm (15 liter) for 80C (+176F); i.e., add 1
gpm to the flow rate for each 25C increase in water temperature above 5C.
Shutdown
Always turn off the RF power first, allow coolant to continue to flow for a few minutes to cool down the resistive
element.
Emergency Shutdown
Immediately remove RF power if water flow is interrupted.
CAUTION
Do not excessively overload these units above the rated 5 kilowatts of power.
Overload for any length of time will cause resistor failure.
CAUTION
Any more than 5 W of power applied to the load resistor without water cooling will
quickly damage the equipment. The new sealed system effectively protects the
resistive film from possible moisture damage by any condensate formation. Flow of
cooling water through the system without applied power represents no danger.

6
Chapter 5 Maintenance
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.
Cleaning
Wipe off dust and dirt from the housing with a dry cloth. Uncouple the RF connector and also wipe it off with a clean
dry cloth. Use a self-drying non-residue forming contact cleaner on the inaccessible portions, especially the metallic
contact surfaces and the exposed faces of the TFE insulators.
Inspection
Check the water connections from time to time for leaks and the load itself for cleanliness. (see "Cleaning" on
page 6 ).
Preventive Maintenance
The necessary preventive maintenance procedures are covered in "Inspection" on page 6 .
Problem Possible Cause Correction
Overheating or high exit
water temperature
Excessive power Reduce RF power
Insufficient water flow Increase water flow
Obstruction in water
flow system
Check the coolant circulation
system
Excessive reflected power
DC resistance of the
load has changed
Check DC resistance (See "RF
Assembly Resistance Test"
on page 7 )
Contaminated water
Check the resistor for scaling.
Replace if necessary.
Check that the water meets the
standards listed in
"Specifications" on page 9 .
Use distilled water if necessary.
WARNING
When using dry cleaning solvents, provide adequate ventilation and observe normal
safety precautions. Many dry cleaning agents emit toxic fumes that could be harmful
to your health, if inhaled.
CAUTION
Do not submerge the device during the cleaning process. The fluid could enter the
inside of the system and cause the failure of the device when power is applied.

Maintenance
7
Customer Service
Any maintenance or service procedure beyond the scope of those in this chapter should be referred to a qualified
service center.
If the unit needs to be returned for any reason, request an Return Material Authorization (RMA) through the Bird
Technologies website. 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: [phone]
E-mail: [e-mail]
For the location of the Sales Office nearest you, visit our Web site at:
http://www.birdrf.com
RF Assembly Resistance Test
Note: These tests are by no means a necessity to the operation of the load but merely guidelines for
the users information.
Accurate measurement of the DC resistance between the inner and outer conductors of the RF input connector will
provide a good check of the condition of the load resistor.
Checking the DC resistance is simply used to measure a change in the resistance over time. Tracking the DC
resistance should start before the unit is first put into service. Perform the following steps and record the value for
future comparison. Resistance measurements should be taken periodically according to use.
Preparation:
Tools: Common hand tools.
Ohmmeter with an accuracy of ± 1% at 50 ohms (or use a resistance bridge).
Use low resistance leads, preferably a short piece of 50 ohm coaxial cable fitted with an appropriate
connector or alligator clips.
Temperature of the load should be stabilized between 20°C to 25°C (68°F to 77°F).
DC Resistance Measurement
Note: It is recommended that this resistance check be performed each time the load is to be used.
1. Turn off RF power and interlock circuitry before making any disconnections.
2. Disconnect the RF coaxial line.
3. Connect the multimeter test leads across the center and outer conductor of the load resistor. See Figure 2 .
4. Record the value of the resistance before the load is put into service. Compare subsequent values with the
latest reading. If the values vary more than 2 ohms this could be an indication of a failing resistive element.
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.

Termaline® Load Resistor
8
Figure 2 Measuring DC Resistance
Disassembly
Other than disconnecting the Model 8720 from the coaxial transmission line and the water lines, no special
disassembly procedures are necessary. (See "Installation" on page 3 ). Repairs must be performed by Bird, see
"Customer Service" on page 7 .
Preparation for Shipment
Disconnect the Model 8720 from both the RF coaxial line, with the RF power shut off, and the water lines. Drain the
water out of the load. Wrap the RF connector with padding and tape securely in place. Pack and brace the load in a
suitable shipping container, a corrugated paper box should suffice.
Storage
No special preparations for storage are necessary other than to cover the equipment to keep out dust and dirt.
Store this unit in a dry and dust free environment where the ambient temperature will remain within -5C to +80C
(+23F and +176F).
Replacement Parts List
There are no field replaceable parts ¡n the Model 8720 because it is a sealed and self-contained unit.
WARNING
Never attempt to disconnect RF equipment from the transmission line while RF power
is being applied. Leaking RF energy is a potential health hazard.

9
Chapter 6 Specifications
Frequency Range DC– 2000 MHz
Power Rating 5 kW continuous duty
Impedance 50 ohms nominal
VSWR
DC to 500 MHz
500 to 900 MHz
900 to 2000 MHz
1.10 max
1.15 max
1.25 max
Connector 1-5/8 inch EIA swivel flange
Cooling Method Force liquid flow,
1 to 4 gallons (3.8 to 15.2 liters) per minute
Water Temperature +5C to +80C(+41F to +176F)
Dimensions 8-1/32”L1x 1-5/8”major body dia.(204 x41 mm)
1 Not including 8 inch (203 mm) water supply tubes.
Weight, Nominal 2.2 lb. (0.96 kg)
Operating Orientation Any

10
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 specifica-
tions, 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 writ-
ing within ten 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, tran-
sistors, 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.