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BIRD Termaline 8775 Series Operation Manual

Load resistor

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®
Termaline
Load Resistor
Series 8775/8776
Operation Manual
© Copyright 2025 by Bird Technologies, Inc.
Instruction Book Part Number 920-8775/76 Rev. E
®
Termaline
is a Registered Trademark
of Bird Electronic Corporation

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Summary of Contents for BIRD Termaline 8775 Series

  • Page 1 ® Termaline Load Resistor Series 8775/8776 Operation Manual © Copyright 2025 by Bird Technologies, Inc. Instruction Book Part Number 920-8775/76 Rev. E ® Termaline is a Registered Trademark of Bird Electronic Corporation...
  • Page 3: Safety Precautions

    Safety Precautions 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 general safety precautions.
  • Page 4: Safety Symbols

    Termaline® Load Resistor Safety Symbols Warning notes call attention to a procedure, which if not correctly performed, could result in personal injury. Caution notes call attention to a procedure, which if not correctly performed, could result in damage to the instrument. Calls attention to supplemental information.
  • Page 5: Caution Statements

    Safety Precautions Caution Statements The following equipment cautions appear in the text and are repeated here for emphasis. Do not use Automotive anti-freeze, stop-leak solutions, sealants, or corrosion inhibitors used in coolant solutions for these loads. Use of these additives can negatively impact load performance and may cause premature failure.
  • Page 6: Safety Statements

    Termaline® Load Resistor Safety Statements USAGE ANY USE OF THIS INSTRUMENT IN A MANNER NOT SPECIFIED BY THE MANUFACTURER MAY IMPAIR THE INSTRUMENT’S SAFETY PROTECTION. 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.
  • Page 7 Safety Precautions 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 SERVICIO LAS INSTRUCCIONES DE SERVICIO SON PARA USO EXCLUSIVO DEL PERSONAL DE SERVICIO CAPACITADO.
  • Page 8: About This Manual

    Termaline® Load Resistor About This Manual This manual covers the operating and maintenance instructions for the following models 8775 8776 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.
  • Page 9: Table Of Contents

    Table of Contents Safety Precautions ..............i Safety Symbols .
  • Page 10 Termaline® Load Resistor Installing the Resistor ............... 14 Replacing Fractured Resistors .
  • Page 11: Chapter 1 Introduction

    "Maintenance" on page Direct Power Measurement When used in conjunction with a Bird Model 6810 Series Thruline Wattmeter or 3127 Series Panel Meters, these RF load resistors may be used for direct reading power measurements up to 50 kilowatts. Optional Equipment Bird recommends the installation of an interlock control circuit to provide instantaneous fail-safe protection of the transmitter and load in the event of even a momentary interruption of the cooling water supply.
  • Page 12: Chapter 2 Theory Of Operation

    Chapter 2 Theory of Operation General The Termaline Coaxial Load Resistor utilizes an external water supply for the direct cooling of the resistor element. By using this technique, the need for an intermediate dielectric fluid to transfer the heat generated in the resistor element has been eliminated, reducing the physical size of the load to a virtual minimum.
  • Page 13: Cooling Water

    Use of unapproved coolants will negatively impact load performance and may cause premature failure. Water is the primary coolant for the Bird 8775/76, however, a mixture of potable / distilled water and pure technical grade ethylene glycol is acceptable in closed systems. Ethylene glycol should be added to prevent bacterial growth and freezing;...
  • Page 14: Chapter 3 Installation

    Chapter 3 Installation General The compact design of the Termaline Load Resistor enables it to be installed in very small spaces. It requires no ventilation and may be placed in any orientation. Do not install where it will be subjected to severe vibration or physical shock.
  • Page 15: Water Line Attachment

    If the unit is factory equipped with the optional control system, the water flow switch is installed on the water inlet line. For rigid piping connections, replace both the water inlet and outlet hose adapters, Bird P/N 5-065-2, with 1/2 inch male pipe or pipe fittings.
  • Page 16: Preoperational Checkout

    Termaline® Load Resistor Preoperational Checkout Before attempting to operate the RF load, whether under test or actual operating conditions, TEST the complete water system as follows: 1. Ensure transmitter power is OFF. 2. Turn on water supply. 3. Ensure water flow from the OUTLET connection of load is at least 9 gpm (34 lpm) at 5° C (41° F) through 11 gpm (42 lpm) at 60°...
  • Page 17: Chapter 4 Operating Instructions

    Chapter 4 Operating Instructions General The Termaline RF Load is not equipped with any operating controls, therefore, operators don’t need to be present when in use. Proper operation of the equipment is assured if the instructions contained in "Installation" on page are followed exactly.
  • Page 18: Shutdown Procedure

    Operating as an RF Wattmeter The RF load can be combined with a Bird Rigid Line Series Thruline Wattmeter to form an absorption-type wattmeter by inserting the wattmeter line section just ahead of the RF load. Installation and operation of the wattmeter is covered in the Thruline Wattmeter operation manual.
  • Page 19: Chapter 5 Maintenance

    Chapter 5 Maintenance General Never attempt to disconnect RF equipment from the transmission line while RF power is being supplied. Leaking RF energy is a potential health hazard. The Model 8775/76 Termaline Coaxial Load Resistors are rugged units of simple design, requiring only nominal and routine attention.
  • Page 20: Rf Assembly Resistance Test

    Termaline® Load Resistor RF Assembly Resistance Test 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.
  • Page 21: Troubleshooting

    Maintenance Troubleshooting For corrections requiring repair or replacement of components, refer to the appropriate section for your specific model. Problem Possible Cause Correction "RF Assembly High load VSWR. Failing resistor Perform Resistance Test " on page 10 . Resistance change of greater than 5 ohms indicates a failing resistor.
  • Page 22: Inspecting The Unit

    Termaline® Load Resistor It may be necessary to rock the chamber gently while carefully pulling it off. 7. Pull the water chamber assembly (with screws) straight off. The inner flow tube [9] will usually come out with the water chamber assembly, being held to it by the compression of the inner O-ring [4] (water input) seal.
  • Page 23 Maintenance Figure 2 Resistor Removal...
  • Page 24: Installing The Resistor

    Termaline® Load Resistor Installing the Resistor 1. Inspect the load housing assembly. See "Inspecting the Unit" on page 12 2. Insert new resistor [1] into the load housing until it reaches its fitting. 3. Push in the resistor until it bottoms snugly. The resistor should not have to be forced into the fitting, but it should be quite snug.
  • Page 25: Replacing Fractured Resistors

    Maintenance Replacing Fractured Resistors The resistor used in this load consists of a resistive film on a special substrate. If the substrate is broken, there will probably be sharp pieces or splinters inside the load housing. Caution should be exercised to avoid possible injury. The load should already be disassembled to the point of step 7 "Replacing a Resistive Ele-...
  • Page 26: Installing A Replacement Resistor

    Termaline® Load Resistor Figure 3 RF Input Assembly Installing a Replacement Resistor 1. Insert replacement resistor [1] into the resistor fitting of the input center conductor assembly to test its tightness. 2. Push in the resistor until it bottoms snugly. The resistor should not have to be forced into the fitting, but it should be quite snug.
  • Page 27: Additional Repairs

    11. Continue using the procedure as given in "Installing the Resistor" on page 14 Additional Repairs Repairs beyond what is covered in this instruction book will require return of the equipment to Bird Electronic Corporation for service. See "Customer Service" on page 18...
  • Page 28: 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.
  • Page 29: Specifications

    Maintenance Specifications Power Rating 50,000 Watts lmpedance 50 ohms Input Connectors Model 8775 3-1/8 EIA flanged, (50 ohm) Model 8776 3-1/8 unflanged (50 ohm) flush center conductor Frequency Range 1 kHz to 900 MHz VSWR 1.10 maximum 1 kHz - 900 MHz Modes CW, AM, FM, SSB, TV, and certain pulse types lnput Water Temperature Range...
  • Page 30: Replacement Parts

    Termaline® Load Resistor Replacement Parts Figure Item Description Replacement Kit Part Number 2 and 3 Resistor RPK8755-027-5 8755-027-5 Outer resistor cap seal, O-Ring 8740-020 8410-009 Water chamber 8755-014 Inlet seal O-Ring 8740-020 5-099 Hose nipple 5-065-2 Socket head cap screws, 1121-2508-00 1/4-20 x 2-1/2”, stainless steel Resistor sleeve...
  • Page 31: Accessory Coupling Kits

    Maintenance Accessory Coupling Kits Fits Model Description Part Number Model 8775 Coupling Kit - 3-1/8” EIA 4600-020 consisting of: Anchor Bullet 4600-021 O-Ring 4600-022 Mounting Hardware 4600-023 Model 8776 Coupling Kit - 3-1/8” Unflanged 5-726 Flush - 50 ohm consisting of: Center Conductor Coupling Bullet Outer Conductor Sleeve Coupling Clamps-2...
  • Page 32: Limited Warranty

    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;...

This manual is also suitable for:

Termaline 8776 series