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1、INSTRUCTION BOOK OPERATING INSTRUCTIONS TERMALINE COAXIAL LOAD RESISTOR MODEL 8251D208 Electronic Corporation Cleveland (Solon) Ohio USA Copyright 1998 by Bird Electronic Corporation Instruction Book Part Number 920-8251D208 Rev. A Termalineis a Registered Trademark of Bird Electronic Corporation Ra
2、dioFans.CN 收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 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
3、all phases of operation and maintenance. 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 equip- ment with the high voltage supply turned on. To avoid casualties, always re-
4、move power. Shock Hazard Do not attempt to remove the RF transmission line while RF power is pres- ent. 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 some- one who is cap
5、able of rendering aid. Safety Earth Ground An uninterruptible earth safety ground must be supplied from the main power source to test instruments. Grounding one conductor of a two conduc- tor power cable is not sufficient protection. Serious injury or death can occur if this grounding is not properl
6、y 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 RadioFans.CN 收音机爱 好者资料库 CAUTION Cau
7、tion notes call attention to a procedure which if not correctly performed, could result in damage to the instrument. This symbol appears on the equipment indicating there is important information in the instruction manual regarding that particular area. +Note: Calls attention to supplemental informa
8、- tion. Warning Statements The following safety warnings appear in the text where there is danger to op- erating and maintenance personnel and are repeated here for emphasis. WARNING The vent plug must be used at all times when the unit is in operation or cooling. Failure to do this could result in
9、damage to the equipment and endanger the operators safety. Be sure to check this plug. WARNING Using this load in the upper end of its power dissipation range will cause the housing to become hot! Care should be exercised in touching it. WARNING Never attempt to connect or disconnect RF equipment fr
10、om the transmission line while RF power is being applied. Leaking RF energy is a potential health hazard. 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 This equipment is designed for o
11、peration in a horizontal position only, with mounting brackets down. Do not operate in any other manner. CAUTION Do not operate this equipment over the rated 1000 watts continuously. Damage to the resistive element will result. ii CAUTION The unit is factory filled to the proper level with 1.1 gallo
12、ns (4.2 liter) of Bird P/N 5-1070. No other coolant should be used CAUTION Do not leave out the O-Ring seal, P/N 5-504 when interchanging the vent and shipping plugs. Safety Statements USAGE ANY USE OF THIS INSTRUMENT IN A MANNER NOT SPECIFIED BY THE MANUFACTURER MAY IMPAIR THE INSTRUMENTS SAFETY PR
13、OTECTION. USO EL USO DE ESTE INSTRUMENTO DE MANERA NO ES- PECIFICADA POR EL FABRICANTE, PUEDE ANULAR LA PROTECCIN DE SEGURIDAD DEL INSTRU- MENTO. BENUTZUNG WIRD DAS GERT AUF ANDERE WEISE VERWENDET ALS VOM HERSTELLER BESCHRIEBEN, KANN DIE GERTESICHERHEIT BEEINTRCHTIGT WERDEN. UTILISATION TOUTE UTILIS
14、ATION DE CET INSTRUMENT QUI NEST PAS EXPLICITEMENT PRVUE PAR LE FABRI- CANT PEUT ENDOMMAGER LE DISPOSITIF DE PRO- TECTION DE LINSTRUMENT. IMPIEGO QUALORA QUESTO STRUMENTO VENISSE UTILIZ- ZATO IN MODO DIVERSO DA COME SPECIFICATO DAL PRODUTTORELAPROZIONEDISICUREZZA POTREBBE VENIRNE COMPROMESSA. iii SE
15、RVICE SERVICING INSTRUCTIONS ARE FOR USE BY SERV- ICE - TRAINED PERSONNEL ONLY. TO AVOID DAN- GEROUS 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 CA- PACITADO. PARA EVITAR EL PELIGRO DE
16、DES- CARGAS ELCTRICAS, NO REALICE NINGN SERVICIO A MENOS QUE EST CAPACITADO PARA HACERIO. WARTUNG ANWEISUNGEN FR DIE WARTUNG DES GERTES GELTEN NUR FR GESCHULTES FACHPERSONAL. ZUR VERMEIDUNG GEFHRLICHE, ELEKTRISCHE SCHOCKS,SINDWARTUNGSARBEITEN AUSSCHLIELICH VON QUALIFIZIERTEM SERV- ICEPERSONAL DURCHZ
17、UFHREN. ENTRENTIEN LEMPLOI DES INSTRUCTIONS DENTRETIEN DOIT TRE RSERV AU PERSONNEL FORM AUX OPRA- TIONS DENTRETIEN. POUR PRVENIR UN CHOC LECTRIQUE DANGEREUX, NE PAS EFFECTUER DENTRETIEN SI LON NA PAS T QUALIFI POUR CE FAIRE. ASSISTENZA TECNICA LE ISTRUZIONI RELATIVE ALLASSISTENZA SONO PREVISTE ESCLU
18、SIVAMENTE PER IL PERSONALE OP- PORTUNAMENTE ADDESTRATO. PER EVITARE PERI- COLOSE SCOSSE ELETTRICHE NON EFFETTUARRE ALCUNA RIPARAZIONE A MENO CHE QUALIFICATI A FARLA. iv About This Manual This instruction book covers the model 8251D208 Termaline Coaxial Resis- tor. This instruction book is arranged s
19、o that essential information on safety is contained in the front of the book. Reading the Safety Precautions Section be- fore operating the equipment is strongly advised. The remainder of this instruction book is divided into Chapters and Sections. Operation First time operators should read Chapter
20、1 - Introduction, Chapter 2 - Theory of Operation, and Chapter 3 - Installation to get an overview of equipment ca- pabilities and how to install it. An experienced operator can refer to Chapter 4 - Operating Instructions. All instructions necessary to operate the equip- ment, are contained in this
21、chapter. Maintenance All personnel should be familiar with preventive maintenance found in Chap- ter 5 - Maintenance. If a failure should occur, the troubleshooting section will aid in isolating and repairing the failure. Parts For location of major assemblies or parts, refer to the parts lists and
22、associ- ated drawings in Chapter - Maintenance. Changes To This Manual We have made every effort to ensure this manual is accurate. 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 updat
23、ed. When inquiring about updates to this manual refer to the part number and revision level on the title page. v vi Bird Model 8251D208Termaline Coaxial Load Resistor Table Of Contents Safety Precautions. .i Warning Statements.ii Caution Statements.ii Safety Statements. .iii About This Manual. .v In
24、troduction.1 Purpose and Function. .1 Applications.1 Performance Characteristics and Capabilities. .1 Power and Utility Requirements.1 Environmental Requirements. .2 Items Supplied. .2 Items Required. .2 Tools and Test Equipment . .2 Specifications.3 Theory of Operation. .5 Cooling.5 Installation. .
25、7 Location. .7 Shipping and Vent Plugs.7 Connecting to Transmitter. .8 Operating Instructions. .9 Normal Operation. .9 vii Operation Under Abnormal Conditions. .9 Shutdown. .9 Emergency Shutdown.10 Maintenance. .11 Troubleshooting. .11 Cleaning. .11 Inspection.12 Preventive Maintenance.12 Checking C
26、oolant Level. .12 DC Resistance Measurement.13 Preparation and Tools Required.13 Checking the DC Resistance .13 Disassembly.14 Tools Required.14 RF Connector. .14 Rear Seal and Coolant. .15 RF Load Resistor Assembly. .15 Radiator Handle. .15 Assembly.16 RF Connector. .16 Diaphragm and Coolant Oil. .
27、16 RF Load Resistor Assembly. .16 Radiator Handle. .16 Storage.17 Customer Service. .17 Sales/Repair Facilities.17 viii Bird Model 8251D208Termaline Coaxial Load Resistor Sales Facilities.17 Preparation for Shipment.17 Replacement Parts List.18 ix x Bird Model 8251D208Termaline Coaxial Load Resistor
28、 Chapter 1 Introduction This publication covers the Termaline Coaxial Load Resistor Model 8251D208. The Termaline Coaxial Load Resistor will generally be referred to as a load thoughout this manual. This chapter contains introductory information including product specifications; items supplied; and
29、accessory items available. Purpose and Function The Bird Termaline Coaxial Load Resistor is a portable, general purpose 50 ohm coaxial transmission line termina- tion. The load is a low reflection, nonradiating termination for coaxial transmission lines operating in the UHF (470 - 860 MHz) band. The
30、 load is rectangular in shape with transverse fins encas- ing a dielectric coolant cylinder. A retractable handle is re- cessed in the radiator fins. The front and rear fins are made of heavier gauge material and are bent 90 to form bottom mounting flanges. These flanges are supports for free stand-
31、 ing use, or brackets for fixed mounting. Holes are provided in the flanges for fixed mounting. ApplicationsUse these loads: sAs a substitute antenna for tuning transmit- ters under nonradiation conditions or making routine test and adjustments. sAs a substitute for any circuit loading ele- ment. sT
32、o measure, with a suitable indication device, the power output of any coaxially transmitted signal within their range. Performance Characteristics and Capabilities The Model 8251D208 load can absorb up to 1000 watts con- tinuously and dissipate it harmlessly as heat over a fre- quency range of 470 t
33、o 860 MHz. The actual VSWR, “voltage standing wave ratio”, will not exceed 1.065:1 over the fre- quency range stated. Power and Utility Requirements This load is a passive device that is self-contained and re- quires only RF input to function. 1 Environmental Requirements The load should be operated
34、 in a dust and vibration free, dry environment. Allow at least 6 inches (153 mm) of clear- ance around the unit to permit adequate heat dissipation. Items SuppliedsLoad Resistor sInstruction Book Items Required Matching connector on the coaxial transmission line to which the load will be attached. T
35、ools and Test Equipment Screwdriver and an adjustable wrench will be necessary for disassembly of this equipment. A resistance bridge or ohmmeter with an accuracy of one percent or better at 50 ohms is useful for checking the resis- tance value of the RF section assembly. 2 Bird Model 8251D208Termal
36、ine Coaxial Load Resistor Specifications 3 Introduction Impedance, Nominal50 ohms VSWR:1.065:1 Connector:1-5/8 EIA flanged Power Range:1000 watts continuous Frequency Range:470 to 860 MHz Ambient Temperature:-40C to +45C (-40F to +133F) Cooling MethodOil dielectric and convection currents Dimensions
37、:17-29/32L x 5-15/16W x 8-1/2H (455 x 151 x 216 mm) Weight: Net Shipping 25 lb. 8 oz. (11.6 kg) 30 lb. (13.6 kg) Operating Position:Horizontal only - vent plug up Finish:Grey Powder Coat European Safety:Meets European Standard EN 61010-1:1993 - Safety, Group II. In accordance with Council Di- rectiv
38、e 73/23/EEC and 93/68/EEC. 4 Bird Model 8251D208Termaline Coaxial Load Resistor Chapter 2 Theory of Operation This load consists essentially of a carbon film resistor on a ceramic substrate immersed in a dielectric coolant. The re- sistor, individually selected for its accuracy, is enclosed in a spe
39、cial exponentially tapered housing. This provides a lin- ear reduction in surge impedance directly proportional to the distance along the resistor. When surrounded by the di- electric coolant, the characteristic impedance is therefore: 50 ohms at the front (connector end), 25 ohms at the mid- point
40、(to compensate for the resistance already passed over), and zero ohms at the rear where the resistor joins the hous- ing, forming the return conductor of the coaxial circuit. This produces a uniform, practically reflectionless line termina- tion over the stated frequencies of the load resistor. Cool
41、ingThe dielectric coolant was chosen for its desirable dielectric and thermal characteristics. Cooling of the load is accom- plished by natural fluid and air convection currents. The 1.1 gallons (4.2 liters) of dielectric coolant carries the electri- cally generated heat from the resistor to the wal
42、ls of the cy- lindrical cooling tank. This tank is encased in a set of radiating fins, constructed from heavy gauge aluminum al- loy, and firmly pressed into the cylinder. The heat from the dielectric oil is transferred to the surrounding air by the fins. Expansion of the coolant, caused by the rise
43、 in its tempera- ture, is allowed for by the use of an expansion tank located on the upper rear of the load. The expansion tank is equipped with a spring loaded vent for relief of the internal pressure. 5 6 Bird Model 8251D208Termaline Coaxial Load Resistor O-ring seal Figure 1 Shipping Plug O-Ring
44、Seal Figure 2 Vent Plug Chapter 3 Installation CAUTION This equipment is designed for operation in a horizontal position only, with mounting brackets down. Do not operate in any other manner. The load is to be installed, and operated in a horizontal posi- tion. The load is shipped horizontal, and no
45、rmally stands on its base brackets. The load may be used for portable operation and stand free, or it may be secured to a bench top or other flat surface for a fixed installation. Mount the load with four screws of up to 1/4 inch diameter. Fasten the screws through the four 9/32 inch holes in the mo
46、unting brackets that arranged in a 5-1/8 inch x 15 inch (130.2 x 381 mm) rectangle. LocationFor operation above 300 watts allow at least six inches (153 mm) of clearance on each side. Operate the load in a hori- zontal position only, with the handle on top. Shipping and Vent Plugs WARNING The vent plug must be used at all times when the unit is in operation or cooling. Failure to do this could result in damage to the equipment and
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