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Chapter 1

Introduction

Purpose and Function

The Model 8792 Termaline Load Resistors are designed as compact, low-reflection, and non-radiating termination 
for RF transmission lines. Cooled by internal water flow, it generates almost no surface heat, making installation 
space minimal and convenient. They can safely dissipate up to 80 kilowatts of continuous power when used in a 50 
ohm coaxial transmission line system.

Each model is designed for use with a standard connector of the types common to 6-1/8 inch coaxial lines, and will 
maintain a VSWR of less than 1.15 to 1.0 from 1000 Hz up to 800 MHz. These loads are intended for use on CW, AM, 
FM, SSB, and W modulation envelopes, and within certain limitation on radar or pulse modes. Information on 
applications involving pulse-type signals should be obtained directly from Bird Electronic Corporation.

Description

The Model 8792 equipment consists of a load resistor unit. They have field replaceable resistive element.  The 
replacement procedure is included in 

"Maintenance" on page 8

.

Optional Equipment

An accessory protective Control System is available as optional equipment. When properly installed, this system 
protects the load by shutting off the RF power when water flow is too low or interrupted. Discussions of the flow 
control pertaining to 

"Installation" on page 4

 and 

"Maintenance" on page 8

 should be ignored when not 

applicable. 

Direct Power Measurement 

When used in conjunction with a Bird Model 6810 Series Thruline Wattmeter or 3127 Series Panel Meters, these 
load resistors may be used for direct reading power measurements up to 80 kilowatts.

Emergency and First Aid Procedures for Ethylene Glycol

Eye 

Contact — 

Immediately flush eyes with plenty of water for at least 15 minutes while holding eyelids open. 

Get medical attention.

Skin Contact — 

Flush skin with water. If irritation occurs, get medical attention.

Inhalation — 

Remove victim to fresh air and provide oxygen if breathing is difficult. Get medical attention.

Ingestion — 

Do not give liquids if victim is unconscious or very drowsy. Otherwise, give no more than two glasses 

of water and induce vomiting by giving 30 cc (2 tablespoons) syrup of Ipecac. If Ipecac is unavailable, give two 
glasses of water and induce vomiting by touching finger to back of victim's throat. Keep victim's head below hips 
while vomiting. Get medical attention.

Summary of Contents for Termaline 8792 Series

Page 1: ...Load Resistor Series 8792 Operation Manual Copyright 2017 by Bird Technologies Inc Instruction Book Part Number 920 8792 93 Rev A Termaline and Thruline are registered trademarks of Bird Electronic Co...

Page 2: ...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 adju...

Page 3: ...ntion to a procedure which if not correctly performed could result in damage to the instrument This symbol indicates that a shock hazard exists if the precautions in the instruction manual are not fol...

Page 4: ...page 10 WARNING Never attempt to disconnect RF equipment from the transmission line while RF power is being applied Leaking HF energy is a potential health hazard WARNING The resistor used in this loa...

Page 5: ...upted full water flow is more critical than temperature CAUTION Verify cooling liquid is flowing through the load before RF power is applied and ensure the cooling liquid supply is not interrupted whi...

Page 6: ...SEGURIDAD DEL INSTRUMENTO BENUTZUNG WIRD DAS GER T AUF ANDERE WEISE VERWENDET ALS VOM HERSTELLER BESCHRIEBEN KANN DIE GER TESICHERHEIT BEEINTR CHTIGT WERDEN UTILISATION TOUTE UTILISATION DE CET INSTRU...

Page 7: ...S GER TES GELTEN NUR F R GESCHULTES FACHPERSONAL ZUR VERMEIDUNG GEF HRLICHE ELEKTRISCHE SCHOCKS SIND WARTUNGSARBEITEN AUSSCHLIE LICH VON QUALIFIZIERTEM SERVICEPERSONAL DURCHZUF HREN ENTRENTIEN L EMPLO...

Page 8: ...OPERATING BRANCHER LE VERROUILLAGE L METTEUR AVANT EMPLOI CONECTE EL INTERBLOQUEO AL TRANSMISOR ANTES DE LA OPERACION VOR INBETRIEBNAHME VERRIEGELUNG AM SENDER ANSCHLIESSEN PRIMA DI METTERE IN FUNZION...

Page 9: ...d revision on the title page Terminology There are some unique terms used throughout this literature They are defined here to clarify any misunderstanding Introduction Describes the features of the lo...

Page 10: ...2 Cooling Water for Models 8792 3 Flow Interlock Control Circuit Optional 3 Chapter 3 Installation 4 Load Resistor Connection 4 Water Line Attachment 4 Cooling Water Quality 4 Flow Switch Optional 5 C...

Page 11: ...cing Fractured Resistor 12 Reassembling the Unit 12 Replacing the RF Connector 14 Replacing the Water Flow Switch 14 Replacing the Time Delay Relay 15 Replacing the Control Box Lamp 15 Storing 16 Ship...

Page 12: ...ive Control System is available as optional equipment When properly installed this system protects the load by shutting off the RF power when water flow is too low or interrupted Discussions of the fl...

Page 13: ...the rear The dielectric characteristics and distinctive design of these enclosures provide a very accurate 50 ohm termination over the specified frequency range of this load 1000 Hz to 800 MHz The ab...

Page 14: ...on is necessary because dissipation of the heat generated by the RF power absorption is critically dependent upon maintaining the required minimum water flow rate regardless of inlet water temperature...

Page 15: ...te Do not disturb the socket head cap screws that join the connector section to the main housing 5 Install water inlet and outlet connections See Water Line Attachment on page 4 Water Line Attachment...

Page 16: ...e box is a safe operation indicator it lights only when AC power is on and an adequate water supply is flowing After the pilot lamp lights a 12 2 second time delay allows sufficient time for the water...

Page 17: ...utdown Procedure 1 Turn off the RF Power to the load 2 Wait at least one minute to allow the resistor substrate time to cool 3 Turn the interlock and AC power off if the load is equipped with an inter...

Page 18: ...oad Installation and operation of the wattmeter is covered in the Thruline Wattmeter Instruction Book Note Select a wattmeter type appropriate to the input connector of the load resistor Consult the B...

Page 19: ...ses and remedies Use this chart as a guide when analyzing symptoms Cleaning Outside Surface The outside surface of these loads should be wiped free of dust and dirt when necessary Periodically wipe th...

Page 20: ...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...

Page 21: ...Set the load on end with RF Connector down 6 Remove the water chamber 1 by unscrewing it in a counterclockwise direction Note A strap wrench and a 3 8 to 1 2 inch rod are useful to overcome the initia...

Page 22: ...ote There is no advantage in separating the front and second housing sections These are removed as an entire unit by removing the six 1 4 20 x 1 inch socket head cap screws on the flange of the front...

Page 23: ...he resistor fitting 22 be sure it is a very snug fit and requires a moderate force to push the resistor into the fitting This fit must not be loose and yet not excessively tight If the resistor is loo...

Page 24: ...Termaline Load Resistor 13 Figure 3 RF Load Midsection Figure 4 RF input Assembly Exploded View...

Page 25: ...the fitting to hold the resistor fitting 22 5 Replace the center conductor assembly by gently manipulating the assembly until it is thoroughly seated in place 6 Reassemble the RF Connector assembly by...

Page 26: ...of the socket 6 Replace the relay by reversing the procedure above Note The socket is an ordinary octal type When inserting the relay rotate the cartridge carefully to align the center post nub in the...

Page 27: ...shipping carton for reshipment 4 Pad the container with sufficient padding to avoid shock damage 5 Seal the container securely Customer Service Any maintenance or service procedure beyond the scope o...

Page 28: ...to 60 C 41 F to 140 F AC Power Required 115 V 60 Hz with optional items only Minimum Water Flow Rate 9 GPM 34 lpm at 5 C 41 F 12 GPM 45 4 lpm at 6O C 140 F Water Connection 3 4 standard hose thread We...

Page 29: ...1 14 1 Cone point socket hd set screw front and second sect 10 32 x 1 4 inch standard 15 1 Outer resistor cap seal O Ring 5 1128 17 1 Flow switch 5 898 7 18 1 Flow switch bushing 5 490 14 19 1 Front s...

Page 30: ...ry 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 exten...

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