RF DIRECTIONAL THRULINE® WATTMETER MODEL 4304A ©Copyright 2011 by Bird Electronic Corporation Instruction Book Part Number 920-4304A Rev.
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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.
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. The caution symbol appears on the equipment indicating there is important information in the instruction manual regarding that particular area Note: Calls attention to supplemental information.
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 Do not drop. Calibration could be disturbed or the meter could be damaged as a result. CAUTION Above 800 MHz, do not exceed 150 W RF power. CAUTION RF power must not exceed range switch setting. CAUTION Do not attempt to remove the RF center conductor. This will damage the line section.
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.
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.
RF VOLTAGE MAY BE PRESENT IN RF ELEMENT SOCKET - KEEP ELEMENT IN SOCKET DURING OPERATION. DE LA TENSION H.F. PEAT ÊTRE PRÉSENTE DANS LA PRISE DE L'ÉLÉMENT H.F. - CONSERVER L'ÉLÉMENT DANS LA PRISE LORS DE L'EMPLOI. HF-SPANNUNG KANN IN DER HF-ELEMENT-BUCHSE ANSTEHEN ELEMENT WÄHREND DES BETRIEBS EINGESTÖPSELT LASSEN. PUEDE HABER VOLTAJE RF EN EL ENCHUFE DEL ELEMENTO RF MANTENGA EL ELEMENTO EN EL ENCHUFE DURANTE LA OPERACION.
About This Manual This manual covers the operating and maintenance instructions for the following models: 43 43P 4301 4521 4522 4526 4305A 4431 4527 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.
Table of Contents Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Warning Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Caution Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v Safety Statements . . . . . . . . . . . . . . . .
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Available “QC” Type Connectors . . . . . . . . . . . . . . .
Chapter 1 Introduction Purpose and Function The Bird 4304A Wattmeter is an in-line sensor that measures RF power and load match in 50Ω coaxial transmission lines. It can be used with CW, AM, FM, and TV modulation, but not pulse modulation. It is supplied with a special broadband element with a frequency range of 25 to 1000 MHz. It can measure up to 500 W, depending on the frequency, and has a maximum VSWR of 1.07 with the standard “N” connectors.
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Chapter 2 Theory of Operation Travelling Wave Viewpoint The easiest way to visualize Thruline operation is from a travelling wave viewpoint. In transmission lines the voltages, currents, standing waves, etc., on any uniform line section result from the interaction of two travelling waves: • • The forward wave (and its power) travels from the source to the load. It has RF voltage Ef and current If in phase, with Ef / If = Zo.
Coupling Circuit Figure 2 Thruline Wattmeter Schematic RF Coaxial Line XMTR or LOAD LOAD or XMTR Diode Directional Coupling Meter Detector Element DC Contact Circuit Board The element, which contains the coupling circuit, and its relationship to the rest of the Bird 4304A is shown in Figure 2. Current is produced in the coupling circuit by travelling waves in the line section, through both inductive and capacitive coupling.
Load Power For loads with a VSWR of 1.2 or less, the power dissipated in a load (Wl) is equivalent (with less than one percent error) to the forward power (Wf). When appreciable power is reflected, as with an antenna, it is necessary to use the exact load power which is given by: W 1 = WattsIntoLoad = W f – W r Good load resistors, such as Bird Termaline loads, will give negligible reflected power. Standing Wave vs.
Figure 3 6 Percent Reflected Power vs. VSWR (1.0 – 1.
Figure 4 Percent Reflected Power vs. VSWR (1.0 – 8.
Component Testing The Bird 4304A is very helpful in component testing, and may be employed in several ways: Note: Measuring small attenuations requires correction for normal instrument errors. For two wattmeters, do this by simply connecting the wattmeters directly, with no line between them, and adjusting their zero settings. For one, make sure to note exact readings, or their difference, on the initial equality check, and correct for this.
Impedance Mismatch In some cases it may be necessary to use the Bird 4304A with a non-50Ω transmission line. If the reflected power is less than 10% and the frequency is below 200 MHz, the resulting mismatch will not be too serious. At higher frequencies or reflected power levels, the load impedance will change when the wattmeter is removed. When the line and load impedances are known, the system’s VSWR equals the ratio of the two.
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Chapter 3 Installation When transporting the Bird 4304A, turn the element so that the arrow points down and set the range switch to 5 W. This will shunt the meter circuit and protect the meter by dampening needle action. 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. CAUTION Do not drop. Calibration could be disturbed or the meter could be damaged as a result.
Note: Cable length is measured from end to end of the outer conductor of the connectors, except for UHF and mini-UHF plugs where it is measured from tip to tip of the center pins. Note: Dimensions shown are for solid polyethylene cable such as RG-58C/U or RG-8/U, which have a velocity of propagation 66% of that of air. If RG-58 or RG-8 type cables with foam polyethylene (v.p. of 79%) are used, multiply the dimensions in the graph by the ratio of the relative velocities; 79% ÷ 66% = 1.2 in this case.
Chapter 4 Operating Instructions WARNING When working with RF powers of 200 watts or more, the potential of the center conductor of the line section will exceed 100 volts. Do not touch the center conductor while RF power is on. CAUTION Above 800 MHz, do not exceed 150 W RF power. CAUTION RF power must not exceed range switch setting. Normal Operation 1. 2. 3. 4. 5. Turn the element so that the arrow points towards the load to measure forward power.
Figure 6 14 VSWR Conversion Graph (Reflected Power 0.2 – 20.
Figure 7 VSWR Conversion Graph (Reflected Power 0.01 – 1.
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Chapter 5 Maintenance 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. CAUTION Do not drop. Calibration could be disturbed or the meter could be damaged as a result. The rugged and simple design of the Bird 4304A means that it requires minimal routine maintenance.
This manual does not list all malfunctions that may occur, or all corrective actions. If a malfunction is not listed or not corrected by the listed actions, contact the nearest Bird Service Center for assistance.
Zero Adjust The meter’s zero setting should be checked when no RF power is present. When no power is applied the pointer should rest exactly on zero. If adjustment is required, turn the adjustment screw until the pointer is set at zero (see Figure 8 on page 18). Connector Replacement 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.
Line Section Replacement 1. Remove the element (See "Element Removal" on page 19). 2. Use a 5⁄16" hex wrench to loosen the nuts on the meter terminals. Remove the wires from the terminals. 3. Use a 5⁄16" allen wrench to loosen the set screws on the range switch knob. Remove the knob. While supporting the line section, remove the screws on the front of the housing, located on either side of the element socket. Pull the line section and attached circuit board out the back. 4. 5.
Calibration Checks Seup Test Note: This test determines if the wattmeter needs recalibration: 1. The following equipment is required, connected in series with the Bird 4304A (Refer to Figure 9). • RF source • • • • Low pass filter Reference, known accurate, wattmeter 50Ω load Cables Note: Keep all connections as short as possible to minimize mismatch and insertion losses. 2. 3. Set the RF source to produce a signal with power in the upper one-third of the scale for each power range.
1. 2. 3. 4. 5. 6. 7. 8. Remove the rear panel from the 4304A to access the adjustment potentiometers. Connect the calibration equipment as shown in Figure 10. Set the range switch to 15 and adjust the RF source to apply 12.5 watts at 100 MHz. Adjust R9 (Figure 11) until the 4304A meter indicates 12.5. Measure the actual power for a meter reading of “12.5” for the following frequencies: 25 MHz, 50 MHz, 80 MHz, 150 MHz, 225 MHz, 400 MHz, 400 MHz, 800 MHz, and 1000 MHz.
20. Multiply by 10 the actual RF source power recorded in Step 15 (the reading at “40” taken at 405 MHz). Set the RF source to this calculated value and the frequency to 405 MHz. 21. Adjust R6 until the 4304A meter indicates 400. Figure 11 Range Adjustment Potentiometers + 10 9 2 1 R10 5 7 4 3 8 R6 500 R7 150 R8 50 R9 15 Storage When storing the Bird 4304A, turn the element so that the arrow points down and set the range switch to 5 W.
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 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: (440) 248-5426 E-mail: bsc@bird-technologies.
Specifications Frequency Range Power Rating 25 – 1000 MHz 500 W, 25 – 800 MHz 150 W, 800 – 1000 MHz 5/15/50/150/500 W Power Range Settings Insertion VSWR (Max.) UHF Connnector 1.08, 25 – 512 MHz 1.12, 512 – 1000 MHz 1.05, 25 – 512 MHz 1.07, 512 – 1000 MHz 0.1 dB, 25 – 512 MHz 0.15 dB, 512 – 1000 MHz 0.1 dB, 25 – 512 MHz 0.13 dB, 512 – 1000 MHz N Connector Insertion Loss (Max.
Available “QC” Type Connectors Connector Part Number Connector Part Number BNC-Female 4240-125 LT-Female 4240-018 BNC-Male 4240-132 LT-Male 4240-012 C-Female 4240-100 N-Female 4240-062 C-Male 4240-110 N-Male 4240-063 HN-Female 4240-268 SMA-Female 4240-336 HN-Male 4240-278 SMA-Male 4240-334 LC-Female 4240-031 7/16 Jack, IEC Type 169-4 4240-344 LC-Male 4240-025 7/16 Plug, IEC Type 169-4 4240-363 UHF-Female 4240-050 TNC-Female 4240-156 UHF-Male 4240-179 TNC-Male 4240-
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.
