INSTRUCTION BOOK RF DIRECTIONAL THRULINE® WATTMETER MODEL 43 Also Covers Models 4431, 43P And Series 4300, 4520 ©Copyright 2008 by Bird Electronic Corporation Instruction Book Part Number 920-43 Rev.
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 applied to all phases of operation and maintenance. Keep Away From Live Circuits Operating personnel must at all times observe general safety precautions.
Bird Model 43 Wattmeter 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. This symbol appears on the equipment indicating there is important information in the instruction manual regarding that particular area.
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 For low reflection measurements, do not rotate the reflected power element to read forward power. Damage to the element or wattmeter could result. CAUTION Handle elements with care. Calibration could be disturbed if they are dropped. CAUTION Do not attempt to remove the RF center conductor. This will damage the line section.
Bird Model 43 Wattmeter 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.
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.
Bird Model 43 Wattmeter About This Manual This instruction book covers RF Directional Thruline Wattmeters Models: 43 43P 4301 4305A 4431 4521 4522 4523 4525 4526 4527 This instruction book is arranged so that essential safety information appears in the front of the book. Reading the Safety Precautions Section before operating the equipment is strongly advised. The remainder of this Instruction Book is divided into Chapters and Sections.
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 comment to our factory. This manual may be periodically updated. When inquiring about updates to this manual refer to the part number and revision level on the title page.
Table of Contents Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Purpose and Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Performance Characteristics and Capabilities . . . . . . . . . . . . . . . . . .
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Contact Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Zero Adjust. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 1 Introduction Purpose and Function This manual covers the operation of the Bird 43 Thruline Wattmeter and its descendants. Two models have RF sampler ports, while the Bird 43P can measure peak power. The Bird 4520 series comes ready for panel mounting. Differences are discussed in Chapter 6, on page 35. Except where indicated, instructions and specifications for the 43 apply to other models also.
Bird Model 43 Wattmeter A shielded cable connects the RF line section to the rest of the wattmeter. This lets you remove the line section from the wattmeter housing for custom installation and still make measurements. The RF line section is precision machined to provide the best possible impedance match to the transmission line under test. A formed phosphor-bronze spring finger protrudes into the element socket to make contact with the element.
Figure 2 Bird 43 Thruline Wattmeter Outline Drawing 3
Bird Model 43 Wattmeter 4
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: y 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.
Bird Model 43 Wattmeter Coupling Circuit The coupling circuit that samples the travelling waves is in the Bird Plug-In Element. The element circuitry and its relationship to the rest of the Bird 43 are illustrated in Figure 3. Figure 3 Thruline Wattmeter Schematic Current is produced in the coupling circuit by the travelling waves in the line section. Both inductive and capacitive coupling contribute to this. The inductive current flows in the direction of the travelling wave.
Theory of Operation capacitive current, while that produced by the wave travelling in the opposite direction will subtract. The additive or “arrow” direction is assigned to the forward wave. The electrical characteristics of the element are carefully adjusted so that, for the reverse travelling wave, the inductive current will completely cancel the capacitive current. The result is directivity greater than 25 dB.
Bird Model 43 Wattmeter Standing Wave vs. Travelling Wave Viewpoint As mentioned previously, the Thruline Wattmeter reacts to forward and reverse travelling waves to measure power in a transmission line. The standing wave viewpoint, also widely used, is highly developed both in theory and in practice. This viewpoint can be traced to the early use of slotted transmission lines.
Theory of Operation NOTE: Attenuation, measured in dB, can be derived from the power ratio by the equation Ndb = 10 log φ. VSWR scales and their attendant controls for setting the reference point have been intentionally omitted from the Bird 43. Experience using the Thruline Wattmeter for transmitter tune-up, antenna matching, etc. will show that the power ratio measurement is as useful in practice as the standing wave ratio.
Bird Model 43 Wattmeter Figure 4 Percent Reflected Power vs. VSWR (1.0 – 1.
Theory of Operation Figure 5 Percent Reflected Power vs. VSWR (1.0 – 8.
Bird Model 43 Wattmeter Low Reflection Measurements φ = 10% (ρ = 2) is the typical limit of antenna match. Further effort is frequently not worthwhile because below this level reflected power is hard to measure, and Wl can not be significantly increased. TV and VHF transmitters are examples of systems requiring lower reflected power but for reasons other than maximizing power transmission. CAUTION For low reflection measurements, do not rotate the reflected power element to read forward power.
Theory of Operation Transmitter Monitoring The Thruline Wattmeter can be used for the continuous monitoring of transmitter output or reflected power, for instance in checking intermittent antenna or line faults. Component Testing The Bird 43 is very helpful in component testing, and may be employed in several ways: 1. VSWR or φ may be measured by placing the component under test between the wattmeter and a good load resistor. 2.
Bird Model 43 Wattmeter unknown line to the wattmeter. The measured φ is the attenuation for two passes along the line (down and back). The attenuation can then be compared with published data for line type and length (remember to halve Ndb or double the line length to account for the measurement technique).
Theory of Operation Figure 6 Representative Frequency Response These curves are typical for all element types (H, A, B, C, D, ...) at their respective frequencies. Since a C type element has a frequency range of 100 - 250 MHz, response curves for other element types can be approximated by replacing the 100 and 250 MHz points on the chart with the extremes of the element’s frequency range, and recalculating the other frequency points accordingly.
Bird Model 43 Wattmeter Impedance Mismatch There may be cases where it is necessary to use the Bird 43 with a non-50 ohm 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 test frequencies and/or higher reflected power levels, the load impedance will change when the wattmeter is removed from the circuit. When the line and load impedances are known, the system’s VSWR equals the ratio of the two.
Chapter 3 Installation When transporting the Bird 43, insert the original dust plug, or an element with the arrow pointing upward, in the element socket and secure with the catch. This will shunt the meter circuit and protect the meter by dampening needle action during handling and shipping. Also, secure spare elements in their sockets with the pivoting knob; just insert the element and twist the knob one-quarter turn. CAUTION Handle elements with care. Calibration could be disturbed if they are dropped.
Bird Model 43 Wattmeter The Bird 43 is normally supplied with Quick-Change Female N type connectors. Other Bird “QC” connectors are available, refer to the Replacement Parts List in the Maintenance Chapter. Quick-Change connectors can be replaced by removing the 8-32 screw at each corner of the connector and then pulling it straight outward. Install the new connector by reversing this procedure. Remote Installation The RF line section can be removed from the meter housing for remote installation.
Installation The RF line section of the Bird 43 lends itself very readily to panel mounting. A layout for the panel cut is given in Figure 7. The thickness of the panel should be about 1⁄4 inch. On thinner panels, build up the thickness with pads or washers to achieve a flush-face mounting. Attach the line section so that the finger catch is in the most accessible position.
Bird Model 43 Wattmeter 20
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. The Bird 43 uses plug-in elements to make measurements. The element’s frequency range and maximum power are listed on its label. The transmitter test frequency should be within the band of the element used.
Bird Model 43 Wattmeter y Turn on the RF source. y Read the power using the scale whose full-scale marking matches the element’s maximum power. Figure 8 Element Direction When readings are being made with the wattmeter connected to an auxiliary RF line section, do not put an element in the unused line section. Otherwise, the dc circuit will be unbalanced or shorted, causing inaccurate or zero power readings. For your convenience, a set of VSWR conversion nomographs is included in this manual.
Operating Instructions Figure 9 VSWR Conversion Graph (Reflected Power 0.2 – 20.
Bird Model 43 Wattmeter Figure 10 VSWR Conversion Graph (Reflected Power 0.01 – 1.
Operating Instructions Load Matching When a Bird 43 is used to tune a load to a transmitter and a good match is obtained, removing the unit will not change the match quality. A good 50 ohm load can terminate a 50 ohm transmission line of any length without altering conditions at the transmitter. The 43 is just an extra length of 50 ohm line in series with the measurement. When the load is not well matched (an antenna with a VSWR of 1.5 or 2.
Bird Model 43 Wattmeter Figure 11 Cable Length / Wavelength Matching 26
Chapter 5 Maintenance The rugged and simple design of the Bird 43 means that it requires minimal routine maintenance. Troubleshooting The following table contains troubleshooting information for problems that can occur during normal operation. Find the problem on the table, review possible causes, and perform the corrective action listed. This manual does not list all malfunctions that may occur, or all corrective actions.
Bird Model 43 Wattmeter Intermittent or inconsistent meter reading High VSWR or reflected power Dirty dc contact on element Clean contact (page 28) Faulty transmission line or antenna Inspect line Sticky or defective meter Return wattmeter for service Foreign material in line section or in RF connector Clean connectors (page 28) Open or shorted transmission line Inspect line Bad load or poor connectors Inspect load, antenna, and connectors Cleaning It is important to keep the following surfac
Maintenance If the RF line section seems dirty, do not loosen any connections. Clean accessible components as described above and use dry, clean air to blow out the interior. The outside of the meter housing can be cleaned with a soft cloth dampened with a mild detergent solution. Do not wipe the meter glass with a dry cloth, or a static charge could develop that would cause an erroneous meter indication. Contact Adjustment When cleaning the socket bore, do not disturb the spring finger of the dc contact.
Bird Model 43 Wattmeter 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 12). Figure 12 Zero Adjust Storage When storing the meter, keep an element or dust plug in the element socket to prevent the intrusion of dust and to prevent damage to the meter movement.
Maintenance Customer Service If you need to return the unit for any reason, contact the Bird Service Center for a return authorization. All instruments returned must be shipped prepaid and to the attention of Bird Service Center: Bird Service Center 30303 Aurora Road Cleveland (Solon), Ohio 44139-2794 Phone: (440) 519-2298 Fax: (440) 519-2326 Sales Facilities For the location of the Sales Office nearest you, give us a call or visit our Web site at: http://www.bird-electronic.
Bird Model 43 Wattmeter Bird 43 Replacement Parts List Description Qty.
Maintenance Available “QC” Type Connectors Connector Part Number Connector Part Number BNC-Female 4240-125 Open Term.
Bird Model 43 Wattmeter 34
Chapter 6 Model Differences Bird 43P Peak Wattmeter The Bird 43P Thruline Wattmeter is the same as the Bird 43, with the added capability of measuring peak power in AM, SSB, and some pulse applications. A conversion kit (P/N 4300-400) is available to give peak reading capability to any standard Bird 43. This kit comes with all necessary parts and easy to follow instructions for simple and quick conversion. Special elements are not required.
Bird Model 43 Wattmeter Rectangular Pulses When measuring rectangular pulse power, note the following signal requirements: y Duty Cycle: 2%, minimum y Rep. Rate: 100 pps, minimum y Pulse Width: 200 µs, minimum Peak Calibration If recalibration is required, refer to figure 15 and these instructions: 1. Unscrew the four 8-32 flat head screws securing the back cover. 2. Grasp the back cover by the side tabs behind the line connectors and pull straight back to remove it. 3.
Model Differences Maintenance Maintenance of the Bird 43P is the same as for the Bird 43 except for battery replacement. Battery life should typically be 48 hours. If the unit does not function properly in peak mode or if calibration cannot be achieved, the batteries may be low. Replace with two new 9 V alkaline or lithium batteries. The batteries fit very tightly in their retaining clips and may have to be pried out one at a time.
Bird Model 43 Wattmeter Bird 4301 Thruline Wattmeter The Bird 4301 Thruline Wattmeter is the same as the Bird 43 except for the following physical differences: The auxiliary DC connector on the Model 4301 can be used to connect to an accessory line section. Make the connection with a standard RG58/U cable.
Model Differences Bird 4305A Thruline Wattmeter The Bird 4305A Thruline Wattmeter is the same as the Bird 43 except for the following physical differences: y The Bird 4305A’s dimensions are 4-5/16”L x 4”W x 6-7/8”H (110 x 102 x 175 mm), including element and bumper feet. The weight is 3.25 lb. (1.5 kg), including the element. y The Bird 4305A does not have holders for spare elements.
Bird Model 43 Wattmeter Bird 4431 Thruline Wattmeter The Bird 4431 RF Sampling Wattmeter is the same as the Bird 43 Thruline Wattmeter except for an RF signal sampler probe. The RF sampler provides a low power sample of the signal being transmitted through the wattmeter’s linesection. This signal is available at the female BNC connector labeled “RF SAMPLE”, on the right side of the housing. The signal level can be set with the control knob on the front of the meter.
Model Differences Maintenance Do not make repairs to the probe assembly. If the sampler malfunctions, we recommend returning the unit to the Bird Service Center for repair. To replace the probe assembly, follow these instructions: 1. To reach the probe, unscrew the four 8-32 flat head screws securing the back cover. 2. Grasp the back cover by the side tabs behind the line connectors and pull straight backward to remove it. 3.
Bird Model 43 Wattmeter Bird 4431 Replacement Parts List Only parts which are not used on the Bird 43 are listed here. Description Qty.
Model Differences Bird 4520 Series Thruline Wattmeters The Bird 4520 RF Thruline Wattmeters (models 4521, 4522, 4523, 4525, 4526, 4527) are the same as the Bird 43, except that they are panel mounted for rack installation. In addition, the Bird 4527 has a RF sampler. These units are intended for fixed installation, generally in rack mounts requiring 19” panels. Installation y Choose a location allowing easy reading and operation of the unit and where the cables used will be short and without sharp bends.
Bird Model 43 Wattmeter Description Qty.
Chapter 7 Specifications These specifications include data covering the Bird 43, 43P, 4305A, 4431, 4521, 4522, 4523, 4525, 4526, and 4527. Specifications for models not listed are identical to the Bird 43. Impedance, Nominal 50 ohm VSWR, Max. All models except 4431 1.05:1 4431 1.
Bird Model 43 Wattmeter 4431* 5000 W max, 2 – 30 MHz 1000 W max, 30 – 1000 MHz 4527 1000 W max, 2 – 200 MHz 500 W max, 200 – 512 MHz RF Coupling 4527 (approximate) –53 dB, 512 – 10 MHz –70 dB, 10 – 2 MHz 4431 (adjustable) 15 – 70 dB Insertion Loss (4431 only)* 2 – 512 MHz 0.1 dB max 512 – 1000 MHz 0.
Specifications 4431 3-7/8”L x 4”W x 6-7/8”H (99 x 102 x 175 mm) 4521/22/23/25/26/27 19”W x 5-1/4”H x 1-3/4”D (483 x 134 x 45 mm) Weight, Nominal 43, 4521/22/23/25/26/27 3 lb. (1.36 kg) 43P 4 lb. (1.8 kg) 4431 3.5 lb. (1.59 kg) 4305A 3.25 lb. (1.47 kg) Operating Position Any Finish Grey Powder Coat * Applicable only for maximum coupling less than 30 dB.
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.
