Instruction/ maintenance manual of the product 4391A Bird Brain
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INSTRUCTION BOOK OPERA TING INSTRUCTIONS MUL TI-PURPOSE THRULINE ® W A TTMETER RF POWER ANAL YST ® MODEL 4391A ©Copyright 2008 by Bird Electron ic Corporation Instruction Book Part Number 920-4391A Rev .
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i Safety Precautions The following are general safety pr ecautions that are not necessarily related to any specific part or proc edure, and do not necessari ly appear elsewhere in this publication. Thes e precautions must be thoroughly understood and apply to all phas es of operation and maintenance.
Bird Model 4391M Power Analyst ii NOTE: Calls attention to supplemental information Fuse Replacement Always use the same type and rating of fuse when replacing the f use.
iii Caution Statements The following equipment cautions appear in th e text whenever the equipment is in danger of damage, and are repeated here for emphasis. CAUTION Long-term storage of this instrument can affect battery performance and reduce battery life.
Bird Model 4391M Power Analyst iv 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.
v PRÉVENIR UN CHOC ÉLECTRIQUE DANGEREUX, NE PAS EFFECTUER D’ENTRETIEN SI L’ON N’A PAS ÉTÉ QUALIFIÉ POUR CE FAIRE. UNITS ARE EQUIPPED WITH RECHAREABLE BATTERIES. THESE ARE TO BE REPLACED BY AUTHORIZED SERVICE PERSONNEL ONLY!!! LAS UNIDADES VIENEN EQUIPADAS CON BATERIAS RECARGABLES.
Bird Model 4391M Power Analyst vi PRIMA DI EROGARE CORRENTE, ASSICUR ARSI CHE IL SELETTORE DI VOLTAGGIO 115/230 V.C.A. SIA REGOLATO CORRETTAMENTE E CHE IL FUSIBLE ADATTO ALLA LINEA DI ALIMENTAZIONE C.A. SIA INSTALLATO. RF VOLTAGE MAY BE PRESENT IN RF ELEMENT SOCKET - KEEP ELEMENT IN SOCKET DURING OPERATION.
vii About This Manual This instruction book is arranged so that essential information on safety is contained in the front of the b ook. Reading the Safety Precautions Section before operating the equipment is strongly advised. The remainder of this manual is di vided into C hapters an d Section s.
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ix T able of Contents Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . i About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . vii Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
x Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . 23 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Front Panel Removal . . . . . . . .
1 Chapter 1 Introduction The Model 4391A is a multi-purpose Radio Frequency wattmeter designed around a microcom puter. A program stored in permanent memory co ntrols the operation of the instrument a.
Bird Model 4391A Power Analyst 2 Description The instrument is housed in an aluminum case approximately 4-3/8 inches hig h by 9-5/8 inches deep by 6-1/ 4 inches wide (111 mm x 244 mm x 159 mm) in cluding connections, see Figure 1.
3 Chapter 2 Theory of Operation Description of Operation Figure 2 is a block diagram of the major functional parts of the Model 4391A RF Wattmeter. The Microcomputer integrated circ uit shown, contro ls all the other portions of the instrument, which fall into two major groups.
Bird Model 4391A Power Analyst 4 Each reading output by the di splay is derived from up to three voltage readings using th e circuitry described abov e. Once these voltages are measur ed, all remaining operations are performed within the computer chip as follows: The voltages are corrected for error due to dc drift in the analog circuitry.
Theory of Operation 5 The electrical values of the element circuits are carefully balanced and designed s o that current from the rev erse wave will cancel the other almost completely. The result is directivity always higher than 25 dB, which means that the element is highly insensitive (nulled) to the REVERSE direction wave.
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7 Chapter 3 Inst allation The Model 4391A RF Power Analyst is completely port able and very suitable for field or laboratory use. Its power is derived from rechar geable ni ckel metal hydride batteries inside the unit or from an AC outlet via the power cord supplied with the device.
Bird Model 4391A Power Analyst 8 Connection s The Model 4391A contains a short sec tion of rigid 50 ohm coaxial air dielectric t ransmission l ine. To make measurements relating to the t ravelling waves in a coaxial line, that lin e must be disconne cted at some convenient point to permit the Model 4391A air line to be inserted.
Installation 9 with the nominal power range of the elements. For example, if the forward element is a 5 wa tt element, th e switche s are set at 5 and x1. For a 250 watt element they are set at 2.5 and x100. Sometimes it is necessary to use milliwatts or kilowatts as the unit of meas ure.
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11 Chapter 4 Operating Instructions Operating Modes The Model 4391A has nine modes of operation whic h are selected by pressing the mode keys momentarily. In addition, each mode has three output options selected by pressing the modifier keys. De tailed descriptions of the modes and output options follow.
Bird Model 4391A Power Analyst 12 signal coming from the elem ent, whereas th e Model 4391A uses peak and negative peak detector circuits to measure peak and minimum square root of power and combines them using the equation: With this technique, operatio n of CW mode is predictable regardless of envelope shape (see Figure 4).
Operating Instructions 13 T abl e 2 Vo l ta g e St anding Wave Ratio (VSWR) Measuring Peak Envelope Power PEP power measurements are made in the same manner as CW power readings described above, except that the FWD PEP and RFL PEP buttons are pr essed and the readings are displayed directly as peak power.
Bird Model 4391A Power Analyst 14 Measuring Amplitude Modulation Only a forward element is requ ired for this mode. Point the element in the direction of fo rward power and press % MOD.
Operating Instructions 15 Measuring Power in dBm Operation of the forward and reflected dBm modes is identical to the forward and reflected CW power modes, except that the resulting readin g is converted to dB above 1 milliwatt before it is displayed.
Bird Model 4391A Power Analyst 16 Insertion Loss or Attenuation Attenuation or insertion loss can be measured directly using an external singl e port line section (P/N 4 230-006-1), a dc feed-in adapter (P/N 4381-050), an d a dc cable (P/N 3170- 058-6).
Operating Instructions 17 Using the Peaking Aid The peaking aid is useful for making adjustments to optimize any of the parameters which the Model 4391A measures.
Bird Model 4391A Power Analyst 18 Battery Care With average use, the nickel metal hydride batteries in the 4391A will power the unit for 12 hours before needing recharged. The 4391A will main tain rated accuracy unt il all the decimal points light, indi cating that rechargin g is required.
19 Chapter 5 Maintenanc e The 4391A RF Power Analyst was designed and bu ilt to provide many years of trouble free service. This section provides the information needed to prevent and correct equipment failure. Preventive Maintenance To avoid unnecessa ry damage, always observe the following cautions: 1.
Bird Model 4391A Power Analyst 20 then perform a full charge agai n. If necessary, repeat this discharge and char ge cycle up to three times. If the batteries do not remain charged after three disch arge-charge cycles, replace the batteries. Calibration The RF Power Analyst should be calibrated once each year or after any repair.
Maintenance 21 5. Switch on t he Calibrator/Source and let it warm up fo r at least one hour. 6. Set the Calibrator/Source to output 30 ±0.05 micr oamps. 7. Adjust potentiometer, R25 (Fig ure 15, page 21), u ntil the RF Power Analyst Displays 1000 ±5.
Bird Model 4391A Power Analyst 22 Perform the following steps to adjust the contact spring. 1. Using a small flat he ad screwdriver, place the flat side of the screwd river behind the contact bar as indicated and bend the contact bar so that the contact rests in the center of the slot adjacent to the element socket (Figure 16).
Maintenance 23 Troubleshooting General The troubleshooting instructions are intended to aid in fault isolation. This is accomplished through the use of a troubleshooting table. First, locate the symptom(s) in the problem column of Table 8. In some cases the same fault can have more than one symptom and more t han one possible remedy.
Bird Model 4391A Power Analyst 24 Disassembly Front Panel Removal 1. Disconnect AC power from the instrument. 2. Remove the six screws that secure the front panel to the Main PCB supports (Figure 18, page 25, item 1). 3. Remove the two screws and lo ck washers tha t secure the front panel at the bottom of the housing (item 2).
Maintenance 25 5. Lift the front panel from the housing. Be careful to c lear the line section blocks. 6. Remove pads from th e three toggle switches. Main Printed Circuit (PC) Board Removal 1. Remove the front panel (Refer to “Front Panel Removal” on page 24) 2.
Bird Model 4391A Power Analyst 26 QC Connectors Removal 1. Remove the eight screws (four on each conn ector) that secure the connectors to the housi ng (Figure 20, it em 1). 2. Remove the two “QC” conn ectors (item 2) by pulling them away from the line section assembly.
Maintenance 27 Line Section Removal 1. Remove the QC connectors (page 26). 2. Remove the four screws and lock washers that se cure line section assembly to the housing (i tem 3). 3. Using minimum pressure, spre ad apart the sides of the lower housing assembly just far enough to allow the line section assembly to be removed.
Bird Model 4391A Power Analyst 28 6. Remove the two screws (i tem 4) that secure the PCB to the line section then pull the PC b oard assembly (item 3 ) away from the line section subassembly. Remove the spacers (item 2). 7. Remove keying beads (item 1) from the element wiper contacts on the PC board as sembly.
Maintenance 29 8. Lower and secure the Main PC board assembly 9. Replace and secure the front cover. 10. Charge the batt eries for 16 hour s before using the instrument.
Bird Model 4391A Power Analyst 30 Parts List This section contains an illustrated list of all authorized replacement parts for the 439 1A RF power Analyst. Pa rts are grouped into major assemblies and subassemblies. Figure 24 Parts Drawing Item No. Description Part No.
Maintenance 31 Figure 25 Line Section Assembly (S/N 1723 and below) Item No. Description Part No. Qty Figure 25 1 Line Section, Subassembly 4381-005 1 2 PC Board, Data Acquisition Assy 4391A006 1 3 Bead, Keying 4391-026 2 4 Spacer 4391-027 2 5 Screw, Machine, filister head, No.
Bird Model 4391A Power Analyst 32 Figure 26 Line Section Assembly (S/N 1724 and above) Part No. Description Part No. Q ty Figure 26 1 Line Section, Subassembly 4381-005 1 2 PC Board, Data Acquisition Assy 4391A006 1 3 Bead, Keying 4391-026 2 4 Spacer 4391-027 2 5 Screw, Machine, filister head, No.
Maintenance 33 Customer Service Any maintenance or service procedure beyond the scope of those in this chapter should be referred to a qualified service center. If you need to return the unit for any reason, contact the Bird Service Center for a retu rn authorization.
Bird Model 4391A Power Analyst 34 Specifications Measuring Medium RF Tran smission in 50 ohm lines RF Power Range * 100 mW to 10 kW full scale using Bird Plug-in E lements. Accuracy not guaranteed with components not su pplied by Bird Usable Over-Range * To 120% of scale on CW, PEP, SW R, and Return loss functions.
Limited W arranty All products manufactured by Seller are warrant ed 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, drawin gs, blueprints and/or samples.
An important point after buying a device Bird Brain 4391A (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Bird Brain 4391A yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Bird Brain 4391A - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Bird Brain 4391A you will learn all the available features of the product, as well as information on its operation. The information that you get Bird Brain 4391A will certainly help you make a decision on the purchase.
If you already are a holder of Bird Brain 4391A, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Bird Brain 4391A.
However, one of the most important roles played by the user manual is to help in solving problems with Bird Brain 4391A. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Bird Brain 4391A along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
