RF DIRECTIONAL THRULINE® WATTMETER Model 4314C ©Copyright 2012 by Bird Technologies Group Instruction Book Part Number 920-4314C 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 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. Note: Calls attention to supplemental information. Warning Statements The following safety warnings appear in the text where there is danger to operating and maintenance personnel, and are repeated here for emphasis.
CAUTION Severe damage to the Plug-In Element or wattmeter can result from exposure to excessive RF power. Make sure the Plug-In Element installed in the wattmeter has a sufficiently high wattage rating to handle the line load when it is first applied to the RF line. On page 4. CAUTION Use reasonable care in handling. Do not drop or subject the wattmeter or elements to hard blows as accuracy may be impaired or other damage may result. On pages 9 and 21.
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: 4314C 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. When inquiring about updates to this manual refer to the part number and revision on the title page.
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Table of Contents Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Warning Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Caution Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Safety Statements . . . . . . . . . . . . . . .
Measuring Percentage Of Positive Modulation . . . . . . . . . . . . . . . . . . . . . . 16 Performance Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Chapter 5 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 1 4341C Introduction Purpose and Function The Model 4314C Thruline Wattmeter is an insertion-type RF wattmeter designed to measure power flow and load match in 50 ohm coaxial transmission lines. It is intended for use on CW, AM, FM, SSB, TV, and pulse signals only. Description The Model 4314C Thruline Wattmeter is a portable unit contained in a die cast aluminum housing.
Power Requirements The Model 4314C can operate from two different power sources. The wattmeter comes supplied with two 9 V alkaline batteries which typically provide 20 hours of operation. An AC adapter is also available rated at 100-240 +/- 10% VAC @ 50/60Hz. Additional Equipment The only additional equipment required by the Model 4314C is a Plug-In Element. Refer to www.bird-technologies.com for a list of current elements available.
Chapter 2 Installation Portability The Model 4314C is a portable instrument; the housing is not designed for fixed mounting. A strap is provided for carrying purposes. CAUTION Do not drop the Thruline Wattmeter or its elements or subject them to hard blows. The meter is shock mounted in the wattmeter housing, but its delicate mechanism may be damaged by severe impact.
CAUTION Severe damage to the Plug-In Element or wattmeter can result from exposure to excessive RF power. Make sure the Plug-In Element installed in the wattmeter has a sufficiently high wattage rating to handle the line load when it is first applied to the RF line.
Chapter 3 Theory of Operation Traveling Wave Viewpoint The operation of this wattmeter is based on the travelling wave concept of RF transmission. As RF power is applied to a transmission line, there is a forward wave travelling from the transmitter to the load, and a reflected wave travelling from the load to the transmitter. The closer the load is matched to the transmission line, the smaller the reflected wave will be.
Peak Power Operation The Model 4314C is designed to measure peak power in addition to average power. When the toggle switch is placed in PEAK mode (Figure 3 on page 7), battery power energizes the amplifier system. If the AC adapter is being used, it energizes the relay and disengages the batteries. The battery test circuit is energized when the push button switch is pressed.
Figure 2 Schematic Diagram - Element RF Coaxial Line XMTR or LOAD LOAD or XMTR Directional Coupling Meter Diode Detector Element DC Contact Circuit Board Component Description Figure 3 Component Diagram Bat Line 1 Meter 2 Battery Test Push Button 3 CW/PEAK Toggle Switch 4 PEAK Circuit Active Light 5 Element 6 Zero-Adjust Screw 7 DC Input Jack 7
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Chapter 4 Operating Instructions Zero Adjust Meter Before taking any readings with the wattmeter, it is necessary to zero the meter pointer under no-power conditions. WARNING Exposure to RF power radiation and the possibility of RF shock or burns exist with some operating conditions. Always be sure to turn off the transmitter when connecting or disconnecting a wattmeter. Be sure the transmission line is terminated into a load or antenna.
Plug-In Element Selection and Insertion The elements determine the power range to be read on the meter scale. The major markings (50 W, 100 W, etc.) are the full scale power value for that element. Elements are also marked for frequency range. • • Note: The transmitter frequency must be within the band of the element used. RF power measurements are made with the insertion of a Plug-In Element. Insert the element into the line section’s socket.
Load Power Where an appreciable amount of power is reflected, as with an antenna, it is necessary to subtract the reflected from the forward power to obtain the effective load power. Power delivered to and radiated by an antenna is given by: W1 = Wf – Wr Where: W1 = load power W f = ForwardPower W r = ReflectedPower A load closely matched to 50 ohms resulting in a VSWR of 1.2 or less will require less than a one percent correction.
12 .2 .4 .6 .8 1.0 1.2 2.0 1.8 1.6 1.4 4 6 8 10 12 20 18 16 14 0.5 VSWR= 1.0 1 1.5 2.0 2.5 3.0 Reflected Power Forward Power Reflected Power 1+ Forward Power 10 0 4. 10 0 3. 5 2. 15 0 2. 20 8 1. 5 1. 25 30 6 1. 40 4 1. 50 3 1. FORWARD POWER - WATTS 4.0 5.0 R W VS 25 1. 20 1. 100 06 1. 300 10 1. 09 1. .08 1 .07 1 150 200 16 1. 14 1. 12 1. 400 5 05 1.
REFLECTED POWER - WATTS .01 .02 .03 .04 .05 .06 .1 .09 .08 .07 .2 .3 .4 .5 .6 1.0 .9 .8 .7 0.5 R W VS 1.0 10 0 4. 1.5 0 3. 0 2. 8 1. 2.0 2.5 3.0 5 2. 5 1. 4.0 5.0 6 1. 4 1. 10 25 1. 20 1. 15 16 1. 20 14 1. 09 1. 10 1. 25 30 12 1. 07 1. 06 1. 40 50 08 1. FORWARD POWER - WATTS 3 1. 05 1. 04 1. 100 03 1.
Making Low Reflection Readings It is sometimes desirable to make more accurate low reflection readings. This can be done using a more sensitive element, provided that care is taken to prevent application of high forward power to the low-power element. This procedure is limited to use with higher power transmitters only. 1. 2. 3. 4. 5. Measure watts forward, using the proper Plug-In Element. Reverse the arrow direction of the element to determine the general level of reflected power.
Determining Attenuation with a Single Wattmeter Note: This measurement must be supplemented with a reflected power to forward power ratio check while using a load or with a DC continuity check or leakage check, since open circuits or shorts may exist part of the way along the line. The ratio determined in these tests should be viewed as a rough estimate, since 100% of the power at the open connector will not be reflected back. Open Circuit Method 1. 2. Attach an RF generator to the wattmeter’s input port.
Measuring Percentage Of Positive Modulation To measure the percentage of positive modulation in an amplitude modulation system, employ the average and peak reading characteristics of the unit since: E MAX – E CARRIER PercentagePosMod = --------------------------------------------- x100 E CARRIER By substitution we get: P P – P C PercentagePosMod = ---------------------------- x100 PC Where: PP = peak power as read with CW/PEAK switch in PEAK mode.
Figure 6 Graph Converting Carrier Power and Peak Power to Percent 17
Performance Notes Although the Model 4314C Thruline Wattmeter is equipped with Quick-Change connectors, it must be remembered that the power rating and insertion loss may be affected if other than “N” type connectors are used. Power limits must be governed by the type of connector or transmission line used. For other types of Quick-Change connectors, see Chapter 5 for the replacement parts list.
Figure 7 Cable Wavelength Matching Graph MEGAHERTZ 36 (600) (700) (800) (900) (1000) I N C H E S 32 28 (10) C A B L E 24 (9) L E N G T H 20 (8) 16 (7) 12 (6) 8 (5) 4 (4) I N C H E S 0 100 200 300 400 500 600 700 FREQUENCY (MEGAHERTZ) Shutdown 1. Ensure the CW/PEAK switch is in CW mode. Note: Leaving the unit in PEAK mode will shorten battery life. WARNING Always be sure transmitter power is off before disconnecting the unit from the transmission line.
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Chapter 5 Maintenance Cleaning If any of the contacts or line connectors become dirty, they should be cleaned with a good contact cleaner or dry cleaning solvent on a cotton swab stick. It is important to keep the following surfaces clean: • • • • Socket bore Element body circumference Bottom rim of the socket in the line section DC contacts on the element Take care not to disturb the spring finger of the DC contact when cleaning the socket bore. The spring finger can be manually adjusted.
If there is evidence of contamination inside the line section, the reachable portions should be cleaned and the interior carefully blown out. Do not attempt to remove the RF center conductor under any circumstances. Any attempt to do so will damage the assembly. Inspection Periodic inspections should be performed at six-month intervals. • • • Inspect the meter for a cracked meter glass. Inspect wattmeter line section for a damaged or missing latch and pivot pin assembly.
PROBLEM POSSIBLE CAUSE CORRECTION No meter indication (PEAK only) Faulty instrumentation Replace the instrumentation module, see module “Replacing the Instrumentation Module” on page 26. Dead or low battery Test battery. See “Battery Procedures” on page 24. Replace if neccesary. See “Replacing the Batteries” on page 24. If pointer does not move from zero during the battery test, remove the batteries and measure their voltage. If less than 6.25 volts, replace the batteries.
Battery Procedures Testing the Batteries The Model 4314C Thruline Wattmeter uses two 9 V alkaline batteries to supply power for the peak circuitry. 1. Press the ON/BATTERY switch. Note: The meter pointer should travel to the right of the “BAT.TEST” mark. 2. If the pointer stops below the mark, replace the batteries. Note: If the push button is pressed continuously for a length of time exceeding 10 seconds, the battery test load will be disconnected from the batteries.
Replacing the Meter 1. Remove the back cover by unscrewing the four 8-32 Phillips flat head screws. Note: The screws are located two on each side of the meter housing near the back edge at the top and bottom of the sides. 2. 3. 4. 5. Loosen the two 8-32 nuts securing the meter leads. Remove the meter leads. Remove the two 10-32 oval head Phillips screws securing the meter shock ring. Pull the meter and shock ring assembly out of the housing from the back.
Replacing the Instrumentation Module CAUTION This instrument contains static sensitive electronic components. Before opening or servicing the unit, make sure that you understand and practice electrostatic discharge component handling. Failure to comply may result in permanent damage to sensitive components. 1. Remove the back as above in meter replacement. Note: The instrumentation module contains the line section and circuit board chassis as an integral part. 2.
Figure 10 Replacing the Instrumentation Module 6 7 8 5 4 1 3 2 1 Dressnut 2 Mounting Screws 3 Meter Wire Assembly (hidden from view) 4 Instrumenation Module 5 DC Jack Assembly 6 Housing Cover Assembly 7 Battery Cable Assembly 8 Housing Assembly Replacing the Quick-Change Connectors 1. 2. 3. Remove the four 8-32 screws from each corner of the square flange on the connector. Pull the connector straight outward. Install the new connector by reversing this procedure.
Calibrating the Wattmeter The 4314C requires a total of three calibrations to set zero and gain. These calibrations must be performed after the meter or instrumentation module has been replaced. Additionally, a mechanical zero adjustment of the meter pointer is done any time the pointer is not exactly aligned with the zero mark on the meter scale when no power is being applied in CW mode. Note: Before beginning this procedure, a DC Input element (4381050) is needed.
Note: This can be verified on both the voltmeter display and the meter face. Note: Set the CW/PEAK switch to PEAK mode while watching the meter pointer. The pointer should deviate or travel about 4/5 scale. There should be no deviation of the pointer from CW to PEAK reading.
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, request an RMA through the Bird Technologies website (link shown below). 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 \ Impedance Insertion VSWR With “N” Connectors Connectors 50 ohms nominal 1.05 Max. to 1000 MHz, 1.1 Max. to 2300 MHz Bird Quick Change “QC” Female N normally supplied‘ RF Power Ranges Average (CW) Mode 100 mW to 10 kilowatts (± 5% of full scale) Peak-pulse or envelope-power (PEAK) Mode 100 mW to 10 kilowatts (± 8% of full scale) Frequency Range Pulse Parameters Minimum duty factor Minimum repetition rate Minimum pulse width 0.45 to 2700 MHz (either mode) 1.0 x 10-4 30 pps 0.
Replacement Parts Note: For this table, refer to Figure 13 on page 33.
Replacement Parts 2 Figure 13 33
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Limited Warranty All products manufactured by Seller are warranted to be free from defects in material and workmanship for a period of one year, unless otherwise specified, from date of shipment and to conform to applicable specifications, drawings, blueprints and/or samples.
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