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Related Manuals for MFJ MFJ-259C
Summary of Contents for MFJ MFJ-259C
- Page 1 HF/VHF SWR Analyzer Model MFJ-259C INSTRUCTION MANUAL CAUTION: Read All Instructions Before Operating Equipment MFJ ENTERPRISES, INC. 300 Industrial Park Road Starkville, MS 39759 USA Tel: 662-323-5869 Fax: 662-323-6551 COPYRIGHT 2013 MFJ ENTERPRISES, INC. VERSION C1...
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Page 2: Table Of Contents
MFJ-259C Instruction Manual HF/VHF SWR Analyzer TABLE OF CONTENTS 1.0 INTRODUCTION............................1 A Quick Word about Accuracy....................1 Typical Uses ..........................2 Frequency Range ........................2 2.0 POWER SOURCES ............................. 2 External Power Supply......................3 Using Internal Batteries ......................3 Using Rechargeable “AA”... -
Page 3: Introduction
However, the MFJ-259C minimizes this problem with careful pc layout and by using low-capacitance microwave-grade surface-mount components with virtually no lead length. -
Page 4: Typical Uses
(Zo) is 50 ohms. A more complete description of the MFJ-259C's features along with proper measurement methods can be found by reading sections covering the particular measurement you wish to make. Consult the table of contents for various applications. -
Page 5: External Power Supply
2.1 mm The MFJ-259C has a recessed 2.1 mm power jack located on the top-right-hand side of the unit. It is labeled Power 13.8 VDC. The jack's outside barrel contact is negative and the center pin is positive. Inserting a power plug into the power jack automatically disables the internal batteries as a power source. -
Page 6: Using Conventional "Aa" Drycell Batteries
IMPORTANT WARNING: Never Apply RF or any other external voltage to the Antenna port of this unit. The MFJ-259C uses zero bias detector diodes that may be damaged by external voltages. Read Section-2.0 before applying power! Incorrect supply voltages will also damage this unit. -
Page 7: Power-Up Display
Impedance Magnitude (Z) measurements for the DUT. The MFJ-259C has five (5) Basic Operating Modes that are used for conducting a variety of measurements. If you tap (momentarily press) the Mode button, the analyzer steps to the next Mode selection. The five main modes and their opening screens are described in Section-3.3 below:... -
Page 8: Blinking "Voltage Low" Display Warning
MFJ-259C Instruction Manual HF/VHF SWR Analyzer 2.) Coax Loss: Use the analyzer's second mode to measure loss incurred in random lengths of 50-Ohm cable, 50- Ohm attenuator pads, 50-Ohm transformers, and 50-Ohm baluns. The top working-display line shows the VFO Frequency in MHz and the lower line presents the measured Loss in dB. Note that the transmission line or device under test must be unterminated at its far end during loss testing. -
Page 9: Main (Or Opening) Mode
For simple handheld analyzers like the MFJ-259C, the calibration plane is always located at the analyzer's RF connector. This is the point where Zo=50 Ohms and Phase shift = 0 degrees. It is the only test point where the analyzer will be calibrated for complex impedance measurements. - Page 10 MFJ-259C Instruction Manual HF/VHF SWR Analyzer Note that the MFJ-259C also has Advanced antenna-measurement modes that are described in Section-5.0. However, unless you have a strong working knowledge of RF systems, you may find these added modes of limited value. Most represent more technical ways of expressing the same data offered by the basic modes.
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Page 11: 4.3 Coax Loss
The lower line displays the computed Capacitance in pF. Normally, the measurement range is from a few pF to a few thousand pF. The MFJ-259C becomes inaccurate when measuring reactance below 7 ohms or above 650 ohms. If reactance falls into the inaccurate range, C(X<7), C(X=0), or C(Z>650) will be displayed. -
Page 12: Inductance
No inductance value is displayed if the range is questionable. Positive Reactance Sign: The MFJ-259C measures Reactance (X) and mathematically converts it to an Inductance value, but its processor can't determine if the reactance is inductive or capacitive. You can usually determine the type (or sign) of the reactance by adjusting the VFO. -
Page 13: Advanced Operation
Distance to fault ........SWR, impedance, and distance to fault Resonance ..........SWR, resistance and reactance Transmit efficiency ........SWR, Impedance, Forward power as percentage of apparent power Forward In Advanced Mode, the MFJ-259C measures: (1.) Distance to Fault, (2.) Impedance Magnitude, (3.) Reactance, (4.) Resistance,... -
Page 14: General Connection Guidelines
SWR, use properly constructed 50-ohm coaxial cables of known quality and check connector condition. (Magnitude of) Impedance mode Impedance Magnitude is the first measurement mode in the advanced menu. The MFJ-259C also allows you to view Impedance Magnitude from the basic-menu SWR/Impedance R&X mode by simply pressing the Gate key. In Advanced Mode, the identification screen for Impedance Magnitude is shown below: θ... -
Page 15: Return Loss And Reflection Coefficient Mode
Unbalanced lines need not be isolated during testing and may be coiled on the floor. For balanced lines (ladder line, open-wire feeders, etc), run the MFJ-259C on internal batteries and keep it at least a few feet away from earth and other conductors. Attach only the DUT (no other wires) -- one lead to the center pin of the Antenna connector and the other to the case via the grounding stud. -
Page 16: Resonance Mode
MFJ-259C Instruction Manual HF/VHF SWR Analyzer 4.) Press Gate again, and the display will indicate the DTF. Multiply the DTF times the velocity factor of the cable (Vf) to get the physical DTF (distance in feet). Dist. to fault 11.3 ft x Vf Resonance Mode From the Advanced menu, tap the Mode switch three times to bring up the Resonance Mode ID screen. -
Page 17: Verticals
MFJ-259C Instruction Manual HF/VHF SWR Analyzer The height of a dipole above ground, as well as any surrounding objects, will influence the feed point impedance and SWR. Typical residential heights usually result in minimum SWR readings below 1.5:1 when using 50-ohm coaxial cable. -
Page 18: Testing And Tuning Stubs And Transmission Lines
MFJ-259C Instruction Manual HF/VHF SWR Analyzer TESTING AND TUNING STUBS AND TRANSMISSION LINES Testing Stubs To measure Resonant Frequency for a matching stub or transmission line, select the SWR/Impedance mode in the Basic Menu (opening mode). Note that DUTs measuring 1/4λ and odd multiples (1/4λ, 3/4λ, 5/4λ, etc) are terminated with an open circuit at the far end. -
Page 19: Impedance Of Transmission Lines Or Beverage Antennas
MFJ-259C Instruction Manual HF/VHF SWR Analyzer To measure velocity factor: 1.) Connect the DUT and tune the analyzer VFO to a frequency where the analog Impedance meter nulls and where reactance displayed on the screen approaches or crosses zero (X=0). -
Page 20: Adjusting Tuners
Important Warning: Always connect the common (rotary contact) of the external RF switch to the tuner. The switch must connect either the MFJ-259C or the station transceiver to the tuner. Transmitting equipment must never be configured in a manner where it could accidentally become connected to the MFJ-259C. -
Page 21: Testing Rf Transformers
Testing RF Transformers The MFJ-259C can test any RF transformer presenting a 25-100 ohm termination on one of its windings. Connect the 25-100 ohm winding to the analyzer's Antenna jack using a very short 50-ohm pigtail (<1° phase shift). The other winding (or windings) should be terminated with a low-inductance resistor equal to the desired load impedance. -
Page 22: Testing Rf Chokes
TECHNICAL ASSISTANCE If you have any problem with your MFJ-259C, first check the appropriate section of this manual. If the manual does not reference your problem and the problem isn't solved by reading the manual, you may call MFJ Technical Service at 662-323-0549 or the MFJ Factory at 622-323-5869. - Page 23 MFJ Enterprises, Inc. warrants to the original owner of this product, if manufactured by MFJ Enterprises, Inc. and purchased from an authorized dealer or directly from MFJ Enterprises, Inc. to be free from defects in material and workmanship for a period of 12 months from date of purchase provided the following terms of this warranty are satisfied.
- Page 24 MFJ ENTERPRISES, INC. MFJ-259C Manual 300 Industrial Park Road Version C1 Starkville, MS 39759 Printed In U.S.A.
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