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Summary of Contents for MFJ MFJ-259D
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Page 2: Table Of Contents
MFJ-259D 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” Type Batteries ................3 Using Conventional “AA”... -
Page 3: Introduction
However, the MFJ-259D 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
-25 dBc (dB below the fundamental-frequency carrier). The internal source impedance (Zo) is 50 ohms. A more complete description of the MFJ-259D'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-259D 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-259D 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-259D 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
Also, confirm the power supply is correct, as described in Section-2.0, before operating this unit. A basic understanding of antenna theory and transmission line behavior will be helpful for making the best use of the data provided by your MFJ-259D. The ARRL Handbook and ARRL Antenna Book provide concise peer-reviewed... -
Page 9: General Connection Guidelines
Antenna SWR Use the SO-239 Antenna connector located on top of the MFJ-259B for all RF measurements (except those using the Frequency Counter mode). Follow the procedure below for measuring SWR: 1.) If your antenna doesn't have a dc-grounded feed system, momentarily short the cable's center conductor to the shield immediately before connecting it to the analyzer. - Page 10 MFJ-259D Instruction Manual HF/VHF SWR Analyzer Antenna hints: 1.) Measuring Antenna Impedance: For complex impedance measurements, you must install the analyzer as close as possible to the element's feed point (within or 1-2 degrees of phase shift) or use a precisely cut 1/2- wavelength of cable displace the calibration plane by a controlled amount (360-degree phase rotation).
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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-259D 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. Capacitance... -
Page 12: Inductance
The lower line shows the Inductance in uH. Inductance is calculated using the measured Reactance (XL) and the VFO frequency. The MFJ-259D will become inaccurate when measuring reactance below 7 ohms or above 650 ohms. If component reactance falls into an inaccurate range, L(X<7) L(X=0) or L(Z>650) will be displayed. No inductance value is displayed if the range is questionable. -
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-259D 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-259D 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: Distance To Fault 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-259D on internal batteries and keep it at least a few feet away from earth and other conductors. -
Page 16: Percentage Transmitted Power
MFJ-259D Instruction Manual HF/VHF SWR Analyzer and Reactance (X). Resonance Mode functions exactly the same as in the analyzer's basic SWR mode, except the analog impedance meter measures Reactance rather than impedance magnitude. This feature allows the operator to more easily observe frequencies where system reactance crosses zero. When Reactance equals zero (X=0), all capacitive and inductive components at the load are cancelled out (XL+Xc=0) and the circuit is said to be Resonant. -
Page 17: Verticals
MFJ-259C Instruction Manual HF/VHF SWR Analyzer result from other installation errors such as running the feedline parallel rather than perpendicular to the radiating element. Repositioning the feedline may reduce unwanted inductive coupling. Verticals Verticals in the "monopole" class require a ground plane. To simplify installation and cut costs, manufacturers sometimes (incorrectly) downplay the importance of an effective radial system. -
Page 18: Velocity Factor Of Transmission Lines
MFJ-259D Instruction Manual HF/VHF SWR Analyzer Antenna connector center pin. The DUT must be suspended and kept away from metallic objects and ground. When tuning frequency-critical stubs, trim them gradually using the method outlined below: 1.) Determine the DUT's target frequency and calculate the length to formula. -
Page 19: Impedance Of Transmission Lines Or Beverage Antennas
MFJ-259C Instruction Manual HF/VHF SWR Analyzer 4.) Tap Gate again, and the display will show electrical distance in feet. 5.) Using a tape measure, find the physical length of the DUT in feet. 6.) Divide your physical length measurement by the electrical length to calculate Vf. -
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-259D 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-259D. -
Page 21: Testing Rf Transformers
Testing RF Transformers The MFJ-259D 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: Technical Assistance
TECHNICAL ASSISTANCE If you have any problem with your MFJ-259D, 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: Full 12-Month Warranty
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.
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