MFJ -259 Instruction Manual
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MFJ -259 Instruction Manual

Hf/vhf swr analyzer
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Introduction................................................................................................................. 1
Powering The MFJ-259 .............................................................................................. 2
Battery Installation ...................................................................................................... 2
Operation Of The MFJ-259 ........................................................................................ 3
SWR and the MFJ-259 ................................................................................... 3
Measuring SWR.............................................................................................. 4
Resistance Meter............................................................................................. 5
Frequency Counter.......................................................................................... 5
Adjusting Simple Antennas ........................................................................................ 7
Dipoles ............................................................................................................ 7
Verticals .......................................................................................................... 7
Tuning an Antenna.......................................................................................... 7
Measuring the Feedpoint Resistance of Antennas .......................................... 8
Finding a Short Circuit in Coax Cables ...................................................................... 8
Testing and Tuning Stubs and Transmission Lines .................................................... 8
Velocity Factor of Transmission Lines ........................................................... 9
Impedance of Transmission Lines .................................................................. 10
Estimating transmission line loss.................................................................... 10
Adjusting Tuners......................................................................................................... 11
Adjusting Amplifier Matching Networks ................................................................... 12
Testing RF Transformers ............................................................................................ 12
Testing Baluns ................................................................................................ 12
Measuring Inductance and Capacitance...................................................................... 13
Measure capacitance. ...................................................................................... 13
Measure inductance. ....................................................................................... 14
Resonant Frequency of tuned circuits ......................................................................... 14
Testing RF Chokes.......................................................................................... 15
Technical Assistance................................................................................................... 16
MFJ-259 Parts List...................................................................................................... 16

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  • Page 1: Table Of Contents

    TABLE OF CONTENTS Introduction......................... 1 Powering The MFJ-259 ....................2 Battery Installation ...................... 2 Operation Of The MFJ-259 ..................3 SWR and the MFJ-259 ................... 3 Measuring SWR....................4 Resistance Meter..................... 5 Frequency Counter..................5 Adjusting Simple Antennas ..................7 Dipoles ......................

  • Page 2: Introduction

    Self resonance, series resonance, value Transmitters and oscillators: Frequency The MFJ-259 is also portable. It can be used with either an external low voltage supply, such the MFJ-1312B AC adapter or with internal AA battery packs. WARNING: Please read this manual thoroughly before using this instrument. Failure to follow the operating instructions may cause false readings or even damage this unit.

  • Page 3: Powering The Mfj-259

    MFJ-1312B, is available from MFJ. The MFJ-259 has a standard 2.1 mm coaxial type jack on the top right edge of the case. This jack is labeled "12VDC" and has the word "POWER" near it. A pictorial polarity marking appears on the case near the power jack.

  • Page 4: Operation Of The Mfj-259

    "ANTENNA" connector will give an SWR reading of 3:1 . The MFJ-259 measures the actual SWR. The load must be 50 ohms of pure resistance for a meter reading of 1:1 . The common misconception that 25 ohms of reactance and 25 ohms of resistance in a load will give a 1:1 SWR is absolutely untrue.

  • Page 5: Measuring Swr

    Measuring SWR The MFJ-259 will measure the impedance ratio (SWR) of any load referenced to 50 ohms. The SWR can be measured on any frequency from 1.8 to 170 MHz. No other devices are required.

  • Page 6: Resistance Meter

    If a short jumper is placed from the center of the SO-239 connector to the center of the BNC connector, the output of the MFJ-259 oscillator will be displayed on the counter readout. The frequency displayed will be the same on both Channel A and Channel B, while the jumper is in place.
  • Page 7 MFJ-259 Instruction Manual HF/VHF SWR Analyzer severely damaged. A coupling loop is useful for directing RF at a reduced level into the counter. A coil of wire, or even a straight piece of wire attached to the BNC connector may be sufficient for operation.

  • Page 8: Adjusting Simple Antennas

    Tuning basic antennas fed with 50 ohm coaxial cable can be accomplished with the following steps: 1. Connect the feedline to the MFJ-259. 2. Adjust the MFJ-259 until the SWR reaches the lowest reading. 3. Read the frequency display. 4. Divide the measured frequency by the desired frequency.

  • Page 9: Measuring The Feedpoint Resistance Of Antennas

    50 ohms. FINDING A SHORT CIRCUIT IN COAX CABLES The MFJ-259 is very effective in locating a short circuit in coax cables. The method is as follows: 1. Connect one end of the cable to the MFJ-259 input.

  • Page 10: Velocity Factor Of Transmission Lines

    ( like 1, 1-1/2, etc.) Connect the PL-259 to the "ANTENNA" connector of the MFJ-259 and adjust the line or stub by the following method. For critical stubs you may want to gradually trim the stub to frequency.

  • Page 11: Impedance Of Transmission Lines

    Estimating Transmission Line Loss The loss of 50 ohm feedlines (between 3 and 10 dB) can be measured with the MFJ-259. It is a simple matter to find the loss at a known frequency and then estimate the loss at a lower frequency.

  • Page 12: Adjusting Tuners

    2dB at 28MHz. ADJUSTING TUNERS The MFJ-259 can be used to adjust tuners. Connect the MFJ-259 "ANTENNA" connector to the tuner's 50 ohm input and the desired antenna to the normal tuner output. This connection can be made with a manual RF switch to facilitate rapid changeover.

  • Page 13: Adjusting Amplifier Matching Networks

    HF/VHF SWR Analyzer ADJUSTING AMPLIFIER MATCHING NETWORKS The MFJ-259 can be used to test and adjust RF amplifiers or other matching networks without applying operating voltages. The tubes and other components should be left in position and connected so that stray capacitance is unchanged.

  • Page 14: Measuring Inductance And Capacitance

    MEASURING INDUCTANCE AND CAPACITANCE To measure capacitance or inductance you will need some standard value capacitors and inductors. These should be collected and tested for accuracy. MFJ suggests the following sets of values: Inductors: 330µH, 56 µH, 5.6 µH, .47 µH Capacitors: 10 pF, 150 pF, 1000 pF, 3300 pF Readings will be the most accurate if the standard test values used are between 0.5 µH to 500...

  • Page 15: Measure Inductance

    F = MHz C = pF RESONANT FREQUENCY OF TUNED CIRCUITS The MFJ-259 can be used to measure the resonant frequency of tuned circuits by two methods. The first method involves placing a 50 ohm resistor in series with the MFJ-259 "ANTENNA"...

  • Page 16: Testing Rf Chokes

    This magnetically couples the MFJ-259 to the resonant circuit. The frequency of the MFJ-259 is adjusted for a dip on the "SWR" meter. The dip occurs at the approximate resonant frequency of the tuned circuit.

  • Page 17: Technical Assistance

    You will be best helped if you have your unit, manual and all information on your station handy so you can answer any questions the technicians may ask. You can also send questions by mail to MFJ Enterprises, Inc., 300 Industrial Park Road, Starkville, MS 39759; by FAX to 601-323-6551; or by email to techinfo@mfjenterprises.com.
  • Page 18 MFJ-259 Instruction Manual HF/VHF SWR Analyzer Designator Description Part Number Jack, 2.1 mm, DC Coaxial Jack 601-6021 Connector, BNC, Chassis Mt. Female, UG-652/U 610-1016 JMP1-JMP3 Wire, Jumper, 1/4"-2" 870-5000 402-3412 Inductor, Var, 66 µH 402-3406 Inductor, Xformer, 1 7.8 µH Inductor, Xformer, 1.8 µH...

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