MFJ Instruction Manual. HF/VHF SWR Analyzer. 1. MFJ HF/VHF SWR ANALYZER. INTRODUCTION. The MFJ SWR Analyzer is an easy to operate . Downloaded by. Page 2. Page 3. Page 4. Page 5. Page 6. Page 7. Page 8. Page 9. Page Page Page Page Page Page MFJ Instruction Manual. HF/VHF/UHF SWR Analyzer. MFJ SWR HF/ VHF ANALYZER. TABLE OF CONTENTS. Warning: READ SECTION BEFORE.
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I reviewed, modified, mfj 259b manual edited that work. It is best to calibrate at typical lower expected battery voltage. Inductors L5 and L6 are located on the component side of the board and are compression-tuned press turns closer together to lower frequency or spread apart to raise frequency. Loads most sensitive to harmonic-induced errors include, but are not limited to, antenna tuners, tank circuits, very short resonant antennas, and distance to mfj 259b manual and stub length measurements.
This page is the most current result. This particular adjustment should be made at the lowest expected operating voltage.
I am not aware of any other source that gives correct calibration procedures. Measurement mfj 259b manual in mfj 259b manual and cable lengths will occur if the harmonic null is not adjusted correctly in the B or ! Dead spots generally indicate a defective tuning capacitor TUNE. Excessive mfj 259b manual can cause severe errors in measurement of frequency-selective loads, even when dummy-load SWR tests appear perfect.
See details for description of any imperfections. The analog meters suffer from some scale-linearity problems, so they will be somewhat less accurate than the digital display in a perfectly calibrated unit. This is accomplished by setting the analyzer to mid-HF, generally around 15 MHz. The best place to spray the switch is from the front side shaft sideright below the nut. I think this occurred sometime aroundbut was later corrected.
MFJB Analyzer Mini-Manual
This is absolutely wrong. Since the loads are used to set the number of bits in critical calculations, the maximum reactance error will always be worse than the percentage of resistive load error. Bias is adjusted for minimum harmonic content, consistent with second harmonic being at least 25 to 30 dB below fundamental. Together, the low-bit and high-bit adjustments compensate diode linearity, making detector system output voltages closely track actual RF voltages mfj 259b manual across bridge resistors.
Note that Mfj 259b manual are slug-tuned and require an insulated hex-head tuning wand.
MFJ antenna analyzer calibration, problems, and service warnings
This unit has tracking and gain adjustments for Vz, Vs, and Vr. It is acceptable to parallel multiple resistors to obtain uncommon resistances, but don’t series connect more than two resistors! To prepare for detector tracking alignment, place the analyzer in Test Mode. For initial adjustments, if the unit has never mfj 259b manual aligned, start here. Three or four series diodes will reduce voltage below 12 volts. This adjustment directly affects output signal mfj 259b manual content.
Otherwise, skip down to the next break.
Some MFJ manuals were re-written and distance-to-fault measurement procedure errors were introduced. The best solution is to use a single-stage bandpass filter and dc isolation on large arrays or with long feed lines. Only precision terminations should be used in the VHF region. This work is all donated. Detector system gain is set at high detector voltages or high-bits, by R53 extreme SWRR72 Vz high load voltage mfj 259b manualand R73 Vs low load impedance, high-Vs series bits.
Hopefully someday a higher cost-design with selective detectors will become available, but for right now this is mfj 259b manual that is available for amateur use from any manufacturer. Since it mfj 259b manual designed to be inexpensive and simple, and since the design is aging now, there are a few pitfalls with this system.
You must remove the switch indexing tab retainer nut and the metal switch retainer stop under the nut. They have different features. These meter adjustments do not affect the digital display, but digital detector adjustments mfj 259b manual affect analog impedance meter readings. This means the diodes, through necessity, must be low-power zero-bias Schottky microwave detector diodes.
Watch for missing or loose hardware.
Proper alignment requires a This is true for ANY antenna analyzer, since you do not want the mfj 259b manual to measure the load at two frequencies! The MFJB does not correct for connector impedance bumps, or correct for the electrical length between an external load and the detectors inside the unit. Never apply external voltages greater than 3 volts to the antenna port! The unit will appear to calibrate correctly, but will produce errors in stub mfj 259b manual, distance-to-fault, and other frequency-selective or resonance functions.
Starting from the highest frequency band, check each band as follows:. There are multiple reasons why, at the time of design, these units were dc coupled with broadband detectors. Harmonics are worse with low supply voltages, and with low impedance loads. They mfj 259b manual the most easily damaged devices in the analyzer. Observe the analyzer frequency reading.
A calibrated spectrum analyzer works best for monitoring harmonic output, but a well-shielded general-coverage receiver with signal-level mfj 259b manual will also work. This is the approximate resonant frequency of the stub.
MFJ-259B HF/VHF SWR Analyzer Instruction Manual
This mfj 259b manual provides access to trim-pots and most inductor adjustments. This type of analyzer contains an RF oscillator, a very linear amplifier to increase power, and an internal resistor bridge in a modified Whetstone bridge configuration. Using this, it is possible to calibrate the B with higher values of load resistance. Never calibrate around a sudden “problem” that appears.