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.
|Published (Last):||15 December 2006|
|PDF File Size:||14.6 Mb|
|ePub File Size:||11.12 Mb|
|Price:||Free* [*Free Regsitration Required]|
Harmonics are worse with low supply voltages, manuxl with low impedance loads. You should clearly see the MFJ analyzer’s fundamental frequency output voltage Vz go through a deep null. A one-bit error can cause mfj 259b manual resistive load to appear reactive total of Vs and Vz must always be below bits for a load to be considered resistive.
MFJ-259B Analyzer Mini-Manual
It is best to calibrate at typical lower expected battery voltage. Make only very small corrections– mfj 259b manual to L5 or L6 –and recheck the band you are adjusting.
Quiescent current bias in the RF amplifier section is adjustable. The original manual was correct. Mfj 259b manual will roughly indicate total even harmonic voltage, when the mfj 259b manual is set at the stub’s exact resonant frequency. Using the wrong size or worn tuning tool may stress and crack a tuning slug. Proper alignment requires a I use male BNC connectors with the locking sleeve removed, with surface mount resistors. Some MFJ manuals were re-written and distance-to-fault measurement procedure errors were introduced.
This critical sequence calibrates A-D conversion for various load conditions.
Acceptable results will be obtained when load resistors are mounted in the very bottom of a UHF-male connector. Follow these rules the entire time you have the unit apart!
MFJB Analyzer Mini-Manual
Because the detector is broadband and mnaual it is dc coupled to mfj 259b manual antenna, any external voltage across the antenna input port causes measurement errors. Be sure the stop goes back exactly as removed. Without changing the analyzer test frequency setting, observe the second harmonic level. If the holder or leads get shorted, you can melt things. This also why bits must be calibrated for near-perfect accuracy.
Although any calibration pot can affect readings, large reactance errors at impedance extremes commonly occur from improper setting of low-bit adjustments. Since the bridge depends on nulls, any external voltage will throw off readings. The best place to spray the switch is from the front side shaft sidemfj 259b manual below the nut. Small set of non-metallic alignment wands for coils, and small jeweler’s screwdrivers for controls.
Loads most sensitive to harmonic-induced errors include, but are not limited to, antenna tuners, tank circuits, very short resonant antennas, and distance to fault and stub length measurements. Bias mxnual adjusted for minimum harmonic content, consistent with second harmonic being at least 25 to 30 dB below fundamental. Skip to main content. The ideal load resistors are surface-mount precision-resistors, but other styles will work.
Before proceeding, be mankal you have printed a copy of the board layout showing adjustment points, mffj read all this, and have suitable loads. This information is here because mfj 259b manual is the correct way to calibrate the MFJB analyzer. The mfj 259b manual detectors are NOT frequency selective, and mmfj to anything from minor dc offsets through microwave signals.
This reading should be manial with the To enter Test Mode:. I’m not sure if any other errors were introduced in the manual rewrite. Otherwise, skip down to the next break. This causes inaccuracies if any voltage over a few millivolts appears mfj 259b manual the antenna port. Starting from the highest frequency band, check each band as follows:.
MFJ 259B Hf/vhf SWR Analyzer Instruction Manual
The bias adjustment was never intended to be 295b to a fixed voltage at a test point. This harmonic will be at twice the MFJ analyzer frequency counter reading.
This is true for ANY antenna analyzer, since you do not want the analyzer to measure the load at two frequencies! Observe the analyzer frequency reading.
L6 oscillator squeeze-spread tunes from below mfj 259b manual This is absolutely wrong. Hopefully someday a higher cost-design with selective detectors will become available, but for right now this is all that is available for amateur use from any manufacturer. In order for the detectors to be accurate within a fraction of a percent one bitdetector diodes must have very low capacitance and very low threshold voltage.
Measurement errors in stubs and cable lengths will occur if the harmonic null is not adjusted correctly in the B or ! The theory is frequency spacing between impedance minimums, when converted to half wavelengths, is the distance to an open or short. Watch for missing or loose hardware. This particular adjustment should be mfj 259b manual at the lowest expected operating voltage. Mfj 259b manual that L1-L4 are slug-tuned and require an insulated hex-head tuning wand.
If you have a sudden problem, it is most likely a defective detector diode. I successfully find opens mfj 259b manual cuts in my trunk cables, some cables are feet long, within a few feet.