MFJ MFJ-269D User manual

MFJ-269D Instruction Manual LF/HF/VHF/UHF SWR Analyz r
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TABLE OF CONTENTS
1.0 INTRODUCTION 2
1.1 TYPICAL USE 2
1.2 FREQUENCY RANGE 3
1.3 ACCURACY NOTES 3
2.0 POWER SOURCES 4
2.1 EXTERNAL POWER SUPPLY 4
2.2 INTERNAL BATTERIES 5
2.3 RECHARGEABLE BATTERIES 5
2.4 USING CONVENTIONAL “AA” DRY CELL BATTERIES 5
2.5 “VOLTAGE LOW” DISPLAY WARNING 6
2.6 SLEEP MODE “POWER SAVING” 6
3.0 MAIN MENU AND DISPLAY 6
3.1 GENERAL CONNECTIONS 6
3.2 POWER UP DISPLAY 7
3.3 MAIN MEASUREMENT MODES (LF/HF/VHF, 0.10 230 MHZ) 7
3.4 FREQUENCY CONTROL 8
4.0 MAIN (OR OPENING) MODE 9
4.1 GENERAL CONNECTIONS 9
4.2 ANTENNA SWR AND IMPEDANCE 9
4.3 COAX LOSS (FUNCTION 2) 11
4.4 CAPACITANCE (FUNCTION 3) 12
4.5 INDUCTANCE (FUNCTION 4) 13
4.6 FREQUENCY COUNTER (FUNCTION 5) 14
5.0 ADVANCED OPERATION 14
5.1 FORWARD 14
5.2 ACCESSING ADVANCED MODES 14
5.3 GENERAL CONNECTIONS 15
5.4 ADVANCED 1 MODES 16
5.5 ADVANCED 2 MODES 21
5.6 ADVANCED 3 (LF/HF/VHF ONLY) 26
6.0 ADJUSTING SIMPLE ANTENNAS 27
6.1 DIPOLES 27
6.2 VERTICALS 28
6.3 TUNING A SIMPLE ANTENNA 28

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7.0 TESTING AND TUNING STUBS AND TRANSMISSION LINES 28
7.1 TESTING STUBS 28
7.2 VELOCITY FACTOR OF TRANSMISSION LINES 29
7.3 IMPEDANCE OF TRANSMISSION LINES OR BEVERAGE ANTENNAS 30
7.4 ADJUSTING TUNERS 30
7.5 ADJUSTING AMPLIFIER MATCHING NETWORKS 31
7.6 TESTING RF TRANSFORMERS 31
7.7 TESTING BALUNS 31
7.8 TESTING RF CHOKES 32
8.0 TECHNICAL ASSISTANCE 33
FULL 12 MONTH WARRANTY 34
Attention: Read section 2.0 before attempting to use this product.
Incorrect power supply voltages or excessive external voltages
applied to the AN ENNA connector will damage this unit.

MFJ-269D Instruction Manual LF/HF/VHF/UHF SWR Analyz r
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1.0 IN RODUC ION
The MFJ-269D is a compact battery powered RF impedance analyzer. It combines ive basic circuits; a
variable oscillator, requency counter, requency multiplier, 50-ohm RF bridge, twelve-bit A-D converter,
and a microcontroller. Together, these circuits per orm a wide variety o use ul antenna and RF
impedance measurements including coaxial cable loss and electrical distance to an open or short.
Although mainly designed or analyzing 50-ohm antenna and transmission line systems, the MFJ-269D
also measures RF impedance rom a ew ohms to several hundred ohms. An easy-to-access user-
controlled Zo setting in the Advanced unction menus acilitates changing SWR and other SWR
unctions (i.e. return loss, re lection coe icient, match e iciency, etc) to any normalized impedance
value between 5 and 600 ohms. The MFJ-269D also unctions as a non-precision signal source and
requency counter. Operating requency extends rom 0.10 to 230 MHz in nine overlapping bands with
extended SWR measurement rom 415 to 470 MHz.
1.1 Typical Use
The MFJ 269D may be used to adjust, test, or measure the following:
Antennas: ...................................SWR, impedance, reactance, resistance, resonant requency, and
bandwidth
Antenna tuners:..........................SWR, bandwidth, requency
Ampli iers:.................................Input and output matching networks, chokes, suppressors, traps, and
components
Coaxial transmission lines:........SWR, length, velocity actor, approximate Q and loss, resonant
requency, and impedance
Filters: ........................................SWR, attenuation, and requency range
Matching or tuning stubs: ..........SWR, approximate Q, resonant requency, bandwidth, impedance
Traps: .........................................Resonant requency and approximate Q
Tuned Circuits: ..........................Resonant requency and approximate Q
Small capacitors:........................Value and sel -resonant requency
RF chokes and inductors:...........Sel -resonant requency, series resonance, and value
Transmitters and oscillators:......Frequency
The MFJ 269D measures and directly displays the following:
Electrical length ( eet or deg) Impedance phase angle(degrees) Resonance (MHz)
Feedline Loss (dB) Inductance (µH) Return loss (dB)
Capacitance (pF) Reactance or X (ohms) Signal Frequency (MHz)
Impedance or Z magnitude (ohms) Resistance or R (ohms) SWR (Zo programmable)
The MFJ 269D is also useful as a non precision signal source. It provides a relatively pure
(harmonics better than -25 dBc) signal o approximately 3 Vpp (~20 mW) into a 50 ohm load. The
internal source impedance is 50 ohms. Although not "stabilized", it provides adequate stability or non-
critical applications such as alignment o broad-bandwidth ilters and circuits.

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Note: For a more complete description o eatures and test methods, consult the table o contents to ind
the manual sections describing the particular measurement you wish to make.
1.2 Frequency Range
The unit's dual-range Frequency switches select the ollowing oscillator bands with a small overlap:
0.10-0.16 MHz 2.1-4.7 MHz 67-113 MHz
0.26-0.52 MHz 4.7-10.9 MHz 113-155 MHz/UHF LO*
0.52-1.02 MHz 10.9-28 MHz 155-230 MHz/UHF HI*
1.02-2.1 MHz 28-67 MHz
*A UHF pushbutton switch located above the LCD display activates 415-470 MHz SWR coverage. See
section 3.4 or VFO operating speci ics.
1.3 Accuracy No es
I measurement errors occur, they will likely be caused by one o the ollowing conditions:
1. Signal ingress rom external sources, usually rom a strong AM broadcast station.
2. Diode detector and A/D converter error.
3. Stray impedance errors contributed by connectors, cables, and adapters.
Broad band Voltage Detectors and External Interference: Laboratory grade network analyzers use
expensive high-selectivity gain-stabilized receivers to avoid o - requency inter erence and ensure
measurement accuracy. Building these sophisticated detectors into the MFJ-269D (or any small handheld
unit) would drive the price ar beyond the reach o most hobbyists. As an alternative, we use broadband
detectors that provide accurate measurements at a much lower cost. The only drawback is that broadband
detectors can be sensitive to power ul out-o -band signals. Most o the time, out-o -band inter erence isn't
an issue, but occasionally a particularly power ul signal may be picked up by the antenna under test and
routed into the analyzer bridge circuit where it con licts with the internally generated VFO signal. When
strong "signal ingress" such as this occurs, it may result in inaccurate readings.
The solution or out-o -band inter erence isn't simple. Increasing the analyzer's generator power would
help, but doing so causes the unit to draw signi icantly more power at the expense o reduced battery
operating time. Higher power may also cause on-air inter erence when testing antenna systems that
radiate e iciently or exhibit directivity gain. Using common low-pass or band-pass ilters similar to those
used in transceivers also wouldn't work because they behave like transmission lines o varying
impedance on di erent requencies. Using them would only introduce gross measurement inaccuracies.
MFJ 731: Fortunately, most analyzer inter erence problems occur on the lower requencies, with near-by
high power AM broadcast signals being the worst o ender. When testing physically large antenna arrays
such as 160-meter verticals, these power ul outside signals may couple very e iciently into the analyzer's
bridge circuit. Other strong local signals may "get in" as well. To correct the problem, we o er the MFJ-
731 tunable ilter, an accessory especially designed to attenuate o - requency signals. The MFJ-731
permits accurate impedance measurements between 1.8 and 30 MHz with virtually no impact on
measurement accuracy.
Detector Errors: At low voltages, detector diodes become non-linear. To address this issue, the MFJ-
269D uses special microwave zero-bias Schottky detectors with matched compensating diodes. Each unit

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is individually compensated to provide the best detector linearity possible. Small errors may also occur
during A/D conversion due to practical limitations on bit resolution.
Connection lengths: Connection lengths both inside and outside the analyzer bridge can upset readings,
especially at higher requencies and when impedance is very high or very low. The MFJ-269D minimizes
internal problems by using sur ace mount low capacitance microwave components with nearly zero lead
length. It's important to remember that any external leads you add, even short leads, will modi y the
impedance o the load at radio requencies. To obtain highest accuracy, always use the shortest test
cables possible with the ewest connectors and adapters in the line.
Note: Some handheld analyzers display erroneous readings alling outside the reliable measurement
range, presenting that data numerically -- as i it were " actual". The MFJ-269D is designed to avoid such
errors by displaying an on-screen warning (Z > 1500) anytime data alls outside the unit's accurate
measurement range.
2.0 POWER SOURCES
This section describes power supply and battery selection.
READ THIS SECTION BEFORE CONNECTING THIS DEVICE TO ANY POWER SOURCE. IMPROPER
CONNECTIONS OR INCORRECT VOLTAGES MAY CAUSE DAMAGE TO THIS PRODUCT!
2.1 Ex ernal Power Supply
The MFJ-1312D satisfies all external voltage and current power source require ents and we highly
reco end using it with your MFJ-269D. External power require ents are as follows:
1. When the unit is ON, supply voltage must be over 11 volts but not exceeding 16 volts.
2. When in Sleep Mode or OFF (supply lightly loaded), voltage ust not exceed 18 volts.
3. The supply must be well filtered against hum and noise.
4. The MFJ 269D case (chassis ground) must be connected directly to the supply's negative terminal.
5. The supply ust not have a grounded positive lead (- center pin).
6. The "ideal" supply voltage is 13.8 volts dc.
7. When rechargeable batteries are used, 14 volts or higher is required for charger operation.
8. Current demand is 150 A (max) on HF and VHF, 250 A (max) on UHF.
WARNING: READ SECTION 2.2 THROUGH 2.4 (BATTERY INSTALLATION INSTRUCTIONS)
BEFORE INSTALLING BATTERIES.
The MFJ-269D has a recessed 2.1 mm power receptacle near the RF connectors. This receptacle is
labeled POWER 13.8 VDC. The outside conductor is negative, the center is positive. Inserting a
power plug in the POWER 13.8 VDC receptacle disables internal batteries as the analyzer's power
source. However, the internal batteries will still be trickle charged when the power supply plug is
inserted into the unit. Power plugs must be wired as shown below:
+
-
+
-
2.1 mm

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WARNING: REVERSE POLARITY OR EXCESSIVE VOLTAGE CAN DAMAGE OR DESTROY THE
MFJ 269D. NEVER APPLY MORE THAN 18 VOLTS, NEVER USE AC OR POSITIVE
GROUND SUPPLIES! NEVER ADD OR REMOVE BATTERIES WITH AN EXTERNAL
POWER SUPPLY CONNECTED TO THIS UNIT, OR WITH THE POWER SWITCH ON.
2.2 In ernal Ba eries
When installing internal batteries, first check the position of a small black-plastic internal jumper plug
that controls charger operation. The jumper is located inside the unit at the top of the printed circuit
board near the area of the OFF-O switch and power connector. To access it, remove all eight screws
on the sides o the case and remove the back cover. The black plastic jumper its over two o three
adjacent pins (see detailed instructions below). The plug must be properly positioned or the type o cell
you plan to use (AA rechargeable or AA non-rechargeable).
2.3 Rechargeable Ba eries
I portant Note: When using rechargeable batteries, your external power source must deliver at least 14
volts. I supply voltage is too low, the charger can't unction and batteries will eventually discharge. I
batteries are depleted, charge with the analyzer power switch turned o -- it may take ten hours or more
to ully restore depleted cells.
I portant Warning: ever change batteries with the power switch "On" or with an external supply
plugged in -- permanent damage may result. Always remove batteries when shipping the analyzer or
storing it for an extended period (more than a month).
When using rechargeable batteries, the internal black plastic jumper must be set to the proper position.
Remove the analyzer cover and locate the jumper on the pc board (near the power jack). Con irm that it
is set correctly. I not, reposition as shown below:
Again, when the Charger Jumper is ON and a 13.8 to 18 volt source is applied, the charger will be
unctional. Typical charging current is 10-20 mA.
2.4 Using Conven ional “AA” Dry Cell Ba eries
When using non-reachable batteries, install only high quality alkaline cells in matched sets (same
manu acturer and date code). Conventional zinc-based cells have a shorter shel and service li e, and they
are also more prone to leakage. Also, to prevent leakage, remove weak alkaline batteries immediately.
WARNING: WHEN USING NON RECHARGEABLE BATTERIES, THE CHARGING SYSTEM MUST
BE DEFEATED! IF YOU FAIL TO FOLLOW THIS WARNING, THE BATTERIES WILL
LIKELY LEAK AND RUIN THE ANALYZER!
When using non-rechargeable batteries, set the internal jumper as shown below:

MFJ-269D Instruction Manual LF/HF/VHF/UHF SWR Analyz r
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Never attempt to charge alkaline (or any other non-rechargeable cells) using the MFJ-269D's internal
charger circuit!
2.5 “Vol age Low” display warning
When the analyzer's supply or battery voltage drops below 11 volts, a blinking Voltage Low warning
will be displayed. Pressing Mode during a low-voltage warning will disable the on-screen alert and allow
you to continue operating. However, measurements may not be reliable when operating the analyzer with
insu icient supply voltage!
2.6 Sleep Mode “Power Saving”
Typical current drain or the MFJ-269D is around 150 mA or HF operation (250 mA or UHF). Battery
operating time is (by de ault) extended signi icantly through the use o Sleep Mode. Sleep mode reduces
current drain to less than 15 mA when it is engaged during periods o non-activity. Power-saving is a
de ault setting or the MFJ-269D unless you defeat it when you turn on the analyzer (instructions below).
Normally, the analyzer's processor looks or manual activation o the Mode switch or or any change in
Frequency greater than 50 kHz. I neither event occurs during any given three-minute interval, Sleep
mode automatically kicks in and places the analyzer in standby. A blinking SLP message in the display
screen lower-right corner indicates power-saving mode (see below):
To pull the unit out o SLP, momentarily press either the Mode or Gate button to resume operation.
To disable Sleep, irst turn the unit Off and then press and hold the Mode button when reapplying
power. Continue holding Mode until a ter the copyright message appears on the LCD screen, then
release. I the “Power Saving” mode has been is success ully disabled, the message shown below will
appear as soon as Mode is released.
Sleep Mode is a de ault unction and will reset automatically each time the analyzer is turned OFF. To
restore Sleep, simply turn the analyzer Off and then On again.
3.0 MAIN MENU AND DISPLAY
WARNING: NEVER APPLY RF OR ANY OTHER EXTERNAL VOLTAGE TO THE ANTENNA PORT.
THE MFJ 269D USES ZERO BIAS DETECTOR DIODES THAT MAY BE DAMAGED BY
EXTERNAL VOLTAGES. ALSO, READ SECTION 2.0 BEFORE APPLYING POWER.
INCORRECT SUPPLY VOLTAGE OR REVERSED POLARITY CAN CAUSE DAMAGE.
3.1 General Connec ions
The N- emale Antenna connector on top o the unit is the primary RF-measurement connection. It is
used or all unctions except requency counter measurements.
The Power connector (2.1 mm) is described in section 2.0. Please read the power-source section
care ully be ore attempting to operate the analyzer! Improper voltage application, the wrong battery
charger setting, or reversed polarity could permanently damage your unit.

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The BNC Frequency Counter Input is or requency counter measurements only. See section 4.5 or
the counter's operating instructions.
3.2 Power-up Display
I portant Note: Be ore powering up the analyzer, check the status o the UHF switch located above the
LCD window on the le t. This switch must be in the "up" or in the Off position unless UHF operation is
intended.
Note: The ollowing is a description o the basic opening (or de ault) menu used by the MFJ-269D.
Your analyzer also has an advanced user section (5.0).
When applying Power, a sequence o message screens appear on the LCD display. The irst screen lists
the so tware version (Ver): Be sure to have this number handy when re erring technical questions about
your analyzer to MFJ Customer Service:
The second message shows the so tware copyright date:
The third message is a voltage check. It displays the operating voltage, indicating battery condition or
the voltage o your external power supply.
The ourth and inal screen is the irst "working display" (Complex Impedance). The two analog panel
meters also activate when the working display comes up.
3.3 Main Measuremen Modes (LF/HF/VHF, 0.10-230 MHz)
Momentarily pressing (or tapping) the Mode button a ter the irst working display appears allows you to
scroll through all ive basic measurement modes provided by the MFJ-269D. The opening mode is
Impedance R & X (resistance and reactance). As each new mode comes up, its title screen appears or
about two seconds, and then the companion data screen appears. Each o the ive Basic Modes are listed
below:
1. Impedance R&X: This is the analyzer's "de ault mode", and it is the unction most commonly used.
The top line o the data screen displays Frequency in MHz and SWR, while the bottom line shows
complex impedance where Rs equals the load's series resistive component and Xs shows the load's series
reactive component. In this unction, the analog SWR and Impedance Meters (Z) are also activeated.
2. Coax Loss: Pressing Mode once brings up the Coax Loss ollowed by the data screen. The top line
shows Frequency in MHz and the bottom line displays Coax Loss in dB.
3. Capacitance in pF: The third mode displays Frequency in MHZ on the top line, ollowed by Xc
(capacitive reactance) on the bottom line. The analog meter also shows reactance X.
MFJ Enterprises
(c) 2014
MFJ-269D
Ver 14.14

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4. Inductance in µH: The ourth mode, Frequency appears on top and XL (inductive reactance) on the
bottom. Meter shows reactance (X).
5. Freq. Counter: The i th unction turns o the analyzer's internal oscillator and routes the input o the
counter to the BNC connector labeled Frequency Counter Input. In this mode, the top line o the LCD
display shows the measured Frequency in MHz and the counter's Gate Time in seconds.
I portant Note: Section-4 o this manual provides detailed instructions or using each o the ive basic
operating modes described above. To ensure accurate measurement and avoid the possibility o
inadvertent damage, please read through this section care ully be ore operating the analyzer!
3.4 Frequency Con rol
The MFJ-269D tunable RF-oscillator covers an exceptionally wide requency span, using two rotary
band switches or LF/HF/VHF coverage (0.10-230 MHz) -- plus an additional pushbutton switch to
activate UHF coverage (415-470 MHz) .
1. LF, HF and VHF Operation: The Lower Range rotary switch selects our LF and HF bands (0.10-
11.0 MHz). The Upper Range switch selects 5 HF and VHF bands or 11-230 MHz coverage. Note that
the Upper Range switch must be set fully clockwise to the Lower Range position or the lower-range
band selector to unction. The variable Tune control (VFO capacitor) provides a small overlap at each
band edge to ensure gap- ree tuning across the spectrum.
2. UHF Operation: UHF coverage is broken into two bands. To measure UHF SWR (415-490 MHz),
irst press in the UHF switch located just above the LCD display. Then, or 415 470 MHz coverage, set
the upper Frequency MHz switch to the 113 155 MHz band (UHF LO). For 470 490 MHz coverage,
set the upper Frequency MHz switch to 155 230 MHz. (UHF HI).
It is normal or the VFO's Tune range to exceed the analyzer's usable UHF measurement range. I the
VFO requency is out o range in UHF Mode, one o the error messages shown below will instruct you to
increase or decrease requency to bring it back in range:
Adjust Tune clockwise to increase frequency and counterclockwise to decrease frequency. When in
range, the operating Frequency will appear on the top line o the LCD display -- along with the SWR
reading. The bottom display line becomes an analog SWR bar graph (see below).
445.75 MHz 1.3
I CREASE
FREQUE CY
DECREASE
FREQUE CY