Mfj 269 Instruction Manual

MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer

MFJ-269 SWR HF/VHF ANALYZER

Warning: READ SECTION 2.0 BEFORE ATTEMPTING TO USE THIS PRODUCT!

INTRODUCTION 1.0 DESCRIPTION

MFJ-269 SWR HF/VHF ANALYZER TABLE OF CONTENTS Warning: READ SECTION 2.0 BEFORE ATTEMPING TO USE THIS PRODUCT

1.0 INTRODUCTION DESCRIPTION

1.1 Typical Uses............................................................................. ….2

1.2 Frequency Range.............................................................................3

1.3 A Quick Word About Accuracy.......................................................3.

2.0 POWER SOURCES ................................................................………………………..

2.1 External Power Supply......................................................................4

2.2 Using Internal Batteries…………………………………….…………5

2.2 Using Rechargeable AA Type Batteries………………………………5

2.4 Using conventional AADrycell Batteries.............................................6.

2.5 Blinking “VOLTAGE LOW” display warning………………………..10

2.6 “Power Saving Mode” (Sleep mode)....................................................6

3.0 MAIN MENU AND DISPLAY ………..

3.1 General Connection Guidelines............................................................7

3.2 Power-up Display...............................................................................7.

3.3 Main Mode Descriptions (HF functions Only)......................................8

3.4 UHF Operation………………………………………………………..

4.0 MAIN (or Opening) MODE

4.1 General Connection Guidelines.............................................................10

4.2 HF/VHF Main modes

4.2.1 Antenna sustem SWR............................................11

4.2.2 Coax Loss....................................................13

4.2.3 Capacitance..................................................14

4.2.4 Inductance....................................................15

4.2.5 Frequency Counter.......................................15

4.3 UHF Main modes

4.3.1 Antenna sustem SWR (UHF)...................................

5.0 ADVANCED OPERATION)...........................................……………………………........

5.1 Forward.................................................................................................16

5.2 Accesing Advanced modes …………....................................................17

5.3 General Connection Guidelines.............................................................17

5.4 Advanced 1………………………………………………………………18

5.4.1 HF/VHF Advanced 1

5.4.1.1 Magnitude and Phase of Load Impedance………..18

5.4.1.2 Series Equivalent Impedance …………………….19

5.4.1.3 Paralell Equivalent Impedance……………………19

………………………….……...............................................10.

4.3.2 Coax Loss (UHF)................................................

................................…………………………7

MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer

5.4.1.4 Return Loss and Reflection Coefficient…………..20

5.4.1.5 Resonance Mode………………………………….20

5.4.1.6 Match Efficiency ………………………………..21

5.4.2 UHF Advanced 1………………………………………………….

5.4.2.1 Return Loss and Reflection Coefficient (UHF) …..

5.4.2.2 Match Efficiency (UHF)……………………..

5.5 Advanced 2…………………………………………………………….21

5.5.1 Distance to Fault (DTF) (for HF/VHF only)…………………

5.5.1.1 DTF balanced lines………………………………22

5.5.1.2 DTF Coax lines…………………………………..22

5.5.1.3 DTF Antenna Length……………………………..23

5.5.1.4 DTF measurement procedures…………………….23

5.5.2 Calculator Functions

5.5.2.1 Line Length in degrees……………………………………….

5.5.3.2 Line length in feet …………………………………………….

5.6 Advanced 3 (for HF/VHF only)…………………

5.6.1 Z Characteristic…………………………………..25

5.6.2 Coax Loss ………………………………………..25

6.0 Adjusting Simple Antennas

7.0 Testing and Tuning Stubs and Transmission Lines

8.0 Technical Assistance

INTRODUCTION

Attention voltages

this unit.

Read section 2.0 before attempt ing to use this product.

or excessive

external voltages applied to the ANTENNA connector

Incorrect power supply

damage

will

1.0 Description

The MFJ-269 RF analyzer is a compact battery powered RF impedance analyzer. This unit combines five basic circuits; a variable oscillator, frequency counter, frequency multiplier, 50 ohm RF bridge, a twelve-bit A-D converter, and microcontroller. This unit performs a wide variety of useful antenna and RF impedance measurements, including coaxial cable loss and electrical distance to an open or short.

Primarily designed for analyzing 50 ohm antenna and transmission line systems, the MFJ-269 also measures RF impedances between a few ohms and several hundred ohms. An easily accessed usercontrolled Zo setting in the functions (i.e. return loss, reflection coefficient, match efficiency, etc) to any normalized impedance value between 5 and 600 ohms.

ADVANCED

function menus allows changing SWR and other SWR

MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer

The MFJ-269 also functions as a non-precision signal source and frequency counter. The operating frequency range of this unit extends from 1.8 to 170 MHz in six overlapping bands, and includes SWR measurements on 415-470 MHz.

1.1 Typical Uses

The MFJ-269 can be used to adjust, test, or measure the following

Antennas:...................................SWR, impedance, reactance, resistance, resonant frequency, and

bandwidth

Antenna tuners:..........................SWR, bandwidth, frequency

Amplifiers:.................................Input and output matching networks, chokes, suppressors, traps, and

components

Coaxial transmission lines:........SWR, length, velocity factor, approximate Q and loss, resonant

frequency, and impedance

Filters:........................................ SWR, attenuation, and frequency range

Matching or tuning stubs:..........SWR, approximate Q, resonant frequency, bandwidth, impedance

Traps:.........................................Resonant frequency and approximate Q

Tuned Circuits:..........................Resonant frequency and approximate Q

Small capacitors: .......................Value and self-resonant frequency

RF chokes and inductors: ..........Self-resonant frequency, series resonance, and value

Transmitters and oscillators: .....Frequency

The MFJ-269 measures and directly displays the following:

Electrical length (feet or deg) Feedline Loss (dB) Capacitance (pF) Impedance or Z magnitude (ohms)

The MFJ-269 is useful as a non-precision signal source.

(harmonics better than -25 dBc) signal of approximately 3 Vpp (approximately 20 milliwatts) into 50 ohm loads. The MFJ-269 internal source impedance is 50 ohms. The MFJ-269 is not a stable generator, but has adequate stability for non-critical applications such as alignment of broad bandwidth filters and circuits.

Note

A more complete description of the MFJ-269's features and proper measurement

methods can be found by reading the sections on the particular measurement you wish to make. Consult the table of contents for the various applications.

Impedance phase angle(degrees) Resonance (MHz) Inductance (µH) Reactance or X (ohms) Resistance or R (ohms)

It provides a relatively pure

Return loss (dB) Signal Frequency (MHz) SWR (Zo programmable)

1.2 Frequency Range

The

FREQUENCY

each range is provided):

1.8 - 4 MHz 27 - 70 MHz 415-470 MHz 4 - 10 MHz 70 - 114 MHz 10 - 27 MHz 114- 170 MHz

switch selects the following internal oscillator frequency ranges. (A small overlap outside

MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer

1.3 A Quick Word about Accuracy

The following text details several common problems and reasons they occur. The most likely source of false readings, when measuring antennas, is unintentional external voltages applied to the antenna port of this unit. An optional HF filter, MFJ-731, greatly reduces external interference without modifying impedance or SWR measurements a significant amount.

Measurement errors.

Unreliable readings are rooted in three primary areas:

1.) Signal ingress from external voltage sources, usually strong AM broadcast stations.

2.) Diode detector and A/D converter errors.

3.) The impedance of connectors, connections, and connecting leads.

Broad-band voltage detectors.

since narrowband detector systems must have at least one selective gainstabilized receiver. Narrowband detectors would price antenna and impedance analyzers far outside the price range of most hobbyists.

Broadband detectors are sensitive to out-of-band external voltages, and solutions to most out-of-band interference are not simple. Common low-pass or

band-pass filters behave like transmission lines of varying impedances on different frequencies. Low-pass or high-pass filters change impedance and SWR readings, just as an additional section of transmission line would. This modification of impedance caused by filters severely limits their usefulness when used with impedance measurement devices.

Most RF interference problems occur on lower frequencies, since high power AM broadcast signals and other external voltage sources couple better into large antennas (especially 160 meter verticals). The MFJ-731 is an adjustable filter that attenuates all off-frequency signals. It also contains an adjustable notch covering the AM broadcast band. Properly used on amateur bands between 1.8 and 30 MHz, this adjustable filter reduces external interference and has almost no effect on system measurements.

Note: A solution often suggested by users is to increase internal generator power. Unfortunately the

power required to operate a low harmonic-distortion broadband VFO system is the single largest drain on the internal batt ery. In this unit, mor e than 70% of the total battery drain (-150 mA) is used to produce the low harmonic-distortion test signal. We have selected the best compromise between battery life and harmonic-distortion.

Component limitations.

269 is enhanced by the use of special microwave zero-bias Schottky detectors with matching compensating diodes. Each unit is individually compensated to provide the best possible detector linearity.

Connection lengths.

impedance is very high or very low. The MFJ-269 minimizes internal problems by using surface mount low capacitance microwave components with nearly zero lead length. Remember any external leads you add, even short leads, modify the impedance of the load at radio frequencies.

At low voltage, detector diodes become very non-linear. The accuracy of the MFJ-

Connection lengths both inside and outside the bridge upset readings, especially when

Narrowband detectors are expensive,

MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer

Note: To obtain greatest accuracy, use the minimum possible length of leads and the f ewest possible

connectors or adapters. Rather than present readings outside the reliable range as exact numbers, the MFJ-269 gives a display warning. If (Z>1500) appears on the display, the impedance is greater than 1500 ohms and outside t he r eliable instrument 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 External Power Supply

MFJ has an optional power supply, the MFJ-1315, that satisfies all external supply requirements. We highly recommend using this supply.

Voltage must be more than 11 volts, and preferably less than 16 volts, when the unit is on and operating. Maximum “sleep mode” and “OFF” voltage (when the power supply is lightly loaded by this unit) is 18 volts. The supply must be reasonably well filtered, the case of the MFJ-269 is connected directly to the negative terminal. The supply must

The MFJ-269 can be used with external low voltage dc supplies (MFJ-1315 AC adapter recommended). The ideal supply voltage is 14.5 volts dc, but the unit will function with voltages between 11 and 18 volts. The current demand is 150 mA maximum on HF and VHF, and 250 mA maximum on UHF).

have a grounded positive lead.

not

WARNING: READ SECTION 2.2 THROUGH 2.4 (BATTERY INSTALLATION

INSTRUCTIONS) BEFORE INSTALLING BATTERIES.

The MFJ-269 has a recessed 2.1 mm power-type receptacle near the RF connectors. This receptacle is labeled

“POWER 12VDC”

The outside conductor of the

Inserting a power plug in the “ Internal batteries, although disabled for operating power by inserting a power supply plug, can still be trickle charged.

POWER

receptacle is negative, the center conductor positive.

POWER 12VDC”

receptacle disables internal batteries as a power source.

WARNING: REVERSE POLARITY OR EXCESSIVE VOLTAGE CAN DAMAGE OR DESTROY

THE MFJ-269. 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.

MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer

2.2 Using Internal Batteries

When batteries are initially installed, a small black-plastic internal jumper must be re-positioned or checked for proper position. The battery setting jumper is located inside the unit at the top of the printed circuit board near the area of the OFF-ON switch and power connector. This jumper is accessed by removing eight screws along the both sides of the MFJ-269. After the cover mounting screws are removed, remove the entire back cover. The black plastic jumper fits over two of three adjacent pins. It must be properly positioned for the type of battery used (either rechargeable or non-rechargeable).

For battery replacement, batteries are accessed by removing the MFJ-269’s cover. Be sure the charger switch is in the correct position when replacing batteries.

2.3 Using Rechargeable “AA” Type Batteries

CAUTION: A

VOID USING EXTERNAL POWER SOURCES HAVING LESS THAN 13 VOLTS IF RECHARGEABLE BATTERIES ARE INSTALLED. IF EXTERNAL SUPPLY VOLTAGE IS TOO LOW, THE CHARGER WILL NOT WORK PROPERLY AND BATTERIES WILL EVENTUALLY DISCHARGE. WE RECOMMEND RECHARGING DISCHARGED BATTERIES WITH THE MFJ-269 POWER SWITCH OFF, WITH ENOUGH CHARGING TIME TO ESTABLISH FULL BATTERY CHARGE (AT LEAST TEN HOURS). NEVER CHANGE BATTERIES WITH THE POWER SWITCH ON, OR WITH AN EXTERNAL SUPPLY PLUGGED INTO THE MFJ-269.

The internal charger trickle can be used to charge internal batteries. The charger functions any time proper external voltage is applied, even when the MFJ-269 is turned off. Proper charger operation requires an external supply operating between 14 to 18 volts. Whenever the external supply is operating between 14-18 volts, the internal trickle charging circuit will operate correctly. Typical battery charging current is 10-20 mA through the internal charging system. The MFJ-1315 supply fulfills all power supply requirements. Batteries should be removed before shipping this unit.

When using rechargeable batteries, the internal black plastic jumper located inside the cover (near the external power jack on the circuit board) must be set to the proper position. If it is not set to the proper position, the batteries will not charge. With rechargeable batteries, the internal charger jumper located on the printed circuit board near the power jack should be set like this:

2.4 Using Conventional “AA” Drycell Batteries

Charger is now ON

batteries can be used with the MFJ-269, but high quality alkaline batteries offer slightly less risk of battery leakage generally provide longer service and shelf life.

If possible, use good quality alkaline batteries. Conventional

MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer

If you use any type of non-rechargeable dry cell battery, removed before storing this unit for extended periods of time (longer than one month). Never ship this unit with batteries installed.

remove weak batteries immediately

. Batteries must be

WARNING: WHEN USING CONVENTIONAL 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 conventional non-rechargeable batteries, the internal jumper located on the printed circuit board near the power jack

must be

set like this:

Charger is now OFF!

2.5 Blinking “VOLTAGE LOW” display warning

a.) If supply or battery operating voltage is less than eleven volts, a blinking “ displayed. Pressing the “ operation with low supply voltage. Readings might not be reliable when operating with supply voltages of under 11 volts.

MODE”

button during a low voltage warning will disable the warning, and allow

VOLTAGE LOW

” warning is

2.6 “Power Saving” Mode (sleep mode)

The operating current drain of the MFJ-269 is approximately 135 mA for HF operation.

Battery life is extended by using an internal "Power Saving” mode. “Sleeping” battery drain is less than 15 mA. If you do not make period, a power saving (Sleep) mode begins. “Sleeping” is indicated by a blinking display’s lower right corner, as shown here:

To wake the unit up, momentarily press the

Disable the “Power Saving” mode by pressing and holding the before the “ after the copyright message appears.

If the “Power Saving” mode is successfully disabled on power up, when the display will momentarily indicate:

POWER”

MODE

switch changes, or change frequency more than 50 kHz during any three minute time

‘‘MODE’’

“MODE”

button on the unit is turned on). You must hold the

‘‘GATE’’

button before power is applied (or

“MODE”

“SLP”

button and only release it

button is released the

message in the

button.

MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer

3.0 MAIN MENU and DISPLAY

WARNING: NEVER APPLY RF OR ANY OTHER EXTERNAL VOLTAGES TO THE ANTENNA

PORT OF THIS UNIT. THIS UNIT USES ZERO BIAS DETECTOR DIODES THAT MAY BE DAMAGED BY EXTERNAL VOLTAGES. READ SECTION 2.0 BEFORE APPLYING POWER TO THIS UNIT! INCORRECT SUPPLY VOLTAGES CAN ALSO DAMAGE THIS UNIT.

3.1 General Connection Guidelines

The

“ANTENNA”

connection. This connector is used for all measurements except frequency counter measurements.

The

“POWER”

this unit. Improper or incorrect power supply voltage or wiring could permanently damage this unit.

The

“FREQUENCY COUNTER INPUT”

of this connector is described in section 4.5.

connector (“N” female) on the top of the MFJ-269 provides the primary RF measurement

connector (2.1 mm type) is described in section 2.0. Be sure to read section 2.0 before operating

connector (BNC type) is for frequency counter use only. Correct use

3.2 Power-up Display

CAUTION: THERE IS A ‘‘UHF’’ SWITCH LOCATED AT THE UPPER LEFT-HAND

SIDE OF THE ANALYZER. THIS SWITCH SHOULD BE PRESSED AND LOCKED FOR UHF OPERATION ONLY WHEN UHF OPERATION IS DESIRED AND ONLY AFTER THE UNIT IS POWERED UP. FOR INFORMATION ON UHF OPERATION, SEE SECTION 3.4

Note

The following is a description of the opening or default menu used by the MFJ-269. This unit

also has an advanced user section in section 4.0.

After turning on the sequence of messages appears on the display.

The first message is a program version, this "VER" number indicates the software version.

"POWER"

switch, or after applying external power with the

“POWER”

switch on, a

MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer

The second message is the software copyright date.

Note

Pressing the continuing to hold the "POWER SAVING OFF" message to appear just as the message appears just before the voltage check. This message confirms the battery saving “sleep mode” has been disabled.

The third message is a voltage check. It displays the operating voltage, indicating battery charge or external power supply voltage.

“MODE”

button before applying power or t urning the

“MODE”

button down until the copyright message appears, causes a

“MODE”

“POWER”

button is released. This

switch on, and

The final power-up display is the “working” display described in 3.3 (Impedance R&X) below.

Two panel meters indicate SWR and Impedance of loads connected to the

If you press the

“MODE”

(or opening) measurement modes are described below.

button, the display will show the type of data measured in the newly selected mode step. The five main

“MODE”

button after the operating display is up, the mode changes. After releasing the

“ANTENNA”

port.

3.3 Main MODE descriptions (HF Functions Only)

CAUTION: THERE IS A ‘‘UHF’’ SWITCH LOCATED AT THE UPPER LEFT-HAND

Mode is changed by momentarily pressing the description of the mode appears on the screen for a few seconds. The five “Main menu” display modes are described below:

The initial power-up mode is

1.)

the front panel display:

Impedance R&X

“MODE”

button during normal operation. As the mode changes, a

. When initialized, the following message appears briefly on

In this mode, the MFJ-269 LCD (liquid crystal display on front panel) shows frequency in MHz, SWR, the resistive part of load impedance (R=), a nd the reactive part of load impedance (X=). T he IMPEDANCE meter displays the complex impedance (Z in ohms), and the SWR meter displays SWR.

MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer

Note: Unless in the advanced modes, this unit displays load impedance in the conventional manner we

are all used to seeing. The standard way we describe impedance is a resistance in series with a reactance.

SWR measurements in this menu are referenced or normalized to 50 ohms Zo., the normal impedance used in transmitting systems.

Note: Advanced mode 3 allows measurement of SWR with lines other than 50 ohms Zo.

2.) Coax Loss

(LCD) indicates the test frequency and approximate loss of any 50 ohm coaxial cable, attenuator pad, or transformer or balun (for differential mode current only). In this mode, the 50 ohm device or cable under test must not be connected or terminated by a load resistance at the far end. If the device under test is terminated in anything that dissipates power, measured loss will be higher than actual loss.

Note: Advanced mode 3 allows measurement of loss in lines other than 50 ohms Zo.

3.) Capacitance in pF

ohms, capacitance (C=) in picofarads or pF. The meter displays SWR.

4.) Inductance in

reactance (Xl=) in ohms, inductance (L=) in microhenries or µH. The ohms, the

5.) Freq. Counter COUNTER INPUT”

from 10 millivolts at 1.7 MHz to 100 millivolts at 180 MHz. The frequency counter. Longer gate times are accompanied by additional digits in the display, increasing counter resolution.

, the second mode, is reached by pressing the

is the third mode. The LCD shows measurement frequency, capacitive reactance (Xc=) in

Impedance

µH is the fourth mode. The digital display indicates measurement frequency, inductive

meter displays SWR.

SWR

is the fifth and final function of the main mode. The BNC connector labeled “

should connect to the RF sample you want to measure. The sensitivity of this port ranges

“MODE”

meter indicates reactance in ohms, and the SWR

button once. The liquid crystal display

Impedance

“GATE”

meter indicates reactance in

FREQUENCY

button controls the gate time of the

14.32 MHz 0.01s Freq. Counter

WARNING: NEVER APPLY MORE THAN TWO VOLTS OF PEAK VOLTAGE, OR ANY DC

VOLTAGE, TO THE FREQUENCY COUNTER BNC PORT.

3.4 UHF Operation

UHF Operation is selected while the frequency adjustment is available by setting the adjusting the range. Typical operating frequency range is 415 to 470 MHz.

“TUNE”

knob. The display will give a warning if the frequency is outside the correct operating

“UHF”

button on the upper left corner is depressed and locked. UHF

“FREQUENCY MHz”

switch to

“114-170 UHF”

position and

MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer

The out-of-range frequency warning displays are:

INCREASE

Be sure the operation. Adjust the

“FREQUENCY MHz”

“TUNE”

control for the correct frequency range.

D E C R E A S E

FR E Q UEN C Y

selector is in the correct extreme counterclockwise position for UHF

4.0 Main (or Opening) mode

Main

CAUTION: THERE IS A ‘‘UHF’’ SWITCH LOCATED AT THE UPPER LEFT-HAND

WARNING:

Never apply RF or any other external voltages to the ANTENNA port of this unit. This unit uses zero bias detector diodes that are easily damaged by external voltages over a few volts. Be sure the power supply is correct, as described in section

2.0, before operating this unit.

A basic understanding of transmission line and antenna behavior and terminology is very important in understanding information provided by the MFJ-269. Most explanations are available in the ARRL Handbooks, and they should suffice for amateur applications. Avoid relying on popular rumor, or unedited, poorly edited, or self-edited handbooks or articles.

4.1 General Connection Guidelines

a.) The connection. This port is used to measure SWR or perform other RF impedance measurements, with the exception of the Frequency Counter mode.

Warning:

b.) Remember to use proper RF connections. Keep leads as short as possible when measuring components or any system or device that is not part of the entire system. When measuring 50 ohm coaxial systems or antennas, interconnecting transmission lines may modify impedance and SWR. Use properly constructed 50 ohm coaxial cables of known quality.

c.) Advanced 3 modes allow user selection of custom impedances in case the system under test is not a 50 ohm system.

ANTENNA

connector (Type “N” female) on top of the MFJ-269 provides the RF measurement output

Never apply external voltages or RF signals to the antenna connector.

MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer

4.2 HF/VHF Main modes

4.2.1 Antenna system SWR

Note: 50 ohms is the def ault SWR impedance. This unit can be set t o impedances other t han 50 ohms

in the Advanced 3 menu.

To measure SWR of an antenna or an antenna tuner input:

a.) If the antenna does not use a dc grounded element and feed system, momentarily short the antenna lead from shield to center. This prevents static charges from damaging the MFJ-269’s zero bias detector diodes.

b.) Immediately connect (in the case of a non-dc grounded feed system) the antenna lead to the MFJ-269

“ANTENNA”

c.) Set the

d.) Turn the MFJ-269 indicate more than 11 volts and less than 16 volts.

e.) The main or opening mode opening menu displays frequency, SWR, resistance, and reactance on the LCD, and SWR and impedance on the analog meters. In this mode, the resistance (real part) and reactance (imaginary part) of the system impedance is displayed in ohms.

connector.

“FREQUENCY”

“POWER”

knob to the proper frequency range.

switch on, while watching the display. Battery voltage should be “OK”, and

f.) Adjust the

Advanced antenna measurement modes are available and described in section 5.0. Many advanced descriptions are just different ways of displaying the same basic information given in the menu. Unless you fully understand the meaning of terms used in advanced mode measurements, we suggest you avoid them.

“TUNE”

Antenna hints:

knob until the counter displays the desired frequency, or until you find the lowest SWR.

MAIN

(or normal opening) mode

Display readings are always the SWR, impedance and resonant frequency of the antenna system ONLY at the point in the system the MFJ-269 is connected. The impedance and resonant frequency (frequency where reactance crosses zero) at the point where this unit is connected m ight no t be the resonant frequency of the antenna itself. This happens because a transmission line can add reactance or cancel reactance, and change the impedance and resonant frequency of the antenna system.

This unit displays the antenna’s complex impedance, 50 ohm SWR (unless another

impedance is selected and measured in Advanced mode 3), and resonant frequency as modified by transmission line “effects” of the feedline and other components between

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