MFJ MFJ-998 User Manual

Legal Limit IntelliTuner

Automatic Antenna Tuner

Model MFJ-998

VERSION 1D

INSTRUCTION MANUAL

CAUTION: Read All Instructions Before Operating Equipment

MFJ ENTERPRISES, INC.

300 Industrial Park Road

Starkville, MS 39759 USA

Tel: 662-323-5869 Fax: 662-323-6551

DISCLAIMER

Information in this manual is designed for user purposes only and is not intended to supersede information contained in customer regulations, technical manuals/documents, positional handbooks, or other official publications. The copy of this manual provided to the customer will not be updated to reflect current data.

Customers using this manual should report errors or omissions, recommendations for improvements, or other comments to MFJ Enterprises, 300 Industrial Park Road, Starkville, MS 39759. Phone: (662) 323-5869; FAX: (662) 323-6551. Business hours: M-F 8-4:30 CST.

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

Contents

THE BASICS

Introduction...................................................................................................................................... 1

Features............................................................................................................................................ 2

Specifications................................................................................................................................... 2

Transceiver Protection ..................................................................................................................... 3

Amplifier Protection ........................................................................................................................ 3

Fast Start .......................................................................................................................................... 4

Front Panel....................................................................................................................................... 5

SWR/Wattmeter.................................................................................................................. 5

Wattmeter Zero Scale Adjustment...................................................................................... 5

Wattmeter Full Scale Adjustment....................................................................................... 6

LCD Display ....................................................................................................................... 6

LCD Contrast Control......................................................................................................... 6

ANT Button ........................................................................................................................ 6

MODE Button.....................................................................................................................6

C-UP and C-DN Buttons .................................................................................................... 6

L-UP and L-DN Buttons..................................................................................................... 6

TUNE Button...................................................................................................................... 7

StickyTune

Automatic/Semi-Automatic Tuning Mode ............................................................ 7

POWER Button................................................................................................................... 7

Back Panel ....................................................................................................................................... 9

Amp Enable In.................................................................................................................... 9

Amp Enable Out .................................................................................................................9

Power .................................................................................................................................. 9

Radio Interface.................................................................................................................... 9

Jumper JP1........................................................................................................... 10

Serial Port ......................................................................................................................... 12

Transmitter........................................................................................................................ 12

Ground .............................................................................................................................. 12

Wire .................................................................................................................................. 12

Antenna 1.......................................................................................................................... 12

Antenna 2.......................................................................................................................... 12

Installation ..................................................................................................................................... 13

SWR/Wattmeter............................................................................................................................. 13

THE MENUS

Main Mode Menus......................................................................................................................... 14

Digital Wattmeter Menu ................................................................................................... 14

Power Bar Meter Menu..................................................................................................... 14

SWR Bar Meter Menu ...................................................................................................... 15

L-Network Menu .............................................................................................................. 15

.......................................................................................................... 7

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

Tuner Indicators............................................................................................................................. 16

Antenna............................................................................................................................. 16

Radio Interface.................................................................................................................. 16

Amp Relay Enable ............................................................................................................ 16

Memory............................................................................................................................. 17

LC Limit ........................................................................................................................... 17

Auto Range ....................................................................................................................... 17

Auto/Semi ......................................................................................................................... 17

StickyTune........................................................................................................................ 17

Setup Mode Menus ........................................................................................................................ 18

Target SWR Menu ............................................................................................................ 18

Auto Tune SWR Menu ..................................................................................................... 18

Amp Bypass SWR Menu.................................................................................................. 18

Meter Range Menu ........................................................................................................... 19

Peak Hold Menu ............................................................................................................... 19

Memory Menu .................................................................................................................. 19

IntelliTune Menu ..............................................................................................................20

SWR Beep Menu .............................................................................................................. 20

Beep Menu........................................................................................................................ 20

Refresh Menu.................................................................................................................... 20

Radio Interface Menu ....................................................................................................... 20

Push Tune <0.5s Menu ..................................................................................................... 21

LC Limit Menu ................................................................................................................. 21

OPERATION

Manual Tuning............................................................................................................................... 21

Morse Code and Beeps ..................................................................................................................22

Foldback Circuit ............................................................................................................................ 23

Grounding Hints ............................................................................................................................ 24

Antenna System Hints.................................................................................................................... 24

Location ............................................................................................................................ 24

Matching Problems ........................................................................................................... 25

APPENDICES

Resetting the Tuner........................................................................................................................ 26

Factory Defaults................................................................................................................ 26

Disable Radio Interface .................................................................................................... 27

Delete Entire Antenna Memory ........................................................................................ 27

Delete Antenna Memory Bank .........................................................................................27

Total Reset ........................................................................................................................ 27

Self Test ......................................................................................................................................... 28

Power-Down Circuit Test .............................................................................................................. 29

Relay Test ...................................................................................................................................... 29

Wattmeter Calibration.................................................................................................................... 29

SWR Bridge Calibration ................................................................................................................ 30

Frequency Counter Calibration...................................................................................................... 31

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

Alinco Radio Interface................................................................................................................... 32

Connections ...................................................................................................................... 32

Operation .......................................................................................................................... 32

Icom Radio Interface...................................................................................................................... 33

Connections ...................................................................................................................... 33

Operation .......................................................................................................................... 33

Kenwood Radio Interface .............................................................................................................. 34

Connections ...................................................................................................................... 34

Operation .......................................................................................................................... 34

Yaesu Radio Interface/MFJ-5114Y ............................................................................................... 35

Connections for FT-100.................................................................................................... 35

Operation for FT-100........................................................................................................ 35

Connections for FT-857 or FT-897................................................................................... 36

Operation for FT-857 or FT-897....................................................................................... 36

Yaesu Radio Interface/MFJ-5114Y3 ............................................................................................. 37

Connections for FT-1000MP series of radios................................................................... 37

Operation for FT-1000MP series of radios....................................................................... 37

Connections for FT-2000 series of radios......................................................................... 37

Operation for FT-2000 series of radios............................................................................. 38

Connections for FT Operation for FT

DX-9000 series of radios..................................................................... 38

DX-9000 series of radios......................................................................... 39

Yaesu Radio Interface/MFJ-5114Y4 ............................................................................................. 39

Connections for FT-2000 series of radios......................................................................... 39

Operation for FT-2000 series of radios............................................................................. 39

In Case of Difficulty ......................................................................................................................40

Technical Assistance...................................................................................................................... 40

List of Accessories......................................................................................................................... 40

Circuit Block Diagram................................................................................................................... 41

FIGURES

Figure 1. Installation Block Diagram.............................................................................................. 5

Figure 2. MFJ-998 Front Panel....................................................................................................... 5

Figure 3. Mode Button Flow Chart and Button Action .................................................................. 8

Figure 4. MFJ-998 Back Panel .......................................................................................................9

Figure 5. Radio Interface Connector............................................................................................... 9

Figure 6. Alinco Interface Cable................................................................................................... 10

Figure 7. Icom Interface Cable .....................................................................................................10

Figure 8. Kenwood Interface Cable .............................................................................................. 11

Figure 9. Yaesu Interface Cable (FT-100, FT-857, FT-897) ........................................................ 11

Figure 10. Yaesu Interface Cable (MP/2000/9000 series)............................................................ 12

Figure 11. Yaesu Interface Cable (FT-2000 series)...................................................................... 12

Figure 12. SWR/Wattmeter .......................................................................................................... 13

Figure 13. Power Bar Meter (High Range)................................................................................... 15

Figure 14. Power Bar Meter (Low Range) ................................................................................... 15

Figure 15. SWR Bar Meter ........................................................................................................... 15

Figure 16. Main Mode Menus Display ......................................................................................... 16

Figure 17. Tuner Indicators........................................................................................................... 17

Figure 18. Power-On Operations .................................................................................................. 26

Figure 19. MFJ-998 Circuit Block Diagram................................................................................. 41

iii

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

TABLES

Table 1. Memory Resolution ........................................................................................................19

Table 2. Tuner Beeps .................................................................................................................... 23

Table 3. Failure Messages............................................................................................................. 28

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

The Basics

Introduction

The MFJ-998 IntelliTuner

an internal SWR/wattmeter and an antenna switch for two antennas. The MFJ-998 lets you rapidly tune almost any unbalanced or single-wire antenna automatically. Balanced feedlines may be used with an MFJ-912 1.5 kW 4:1 balun connected to the MFJ-998 antenna output.

The MFJ-998 includes MFJ’s Amplifier Bypass Control

fully protects your amplifier during tuning, and will even take your amplifier off-line should the SWR increase above a user-defined pre-set limit.

MFJ's exclusive InstantRecall tuning with more than 20,000 non-volatile VirtualAntenna

has four banks of memory; and each memory bank has over 2500 non-volatile memories for tuner settings.

The tuner includes a highly efficient switched-L network with wide matching capability, 1.8 to 30 MHz coverage, cross-needle power meters, backlit LCD display, a radio interface port, and heavy-duty 16 amp/1000 volt relays. It is rated at 1500 watts SSB/CW and will match impedances from 12 to 1600 ohms (SWR up to 32:1).

A maximum of 256 values of inductance and 256 values of input capacitance or 64 values of output capacitance are available. This provides a total of 81,664 L/C tuning combinations. The nominal tuning ranges are 0 to 24 μH and 0 to 3900 pF (input) or 0 to 970 pF (output). And once a match is found, the matching network values can be displayed so you may design your own fixed matching network if desired.

Like all MFJ IntelliTuners

adjusts for minimum SWR and remembers the frequency and tuner settings, safely stored in non-volatile memory. The next time you operate on that frequency (or close to it) and antenna, these tuner settings are instantly restored and you’re ready to operate in milliseconds. Each of the two switched antenna outputs has four banks of memory, which can learn and remember more than 2500 frequencies and tuner settings per bank.

When you key your transmitter, MFJ’s InstantRecall

that frequency before. If so, tuning is instantaneous and you’re ready to operate. If not, MFJ’s

IntelliTune

algorithm (based on MFJ’s famous SWR Analyzer technology) kicks in. It measures the complex impedance of your antenna. Next it calculates the components needed and instantly snaps them in. Finally, it fine-tunes to minimize SWR, and you’re ready to operate--all in a fraction of a second.

If the antenna impedance is not within the tuner’s measurement range, MFJ’s AdaptiveSearch

algorithm goes into action. Frequency is measured and relevant components values are determined. Only those values are searched for fast tuning. If it still cannot find a match, the search is performed again using a different search pattern.

The target SWR can be set at 1.0 through 2.0. The minimum power to tune is approximately five watts. You can manually tune where you can’t transmit (for listening outside of the ham bands).

is a comprehensive Full Legal Limit automatic antenna tuning center with

. This exclusive MFJ antenna tuner feature

, IntelliTuneTM and AdaptiveSearch

, the MFJ-998 learns and remembers. When you transmit, it automatically

memories. Each of the two antenna outputs

checks its memory to see if you have operated on

algorithms give you fast automatic

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

All MFJ’s IntelliTuners

support radio tuner interfaces that are compatible with Alinco EDX-2 tuner, Icom AH-3 and AH-4 tuners, Kenwood AT-300 tuner, Yaesu FC-30 tuner, and Yaesu FH-1 and FH-2 remote controls. Optional interface cables MFJ-5114A (for Alinco), MFJ-5114I (for Icom), MFJ-5114K (for Kenwood); and MFJ-5114Y, MFJ-5114Y3 and MFJ-5114Y4 (for Yaesu) are available from MFJ Enterprises, Inc.

The tuners enter a “sleep” mode when idle and when no transmit signal is present, turning off the microprocessor clock to avoid the generation of spurious signals.

Features

• Automatically matches antennas from 12 to 1600 ohms impedance (SWR up to 32:1)

• Handles 1500 watts SSB/CW

• Tune in less than 20 seconds, usually less than 5 seconds

• Amplifier Bypass Control

automatically protects your amplifier during tuning and external high

SWR events

• Over 20,000 non-volatile memories for tuner settings

• Four memory banks per antenna with over 2500 memories per bank

• Highly efficient switched–L network matching circuit

• Direct read-out of matching L/C values available after tuning

• 1.8 to 30 MHz continuous frequency coverage

• Adjustable target SWR from 1.0 to 2.0

• Adjustable SWR threshold from 0.5 to 1.5

• Adjustable amp bypass SWR from 1.5 to 3.0

• Lighted cross-needle SWR/wattmeter with high, low, and auto range options

• Multifunction backlit LCD display with contrast control

• Numeric readings for SWR, forward and reflected power

• Bar meters for SWR, forward and reflected power with peak hold and range options

• Audio SWR meter

• Built-in frequency counter

• Built-in radio interface circuitry for compatible radios

• Two SO-239 coax fed antenna connectors

• Connector for random wire or single wire antennas

• Built-in bootloader for field upgradeable firmware

Specifications

• Impedance matching range : 12 to 1600 ohms

• SWR matching range : Up to 4:1 for < 50 ohms and up to 32:1 for > 50 ohms

• Minimum power for tuning : 5 watts

• Maximum power while tuning : 100 watts with foldback, 20 watts without foldback

• RF power limit : 1500 watts SSB/CW

• Frequency range : 1.8 to 30 MHz continuous coverage

• Frequency counter accuracy : ±1 kHz across HF bands

• A/D conversion resolution : 10-bit

• Forward power display resolution : 0.1 for < 100 watts and 1 for ≥ 100 watts

• Reflected power display resolution : 0.1 for < 10 watts and 1 for ≥ 10 watts

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

• SWR display resolution : 0.1

• Power bar meters resolution : 60 segments

• SWR bar meter resolution : 31 segments

• Capacitance range : 0 to 3926 pF nominal (256 values) on input side

: 0 to 976 pF nominal (64 values) on output side

• Inductance range : 0 to 24.28 μH nominal (256 values)

• Relay rating : 16 amp 1000 volts

• Relay electrical life : 100,000 operations

• Relay mechanical life : 10 million operations

• Memory endurance : 1 million erase/write cycles

• Memory data retention : > 200 years

• Power supply requirement : 12 - 15 volts DC

• Current consumption : 1.4 amps or less

• Dimensions (projections included) : 12 ¾ × 4 × 14 ¾ in; 325 × 102 × 375 mm (w × h × d)

• Weight : Approx. 7 lb 12 oz; 3.5 kg

• Display : 2-line × 16-character backlight LCD

• TRANSMITTER connector : SO-239

• ANTENNA connectors : SO-239 × 2

• WIRE connector : Ceramic binding post

• POWER connector : 2.1 × 5.5 mm coaxial plug, center pin positive

• RADIO INTERFACE connector : 8-pin modular (RJ-45)

• RS-232 connector : D-sub 9-pin

• AMP ENABLE connectors : Phono (RCA) × 2

† Specifications and design are subject to change without notice or obligation.

Transceiver Protection

Like all MFJ IntelliTuners

transceivers through optional transceiver interface cables. When interfaced to your transceiver with the appropriate cable, the MFJ-998 automatically puts your transceiver into a low power CW tune mode when tuning is initiated. More details are provided in the “Radio Interface” section of this manual.

Note: An optional transceiver interface cable is NOT necessary for normal operation. However, a

transceiver interface cable simplifies operation by automatically keying your transceiver in a low power TUNE mode.

, the MFJ-998 can provide automatic control interfacing with most popular

Amplifier Protection

The MFJ-998 is unique in that it provides Amplifier Bypass Control

amplifier during tuning and high SWR events. This capability is provided by passing the amplifier enable

control line to your amplifier through the MFJ-998 AMP ENABLE IN/OUT connectors. A normally

closed high-speed reed relay interrupts the amplifier enable signal when the MFJ-998 begins tuning, or when a user high-SWR pre-set is exceeded. A normally closed relay is used so that your amplifier system works properly when the MFJ-998 is turned off.

Note: MFJ recommends that the amplifier enable control signal be always connected through the

AMP ENABLE IN/OUT connectors on the MFJ-998.

for hands-free protection of your

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

Fast Start

WARNING

● Never operate the tuner with its cover removed. Contact with the components inside the tuner while transmitting will result in painful RF burns.

● Locate the tuner so that the rear terminals are not accessible during operation. The single wire connection may have high voltage while transmitting.

● Disconnect all antennas from the tuner during lightning storms.

● Always tune with low power (approximately 10-30 watts). Apply maximum power only

after tuning up.

● Never exceed tuner specifications.

Connect the MFJ-998 to the transceiver, the amplifier, and the antenna as shown in Figure 1 and per the following directions:

1. Connect the MFJ-998 to a 12-15 VDC voltage source capable of supplying at least 1.4 amps.

2. Connect your transceiver to the TRANSMITTER connector using a 50-ohm coaxial cable.

3. Connect your coax-fed antenna to the ANTENNA 1 connector using a 50-ohm coaxial cable, or connect your random wire to the WIRE binding post.

4. Connect your ground connection to the GROUND post.

5. Connect the AMPLIFIER ENABLE output from your transceiver to the AMP ENABLE IN on the MFJ-998, and connect the AMP ENABLE OUT on the MFJ-998 to the AMPLIFIER ENABLE INPUT on your amplifier.

Note: If you use an amplifier keying interface between your transceiver and your amplifier,

such as the Ameritron ARB-704, this amplifier keying interface may be placed either between the transceiver and MFJ-998, or between the MFJ-998 and amplifier.

6. If available, connect an MFJ-5114 transceiver control cable between the MFJ-998 and your transceiver. Make sure to select your transceiver in the MFJ-998 Radio Interface setup menu.

7. Press the [POWER] button to turn on the MFJ-998 tuner.

8. Press the [ANT] button momentarily until a small “1” appears on line one of the display. This selects antenna 1 and is indicated with one beep.

9. Key your transceiver to output a carrier of 5-30 watts CW, FM or AM.

Note: When a transceiver interface cable is used, initiating the TUNE cycle automatically keys

your transceiver in the low power TUNE mode.

10. Press and hold the [TUNE] button on the MFJ-998 for one second to start the automatic tuning process. When completed, check to ensure an SWR of 1.5 or less before increasing RF power.

Note: During the automatic tuning process, the tuner will make some noise. These are the

relays switching at a very high rate, and it is normal. Do not be alarmed.

11. You are ready to transmit.

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

Note: When the tuner power is OFF, the tuner is bypassed and RF from the transmitter goes

directly to ANTENNA 1 with no matching. The tuner also powers up in the bypass mode. When the tuner power is ON, pressing [C-DN] and [L-DN] simultaneously or pressing [TUNE] quickly places the tuner in bypass mode if desired, which is indicated by one beep.

ntenna 1

ntenna 2

Amp Enable Out

Transceiver MFJ-998

Front Panel

Amp Enable

Amplifier

MFJ-5114 Radio Interface

Figure 1. Installation Block Diagram.

Amp Enable

SWR PWR

Out

Amp Enable In

Station Ground

14.100MHz 1.2 FWD=1000 REF= 10

11.2 1.52 3

0255075100

MFJ IntelliTuner

AUTOMATI C ANTENNA TUNER

+12V

300

1500 Watts SSB / CW

SWR

HI x10

C-UP L-UPANT TUNE

MODE POWERC-DN L-DN

MODEL

MFJ-998

Figure 2. MFJ-998 Front Panel.

• SWR/Wattmeter: The cross-needle meter measures forward power, reflected power, and SWR. It

operates whenever the tuner is powered on. Full-scale readings are 300 watts forward and 60 watts reflected. The meter can be set to high power range of 3000 watts forward and 600 watts reflected. The SWR is measured at the point where the two needles cross. See “SWR/Wattmeter” on page 13 for more detailed information.

• Wattmeter Zero Scale Adjustment: Two trimpots located below the wattmeter calibrate the zero

scales of the forward and reflected needles. The small hole on the right adjusts the forward needle and the small hole on the left adjusts the reflected needle. See “Wattmeter Calibration” section on page 29 for the calibration procedure.

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

• Wattmeter Full Scale Adjustment: Two trimpots located to the left of the LCD display that

calibrate the full scales of the forward and reflected needles. The small hole on the top adjusts the forward needle and the small hole on the bottom adjusts the reflected needle. See “Wattmeter Calibration” section on page 29 for the calibration procedure.

• LCD Display: A 2-line by 16-character alphanumeric display with backlight. It displays the tuner’s

various menus and status. The display contrast can be adjusted by the LCD contrast control on the front panel. Below the display are the SWR and power bar meter scales. Refer to Figures 16 and 17 for descriptions of the various displayed information.

• LCD Contrast Control: A trimpot control that adjusts the contrast of the LCD display. Use a small

flat blade screwdriver, insert into the small hole to the right of the display, and turn clockwise to increase contrast.

• ANT Button: Has two different functions based on the length of time you press and hold it before releasing. Press [ANT] quickly (less than one second) to toggle between Antenna 1 and Antenna 2.

The Antenna indicator on the main display indicates the selected antenna. A single-wire antenna is, by default, Antenna 1.

Press and hold [ANT] for one second to cycle among the four memory banks of the current antenna. The selected bank is indicated by a series of short beeps, where one beep indicates bank A, two beeps indicate bank B, three beeps indicate bank C, four beeps indicate bank D, and five beeps indicate antenna memory is OFF. The Memory indicator on the main display also indicates the selected bank.

Pressing the [ANT] button switches the antenna or bank only when there is no RF power. Also, the

tuner setting for the selected antenna or bank, if available, is instantly restored from memory when enabled.

• MODE Button: Time-sensitive and used to navigate through the various main menus and to enter or

exit the setup menus.

• C-UP and C-DN Buttons: Used to manually increase or decrease the capacitance of the L-network

matching circuit. The capacitance ranges are 0 to 3926 pF (picofarads) on the input side and 0 to 976 pF on the output side. The upper limit of capacitance, dependent on frequency, is used to limit the maximum voltage and current across the tuner’s components. This limit can be removed in the LC Limit setup menu, but is not recommended.

Note: Pressing [C-UP] and [C-DN] simultaneously toggles the capacitor between the input

and output sides of the L-network. One beep when the capacitor is on the antenna side. Two beeps when the capacitor is on the transmitter side.

• L-UP and L-DN Buttons: Used to manually increase or decrease the inductance of the L-network

matching circuit. The inductance range is 0 to 24.28 μH (microhenries). The upper limit of inductance, dependent on frequency, is used to limit the maximum voltage and current across the tuner’s components. This limit can be removed in the LC Limit setup menu, but is not recommended.

Note: Pressing [C-DN] and [L-DN] (both DOWN buttons) simultaneously places the tuner in

bypass mode. One beep sounds to indicate bypass mode, and RF from the transmitter goes directly to the antenna with no matching.

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

• TUNE Button: Has three different functions based on the length of time you press and hold it before

releasing. Press [TUNE] quickly (less than 0.5 second) to bypass the tuner. One beep indicates bypass mode, where RF from the transmitter goes directly to the antenna with no matching. A second quick press toggles the tuner back to its last L/C setting, and the tuner responds with two beeps.

Note: Always connect the amplifier enable line from your transceiver output through the MFJ-

998 to the amplifier. This always ensures that the amplifier will be taken off-line prior to any tuning events.

Press [TUNE] for 0.5 to 2 seconds to start the automatic tuning process. Tuning starts when [TUNE] is released after the 0.5-2 second hold-time. The transmitter must be keyed first with at least five watts of power. When the SWR is already below the target SWR, pressing [TUNE] will fine-tune the match for a lower SWR, if possible.

Note: You can reverse the two functions above by pressing and holding the [TUNE] button for

approximately 10 seconds. I.e., when the [TUNE] button is pressed and held for 10 seconds. You will hear two beeps. Now pressing [TUNE] momentarily starts the tuning process, and pressing and holding the [TUNE] button for 0.5-2 seconds puts the tuner into the bypass mode.

“StickyTune

transmitter with one hand and using the other hand to push the [TUNE] button to start the tuning

process. To toggle the StickyTune

” allows for one-handed tuning operation. Normal tuning requires keying the

mode on and off, press and hold the [TUNE] button for two seconds. When enabled, a bar appears on top of the Auto/Semi indicator, and the tuning process starts automatically when the transmitter is keyed with at least five watts of power regardless of the SWR. This works in both automatic and semi-automatic modes. One beep indicates “on” and two beeps indicate “off”.

Automatic/Semi-Automatic Tuning Mode

Pressing [TUNE] and [ANT] simultaneously toggles between automatic and semi-automatic tuning mode. In automatic mode, the tuning routine is automatically started when at least five watts of power is applied and the SWR is a preset amount above the preset target SWR. In semi-automatic mode, the tuning routine starts only when the [TUNE] button is pressed for 0.5 to 2 seconds. The Auto/Semi indicator on the main display indicates the selected mode. Refer to Figures 16 and 17 for the on-screen Auto/Semi indicator.

Note: During the tuning process, the tuner will make some noise. These are the relays

switching at a very high rate, and it is normal. Do not be alarmed.

• POWER Button: Used to turn the power on and off. When the power is off, the tuner is placed in

bypass mode, Antenna 1 is selected, and the amplifier bypass control line is uninterrupted by the MFJ-998. When turning on the power, the tuner powers up in the bypass mode and displays the target SWR on the main screen.

WARNING: Do not turn the power on and off rapidly, otherwise the tuner setting memory

can be corrupted and the unit will have to be reset to factory defaults.

Note: When the tuner power is OFF, the tuner is in bypass mode and RF from the transmitter

goes directly to ANTENNA 1 with no matching.

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

MODE BUTTON FLOW CHART

MAIN MODES

Digital Wattmeter

Power Bar Meter

SWR Bar Meter

L-Network

MODE

For 2 sec.

MODE

For 2 sec.

Idle for 8 sec.

MODE

14.100MHz 1.1 FWD=1000 REF=5.0

14.100MHz 1.1 1000

0.00uH 1,0 0pF 1500

BUTTON ACTION

(while in the main modes)

Press in to turn power on, out to turn power off. Press less than one second to toggle between antenna 1

and antenna 2; press and hold for more than one second to cycle the 4 antenna memory banks.

Press to switch main modes and setup modes. Press to increase capacitance. Press to decrease capacitance. Press to increase inductance.

POWER

ANT

MODE C-UP C-DN L-UP

SETUP MODES

TARGET SWR

UTO TUNE SWR

AMP BYPASS SWR

METER RANGE

PEAK HOLD

MODE

MEMORY

IntelliTune

SWR BEEP

BEEP

REFRESH

ADIO INTERFACE

USH TUNE <0.5s

MODE

C-UP

L-UP

LC LIMIT

Press or to turn on or increase setting.

Press or to turn off or decrease se tting.

-UP L-UP

-DN L-DN

ANT

Press to decrease inductance. Press less than 0.5 second to toggle bypass mode; press and hold for 0.5 to 2 seconds to start the

tuning process; press and hold for more than two seconds to toggle the StickyTune on and off. Press + to switch the capacitor between the input and output side. Press + to increase both capacitance and inductance.

Press + to bypass the ante nna tuner.

Press + to toggle between automatic and semi-automatic mode. Press + to overwrite tuner memory with the cu rrent tuner setting.+ Press + to manually toggle the amp relay enable.+

L-DN TUNE

C-UP C-DN C-UP L-UP C-DN L-DN

TUNE ANT TUNE L-DNC-DN

L-DNMODE L-UP

Figure 3. Mode Button Flow Chart and Button Action.

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

Back Panel

ENABLE

POWER

12VDC

1.4A

AMP

RADIO

INTERFAC E

AMP

ENABL E

OUT

SERI AL

PORT

TRANSMITTER

MFJ ENTERPRISES, INC.

STA RKVILLE , MS USA

GROUND

Do not connect

WIRE and

ANTE NNA 1

at same time!

WIRE

ANTENNA 1

ANTENNA 2

Figure 4. MFJ-998 Back Panel.

• Amp Enable In: RCA phono connector for connecting to the radio’s amplifier control output.

• Amp Enable Out: RCA phono connector for connecting to the amplifier’s relay control input.

• Power: This jack accepts a standard 2.1 × 5.5 mm coaxial plug with positive center and negative

sleeve. The tuner requires 12 volts DC at up to 1.4 amps. The use of a regulated supply is not mandatory but is recommended for best performance. An optional 12 volt DC 1.5 amp power supply, the MFJ-1316, is available from MFJ Enterprises, Inc.

WARNING: Do not apply voltages greater than 18 volts to this unit, or permanent damage

to the unit may result.

Note: When the tuner power is OFF, the tuner is in bypass mode and RF from the transmitter

goes directly to ANTENNA 1 with no matching. When turned on, the tuner powers up in bypass mode.

• Radio Interface: An 8-pin modular (RJ-45)

+13.8 V DC input (1.4 A)

connector for connecting to the tuner interface connector of compatible radios. While most radios provide +13.8 VDC power though their tuner interface connector, a separate power supply is necessary to power the MFJ-998 due to its 1.4 amp power requirement. The MFJ998 should be powered on first (for certain radios,

TURN ON RADIO will display) and

then the radio powered on so the radio knows an external tuner is attached. The radio will

Rear Panel View

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Figure 5. Radio Interface Connector.

1 2

+13.8 V DC input (1.4 A) +13.8 V DC input (1.4 A)

3 4

Ground Ground

5 6

Key/TT/TX

TX INH

Start/TS/RX

disable its internal tuner, if it has one, and use the external tuner.

The Radio Interface works with radios that are compatible with Alinco EDX-2, Icom AH-3 and AH4, Kenwood AT-300, and Yaesu FC-30, FH-1 and FH-2. When connected to a compatible radio, simply press the [TUNER] or [AT] button on the radio; for FH-1 or FH-2 compatible Yaesu, press the

[TUNE] button on the tuner to start the automatic tuning process. The radio will automatically switch

MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner Instruction Manual

to CW mode, transmit a low power (typically 10-30 watt) carrier, and start the tuning process. Once the automatic tuning is completed, the radio will return to its previous mode and power setting.

Jumper JP1

There is a jumper JP1 inside the MFJ-998 that must be configured properly when interfacing to the

various radios. Normally this jumper is installed and is the factory default. Remove this jumper when interfacing to an Icom IC-7000. Make sure this jumper is installed when interfacing to

Kenwood radios and FC-30 compatible Yaesu radios using the MFJ-5114K and MFJ-5114Y interface cables, respectively. For the other radios, the position of jumper JP1 is irrelevant.

Note: The MFJ-998 must be powered from a separate DC source. Power from the

accessory or tuner sockets is not passed to the MFJ-998 via the transceiver interface cable.

Note: If the wrong interface is selected and the

TURN ON RADIO

message does not go away, disable the interface by pressing and holding both [TUNE] and [MODE] buttons while turning on the power. The tuner will respond with two beeps. Then select the correct interface using the MFJ-998 Radio Interface setup mode.

The MFJ-5114A interface cable provides control signals between an Alinco radio and the MFJ automatic tuner. Supported Alinco radios are DX-70, DX-77, DX-701, DX-801, and any Alinco radio that supports the Alinco EDX-2 tuner. Press the radio’s [TUNE] button to start the tuning process; for DX-70 press [FUNC] then [TUNE]. Refer to “Alinco Radio Interface” on page 32 for connections and operation.

Pin 1 (Ground) connects to pins 4 and 5 of Ra di o In terface Plug.

Pin 2 (+13.8V) connects to pins 2 and 3 of Radio Interface Plug.

Pin 3 (Key) connects to pin 6 of Radio Interface P lug.

Pin 4 is not connected. Pin 5 (Sta rt) connects to pin 8 of Ra dio Interface Plug.

Figure 6. Alinco Interface Cable.

The MFJ-5114I interface cable provides control signals between an Icom radio and the MFJ automatic tuner. Supported Icom radios are IC-706, IC-707, IC-718, IC-725, IC-728, IC-736, IC-738, IC-746, IC-756, IC-775, IC-7000, and any Icom radio that supports the Icom AH-3 or AH-4 tuner. Push and hold the radio’s [TUNER] button for two seconds to start the tuning process. Push

[TUNER] quickly to bypass the tuner. Make sure jumper JP1 is removed for IC-7000. Refer to

“Icom Radio Interface” on page 33 for connections and operation.

Pin (Key) connects to pin 6 of Radio Interface Plu

1g.

Pin (Start) connects to pin 8 of Radio Interface Plug.

Pin 3 (+13. 8V) connects to pi ns 2 and 3 of Radio Interface Plug.

Pin (Ground) connects to pins 4 and of Radio Interface Plug.

Figure 7. Icom Interface Cable.

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