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MFJ IntelliTuner -991 Instruction Manual

Automatic antenna tuners
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IntelliTuner
TM
Automatic Antenna Tuners
Models MFJ-991 and MFJ-994
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
C
COPYRIGHT
2004 MFJ ENTERPRISES, INC.
VERSION 1A

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Summary of Contents for MFJ IntelliTuner MFJ-991

  • Page 1 IntelliTuner Automatic Antenna Tuners Models MFJ-991 and MFJ-994 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 COPYRIGHT 2004 MFJ ENTERPRISES, INC. VERSION 1A...

  • Page 3: Table Of Contents

    MFJ-991 / MFJ-994 IntelliTuner Automatic Antenna Tuners Instruction Manual Contents THE BASICS Introduction............................1 Features............................2 Specifications........................... 2 Fast Start ............................3 Front Panel............................4 SWR/Wattmeter........................4 C-UP and C-DN Buttons ....................4 L-UP and L-DN Buttons..................... 4 AUTO Button ........................4 TUNE Button........................
  • Page 4 MFJ-991 / MFJ-994 IntelliTuner Automatic Antenna Tuners Instruction Manual APPENDICES Firmware Version Number ......................15 Resetting the Tuner ........................15 Factory Defaults........................ 15 Delete Antenna Memory....................16 Total Reset ........................16 Self Test ............................16 Power Down Circuit Test....................... 17 Relay Test ............................

  • Page 5: The Basics

    131,072 L/C tuning combinations. The nominal tuning ranges are 0 to 3900 pF and 0 to 24 µH (0 to 2950 pF and 0 to 17 µH for MFJ-994).

  • Page 6: Features

    Frequency counter range: up to 50 MHz • Capacitance range: 0 to 3900 pF (MFJ 991, 256 values); 0 to 2950 pF (MFJ-994, 192 values) • Inductance range: 0 to 24 µH (MFJ-991, 256 values); 0 to 17 µH (MFJ-994, 192 values) •...

  • Page 7: Fast Start

    MFJ-991 / MFJ-994 IntelliTuner Automatic Antenna Tuners Instruction Manual Fast Start WARNINGS ● 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.

  • Page 8: Front Panel

    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 µH (0 to 17 µH in the MFJ-994). The upper limit of inductance, dependent on frequency, is restricted to limit the maximum voltage and current across the tuner’s components.

  • Page 9: Tune Button

    TUNE Button: Press this button briefly to start the tuning process. The transmitter must be keyed first with at least 5 watts (10 watts for MFJ-994) of power. When the SWR is already below the target SWR, pressing [TUNE] will fine-tune the match for a lower SWR, if possible.

  • Page 10: Back Panel

    A female DB-9 connector for connecting to the MFJ-993RC Remote Control, Remote Port: allowing remote operation of the tuner. The MFJ-993RC duplicates all the front panel buttons except [POWER]. In addition, there are two LEDs on the remote control. The red Tuning LED lights to indicate tuning is in progress and the green SWR LED lights when the SWR is below the target SWR.

  • Page 11: Transmitter

    MFJ-991 / MFJ-994 IntelliTuner Automatic Antenna Tuners Instruction Manual cable provides power and control between an Alinco radio and the MFJ automatic tuner. Supported Alinco radios are DX-70, DX-77, and any Alinco radio that supports the Alinco EDX-2 tuner. Pin 1 (Ground) connects to the Sleeves of both 3.5 mm Stereo Phone Plug and Power Plug.

  • Page 12: Installation

    5. Connect a 12 to 15 VDC power source to the input jack labeled POWER. SWR/Wattmeter Note: All meter power readings and ranges are ×2 in the model MFJ-994. The backlit cross-needle meter measures forward power, reflected power, and SWR, and operates whenever the tuner is powered on.

  • Page 13: Setup

    SWR of 1.5 and auto tune SWR of 1.0, the tuning process will start whenever the SWR is above 2.5 (1.5 + 1.0) and there is at least 5 watts (10 watts for MFJ-994) of RF power. Default is 1.0.

  • Page 14: Meter Range

    Instruction Manual Meter Range Note: All meter power readings and ranges are ×2 in the model MFJ-994. You can select a meter scale range or use auto range. In the 30 watts (low) range, the forward full scale is 30 watts and the reflected full scale is 6 watts (divide the meter reading by 10). In the 300 watts (high) range, the forward full scale is 300 watts and the reflected full scale is 60 watts.

  • Page 15: Component Limit

    MFJ-991 / MFJ-994 IntelliTuner Automatic Antenna Tuners Instruction Manual Component Limit The upper limits of inductance (L) and capacitance (C) are factory-limited according to frequency and maximum power rating; i.e., higher frequencies need less inductance and less capacitance when the L- network is properly tuned.

  • Page 16: Tuner Status Indicators

    SWR is greater than 3.0, or when the forward power exceeds 125 watts regardless of the SWR. If more than 150 watts (600 watts for MFJ-994) is applied to the tuner, the tuner will go into bypass mode; both Forward and Reflected meter needles will bounce to full scale.

  • Page 17: Grounding Hints

    MFJ-991 / MFJ-994 IntelliTuner Automatic Antenna Tuners Instruction Manual Grounding Hints To minimize RFI, single wire feedlines (such as used with Windom or longwire antennas) should be kept away from other wiring. Radiation will be minimized if the single wire feeder runs parallel and reasonably close to the wire that connects the tuner to the outdoor ground.
  • Page 18 MFJ-991 / MFJ-994 IntelliTuner Automatic Antenna Tuners Instruction Manual wavelength feedline converts the low antenna impedance to a very high impedance at the tuner. A similar problem occurs if the antenna has an extremely high impedance and the transmission line is a multiple of a half-wavelength.

  • Page 19: Appendices

    The unit is shipped with the following default settings: • Inductance 0 µH • Capacitance 0 pF on transmitter side • Target SWR • Auto Tune SWR 1.0 above target SWR • Meter Range 300 watts (high range) (600 watts in model MFJ-994) © 2004 MFJ Enterprises, Inc.

  • Page 20: Delete Antenna Memory

    30 seconds. This test also can be used to test the MFJ-993RC Remote Control. Make sure to lock in the [AUTO] button on the tuner before starting the self-test, and press the buttons on the MFJ-993RC instead of the front-panel buttons when prompted.

  • Page 21: Power Down Circuit Test

    MFJ-991 / MFJ-994 IntelliTuner Automatic Antenna Tuners Instruction Manual 5. The reflected needle goes to the 3-watt mark. Now, press each of the front panel buttons in this sequence: [C-UP], [C-DN], [L-UP], [L-DN], [AUTO], and then [TUNE]. The forward needle should bounce once for each press, and the reflected needle should move up a division for each press.

  • Page 22: Relay Test

    To calibrate the wattmeter, you will need a Phillips screwdriver and a tuning tool or small flat blade screwdriver. WARNING: Never operate the MFJ-991/4 with its cover removed; dangerous voltages and currents can be present during operation. Never exceed tuner specifications.

  • Page 23: Swr Bridge Calibration

    WARNING: Do not touch anything inside the tuner during operation! Serious, painful RF burns can result. WARNING: Never operate the MFJ-991/4 with its cover removed; dangerous voltages and currents can be present during operation. Never exceed tuner specifications. Note: The trimmers involved in this calibration are located on the main circuit board in front of the TRANSMITTER connector;...

  • Page 24: Frequency Counter Calibration

    WARNING: Do not touch anything inside the tuner during operation! Serious, painful RF burns can result. WARNING: Never operate the MFJ-991/4 with its cover removed; dangerous voltages and currents can be present during operation. Never exceed tuner specifications. 1. Turn off the power to the tuner and the transmitter.

  • Page 25: Technical Assistance

    If you have any problem with this unit first check the appropriate section of this manual. If the manual does not reference your problem or your problem is not solved by reading the manual, you may call MFJ Technical Service at 662-323-0549 or the MFJ Factory at 662-323-5869. You will be best helped if you have your unit, manual and all information on your station handy so you can answer any questions the technicians may ask.

  • Page 26: Circuit Block Diagram

    MFJ-991 / MFJ-994 IntelliTuner Automatic Antenna Tuners Instruction Manual © 2004 MFJ Enterprises, Inc.
  • Page 27 MFJ Enterprises, Inc. warrants to the original owner of this product, if manufactured by MFJ Enterprises, Inc. and purchased from an authorized dealer or directly from MFJ Enterprises, Inc. to be free from defects in material and workmanship for a period of 12 months from date of purchase provided the following terms of this warranty are satisfied.
  • Page 28 MFJ ENTERPRISES, INC. MFJ-991/994 Manual 300 Industrial Park Road Version 1A Starkville, MS 39759 Printed In U.S.A. 01/04...

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