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MFJ IntelliTuner -991B Instruction Manual

Automatic antenna tuner
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IntelliTuner
TM
Automatic Antenna Tuner
Model MFJ-991B
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
5
C
COPYRIGHT
200
MFJ ENTERPRISES, INC.
VERSION 1A

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Summary of Contents for MFJ IntelliTuner MFJ-991B

  • Page 1 IntelliTuner Automatic Antenna Tuner Model MFJ-991B 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 MFJ ENTERPRISES, INC. VERSION 1A...

  • Page 3: Table Of Contents

    MFJ-991B IntelliTuner Automatic Antenna Tuner 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 Figure 6. Icom Interface Cable ....................... 7 Figure 7. SWR/Wattmeter ......................9 Figure 8. Power-On Operations ....................16 Figure 9. MFJ-991B Circuit Block Diagram ................22 TABLES Table 1. Antenna Memory Resolution..................10 Table 2. Meter Needle Stationary Codes ..................13 Table 3.

  • Page 5: The Basics

    When you key your transmitter, MFJ’s InstantRecall checks its memory to see if you have operated that frequency before. If so, tuning is instantaneous and you’re ready to operate. If not, MFJ’s algorithm (based on MFJ’s famous SWR Analyzer technology) kicks in. It measures the IntelliTune complex impedance of your antenna.

  • Page 6: Features

    MFJ-991B IntelliTuner Automatic Antenna Tuner Instruction Manual Features • Automatically matches antennas with impedances of 6 to 1600 ohms or 6 to 3200 ohms • Handles 300 watts (match 6 to 1600 ohms) or 150 watts (match 6 to 3200 ohms) •...

  • Page 7: Fast Start

    MFJ-991B IntelliTuner Automatic Antenna Tuner 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

    MFJ-991B IntelliTuner Automatic Antenna Tuner Instruction Manual Front Panel C-UP L-UP AUTO POWER 3.0 2.0 MFJ IntelliTuner C-DN L-DN TUNE Hi x1 Lo x.1 400-3083 AUTOMATIC ANTENNA TUNER BYPASS Dual Power Level MODEL MFJ-991B 300/150 Watts Figure 2. MFJ-991B Front Panel.

  • Page 9: Power Button

    MFJ-991B IntelliTuner Automatic Antenna Tuner Instruction Manual Press and hold [TUNE] for 0.5 to 2 seconds to start the automatic tuning process. 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.

  • Page 10: Back Panel

    Most radios provide +13.8 VDC power thought its tuner interface connector. If separate power supplies are used to power the MFJ-991B, the MFJ-991B should be powered on first (both needles will bounce) and then turn on the radio, so the radio knows an external tuner is attached.

  • Page 11: Transmitter

    MFJ-991B IntelliTuner Automatic Antenna Tuner Instruction Manual The MFJ-5124A interface 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.

  • Page 12: Wire

    MFJ-991B IntelliTuner Automatic Antenna Tuner Instruction Manual • Wire: Binding post for connecting single wire antenna. Notice the WIRE binding post is internally connected to the ANTENNA connector. Note: To use the WIRE binding post, make sure to remove the antenna, if any, from the ANTENNA connector.

  • Page 13: Swr/Wattmeter

    12 for more details. Setup You can set up how the MFJ-991B tuner works and behaves. In addition to displaying power and SWR, the meter also indicates tuner status when you make setup changes. The meter needles bounce, or rise to one point and stay, to provide information.

  • Page 14: Target Swr

    MFJ-991B IntelliTuner Automatic Antenna Tuner Instruction Manual Target SWR You can set the target SWR to 1.5 or 2.0. The tuning process will stop when a match with an SWR less than or equal to the target SWR is found. The default is 1.5. Setting the target SWR to 2.0 may require shorter tuning times.

  • Page 15: Meter Range

    MFJ-991B IntelliTuner Automatic Antenna Tuner Instruction Manual To clear the antenna memory, turn off the power to the tuner, then press and hold both [TUNE] and [C- DN] buttons while turning on the power. Both meter needles will read half scale, forming a triangle, asking you to confirm the deletion.

  • Page 16: Component Limit

    MFJ-991B IntelliTuner Automatic Antenna Tuner Instruction Manual Pressing [C-DN] and [L-DN] simultaneously or pressing [TUNE] quickly places the tuner in bypass mode; i.e. zero inductance and zero capacitance. RF from the transmitter goes directly to the antenna with no matching. The reflected needle bouncing to 20-watt mark indicates changing to bypass mode.

  • Page 17: Table 2. Meter Needle Stationary Codes

    MFJ-991B IntelliTuner Automatic Antenna Tuner Instruction Manual watts and the SWR is greater than 3.0, or when the forward power exceeds 125 watts regardless of the SWR. If more than 300 watts (or more than150 watts when 150 watts power level is selected) is applied to the tuner, the tuner will go into bypass mode;...

  • Page 18: Grounding Hints

    MFJ-991B IntelliTuner Automatic Antenna Tuner 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 19 MFJ-991B IntelliTuner Automatic Antenna Tuner 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 20: Appendices

    MFJ-991B IntelliTuner Automatic Antenna Tuner Instruction Manual Appendices POWER-ON OPERATIONS (Press and hold buttons while turning on the power.) Press and hold to get the firmware version number. C-UP POWER L-UP POWER Press and hold to start the self test.

  • Page 21: 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 22: Power Down Circuit Test

    MFJ-991B IntelliTuner Automatic Antenna Tuner Instruction Manual 3. If testing the MFJ-993RC Remote Control, connect it to the Remote Port and make sure the [AUTO] button on the tuner is locked in; otherwise, go to next step. 4. Press and hold only the [L-UP] button while turning the power on.

  • Page 23: 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-991B with its cover removed; dangerous voltages and currents can be present during operation. Never exceed tuner specifications.

  • Page 24: Swr Bridge Calibration

    WARNING: Do not touch anything inside the tuner during operation! Serious, painful RF burns can result. WARNING: Never operate the MFJ-991B 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 25: Frequency Counter Calibration

    WARNING: Do not touch anything inside the tuner during operation! Serious, painful RF burns can result. WARNING: Never operate the MFJ-991B 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 26: 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 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-991B Manual 300 Industrial Park Road Version 1A Starkville, MS 39759 Printed In U.S.A. 10/2005...

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