MFJ MFJ-928 User Manual

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 200 MFJ ENTERPRISES, INC.5
C
Model MFJ-928
VERSION 0A
Compact IntelliTuner
Automatic Antenna Tuner
TM

MFJ MFJ-928 Specifications

General

Brand	MFJ
Model	MFJ-928
Category	Tuner
Language	English

Summary

Introduction to the MFJ-928 IntelliTuner

Product Overview and Technology

Introduction to the MFJ-928 IntelliTuner, its algorithms, and memory capabilities.

MFJ-928 Features and Specifications

Key Features

Highlights of the MFJ-928's automatic tuning, memory, and matching capabilities.

Technical Specifications

Detailed technical data including impedance, power, frequency, and physical dimensions.

Getting Started with the MFJ-928

Fast Start Procedure

Quick steps for initial setup, connection, and basic operation of the tuner.

MFJ-928 Front Panel Interface

Front Panel Controls and Indicators

Description of the LEDs (SWR, TUNE) and buttons (TUNE, ANT, POWER).

Button Actions and Modes

Button Functionality Summary

Explanation of single press, hold, and combined button actions for tuning and modes.

Back Panel Connections and Configuration

Power Input and Radio Interface

Details on connecting power and compatible radio interfaces to the tuner.

Radio Interface Configuration

Configuring JP2 jumper and selecting appropriate interface cables for radios.

Interface Cables for Radio Brands

Specifics on interface cables for Kenwood and Yaesu radios, including wiring.

Physical Connection Ports

Description of Transmitter, Antenna 1/2, Wire, and Ground connection terminals.

Installation of the MFJ-928

Installation Steps and Warnings

Step-by-step instructions for physically installing the MFJ-928 antenna tuner.

Miscellaneous Functions

Antenna Memory and Tuning

Details on memory resolution, IntelliTune algorithm, and LC tuning limits.

Tuner Feedback and Protection

Understanding tuner feedback signals (beeps, Morse code) and foldback circuit operation.

Grounding and Antenna System Hints

Grounding Best Practices

Recommendations for effective RF and safety grounding connections.

Antenna System Location Tips

Guidance on optimal placement of antennas for best performance.

Troubleshooting Matching Issues

Antenna Matching Problems

Analysis and solutions for common impedance matching challenges with antennas.

Appendices and Special Operations

Power-On Operation Modes

Special functions and tests initiated by holding buttons during power-on.

Tuner Reset and Memory Management

Resetting and Deleting Memories

Procedures for resetting to factory defaults and deleting antenna memories.

Self-Test and Diagnostics

Performing the Self-Test

Steps to run the self-test routine and interpret failure messages.

Circuit and Relay Testing

Power-Down and Relay Tests

Testing the power-down circuit and individual relays for proper function.

Calibration Procedures

Frequency Counter Calibration

Steps to calibrate the internal frequency counter using test equipment.

SWR Bridge Calibration

Procedure for calibrating the SWR bridge using a transmitter and wattmeter.

Troubleshooting and Difficulties

Addressing Common Issues

Guidance for resolving issues like blank screens, erratic behavior, or tuning failures.

Support and Accessories

Technical Assistance and Accessories

Contact information for technical help and a list of available accessories.

MFJ-928 Circuit Block Diagram

Internal Circuitry Overview

Visual representation of the MFJ-928's internal components and their interconnections.

MFJ-928 Warranty Information

Limited 12 Month Warranty Terms

Details of the warranty coverage, terms, and conditions for the MFJ-928.