MFJ MFJ-9232 Instruction Manual

QRP Mini Loop Tuner

Model MFJ-9232

CAUTION: Read All Instructions Before Operating Equipment

MFJ ENTERPRISES, INC.

Tel: [phone] Fax: [phone]

VERSION 1A

INSTRUCTION MANUAL

300 Industrial Park Road

Starkville, MS 39759 USA

COPYRIGHT 2016 MFJ ENTERPRISES, INC.

MFJ-9232 Mini Loop TunerTM Instruction & Technical Manual

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: [phone]. Business hours: M-F 8-4:30 CST.

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MFJ-9232 Mini Loop TunerTM Instruction & Technical Manual

INTRODUCTION & FEATURES

MFJ-9232 MINI LOOP TUNERTM INTRODUCTION

TM

The MFJ-9232 Mini Loop Tuner

is a small, versatile, high-efficiency device that turns any wire loop
into a high-efficiency multi-band transmitting antenna system. It is designed for 50-ohm use at QRP­power input on all modes. Two items are required:

• MFJ-9232 Mini Loop Tuner

TM

(Shown in Figure 1)

• Wire Loop(s) (not included)

Figure 1: MFJ-9232 Mini Loop Tuner

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MFJ-9232 Mini Loop TunerTM Instruction & Technical Manual

INTRODUCTION & FEATURES

The MFJ-9232 Mini Loop Tuner

TM

resonates various lengths of wire to create a Hi-Q tuned-circuit
that functions as a transmitting loop. It uses special low-loss capacitors for high efficiency and
interfaces the Hi-Q transmitting loop circuit with any length of 50-Ohm coaxial cable.

No ground, radials, or counterpoise system are needed. The MFJ-9232 Mini Loop Tuner

TM

functions
with wire loops of any shape -- circle, square, rectangle etc. For highest efficiency, use wires
approaching one quarter wavelength erected in the shape of a circle.

The MFJ-9232 Mini Loop Tuner

TM

uses fixed wire lengths to cover roughly a 1.5:1 frequency ratio
(28-18 MHz, 10-7 MHz, etc.). Exact frequency coverage depends on each individual installation and
involves your choice of wire length, loop diameter, loop shape, height above ground level, plus other
stray factors in the immediate operating environment.

MFJ-9232 MINI LOOP TUNERTM FEATURES:

• Passive Network: No power supply required.

• Maximum Input Power: 25 Watts, all modes

• Small Physical Profile: 1.5" D, 2.75" W, 4.0" H

• Low Radiation Angle: Radiation pattern rivals full size dipoles.

• Quiet Reception: Loops make extremely quiet receiving antennas. Hi-Q rejects overload from

out-of-band interference, rejects transmit harmonics.

• Indoor Use: Perfect for portable operation or antenna-restricted locations. Sets up quickly in
apartments and motel/hotel rooms.

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MFJ-9232 Mini Loop TunerTM Instruction & Technical Manual

RF HAZARD PRECAUTIONS

RF HAZARD BACKGROUND INFORMATION

The following WARNINGS should be observed when using your MFJ-9232 MINI LOOP TUNERTM:

ACUTE INJURY WARNING

DO NOT touch or make skin contact with the Loop

Connectors or Loop Antenna Wire while transmitting

YOU Could BE SERIOUSLY INJURED

The Hi-Q MFJ-9232 Mini Loop Tuner
operation. Even at low QRP power levels, the resonant loop circuit can produce RF voltages capable
of causing extremely painful RF-burns on unprotected skin! When tuning or transmitting, always avoid
skin contact with the loop connectors and unjacketed loop wire. Also, avoid exceeding the
recommended power limitation (25W). RF burns can be exceptionally painful and slow to heal!

TM

can yield DANGEROUS RF-voltage potentials during normal

!!!

EXCESSIVE RF-EXPOSURE NOTICE

You must follow all PRECAUTIONS, WARNINGS, and FCC Guidelines for Human Exposure to

Radio frequency (RF) Electromagnetic Fields

What Is Radio Frequency (RF) Radiation?

Radio frequency (RF) energy is one form of electromagnetic energy. Electromagnetic waves and
associated phenomena can be discussed in terms of energy, radiation or fields. Electromagnetic
"radiation" is defined as waves of electric and magnetic energy moving together (i.e., radiating)
through space. The movement of electrical charges generates these waves. For example, the
movement of charge in a radio station antenna (the alternating current) creates electromagnetic
waves radiating away from the antenna and intercepted by receiving antennas. Electromagnetic
"field" refers to the electric and magnetic environment existing at some location due to a radiating
source such as an antenna.

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