MFJ MFJ-644 User Manual

Model MFJ-644

VERSION 1A

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

TABLE OF CONTENTS

TOPIC PAGE

1. TABLE OF CONTENTS 2

2. LIST OF FIGURES AND TABLES 2

3. INTRODUCTION AND FEATURES 3

4. SYSTEM CONTROLS AND INDICATORS 4

5. SYSTEM SETUP 6

a. INTERNAL HEADERS 6 b. INTERNAL JUMPER BLOCKS 7 c. CABLES 13 d. POWER 13 e. HEADPHONES 14 f. RADIO AUDIO 14

7. THEORY OF OPERATION 14

8. MFJ-644 EASY-START INSTRUCTIONS 15

9. IN CASE OF DIFFICULTY 18

10.TECHNICAL ASSISTANCE 18

LIST OF FIGURES

Figure 1 Front Panel Jacks and Controls 4 Figure 2 Rear Panel Jacks and Controls 5 Figure 3 Internal Headers 6 Figure 4-10 Internal Jumper Blocks 7-11 Figure 11 Yaesu Mic Jack Pinout, Front View 12 Figure 12 Block Diagram 15 Figure 13 Schematic 17

LIST OF TABLES

Table 1 Sample Jumper Settings Table for Yaesu FT-1000 Series 12 Table 2 Microphone Pinout 13

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MFJ-644 Universal SO2R Switch Instruction and Technical Manual

INTRODUCTION & FEATURES

INTRODUCTION:

The MFJ-644 hamProAudio Universal SO2R Switch is a quality Single Operator 2 Radio Switch. With the ability to switch the microphone audio between 2 radios and full control of the audio from both radios, you will have the ultimate SO2R switch at a great value.

hamProAudio Quality: Designed with the serious ham in mind. Choice of components and extensive RF filtering and bypassing allows for a unit designed for an RF environment.

Designed for ease of use: Set the internal jumpers for the MFJ-393 Professional BoomMic Headphones, The Heil Pro Set series of Boom-Mic Headsets or even a Computer Boom-Mic Headset.

Instant visual indication of transmit audio path: With wide spaced LED indicators you instantly know which radio your audio is being passed to.

Choice of PTT function: Use your microphone PTT switch, a foot or hand switch, or the convenient PTT switch located on the front of the MFJ-644.

Full control of audio output: With Mix, Radio 1, Stereo, or Radio 2 in the headphones you can instantly select how you want to hear the audio in the headphones.

Full control of accessories: Additional inputs and dual outputs for your keyer and 2 lines to control anything you want or need to switch an antenna between radios or key an amplifier.

Rugged Construction: Attractive all-metal cabinet, conservative component selection and extensive RF filtering ensure solid performance for years to come. Fully covered by MFJ’s “No Matter What” one year limited warranty.

IMPORTANT: Before attempting to operate your MFJ-644, please read the manual thoroughly. It contains important detail about setting up your unit to obtain the best performance.

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MFJ-644 Universal SO2R Switch Instruction and Technical Manual

SYSTEM CONTROLS AND INDICATORS

Front Panel Jack and Controls

™

RADIO 1

MIC

INPUT

RADIO 1

POWER

OFF

HEADPHONES

MIC

INPUT

HEADPHONE AUDIO

MIX

BOTH

MIX

MIC TO

RADIO

MFJ-644

RADIO 2

STEREO

RADIO 2

PTT

LOCK

RADIO 2RADIO 1

UNLOCK

1 2 3 4 5 6 7 8 9 10 11 12

Figure 1: MFJ-644 Front Panel Jacks and Controls

1. Radio 1 LED Indicator: Indicates Radio 1 is selected for microphone audio.

2. RJ-45 Microphone Input Jack: Accepts input from a standard RJ-45 Microphone.

3. 8-Pin Microphone Input Jack: Accepts input from a standard 8 pin round

microphone.

4. Power Switch: Turns the unit on or off.

5. ¼ Inch headphone Jack: Stereo jack to hook up a standard set of ¼ inch stereo

headphones.

6. 3.5 –mm stereo headphone jack: Stereo jack to hook up a pair of quality stereo

3.5–mm headphones.

7. 3.5 –mm microphone input connector. Microphone input. Phantom voltage is also available on the either the tip or ring for your specific need.

8. Mix Control: Control the audio from either radio from Radio 1 only to Radio 2 only and everything in between when in the Mix position.

9. Audio selection switch: Choose from Mix, Radio 1, Stereo or Radio 2 audio.

10. PTT: Use this locking switch to key the radio.

11. Radio 1/ Radio 2-selection switch: This switches between Radio 1 and Radio 2.

12. Radio 2 LED indicator: Indicates Radio 2 is selected for microphone audio.

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MFJ-644 Universal SO2R Switch Instruction and Technical Manual

SYSTEM CONTROLS AND INDICATORS

Rear Panel Jacks

MFJ ENTERPRISES, INC.

STARKVILLE, MS USA

AUX.

AUDIO

INPUT

AUX.

AUDIO

OUTPUT

RADIO2RADIO

KEY

INPUT

KEY

OUTPUT

RADIO2RADIO

EXTERNAL

PTT

SWITCH

RADIO 2

AUDIO

INPUT

RADIO 2

AUDIO

OUTPUT

RADIO 1

AUDIO

INPUT

RADIO 1

AUDIO

OUTPUT

POWER

12VDC

1 2 3 4 5 6 7 8 9 10 11 12

Figure 2: MFJ-644 Rear Panel Jacks

1. Auxiliary Input: This stereo 3.5 –mm jack allows 2 independent lines to be

controlled.

2. Auxiliary Output Radio 2: This stereo 3.5 –mm jack allows the lines to be fed to radio 2 devices.

3. Auxiliary Output Radio 1: This stereo 3.5 –mm jack allows the lines to be fed to radio 1 devices.

4. Key/Keyer in: This 3.5 –mm jack allows a key or keyer to be passed through the unit. Can also be used as an additional auxiliary input.

5. Key/Keyer out Radio 2: This allows the Key or Keyer to be connected to Radio 2.

6. Key/Keyer out Radio 1: This allows the Key or Keyer to be connected to Radio 1.

7. PTT Input: This ¼ inch jack allow a foot or hand switch to be connected to the

MFJ-644.

8. Radio 2 Audio: This 3.5 –mm jack allows audio to be fed from Radio 2.

9. Radio 2 Output: This is where either a MFJ-5398 or MFJ-5397MX connects the unit

to your radio.

10. Radio 1 Audio: This 3.5 –mm jack allows audio to be fed from Radio 1

11. Radio 1 Output: This is where either a MFJ-5398 or MFJ-5397MX connects the

unit to your radio.

12. Power: Accepts 2.1 –mm plug to supply 12-15 Vdc to the MFJ-644.

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MFJ-644 Universal SO2R Switch Instruction and Technical Manual

SYSTEM SETUP

Internal Headers

Figure 3: MFJ-644 Internal Headers

1. Header 1: This header allows phantom voltage to be fed to electret microphones

Default is 0 volts pins 1-2 shorted. Move this jumper to pins 3-4 for 1.5 volts, 5-6 for 5 volts or 7-8 for 8 volts. If used with standard computer microphone/headphones set to 5 volts.

2. Header 2: This header allows the phantom voltage set by header 4 to be passed to the ring or tip of the Auxiliary input jack. Pins 1-2 place the voltage on the tip. Pins 3-4 place the voltage on the ring. Default is off. Pins 1-2 also place the voltage on the Microphone Input connector and must be shorted for stock microphones that require phantom voltage.

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