MFJ MFJ-407D User Manual

MFJ-407D Instruction Manual Deluxe Electronic Keyer

Introduction

The MFJ-407D Deluxe Electronic Keyer is a microprocessor controlled keyer
that provid es iambic key operation and dot-and-dash memory to make sending
perfect code easier. It has tunable code speed, code weight, and sidetone
frequency; it supports both direct and grid-block keying outputs. You also get to
choose between Iambic Type "A" and Type "B" keying.

Control Functions

1. The Power button turns the unit ON and OFF. The power is ON when the

button is locked in the "in" position and OFF in the "out" position.

2. The Tune button continuously keys the transmitter for tuning.

3. The Semi-Auto/Auto button allows semi-automatic "bug" and manual

operations. The keyer generates dots automatically when a squeeze or
single lever key is used. Dashes are manually made. The keyer is
completely manual when a straight key is used. Semi-Auto is active when
the switch is in the "in" position and Auto when in the "out" position.

4. The Speed control varies the code speed. The speed range is configured

with an internal jumper (JMP9) for 5 to 65 WPM or 10 to 40 WPM. Turn
the control clockwise to increase speed and counter-clockwise to decrease
speed. The unit is factory set to 5 to 65 WPM. To make the speed
adjustment less sensitive, change the speed range to the narrower range of
10 to 40 WPM. To change the speed range the power must be off, then
remove the cover by removing the two screws (one on each side) that secure
it. Locate jumper JMP9 next to the microprocessor and set it to the "H"
position.

Note: Power must be off when changing the jumper settings.

5. The Weight control varies the code weight from approximately 25% to

75%, with the standard dot defined as 50% weight. The standard dot-dash­space ratio is 1:3:1 (trimpot at mid-range). This control is turned clockwise
to increase dot and dash lengths and counter-clockwise to decrease dot and
dash lengths.

6. The Tone control sets the desired sidetone pitch from approximately 300 to

1200 Hz. This control is turned clockwise to raise the pitch and counter­clockwise to lower the pitch.

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MFJ-407D Instruction Manual Deluxe Electronic Keyer

7. The Volume control adjusts the sidetone level of the internal speaker. Turn

the control clockwise to increase the volume and counter-clockwise to
decrease the volume.

8. The Direct/Grid-Block Output keying circ uit allows keying of grid-bl ock

and solid state transmitters. The MFJ-407D can only key one type of
transmitter at a time. This is an internal jumper selected option. The unit is
factory set to d ire ct keying. T o change t o gri d-bl ock ke ying the power must
be off, then remove the cover by removing the two screws (one on each
side) that secure it. Locate JMP1 and JMP2. JMP2 is directly behind the
RCA jack and JMP1 is approximately one inch in front of JMP2. Set both
jumpers JMP1 and JMP2 to the "G" position. To key a solid state
transmitter, set both jumpers to the "D" position.

Note: Power must be off when changing the jumper settings.

9. The Iambic Type A/B mode is also set inside the unit with a jumper. The

unit is factory set for Type "A" Iambic. If you prefer Type "B" Iambic,
remove the cover by removing the two screws (one on each side) that secure
it. Locate jumper JMP3 and set it to the "B" position. For Type "A"
Iambic, set the jumper to the "A" position.

Note: Power must be off when changing the jumper settings.

When a squeeze is released during an element (dot or dash), type "B" adds
the opposite element. Type "A" just finishes the element in progress and
does not produce a following alternate element. For example, in Type "A"
Iambic, a squeeze release during the "dah" in the letter A will produce "di­dah" (A). In Type "B" Iambic, a squeeze release during the "dah" in the
letter A will produce "di-dah-dit" (R).

Installation

1. A 9-volt battery (not included) may be installed. Remove the cover by
removing the two screws (one on each side) that secure it.. A battery holder,
located inside the enclosure, is provided for installing a 9-volt battery.

2. A 12 Vdc power supply may also be used to power the MFJ-407D. A

2.1mm coaxial plug with a positive center and a negative sleeve should be
used to power this unit. The MFJ-1312B, an optional 12 volts adapter, is
available from MFJ Enterprises, Inc. The battery is automatically
disconnected when external power is used.

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MFJ-407D Instruction Manual Deluxe Electronic Keyer

3. A squeeze or single lever key can be used. Squeeze key allows Iambic
operation. A 1/4-inch stereo phono plug and a two-conductor shielded cable
should be used. If separate shielded cables are used, the two shields should
be tied together and connected to ground. The dot wire should be connected
to the tip of the plug and the dash wire to the ring. The MFJ-407D becomes
a manual keyer when a straight key is used. The unit will safely key your
transmitter and eliminate the shock hazard of high voltage being present on
the straight key.

Note: To use a straight key, first switch the keyer to the Semi-Auto mode

(button in). Again a 1/4-inch stereo phono plug should be used
because a mono plug will not work on a straight key in Semi-Auto
mode. Connect one wire to the ring of the plug and another wire to
ground. The tip of the plug should not used.

4. Output keying circuit allows keying of grid-block and solid state
transmitters. Remember this is internally jumper selected (refer to page 2).
The keying output c onnection is made with a RCA phono plug.

Note: Consult the transmitter's instruction manual to determine which

output to use. When in doubt, try both jumper positions. The
transmitter will key continuously when the jumpers are connected to
the wrong positions.

Keyer Operation

1. A 9-volt battery or an optional dc adapter may be used to supply power to
the keyer.

2. The key paddle should be connected to the Key jack on the rear panel of the
unit. A dual paddle squeeze key or a single lever key can be used.

3. An external speaker can be connected to the Speaker jack on the rear panel
of the unit.

4. Next, the keyer should be turned on with the Power switch.

5. The Semi-Auto/Auto switch should be in the "out" position for automatic
operation.

6. The user should now start sending with the paddle and adjust volume, tone,
weight, and speed to his or her preference.

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