MFJ MFJ-441 User Manual

MFJ-441 Instruction Manual SlimLine Econo Keyer

Introduction

The MFJ-441 SlimLine™ Econo Keyer with Memory is a microprocessor
controlled keyer that provides 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. It even has a
volatile memory to record and play a message of your choice.

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 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.

3. The Message button lets you record and play a message from the volatile

memory. It is a momentary push-button that is time sensitive.

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 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). Turn the control clockwise to
increase dot and dash lengths and counter-clockwise to decrease dot and
dash lengths. This control is located internally. When looking at the unit's
front panel, it is accessible through the small hole on the left side, closest to
the rear and may be adjusted by inserting a small, flat-headed screwdriver.

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

1200 Hz. Turn the control clockwise to raise the pitch and counter-

1

MFJ-441 Instruction Manual SlimLine Econo Keyer

clockwise to lower the pitch. This control is located internally. When
looking at the unit's front panel, it is accessible through the small hole on the
left side, closest to the front and may be adjusted by inserting a small, flat­headed screwdriver.

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-441 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

2

MFJ-441 Instruction Manual SlimLine Econo Keyer

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-441. 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.

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-441 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.

3

MFJ-441 Instruction Manual SlimLine Econo 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. Next, the keyer should be turned on with the Power switch.

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

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

6. The dot and dash memories make sending easier. The memories allow the
user to key a dot before the completion of a dash and vice versa. This
feature can be checked by setting the keyer to the lowest speed and tapping
first the dash lever and then the dot lever before the completion of the dash.
The keyer will provide both the dash and the dot. The dash memory can be
checked in a similar manner. The dot insertion feature allows the user to
insert a dot by tapping the dot lever while holding the dash lever in. The
dash insertion feature allows the user to insert a dash while holding the dot
lever in. The Iambic operation allows sending of alternate dots and dashes
when using squeeze key and with both paddles squeezed. The first paddle
contacted will determine whether a dot or dash occurs first.

7. The user may select either Iambic A or B according to his preference.

Message Memory

The Message button is used to record and play your message. To record the
message, press and hold the Message button until the keyer plays "GO" (dah­dah-dit dah-d ah-dah) i n Morse c ode and the LED fla shes. You may now key in
the message of your choice. As you pause after every word, the keyer will play a
"W" (di-dah-dah) over the sidetone speaker to show that it is inserting a word
break (uses one unit of memory). If you make a mistake entering a word, you
can back up over it by briefly pressing and releasing the Message button. The
keyer will erase the last word, then play the word before it (if any) to let you
know where you stopped. If deleting the first word of the message, the keyer
will play "GO" instead. At the end of your message, press and hold the Message
button until the keyer sends an end of message character "+" (di-dah-di-dah-dit)
and the LED stops flashing. When there are ten or less units of memory
remaining, the LED will flash faster to let you know the memory is running low.
If you try to save more characters than you have memory, the keyer will
automatically end your message and send you an end of message character. The

4