OPERATION
NOTE: The Farnsworth Spacing feature is only operative in the Random Code Generation mode.
Farnsworth does not affect the normal keying or Memory Playback modes.
A & B Type Keying:
The MFJ-486 features selectable A-type or B-type iambic keying modes. Type "A" does NOT pro-
duce a following alternate element when a squeeze is released during a dot or dash. Type "B" does
produce a following alternate element after squeeze release. For example, in Type "A", squeeze re-
lease during the "dah" in the letter A will produce just the A. In Type "B", squeeze release during
the "dah" in the letter A will produce an R. The MFJ-486 is shipped in the B-type keying mode. To
change keying modes, follow these steps:
A. Place all pushbutton switches in the "off" or "out" position. The power should now be off.
B. Squeeze both the dot and dash paddles.
C. While maintaining the squeeze on the dot and dash paddles, turn the power on. The Delay/Ed-
it LED should turn on.
D. When the Delay/Edit LED turns on, release the dot and dash paddles. The keying modes are
now changed.
This is a toggle function so if you are in the A-type keying mode you will be changed to the B-type
keying mode. Likewise if you are in the B-type keying mode, you will be changed to the A-type
keying mode.
SPEED ADJUSTMENT:
The Speed Control Potentiometer is used in conjunction with the Speed Set Switch to adjust key-
ing speed. The Speed Control Potentiometer will adjust the keying speed over a 5 to 1 ratio. The
Speed Set Switch will make the current speed control setting equal to 20 WPM. For example, if the
Speed Control Pot is all the way clockwise and the Speed Set Switch is pressed, the keyer will be
set to 20 WPM. The Speed Control Pot will then adjust the speed from a minimum of 4 WPM to a
maximum of 20 WPM. If the Speed Control Pot is set all the way counter-clockwise and the Speed
Set Switch is pressed, the keyer will again be set to 20 WPM and the control pot will adjust the
speed from a minimum of 20 WPM to a maximum of 100 WPM. When the Speed Control Pot is set
midrange and the Speed Set Switch is pressed, the keying speed will be set to 20 WPM and the
range of the pot will be adjusted accordingly. The speed is set in this manner to avoid making the
Speed Control Pot setting too critical.
This technique gives the user the widest range of speeds possible and allows for simple operation.
SPEED SET SWITCH:
This switch is used in conjunction with the Speed Control Pot to adjust keying speeds. Another
function of this switch is weight reset. When this switch is pressed the weight will be reset to a ra-
tio of 1:3:1.
DOT WEIGHT ADJUSTMENT:
The dot weight is adjusted by holding the dot paddle down for more than eight consecutive dots
and adjusting the weight control. This adjustment should be made slowly as the weight changes
only after the eighth dot. The dot-dash weight may be reset to 1:3:1 by pressing the speed I V set
switch.
