MFJ-452 CW Keyboard
Instruction Manual
2
Keyboard Operation
When the MFJ-452 is activated, it will send the characters "ON" in Morse code over the sidetone speaker
and turn on the
POWER
LED. This confirms that the unit is ready for operation. Character message
memories can now be set along with the speed, tone, and weight of the code. Volume level can also be
adjusted using the volume control on the front of the unit.
Pressing a key will send a character to the key output and the speaker. Characters typed faster than can be
transmitted at the current code speed will fill the type-ahead buffer. This buffer empties as the code is
played. Characters may be removed from the buffer by pressing the backspace key. When the buffer
reaches 130 characters the sidetone frequency will lower. If the buffer fills to capacity, an error tone will
sound every time a key is pressed, and any characters typed over 150 will be lost.
Transmitted characters and buffer text may be monitored using the LCD display on the MFJ-452. This
readout is comprised of two lines of text, each containing 16 characters. The top line shows the text in the
buffer. The bottom line shows the text currently being transmitted.
During transmission, the type ahead buffer may be cleared by pressing
Esc
. When the buffer is empty, a
new message may be played, or new text entered. Selecting
Pause
during transmission stops playback of
the buffer text and allows entry of text with the paddle.
Esc
resumes the playback of the buffer text from
the point where it was interrupted.
Adjusting Code Parameters
Note:
The output key is disabled during parameter changes so that no erroneous code is transmitted.
Code WPM Speed
Code speed is set using the
F10
key. After
F10
is pressed, the MFJ-452 sends a series of dot-dashes over
the sidetone speaker to indicate the current speed. The up and down arrow keys can be used to vary the
speed gradually. Code speed can also be set to an approximate words-per-minute by entering a two-digit
number (i.e., 05 or 13). The speed will then change to the new setting automatically. When all speed
changes are complete, press
Esc
or
Enter
to exit the speed change mode.
Code Weight
To adjust the code weight, select
F9
to enable the command mode and press
W
. A series of dot-dashes is
played from the sidetone speaker. The up and down arrows may be used to adjust the on-time and off-
time length of a dot or dash. Press either
Esc
or
Enter
to exit. This feature allows personalized code and
can help to avoid clipping if the radio or amplifier has a send delay. It can also increase the radio's power
out by increasing on time.
Sidetone Frequency
To adjust sidetone frequency, press
F9
to enable the command mode, and press
T
. This command will
toggle the sidetone on, and
the unit will sound the present tone setting. Use the up and down arrow keys
to increase or decrease the sidetone setting. Note that the tone will not affect the transmitted signal. Only
the sidetone speaker frequency changes. Press either
Esc
or
Enter
to exit the tone change mode.
Note:
All code parameters, speed, weight, sidetone, random code setup, and message memories are
saved in nonvolatile memory. Memory life is rated greater than 20 years.
