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MFJ-1278B MULTI-MODE BASIC OPERATION
Receiving CW
The MFJ-1278B receives international Morse Code from 1 to 99 WPM. Reception of
alphabetic and numeric characters, including the puncuations and prosigns listed in Table 4-
4.
From command mode, put the MFJ-1278B in the CW Mode by typing:
MODE CW,xx <ENTER>, where "xx" is the CW transmit speed.
The MFJ-1278B will respond with the mode status lines, and end with the command prompt.
Note that if the user does not select a transmit speed, the MFJ-1278B selects the default
speed of 20 WPM.
The MFJ-1278B is now in the CW mode of operation. To receive CW you go into
CONVERSE mode. Enter CONVERSE mode by typing:
K <ENTER>
The MFJ-1278B is now ready to receive Morse code.
The Tuning Indicator and the DCD led on the front panel, assist the user in tuning in CW
signals Tune your receiver to approximately center the tuning indicator when there is a CW
audio tone actually present. Note that between code elements (dots and dashes), the tuning
indicator will indicate randomly. Once the CW signal has been coarsely tuned in by using the
tuning indicator, further CAREFUL tuning should reveal a spot where the DCD LED flashes
in synchronism with the incoming code. If the DCD LED does not light, then you must
rotate the THRESHOLD control on the MFJ-1278B clockwise until the DCD LED flashes
with the CW signal. If the DCD LED is lit, but does not flash with the CW signal, then rotate
the THESHOLD control counter-clockwise until the DCD LED does flash with the CW
signal.
The demodulator is an extremely narrow filter. It is much narrower than the 500 Hz CW
filter in your radio (if you have such a filter in the radio). This means that very careful tuning
will be required for proper CW demodulation. You should attempt to tune for the center of
the range where the DCD flashes with the incoming CW tone. Once tuned to that spot, the
THRESHOLD control setting should be reduced (counter-clockwise) to a point just above
where the DCD LED stops flashing with the incoming CW tone. The adjustment of the
THRESHOLD control is critical and must be based upon your judgment of best copy. Once
the optimum setting is found it can be pre-set and all remaining tuning done with the receiver
frequency control.
The MFJ-1278B will automatically LOCK and TRACK the speed of the signal, once proper
tuning of the signal has been established. The automatic LOCK and speed TRACKING