Icom IC-718 - Manual (Page 23)

21
5
RECEIVE AND TRANSMIT
n Function for receive
The IF shift function electronically narrows the
passband frequency of the IF (intermediate frequency)
and cuts out higher or lower frequency components of
the IF to reject interference. The function shifts the IF
frequency up to ±1.2 KHz in SSB/CW/RTTY modes
and up ±250 Hz in CW-narrow/RTTY narrow modes.
The IF shift is not available in AM mode. IF SHIFT OPERATION EXAMPLE
• Adjust the [SHIFT] control for a minimum
interference signal level.
• When IF shift is used, the audio tone may be
changed.
• Set the IF shift control to its center position when
there is no interference.
SHIFT SHIFT SHIFT
IF center frequency
Interference
Desired signal
Passband
Both controls at
center position Cutting a lower
passband Cutting higher
passbands
Interference
Desired signal
Passband
ï IF shift function
ï RIT function
The RIT (Receive Incremental Tuning) function
compensates for off-frequencies of communicating
stations. The function shifts the receive frequency up
to 1.2 KHz without moving the transmit frequency.
q Rotate the RIT control to cancel the off-
frequencies.
• “
RIT
” appears on the display.
• The transmit frequencies are not shifted.
w T o c a n c e l t h e R I T
function, rotate the RIT
control to the center
position.
• “
RIT
” disappears.
RIT off position
ï Preamp
The preamp amplifies received signals in the front
end circuit to improve the S/N ratio and sensitivity.
Turn this function ON when receiving weak signals.
 Push [P.AMP] to toggle between preamp or turn
the preamp OFF.
• Preamp functions below 1.59999 MHz, but sensitivity
may reduce in some cases.
Appears when the
preamp ON.