Icom IC-718 Instruction Manual - Page 23

5 RECEIVE AND TRANSMIT s Function for receive ï IF shift function 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. Both controls at center position SHIFT Cutting a lower passband SHIFT Cutting higher passbands SHIFT Interference Passband Passband Interference IF center frequency Desired signal Desired signal 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. • " " appears on the display. • The transmit frequencies are not shifted. w To cancel the RIT function, rotate the RIT control to the center position. • " " 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. 21