Icom IC-78 Instruction Manual - Page 21

4 OPERATION s Functions for receive 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 turn the the preamp ON and OFF. • Preamp functions below 1.6 MHz, but sensitivity may be reduced in some cases. Appears when the preamp is ON. ï Attenuator The attenuator prevents desired signals from distorting when very strong signals are near the desired frequency or when very strong electric fields, such as from broadcasting stations, are near your location. ¯ Push [ATT] to turn the 20 dB attenuator function ON and OFF. • "ATT" appears when the attenuator is turned ON. Appears when the attenuator is ON. ï Noise blanker The noise blanker reduces pulse-type noise such as that generated by automobile ignition systems. q Push the [NB] switch to turn the noise blanker ON. • [NB] indicator appears. w Push the [NB] for 1 sec. to enter the noise blanker level setting condition. e Rotate the channel selector to adjust the noise blanker level. r Push [NB] to exit the setting condition. t Push [NB] again to turn the noise blanker function OFF. • [NB] indicator disappears. • When using the noise blanker, received signals may be distorted if they are excessively strong. •The noise blanker function in AM mode can be deactivated depending on initial set mode setting. (p. 31) [NB] switch Appears when the noise blanker is ON. 19