Icom IC-7800

4-14
D Convenient functions for receive
• Preamp (p. 5-10)
➥ Push [P.AMP] several times to set the preamp
OFF, preamp 1 ON or preamp 2 ON.
•“P.AMP1”or“P.AMP2”appearswhenthepreamp1
or preamp 2 is ON. Main and sub have independent
preamp controls.
• Attenuator (p. 5-10)
➥ Push [ATT] several times to set the attenuator in
6 dB steps.
•Holddown[ATT]for1secondtosettheattenuatorin
3 dB steps.
•“ATT”andattenuationlevelappearwhentheattenu-
ator is ON.
• Noise blanker (p. 5-18)
➥ Push [NB] switch to turn the noise blanker ON or
OFF, and then rotate [NB] control to adjust the
threshold level.
•Noise blanker indicator (above [NB] switch) lights
when the noise blanker is ON.
•Hold down [NB] for 1 second to enter the noise
blanker set mode.
• Twin PBT (passband tuning) (p. 5-13)
➥ Rotate [TWIN PBT] controls (inner/outer).
•Holddown[PBTCLEAR]for1secondtoclearthe
settings.
• Noise reduction (p. 5-19)
➥ Push [NR] switch to turn the noise reduction ON
or OFF.
•Rotate [NR] control to adjust the noise reduction
level.
•Noisereductionindicator(above[NR]switch)lights
when the noise reduction is ON.
• Notch filter (p. 5-20)
➥ Push [NOTCH] switch to turn the manual notch
function ON or OFF.
•Rotate[NOTCH]controlto settheattenuatingfre-
quency.
•Notchindicator(above[NOTCH]switch)lightswhen
either the auto or manual notch is ON.
• AGC (auto gain control) (p. 5-12)
➥ Push [AGC] switch several times to select AGC
FAST, AGC MID or AGC SLOW.
➥Push[AGCVR]toturntheAGCtimeconstant
manual setting ON or OFF.
•Rotate[AGC]controltoadjustthetimeconstant.
•
1
⁄4 function (p. 3-6)
➥ Push [1/4] to turn the
1
⁄4 function ON or OFF.
D About RTTY reverse mode
Normal Reverse
Space
Mark
BFO
Space
Mark
BFO
170 Hz 2125 Hz 170 Hz2125 Hz
Received characters are occasionally garbled when
the received signal has Mark and Space tones re-
versed. This reversal can be caused by incorrect TNC
connections, setting, commands, etc. To receive re-
versed RTTY signals correctly, select RTTY-R mode.
➥ During RTTY mode, hold down [RTTY/PSK] for 1
second to select RTTY and RTTY-R mode.
D Twin peak filter
[APF/TPF]
(SUB)
[APF/TPF]
(MAIN)
The twin peak filter changes audio frequency response
by boosting the mark and space frequencies (2125
and 2295 Hz) for better reception of RTTY signals.
➥ During RTTY mode, push [APF/TPF] to turn the
twin peak filter ON or OFF.
•“ ” appears in the LCD and the [APF/TPF] indicator
above this switch lights green while the filter is in use.
NOTE: When the twin peak filter is in use, the re-
ceived audio output may increase. This is a normal,
not a malfunction.
4
RECEIVE AND TRANSMIT