Icom IC-7800

4-22
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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.
• 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.
• Fine tuning (p. 3-7)
➥ During PSK, make sure that the kHz tuning step
function is OFF (no “Z” indication), hold down
[TS] for 1 second.
•PSKmaynotbedecodedcorrectlyusingthe10Hz
step tuning.
•
1
⁄4 function (p. 3-6)
➥ Push [1/4] to turn the
1
⁄4 function ON or OFF.
D About BPSK and QPSK mode
BPSK and QPSK modes are available for PSK31.
[F-3•DECODE][F-2•B/QPSK][F-1•<MENU1>]
 •BPSK(BinaryPhaseShiftKeying)modeisthemost
commonly used mode.
•QPSK(QuadraturePhaseShiftKeying)modehas
error correction capability to provide better decoding
than BPSK mode in marginal condition. However,
more accurate tuning is required with QPSK mode,
due to the tight phase margin of QPSK.
qDuringPSKmodeselection,push[F-3•DECODE]
to display the PSK decode screen.
wPush[F-1•<MENU1>]toselectPSKdecodemenu
2.
ePush[F-2•B/QPSK]totogglebetweenBPSKand
QPSK mode alternately.
4
RECEIVE AND TRANSMIT
• PSK decode screen— BPSK mode
• PSK decode screen— QPSK mode
l About the 5 MHz frequency band operation (USA version only)
See page 4-3 for details.