Icom IC-7800 Instruction Manual - Page 93

AGC function

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5 FUNCTIONS FOR RECEIVE I AGC function [AGC] control for main [AGC] control for sub [AGC VR] for main [AGC VR] for sub [AGC] The AGC (auto gain control) controls receiver gain to produce a constant audio output level even when the received signal strength varies greatly. The transceiver has 3 preset AGC characteristics (time constant: fast, mid, slow) for non-FM mode. The FM mode AGC time constant is fixed as 'FAST' (0.1 sec.) and AGC time constant cannot be selected. D Selecting the preset value q Select non-FM mode. w Push [AGC] several times to select AGC fast, AGC medium (MID) or AGC slow. • Push [AGC VR] for 1 sec. to turn the AGC function OFF. D Adjusting the AGC time constant q Select non-FM mode. w Push [AGC VR], then rotate [AGC] control to adjust the AGC time constant. • [AGC VR] indicator above the switch lights green. D Setting the AGC time constant preset value q Select the desired mode (not FM mode). w Push [AGC] for 1 sec. to enter AGC set mode. e Push [AGC] several times to select FAST time con- stant. r Rotate the main dial to set the desired time constant for 'AGC FAST.' • Selectable AGC time constant (unit: sec.) • AGC time constant can be set between 0.1 to 8.0 sec. (depends on mode) or turned OFF. Mode Default Selectable AGC time constant SSB 0.3 (FAST) 0.1, 0.2, 0.3, 0.5, 0.8, 1.2, 1.6, 2.0, 2.0 (MID) 2.5, 3.0, 4.0, 5.0, 6.0 6.0 (SLOW) 0.1 (FAST) 0.1, 0.2, 0.3, 0.5, 0.8, 1.2, 1.6, 2.0, CW 0.5 (MID) 2.5, 3.0, 4.0, 5.0, 6.0 1.2 (SLOW) 0.1 (FAST) RTTY 0.1, 0.2, 0.3, 0.5, 0.8, 1.2, 1.6, 2.0, 0.5 (MID) PSK 2.5, 3.0, 4.0, 5.0, 6.0 1.2 (SLOW) 3.0 (FAST) 0.3, 0.5, 0.8, 1.2, 1.6, 2.0, 2.5, 3.0, AM 5.0 (MID) 4.0, 5.0, 6.0, 7.0, 8.0 7.0 (SLOW) FM 0.1 (FAST) Fixed • Push [F-4•DEF] for 1 sec. to select a default value. t Push [AGC] to select medium time constant. y Rotate the main dial to set the desired time constant for 'AGC MID.' • AGC time constant can be set between 0.1 to 8.0 sec. (depends on mode) or turned OFF. • Push [F-4•DEF] for 1 sec. to select a default value. u Push [AGC] to select slow time constant. i Rotate the main dial to set the desired time constant for 'AGC SLOW.' • AGC time constant can be set between 0.1 to 8.0 sec. (depends on mode) or turned OFF. • Push [F-4•DEF] for 1 sec. to select a default value. o Select another mode (not FM). Repeat steps e to i if desired. !0 Push [EXIT/SET] to exit the AGC set mode screen. 5-11

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5-11
■
AGC function
The AGC (auto gain control) controls receiver gain to
produce a constant audio output level even when the
received signal strength varies greatly.
The transceiver has 3 preset AGC characteristics (time
constant: fast, mid, slow) for non-FM mode.
The FM mode AGC time constant is fixed as ‘FAST’
(0.1 sec.) and AGC time constant cannot be se-
lected.
D
Selecting the preset value
q
Select non-FM mode.
w
Push [AGC] several times to select AGC fast, AGC
medium (MID) or AGC slow.
• Push [AGC VR] for 1 sec. to turn the AGC function OFF.
D
Adjusting the AGC time constant
q
Select non-FM mode.
w
Push [AGC VR], then rotate [AGC] control to adjust
the AGC time constant.
• [AGC VR] indicator above the switch lights green.
D
Setting the AGC time constant preset value
q
Select the desired mode (not FM mode).
w
Push [AGC] for 1 sec. to enter AGC set mode.
e
Push [AGC] several times to select FAST time con-
stant.
r
Rotate the main dial to set the desired time constant
for ‘AGC FAST.’
• AGC time constant can be set between 0.1 to 8.0 sec.
(depends on mode) or turned OFF.
• Push [F-4•DEF] for 1 sec. to select a default value.
t
Push [AGC] to select medium time constant.
y
Rotate the main dial to set the desired time constant
for ‘AGC MID.’
• AGC time constant can be set between 0.1 to 8.0 sec.
(depends on mode) or turned OFF.
• Push [F-4•DEF] for 1 sec. to select a default value.
u
Push [AGC] to select slow time constant.
i
Rotate the main dial to set the desired time constant
for ‘AGC SLOW.’
• AGC time constant can be set between 0.1 to 8.0 sec.
(depends on mode) or turned OFF.
• Push [F-4•DEF] for 1 sec. to select a default value.
o
Select another mode (not FM). Repeat steps
e
to
i
if desired.
!
0
Push [EXIT/SET] to exit the AGC set mode screen.
[AGC]
[AGC] control for main
[AGC VR] for main
[AGC VR] for sub
[AGC] control for sub
5
FUNCTIONS FOR RECEIVE
Mode
Default
Selectable AGC time constant
0.3 (FAST)
0.1, 0.2, 0.3, 0.5, 0.8, 1.2, 1.6, 2.0,
SSB
2.0 (MID)
2.5, 3.0, 4.0, 5.0, 6.0
6.0 (SLOW)
0.1 (FAST)
0.1, 0.2, 0.3, 0.5, 0.8, 1.2, 1.6, 2.0,
CW
0.5 (MID)
2.5, 3.0, 4.0, 5.0, 6.0
1.2 (SLOW)
RTTY
0.1 (FAST)
0.1, 0.2, 0.3, 0.5, 0.8, 1.2, 1.6, 2.0,
PSK
0.5 (MID)
2.5, 3.0, 4.0, 5.0, 6.0
1.2 (SLOW)
3.0 (FAST)
0.3, 0.5, 0.8, 1.2, 1.6, 2.0, 2.5, 3.0,
AM
5.0 (MID)
4.0, 5.0, 6.0, 7.0, 8.0
7.0 (SLOW)
FM
0.1 (FAST)
Fixed
•
Selectable AGC time constant
(unit: sec.)