Gc Function Control; Selecting The Preset Value; Adjusting The Agc Time Constant; Setting The Agc Time Constant Preset Value - Icom IC-7851 Instruction Manual

7
FUNCTIONS FOR RECEIVE
■ AGC function control
The AGC (Automatic Gain Control) controls receiver
gain to produce a constant audio output level, even
when the received signal strength varies greatly.
The transceiver has three preset AGC settings (time
constants: fast, mid, slow) for non-FM modes.
The FM mode AGC time constant is fixed as 'FAST'
(0.1 seconds) and the AGC time constant cannot be
selected.
D Selecting the preset value
q
Select a non-FM mode.
w
Push the Multi-function [AGC](
to select AGC fast, mid or slow.
• Hold down [AGC VR] for 1 second to turn OFF the AGC
function.
D Adjusting the AGC time constant
q
Select a non-FM mode.
Push [AGC VR], then rotate the [AGC] control to ad-
w
just the time constant.
• The [AGC VR] indicator lights.
• "VR" is displayed to the right of the Multi-function [AGC]
() key.
• To set the time constant to fast, rotate to the right. And to
set the time constant to slow, rotate to the left.
D Setting the AGC time constant preset value
q
Select a non-FM mode.
w
Push the Multi-function [AGC](
to select AGC fast, mid or slow.
e
Hold down the Multi-function [AGC](
ond.
• The AGC screen is displayed.
r
Rotate [MAIN DIAL] to set the desired time con-
stant.
• The selectable time constant is shown to the right.
• Hold down [DEF](F) for 1 second to select the default
value.
• While in the AGC Set mode, you can select the AGC or
the operating mode.
t
Push [EXIT/SET].
• Exits the AGC screen.
NOTE: When you are receiving a weak signal, and
a strong signal is momentarily received, the AGC
function quickly reduces the receiver gain. When
that signal disappears, the transceiver may not re-
ceive the weak signal because of the AGC action. In
that case, select AGC fast, or hold down [AGC-VR]
for 1 second to turn OFF the time constant.
) key several times
) key several times
) key for 1 sec-
7-4
[AGC] control (≈) Multi-function keys
[AGC VR] (F) Function keys
AGC indicator
• When selecting "AGC-MID"
• The AGC screen
• Selectable AGC time constant
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)
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) 0.1 (Fixed)
[MAIN DIAL]
[EXIT/SET]
• When selecting "AGC VR"
(unit: seconds)