Icom IC-7850 Instruction Manual page 21

#0 MULTI-FUNCTION KEYS
Push to select the functions indicated in the display
to the right of these keys.
• Functions vary, depending on the operating mode.
➥ Push to select the ANT1, ANT2, ANT3 or
ANT4 antenna connector.
➥ Hold down for 1 second to display the
antenna selection memory.
• When the receive antenna is activated, the
antenna that is connected to [ANT4] is used
only for receive.
When a transverter is used, this [ANT]
does not function and "TRV" appears.
➥ Push to select the RF power
ALC, COMP, V
transmitting.
➥ Hold down for 1 second to turn the Digital
multi-function meter ON or OFF.
➥ Push to select one of two receive RF
preamps, or bypass them.
• "P.AMP1" activates a 10 dB preamp.
• "P.AMP2" activates a 16 dB high-gain pre-
amp.
✔ What is a preamp?
A preamp amplifies received signals in the front end
circuit to improve S/N ratio and sensitivity. Select
"P.AMP1" or "P.AMP2" when receiving weak signals.
➥ Push to select the 6 dB, 12 dB or 18 dB
attenuator.
➥ Hold down for 1 second to select the 3
dB, 6 dB, 9 dB, 12 dB, 18 dB, or 21 dB
attenuator.
✔ What is an attenuator?
An attenuator prevents a desired signal from distorting
when very strong signals are near the desired frequen-
cy, or when very strong electric fields, such as from a
broadcasting station, are near your location.
(p. 13-2)
(p.13-5)
, SWR,
(P o )
d or I d metering while
(p. 4-11)
(p. 4-11)
(p. 7-2)
(p. 7-2)
(p. 7-2)
➥ Push to activate and then select the
"FAST," "MID," or "SLOW" AGC time con-
stant. (p. 7-4)
• In the FM mode, only "FAST" is selectable.
➥ Hold down for 1 second to enter the AGC
set mode.
The AGC time constant can be set be-
tween 0.1 to 8.0 second
mode)
"OFF," the S-meter does not function.
✔ What is AGC?
The AGC controls receiver gain to produce a constant
audio output level, even when the received signal
strength varies dramatically. Select "FAST" for tuning
and then select "MID" or "SLOW" depending on the re-
ceiving condition.
➥ Turns the speech compressor ON or
OFF in the SSB mode.
➥ Selects the narrow, middle or wide com-
pression when held down for 1 second.
✔ What is a speech compressor?
A speech compressor compresses the transmitter au-
dio input to increase the average audio output level,
and therefore increase the talk power. This function
is effective for long-distance communication, or when
propagation conditions are poor.
➥ Push to turn the
tion ON or OFF in the SSB data, CW,
RTTY and PSK modes.
1
• ⁄ function sets the dial rotation to
4
normal speed for fine tuning.
➥ In the FM mode, push to toggle between
the tone encoder, tone squelch function
and no-tone operation.
➥ In the FM mode, hold down for 1 second
to enter the Tone set mode.
5-39)
➥ Push to turn the Voice squelch control
function ON or OFF. This is useful for
scanning.
1-5
PANEL DESCRIPTION
(p. 7-4)
(depending on the
, or turned OFF. When AGC is
(p. 8-6)
1 ⁄ -speed tuning func-
4
(p. 4-9)
(p. 5-39)
(p. 12-10)
1
1
⁄ of the
4
(pp. 5-38,