Icom IC-7800 Instruction Manual page 14

@9 MULTI-FUNCTION SWITCHES
Push to select the functions indicated in the LCD
display to the right of these switches.
• Functions vary depending on the operating condition.
➥ Selects the antenna connector from
ANT1, ANT2, ANT3 and ANT4 when
pushed. (p. 10-2)
➥ Displays antenna selection memory
when pushed for 1 sec.
• When the receive antenna is activated, the
antenna which is connected to the [ANT4] is
used for receive only.
When a transverter is in use, this [ANT]
does not function and 'XVERT' appears.
➥ Selects RF power
COMP, V or I
D
(p. 3-10)
➥ Switches the multi-function digital meter
ON and OFF when pushed for 1 sec.
(p. 3-10)
➥ Selects one of 2 receive RF preamps or
bypasses them. (p. 5-9)
• "P. AMP1" activates 10 dB preamp.
• "P. AMP2" activates 16 dB high-gain preamp.
✔ What is the preamp?
The preamp amplifies received signals in the front end cir-
cuit to improve the S/N ratio and sensitivity. Select "P. AMP1"
or "P. AMP2" when receiving weak signals.
➥ Selects 6 dB, 12 dB or 18 dB attenuator
when pushed. (p. 5-9)
➥ Selects 3 dB, 6 dB, 9 dB, 12 dB, 18 dB,
or 21 dB attenuator when pushed for
1 sec. (p. 5-9)
✔ What is the attenuator?
The attenuator prevents a desired signal from distorting
when very strong signals are near the desired frequency, or
when very strong electric fields, such as from a broadcast-
ing station, are near your location.
➥ Activates or selects fast, middle or slow
AGC time constant when pushed. (p. 5-
11)
• "FAST" is only available for FM mode.
➥ Enters the AGC set mode when pushed
for 1 sec. (p. 5-11)
AGC time constant can be set between 0.1 to
8.0 sec.
(depends on mode)
"OFF" is selected, the S-meter does not function.
✔ What is the AGC?
The AGC controls receiver gain to produce a constant audio
output level, even when the received signal strength is varied
by fading, etc. Select "FAST" for tuning and select "MID" or
"SLOW" depending on the receiving condition.
, SWR, ALC,
(Po)
metering during transmit.
D
, or turned OFF. While
➥ Turns the speech compressor ON and
OFF in SSB mode. (p. 6-5)
➥ Switches the narrow, middle or wide
transmit filter when pushed for 1 sec.
✔ What is the speech compressor?
The speech compressor compresses the transmitter audio
input to increase the average audio output level. Therefore, talk
power is increased. This function is effective for long distance
communication or when propagation conditions are poor.
➥ Turns the
SSB data, CW, RTTY and PSK modes.
(p. 3-6)
• 1 ⁄ function sets dial rotation to
4
for fine tuning.
➥ Switches the tone encoder, tone squelch
function and no tone operation when
pushed in FM mode. (pgs. 4-32, 4-33)
➥ Enters the tone set mode when pushed
for 1 sec. in FM mode. (pgs. 4-32, 4-33)
➥ Switches the voice squelch control func-
tion ON and OFF. (p. 9-3)
#0 TRANSMIT INDICATOR [TX] (for MAIN band)
#1 TRANSMIT INDICATOR [TX] (for SUB band)
Lights red while transmitting.
• SUB band's [TX] indicator lights only when the split op-
eration.
#2 ANTI VOX CONTROL [ANTI VOX] (p. 6-2)
Adjusts the VOX deactivate level to prevent un-
wanted VOX control from the speaker audio.
Push
Decreases
cut-off level
#3 LCD CONTRAST CONTROL [CONTRAST]
Adjusts the LCD contrast.
Push
#4 LCD BRIGHTNESS CONTROL [BRIGHT]
Adjusts the LCD brightness.
Push
1-5
PANEL DESCRIPTION
1 ⁄ function ON and OFF in
4
1 ⁄ of normal
4
Increases
cut-off level
High
contrast
Low
contrast
Bright
Dark
1