What is the preamp, What is the break-in function, Panel description – Icom IC-756 User Manual
Page 6
NB
NR
BAL
NR
COMP
KEY SPEED BK-IN DELAY
APF
APF
LOCK
TX
RX
AUTO NOTCH
TWIN PBT
CW PITCH
F-1
SSB
F-2
F-3
F-4
F-5
SPEECH
LOCK
RIT/
TX
TX
RIT
CLEAR
CW
RTTY
AM
FM
SPLIT
MP-W
MP-R
DUAL
WATCH
VFO/
MEMO
MAIN/
SUB
CHANGE
1.8
1
3.5
2
7
3
10
4
14
5
18
6
21
7
24.5 8
28
9
GENE
50
0
F-INP
ENT
MW
M-CL
TS
XFC
i756
1ß
VFO
VFO
14.195.000
VFO
VFO
USB
USB
USB
14.100.00
14.100.00
14.205.000
14.205.000
USB
USB
USB
14.100.00
14.100.00
56
56
ß
T X
T X
FILTER
SCAN
MEMORY
SET
VOX
VOX
OFF
OFF
COMP
COMP
OFF
OFF
SCOPE
ANT
ANT
1
METER
METER
Po
Po
P.AMP
P.AMP
OFF
OFF
ATT
ATT
OFF
OFF
AGC
AGC
MID
MID
2.4k
2.4k
9
2.8k
2.8k
455
455
12:34
12:34
!8
@5
@6
@7
@8
@9
@1
@0
!9
@2
@3
@4
!8
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.
• Push to input a character for memory keyer pro-
gramming or memory name. (pgs. 36, 45)
• Toggles the antenna connector selection
between ANT1/R and ANT2/R when
pushed. (p. 37)
• Toggles the receive antenna ON and OFF
when pushed for 2 sec.
• Selects RF power (Po), SWR or ALC me-
tering during transmit. (p. 34)
• Selects one of 2 receive RF preamps or
bypasses them.
- “P. AMP1” activates 10 dB preamp for HF all
bands.
- “P. AMP2” activates 16 dB high-gain preamp
for 21 MHz band and above.
✔
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,
or bypasses them.
✔
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 broad-
casting station, are near your location.
• Activates or selects fast, middle or slow
AGC time constant when pushed.
- The setting becomes “fast” in FM mode re-
gardless of this setting.
• Deactivates the AGC circuit when pushed
for 2 sec.
NOTE: While “AGC 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 se-
lect “MID” or “SLOW” depending on the receiving condi-
tion.
• Turns the VOX function ON and OFF when
pushed in non-CW modes. (p. 33)
• Enters the VOX set mode when pushed for
2 sec. in non-CW modes. (p. 33)
• Selects semi break-in, full break-in opera-
tion, or turns the break-in operation OFF
when pushed in CW mode.
✔
What is the VOX function?
The VOX function (voice operated transmission) starts
transmission without pushing the transmit switch or PTT
switch when you speak into the microphone; then, auto-
matically returns to receive when you stop speaking.
✔
What is the break-in function?
The break-in function toggles transmit and receive with
CW keying. Full break-in (QSK) can monitor the receive
signal during keying.
VOX
VOX
OFF
OFF
BK-IN
BK-IN
OFF
OFF
AGC
AGC
MID
MID
ATT
ATT
OFF
OFF
P.AMP
P.AMP
OFF
OFF
METER
METER
Po
Po
ANT
ANT
1
3
1
PANEL DESCRIPTION