Icom Ic_r20 Communications Reciever Instruction Manual

18
4
BASIC OPERATION
4
■Squelch level settingThe squelch circuit mutes the received audio signal depend-
ing on the signal strength. The receiver has 9 squelch levels,
a continuously open setting and an automatic squelch setting.
➥While pushing and holding [SQL], rotate [R-DIAL]to se-
lect the squelch level.
•“LEVEL 1” is loose squelch and “LEVEL 9” is tight squelch.
•“AUTO” indicates automatic level adjustment with a noise pulse
count system.
•“OPEN” indicates continuously open setting.
■Monitor...

■Attenuator functionThe 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 broadcasting sta-
tion, are near your location. The attenuator gain is about 30
dB.
➥Push 
[Ω ΩΩ
Ω
ATT]
for 1 sec. to toggle the attenuator function
ON and OFF.
•“ATT” appears when the attenuator function is in use.
■RF gainThe receiver gain can be reduced with the RF gain setting.
This may help to remove undesired weak...

20
4
BASIC OPERATION
4
Duplex communication uses 2 different frequencies for trans-
mitting and receiving. Generally, duplex is used in communi-
cation through a repeater, some utility communications, etc.
During duplex operation, the transmit station frequency is
shifted from the receive station frequency by the offset fre-
quency. Repeater information (offset frequency and shift di-
rection) can be programmed into memory channels. (p. 26)D D
SettingqSet the receive station frequency 
(repeater output...

21
4
BASIC OPERATION
■AFC functionThe AFC (Automatic Frequency Control) function tunes the
displayed frequency automatically when an off-center fre-
quency is received. It activates in FM/WFM modes only with
single band operation.
➥Push 
[0 AFC]
to toggle the AFC function ON and OFF.
•“AFC” appears when the AFC function is in use.NOTE: The AFC function is not available during dualwatch
operation.
■NB/ANL functionThe NB (noise blanker) function removes pulse-type noise
when USB, LSB or CW mode is...

22
4
BASIC OPERATION
4
■Band scopeThe band scope function allows you to visually check a spec-
ified frequency range. Sweep range can be selected from
±14kHz through ±1400 kHz.
qSet the desired frequency as band scope center frequency.
wWhile pushing and holding [2 SWEEP], rotate [R-DIAL]to
select the sweep steps, if desired.
•Available steps are 1, 5, 6.25, 8.33, 9, 10, 12.5, 15, 20, 25, 30,
50 and 100 kHz.
•Pushing [2 SWEEP]changes the sweep step and starts single
sweeping at each times.
ePush...

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4
BASIC OPERATION
■[DIAL] function assignmentThe frequency control dial can be traded with an audio volume
control dial or [Y Y
]/[Z Z
]keys to suit your preference. ➥Push [1 DIAL.SEL]for 1 sec. to toggle the dial function
from tuning dial and audio volume.
•Single band operation
•Dualwatch operation
√MODE
ANLAFC TSQL
FM
146560
PSKIP
-DUP∂145250438000AFC
-DUP -DUP
FM
TSQL TSQL
PS PS
PRIO PRIO
FM000 000
00 00
FM
[R-DIAL]
[L-DIAL]DIAL.SEL1
“ ” indication “ ” indication
• Frequency, Memory chan-
nel,...

24
5
DUALWATCH OPERATION
45
■Main band selection➥Push [MAIN/SUB]momentarily to select the upper band
or lower band as main band (operating band) alternately.
■Band exchange➥Push [MAIN/SUB]for 1 sec to exchange the upper band’s
frequency and lower band’s frequency.
• The A-side is upper side on the display, and B-side is
lower side, if the band exchange function (see above) is
not performed (default).
• Available frequency bands are different depending on
version. See the specification for details.
• *Some...

25
5
DUALWATCH OPERATION
■Setting audio volumeqPush [DUALWATCH]for 1 sec. to enter the dualwatch op-
eration, if necessary
wPush and hold [SQL], p
ush [Y Y
]or [Z Z
]to adjust the audio
level for the main band. 
•Pushing and holding either key changes the audio level continu-
ously.
•The display shows the volume level while setting.While pushing either 
[Y Y
]or [Z Z
]
, rotate [L-DIAL]for upper
band’s volume adjustment, or [R-DIAL]for lower band’s
volume adjustment.
■Squelch level settingqPush...

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6
MEMORY CHANNELS
■General descriptionThe receiver has 1050 memory channels including 50 scan
edge memory channels (25 pairs) for storage of often-used
frequencies. And a total of 26 memory banks, A to Z are avail-
able for usage by group, etc. Up to 100 channels can be as-
signed into a bank.D D
Memory channel contentsThe following information can be programmed into memory
channels:
•Operating frequency (p. 14)
•Receive mode (p. 16)
•Duplex direction (+DUP or –DUP) with an offset fre-
quency (p. 20)...

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6
MEMORY CHANNELS
■Memory bank settingThe IC-R20 has a total of 26 banks 
(A to Z)
. Regular memory
channels, 000 to 999, are assigned into the desired bank for
easy memory management.
qPush [MR S.MW]for 1 sec. to select the select memory
write condition.
•1 short and 1 long beep sound.
•“µ µ
” indicator blinks.
wRotate [R-DIAL]to select the desired memory channel.
eWhile pushing [8 SET], rotate [R-DIAL]to select “BANK.”
•“BANK” item can also be selected by pushing [8 SET]several
times.•Bank group and...