Preamp; Attenuator; Agc Time Constant; Antenna Selection - Icom IC-R75 Instruction Manual

5
RECEIVE FUNCTIONS

Preamp

The preamp amplifies received signals in the front
end circuit to improve the S/N ratio and sensitivity.
Turn this function ON when receiving weak signals.
Push [P.AMP] to toggle between preamp-1 and
preamp-2 or turn the preamp OFF.

Attenuator

The attenuator prevents desired signals from distort-
ing when very strong signals are near the desired fre-
quency or when very strong electric fields, such as
from broadcasting stations, are near your location.
Push [ATT] toggle the 20 dB attenuator function
ON and OFF.
• "ATT" appears when the attenuator is turned ON.

AGC time constant

The AGC (Automatic Gain Control) controls receiver
gain to produce a constant audio output level even
when the received signal strength is varied by fading,
etc. Use AGC slow for normal phone operation; AGC
fast for receiving data and searching for signals.
Push [AGC] momentary to toggle the AGC time
constant between fast and slow.
• "F.AGC" appears when the fast time constant is se-
lected.
• "AGC" appears when the slow time constant is se-
lected.
Push [AGC] for 2 sec. to turn the AGC circuit OFF.
• "AGC OFF" appears when the AGC circuit is turned
OFF.
• Push [AGC] to turn the AGC circuit ON.

Antenna selection

2 types of antenna can be connected to this receiver.
When 2 antennas are connected, select an antenna
depending on the operating condition.
Push [ANT
(SET)
antenna 1 and 2 connectors.
• If a blank memory channel has been selected, push
[V/M] to select VFO mode in advance.
16
] for 2 sec. to toggle between the
USB
R X
PREAMP 1 ANT 1 AGC
BLANK BLANK
S1 3 5 7 9 20 40 60dB
VFO
"PREAMP" appears while the
preamp is activated.
USB
R X
ATT ANT 1 AGC
BLANK BLANK
S1 3 5 7 9 20 40 60dB
VFO
"ATT" appears while the attenuator
is activated.
USB R X
ANT 1 F. AGC AGC BLANK BLANK
S1 3 5 7 9 20 40 60dB
VFO
"F.AGC" appears when the fast time
constant is selected.
USB
ANT 1 AGC BLANK BLANK
S1 3 5 7 9 20 40 60dB
VFO
"ANT1" appears when the
[ANT1] connector is in use.
R X