Yaesu FT-991 User Manual

Page 57FT-991 OperaTing Manual
Agc
(
AutoMAtic gAin control
)
The AGC system is designed to help compensate for fading and other propagation effects. The AGC characteristics can
beindividuallysetforeachoperatingmode.ThebasicobjectiveofAGCistomaintainaconstantaudiooutputlevel
once a certain minimum threshold of signal strength is achieved.
Press the
F(M-LIST)
button, then touch
[
AGC
]
on the
LCD repeatedlytoselect the desired receiver-recovery
timeconstant.YouwillobservetheAGCstatusnotation
in the AGC column of the Key Function Display on the
TFT display, denoting the AGC receiver-recovery time
currently in use. For most operations, we recommend
the“AUTO” mode.Additionally, youmay disable the
AGCbytouching
[
AGC
]
ontheLCD.
F(M-LIST) Button
tools for coMfortable anD effective reception
note:

 The“AUTO”selectionmodeselectstheoptimum
receiver-recovery time for the reception mode.
In this case, the selected receiver-recovery time in
the AGC column of the Key Function Display glows
green(Normallyitglowsblue).

Touching
[
AGC
]
ontheLCDallowsselectionofthe
desiredreceiver-recoverytime constant.Normally,
the “AUTO”selection is satisfactory for most situ-
ations,but inthe eventof operationonacrowded
bandwhereyou wishtoreceive aweaksignal,you
maywishtochangethesettingtoFAST.TheAUTO
mode selections are:
Advice:

 IftheAGCreceiver-recoverytimeissetto“Off”by
touching
[
AGC
]
on theLCD,the S-meterwillno
longerdeect.Additionally,youwilllikely encoun-
terdistortiononstrongersignals,astheIFampliers
andthefollowingstages areprobably beingover-
loaded.
quick point:
SeveralaspectsofAGCperformancemaybecongured
viatheMenu.However,becauseAGCcanhavesucha
profound impact on overall receiver performance, we
generally do not recommend any changes to the AGC
Menu selections until you are thoroughly familiar with
the performance of the
FT-991
.
terMinology:
Automatic Gain Control, or AGC, is a circuit that senses
the received signal strength, and then limits the gain of
theRFandIFstagestokeeptheoutputaudiovolumeat
amore-or-lessconstantlevel.AGCalsoprotectstheRF,
IF, Audio, and DSP stages from overload, as it limits the
signalstrengththatisallowedtoow,irrespectiveofthe
input signal level.
Auto Agc Selection
SLOW
FAST
MID
operAting Mode
LSB/USB/AM
CW/FM/DATA-FM
RTTY/DATA-LSB/DATA-USB

Yaesu FT-991 Specifications

General

Brand	Yaesu
Model	FT-991
Category	Transceiver
Language	English