Tools For Comfortable And Effective Reception; Agc (Automatic Gain Control) - Yaesu FT-2000D Operating Manual

T C
OOLS FOR
The AGC system is designed to help compensate for fading and other propagation effects, with characteristics that can be
of particular value on 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.
Main Band ( VFO-A ) AGC Selection
Press the [ AGC ] button repeatedly to select the desired
receiver-recovery time constant. You will observe the AGC
status notation in the AGC column of the Receiver Con-
figuration Indicator on the display, denoting the AGC re-
ceiver-recovery time currently in use. For most operation,
we recommend the "AUTO AUTO" mode. Additionally, you may
AUTO AUTO AUTO
disable the AGC by pressing and holding in the [ AGC ]
button for two seconds.
Sub Band ( VFO-B ) AGC Selection
1. Press the [ B ] button.
2. Within five seconds of pressing the [ B ] button (while
the imbedded orange LED is blinking), press the [ AGC ]
button repeatedly to select the desired receiver-recov-
ery time constant. You will observe the AGC notation
below the Sub frequency on the display, denoting the
Sub receiver's current AGC receiver-recovery time. For
most operation, we recommend the "AUTO
Additionally, you may disable the AGC by pressing
and holding in the [ AGC ] button for two seconds.
N :
OTE
Pressing the [ AGC ] button allows selection of the desired
receiver-recovery time constant. Normally, the "AUTO
selection is satisfactory for most situations, 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,
for example). The "AUTO AUTO" mode selections are:
AUTO AUTO AUTO
O M
PERATING ODE
LSB
USB
CW
AM
FM
RTTY
PKT ( FM )
PKT ( LSB )
A A A A A
D D D D D VICE
When a received signal of the Main Band (VFO-
A) becomes degraded due to pulse type noise, you
may improve signal readability by setting the AGC
HOLD TIME in Menu Items AGC 002, AGC 004,
and AGC 006 to "0 msec".
Page 62
OMFORTABLE AND
AGC ( A
UTOMATIC
AUTO" mode.
AUTO AUTO AUTO
AUTO AUTO
AUTO AUTO"
AUTO AGC S
ELECTION
SLOW
SLOW
FAST
FAST
FAST
SLOW
FAST
SLOW
VICE VICE VICE VICE
E
FFECTIVE
)
G C
AIN ONTROL
[ AGC ] Button
[ B ] Button
A :
DVICE
If the AGC receiver-recovery time is set to "Off
ing and holding in the [ AGC ] button, the S-meter will no
longer deflect. Additionally, you will likely encounter dis-
tortion on stronger signals, as the IF amplifiers and the
following stages are probably being overloaded.
Q
UICK POINT
Several aspects of AGC performance may be configured
via the Menu. However, because AGC can have such a
profound impact on overall receiver performance, we gen-
erally do not recommend any changes to the AGC Menu
selections until you are thoroughly familiar with the per-
formance of the FT-2000D.
T :
ERMINOLOGY
Automatic Gain Control, or AGC, is a circuit that senses
the incoming signal strength, and then limits the gains of
the RF and IF stages so as to keep the output audio vol-
ume 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 flow, irrespec-
tive of the input signal level.
FT-2000D O
R
ECEPTION
Off" by press-
Off Off Off
M
PERATING ANUAL