Yaesu FTdx5000MP, Руководство по эксплуатации

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Page 53 FT
DX
5000 O
PERATING
M
ANUAL
C
ONVENIENCE
F
EATURES
RF G
AIN
(
SSB/CW/AM M
ODES
)
The RF Gain controls permit manual adjustment of the receiver RF and IF stages gain levels, to account for noise and/or
signal strength conditions.
VFO-A Receiver RF GAIN Adjustment
The (
VFO-A
)[
RF GAIN
] knob should, be rotated, initially,
to the clockwise position. This is the point of maximum
sensitivity, and counter-clockwise rotation will gradually
reduce the receiver RF gain.
VFO-B Receiver RF GAIN Adjustment
The VFO-B receiver RF Gain operates identically to the
VFO-A receiver RF Gain.
Press the ( VFO-B
)[
RX
] button to engage the Dual
Receive operation. The (
VFO-B
)[
RX
] button will glow
green.
Always utilize the fully clockwise position of the (
VFO-
B
)[
RF GAIN
] knob as the starting point for operation.
A
DVICE
:
As the [
RF GAIN
] knob is rotated counterclockwise
to reduce the gain, the S-meter reading will rise. This
indicates that the AGC voltage being applied to the
receiver is increasing (which causes a
reduction in re-
ceiver gain).
Rotating the [ RF GAIN
] knob control to the fully
counter-clockwise position will essentially disable the
receiver, as the gain will be greatly reduced. In this
case, as well, the S-meter will appear to be “pegged”
against the right edge of the analog S-meter scale.
The (
VFO-B
)[
RF GAIN
] knob operates identically to
the ( VFO-A
)[
RF GAIN
] knob. The effects of counter-
clockwise rotation of the VFO-B receiver RF Gain
control may be observed visually on the VFO-B S-
meter.
Q
UICK
P
OINT
:
Reception can often be optimized by rotating the [
RF
GAIN
] knob slightly counter-clockwise, to the point
where the S-meter stationary needles position is just
about the same as the receiver noise level. This setting
ensures incoming signals will be heard with minimal
noise. The S/N (signal to noise) of the receiver will be
improved, without so much gain reduction that weak
signals cannot be heard.
The RF GAIN control, along with the IPO and ATT
(attenuator) features, all affect the system receiver gain
in different ways. As a first step in dealing with high
noise or a crowded, high-level signal environment, the
IPO generally should be the first feature engaged, if
the frequency is low enough to allow the preamplifier
to be bypassed. Thereafter, the RF GAIN and ATT (at-
tenuator) features may be employed to provide pre-
cise, delicate adjustment of the receiver, and fully op-
timize performance.
(VFO-A)[RF GAIN] Knob
(VFO-B)[RF GAIN] Knob (VFO-B)[RX] Button