Yaesu FTDX-9000MP, Руководство по эксплуатации

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Page 68 FT
DX
9000MP O
PERATION
M
ANUAL
U
SING THE
VRF
(
V
ARIABLE
RF F
RONT
-
END
F
ILTER
)
The VRF system is a high-performance RF front-end preselector that provides outstanding rejection of out-of-band signals.
VRF
ON THE
M
AIN
B
AND
(VFO-A) F
REQUENCY
1. Press the [ VRF/µ
] switch momentarily. The LED in-
side the switch will become illuminated, and the VRF
system will be engaged, centered on your current
Amateur band.
2. You may rotate the [ VRF/µ
] knob to skew the posi-
tion of the VRF system relative to your operating fre-
quency. Because the VRF system is relatively broad,
although still much narrower than the fixed bandpass
filter), you may not hear much difference in the back-
ground noise or signal quality when you make minor
adjustments. However, if you have receiving problems
associated by a very strong signal, rotation of the
[
VRF/µ
] knob may help reduce the strength of the
interfering station, allowing improved reception of the
desired signal.
After moving the passband of the VRF system
manually, you may re-center it on the current Ama-
teur band by pressing and holding in the [
VRF/µ
]
switch for two seconds.
To switch VRF off, press the [
VRF/µ
] switch mo-
mentarily again. The LED imbedded in the switch
will go out, and the VRF circuit will be removed
from the incoming received signal path.
AAAAA
DDDDDVVVVVANCED ANCED
ANCED ANCED
ANCED
I I I I I
NTERFERENCE NTERFERENCE
NTERFERENCE NTERFERENCE
NTERFERENCE
-S-S-S-S-S
UPPRESSION UPPRESSION
UPPRESSION UPPRESSION
UPPRESSION
F F F F F
EA EA
EA EA
EATURES TURES
TURES TURES
TURES
::::: RF F RF F
RF F RF F
RF F
RRRRRONT ONT
ONT ONT
ONT
E E E E E
ND ND
ND ND
ND
Q Q
Q Q
Q
UICK UICK UICK UICK UICK
P P
P P
P
OINT OINT OINT OINT OINT
The VRF filter, utilizing high-quality coils and capacitors that provide high Q, yields a passband that is approxi-
mately 20% to 30% the width of a traditional, fixed bandpass filter. As a result, significantly more unwanted signal
rejection is provided. Within each Amateur band, 64 adjustment steps are provided (50 MHz: 8 steps), if you wish
to skew the response in a particular direction so as to enhance interference rejection even more.
MAIN(VFO-A) [VRF/ μ ] Switch
MAIN(VFO-A) [VRF/ μ ] Knob
SUB(VFO-B) [VRF] Switch
SUB(VFO-B) [VRF] Knob
VDD TEMP SWR BIAS
U
SING
VRF
ON THE
S
UB
B
AND
(VFO-B) F
REQUENCY
1. Press the Sub (VFO-B) [ RX
] switch to engage Dual
Receive operation.
2. Press the Sub (VFO-B) band’s [ VRF
] switch to en-
gage the VRF. The LED imbedded in the switch will
light up, confirming that VRF is now in the signal path
for the Sub (VFO-B) receiver.
The settings of the VRF are set and held in memory
independently for each Amateur band, so any cus-
tom settings will be maintained despite any band
changes you perform.
3. Rotation of the [ VRF
] knob allows adjustment of the
center frequency of the VRF circuit.
If you have made adjustments to the VRF circuit’s
center frequency, press and hold in the [
VRF
]
switch for two seconds to re-center the VRF on
the center of the Amateur band on which you cur-
rently are operating.
To switch VRF off, press the [
VRF
] switch mo-
mentarily again. The LED imbedded in the switch
will go out, and the VRF circuit will be removed
from the Sub (VFO-B) receiver’s incoming signal
path.