Optional Data Management Unit ( Dmu-9000 ) / Tft Display Unit ( Tft-9000 ) - Yaesu FT DX 9000 CONTEST Operation Manual

RF μ-T RF μ-T RF μ-T U U U U U
RF μ-T RF μ-T
UNING UNING UNING NITS NITS NITS
UNING UNING NITS NITS
The μ-Tune filters are the most advanced, selective RF preselector filters ever incorporated into an Amateur
Radio transceiver. The RF selectivity provided by μ-Tune can be of tremendous value in ensuring quiet, intermod-
free reception even in the most crowded bands on a contest weekend. The μ-Tune filters provide RF selectivity
on the order of a few dozen kHz at -6 dB, at the expense of a few dB of system gain on bands where noise figure
is seldom an issue. You will notice that the S-meter deflection, when μ-Tune is engaged, is slightly less than
when it is out of the circuit; this is normal. If your antenna system gain is so low as to make it impossible to hear
band noise when μ-Tune is engaged (highly unlikely), just switch it out or revert to the VRF system, which has
slightly less insertion loss.
As you tune around on an amateur band with μ-Tune engaged, the microprocessor automatically commands the
stepper motor driving the toroid core stack to center the filter on your current operating frequency. You may,
however, use the [ VRF/μ-T ] knob to skew the filter response to one side or the other from your operating
frequency, to deal with heavy interference on one side. To re-center the μ-Tune filter on your operating fre-
quency, and eliminate any offset, press and hold in the [ VRF/μ-T ] switch for two seconds.
While μ-Tune is a superior RF preselection circuit, it may be disabled via the Menu; if this is done, the VRF
circuit will engage when the [ VRF/μ-T ] switch is pressed. To disable μ-Tune, go to Menu item "GENERAL
043 μTUNE DIAL STEP" and set the selection to "OFF."
With μ-Tuning, the center frequency of the filter is continuously
adjustable throughout its operating range, and the quality L/C com-
ponents ensure a tight passband due to the high Q of the circuit. The
RF preselection design task involves not only the selection of qual-
ity L/C components, but the crafting of a tuning mechanism and
tuning concept that preserves system Q (thus assuring a tight band-
width) while providing a wide operating frequency range and con-
sistent, automated tuning. The smooth tuning is achieved by varying
the inductance over a wide range; this is accomplished by motor-
driving a large 1.1" (28 mm) ferrite core stack through a 2" high (50
mm) coil structure. Three μ-Tune modules provide coverage of the
1.8, 80/40, and 30/20 meter bands, and the Q of this circuit, being
over 300, yields unmatched RF selectivity for outstanding rejection
of undesired signals.
Page 174
( MTU-160, MTU-80/40, MTU-30/20 MTU-160, MTU-80/40, MTU-30/20 )
MTU-160, MTU-80/40, MTU-30/20 MTU-160, MTU-80/40, MTU-30/20
MTU-160, MTU-80/40, MTU-30/20
A A A A A
D D D D D VICE VICE VICE VICE VICE
A A A A A
D D D D D VICE VICE VICE VICE VICE
ANTENNA
VFO-A
VRF
1
2
μ-T
3
4
VFO-B
VRF
FT 9000 C O
DX ONTEST
BPF
50-60 MHz
22-30 MHz
14.5-22 MHz
13.5-14.5 MHz
10-11 MHz
6.5-7.5 MHz
3.5-4 MHz
1.8-2.5 MHz
50-60 MHz
22-30 MHz
14.5-22 MHz
13.5-14.5 MHz
10-11 MHz
6.5-7.5 MHz
3.5-4 MHz
1.8-2.5 MHz
M
PERATION ANUAL