Yaesu FT DX 1200, Руководство по эксплуатации

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Page 47
FT
DX
1200 O
PERATING
M
ANUAL
μ -T
UNE
F
ILTER
(
R
EQUIRES THE OPTIONAL
RF μ T
UNING
K
IT
)
The 5 F — Tuning . it provides ultra-sharp 5 F selectivity for the front end of the transceiver. Very high Q is made pos-
sible by the narrow-band design. Three 5 F — Tuning . its are available. The
MTU-160
covers the 1.8 0 H ] band. The
MTU-80/40 covers the 3. and 7 0 H ] bands. The MTU-30/20 covers 10.1 and 14 0 H ] bands.
When any or all) of the three optional units are connected, they will be automatically adjusted to center on your operat-
ing fre T uency.
The narrow bandwidth is especially useful on the low bands, when many strong signals are being received via 1 VIS
propagation 1 ear Vertical-Incidence Signals) within a narrow bandwidth. The added protection for the 5 F stage is es-
pecially helpful in preventing I 0' and blocking.
μ -Tune Operation
1. 3 ress and hold in the [ MHz/ μ T
] button for one sec-
ond to activate the — -Tune ¿ lter. The “
μ -Tune
” will
appear on the TFT display. The [ VFO-B/CLAR
]
knob works as the — -TU 1 I 1 G knob.
A
DVICE
:
ˆ
The — -Tune circuit will automatically align itself
to the operating fre T uency.
ˆ
5 emember that — -Tune only operates on the 14
0 H ] and lower bands.
. 5 otate the [
VFO-B/CLAR
] knob to peak the re-
sponse background noise) or reduce interference.
A
DVICE
:
ˆ You may observe the relative peak point of the
— -Tune filter in the Tuning 2 ffset Indicator on
the display, while tuning the [ VFO-B/CLAR
]
knob.
ˆ The amount of change in the center fre T uency
of the — -Tune filter, when rotating the [
VFO-
B/CLAR
] knob, can be con
¿ gured using 0 enu
item “
046 uTUNE DIAL STEP
”.
ˆ If the ȝ -Tune filter has been manually adjusted
away from the center fre T uency, you may press
the [ CLEAR
] button to re-center the filter re-
sponse on the current operating fre T uency.
3. 3 ress and hold in the [ MHz/ μ T
] button for one sec-
ond to disengage the — -Tune ¿ lter
A
DVICE
:
$ lternate presses of the [
MHz/ μ T
] button will switch
the — -Tune ¿ lter between on or off.
A
DVICE
:
ˆ
You may change the indication of the Tuning 2 ffset
Indicator to display the — -Tune filter continuously
while the — -Tune filter is activated. This is 0 enu
item “
011 BAR DISPLAY SELECT
”. See “Changing
the Tuning 2 ffset Indicator” on the next page for de-
tails of the setting.
ˆ
The — -Tune ¿ lters are the most advanced, selective
5 F preselector ¿ lters ever incorporated into an $ ma-
teur 5 adio transceiver. The 5 F selectivity provided
I
NTERFERENCE
R
EJECTION
[MHz/
μ T] Button
[VFO-B/CLAR] Button
by — -Tune can be of tremendous value in ensur-
ing T uiet, intermod-free reception even in the most
crowded bands on a contest weekend. The — -Tune
¿ lters provide 5 F selectivity on the order of a few
do ] en kH ] at -6 dB, at the expense of a few dB of
system gain on bands where noise ¿ gure is seldom
an issue. You will notice that the S-meter de À ection,
when — -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 that you cannot hear the band
noise when
— -Tune is engaged highly unlikely), just
switch it out, to eliminate the slight insertion loss.
T
UNING
O
FFSET
I
NDICATOR