Yaesu FT-950, Руководство по эксплуатации, Страница: 45 / 132

Page 43 FT-950 O
PERATING
M
ANUAL
A
DVICE
:
ˆ 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 recep-
tion 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 that you cannot hear the band noise when μ -Tune is engaged (highly
unlikely), just switch it out, to eliminate the slight insertion loss.
ˆ 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
[
SELECT
(
μ -TUNE
)] 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 frequency, and eliminate any
offset, press the [ CLEAR
] button.
Q
UICK
N
OTE
:
The permeability-tuning concept utilized in the μ -Tune circuit dates back many decades, as it was incorporated in such
classic transceivers as the FT-101 , the FT-901 series, the FT
DX
400 , and similar models. The μ -Tuning Kit uses the same
circuit as our flag ship model the FT
DX
9000 , which is the highest development of this circuit concept ever employed in an
Amateur transceiver.
I
NTERFERENCE
R
EJECTION
μ -T
UNE
F
ILTER
(
R
EQUIRES THE OPTIONAL
RF μ T
UNING
K
IT
)
Changing the Tuning Offset Indicator
1. Press the [
MENU
] button to engage the Menu
mode.
2. Rotate the [ SELECT
] knob to select Menu item
“
006 DISP BARSEL 006 DISP BARSEL 006 DISP BARSEL 006 DISP BARSEL 006 DISP BARSEL
”.
A
DVICE
:
Press the [ SELECT
] knob to toggle the Menu item
display between “
006 DISP 006 DISP 006 DISP 006 DISP 006 DISP
” and “
BARSEL BARSEL BARSEL BARSEL BARSEL
”.
3. Rotate the [ CLAR/VFO-B
] knob to select “
u-tn u-tn u-tn u-tn u-tn
( μ -Tune)” (replacing the default “
C-tn C-tn C-tn C-tn C-tn
(CW TUN-
ING)” selection).
4. Press and hold in the [ MENU
] button for one sec-
ond to lock in the new setting and exit to normal
operation.
[CLAR/VFO-B] Knob [MENU] Button
[SELECT] Knob