Yaesu FT-902DM, Инструкция по эксплуатации

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improve ment in signal-to-n oise ratio. The
selectivity of the APF circuit may be varied
by adjusting V R 501 un der the top cover.
(7)
For ex tremely strong signals, the ATT (RF
attenuator)· switch may be pressed to activate
a 20 dB attenuation of the incoming signal.
This should prevent any chance of overload
of the receiver front end.
T RANSMITTER TUNE-UP
The following tune-up procedure must be per­
formed p rior to c ommencing ope ration on the
desired mode: LS B , U S B , CW, FSK, AM , or FM.
See the. paragraphs relating to the specific mode
after basic transmi tter tune-up is described.
Connect a dummy load or matched antenna to
the coaxial fitting on the rear apron. Preset the
controls as foll ows:
POWE R . . . . . . . . OFF
HE ATER . . . . . . . OFF
CARR . . . . . . . . . Fully c ounter-clockwise p osition
MIC GAIN .. . . . . Fully c ounter-clockwise p osition
AM GC . . . . . . . . . OFF
ME TE R switch . .IC
SE LE CT . . . . . . . YFO (Depressed)
B AND . . . . . . . . . Desired b and segment
MODE . . . . . . . . . U S B or LSB
PLATE . . . . . . . . Desired b and segment
PRE SE LE CT . . . . D esire d b and segment
L OAD ING .. . . . .To p osition shown in table
P RO C . . . . . . . . . OFF (Not depressed)
TUNE .. . . . . . . . OFF (Not depressed )
C LA R TX . . . . . . OFF (Not depressed)
VOX GAIN . . . . . PTT position
Turn the PO WE R and HE ATE R switches to ON.
Fro m a cold start, allow 6 0 se conds after the
HE ATE R switch is turnecl on for warm-up of the
transmitter tu bes. Be ce rtain that the accessory
p lug is inserted in the accessor y plug is inserted
in the accessory socket; without this plug being
so con nected, there will b e no power applied to
the tube he aters. Heater voltage is supplied through
p in s 1 and 2 of the accessory socke t.
Note:
LOADING POSITION S
BAND POSITION
1 60 5
80
4
40 3. 5
3 0 5
20 3
1 7 3
1 5 2. 5
1 2 3
lOA 3
lOB
3
lOC 3
lOD 3
LOAD ING p ositions are nominal. M inor
variations from positions shown are to
be expected.
Set the VOX GAIN control t o MOX. The meter
will now read final amplifier resting c athode
current. This should read . 0 5 (50 mA). * If it is
not, adjust the bias control located under the top
cove r near the rear of the set. Set the ME TE R
switch to ALC and adjust the AL C control under
the top cover for full scale deflection of the me ter.
Return the me ter switch to IC and the YOX GAIN
control to PTT.
* Note: On the FT-902SD, resting cathode
current should be . 0 2 5 (25 mA).
PRE -TUNING
(IMPORTANT NOTE: Subsequent transmitter
tuning utilizes the TUNE button instead of M OX
for actuating the transmitter. Whe n p ressed , the
TUNE button causes the transmitter to be acti­
vated for ten second s, after wh ich tim e the FT-
902DM returns to the rec� ive condition. This is
a protective feature that should not b e nullifie d
by use of the MOX control. )
( 1 ) Adju st the PRE SE LE CT control for maxi­
mum receiver noise level.
( 2 ) Depress the TUNE button. Rotate the C A R R
control until t h e meter reading rises just
ab ove the n ormal idling current of .05 ( 5 0
mA).
(3 ) Adjust the P RE SE LE CT c on trol for a maxi­
m um me ter indication .
Caution: if t
�
e m e te r reading exceeds . 1 ( 1 00
mA) reduce the setting of the CARR control.
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