Yaesu FT-902DM, Инструкция по эксплуатации

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(4) R otate the PLATE con trol for a minimum
meter reading ("dip"
m
final am plifier
cathode curren t).
(5)
Push the TUNE button again to return the
transceiver to the receive condition.
FINAL TUNING
Final p eak tuning utilizes the relative power out­
put position of the METE R switch. At full rated
power into a 50 O hm load, the meter will read
approximately 1 /2 to 2/3 full scale. If the PO
reading is too high (off scale) or too low ( 1 /4 scale
or less) and the load imp edance is very close to
50 O hm s , the PO AD J control on the rear apron
may be adjusted so as to p rovide
l
/2 to 2/ 3 scale
deflection at full power. O nce the PO meter is
calibrated , off-scale meter defle c tions are the
result o f reflected power due to high SWR , and
corrective action ma y be required in the an tenna
system.
Final transmitter peaking is described below:
(1)
Set the METE R s witch to the PO p osition
and rotate the CA.RR control to the 1 1
o'clock position.
(2) Press the TUNE button and rotate the PRE­
S ELECT control for a maximum meter read­
ing. Press the TUNE button again to return
to the receive condition.
(3 ) Press the TUNE button and ro tate the LO AD ­
ING c ontrol for a maximum me ter reading.
Press the TUNE button again to return to
the receive condition.
(4) Press the TUNE b utton and ro tate the P LATE
con trol fo r a ma ximu m meter reading. Press
the TUNE button again to re turn to the re­
ceive c ondition.
( 5 ) Repeat steps 2 through 4, advancing the
CARR cont rol appro ximately 2 units for
each se t of adjustments until th e CARR c on­
trol is fully clockwise. The transmitter is now
tuned for maximu m p ower output.
(6) Re turn the C AR R control to the fully coun­
ter-clockwise p o sition. Re turn the METER
switch to IC .
W ith familiarity, some of steps 2 - 4 may b e per­
formed wi thin one p ress of th e TUNE button ,
taking advantage o f the 1 0-second timer. The
operator is discouraged , through, from exceeding
the 1 0-second limi tation imposed by the timer
thro ugh use of th e MO X position or the micro­
phone PTT switch.
SSB OPERATION
After completion of the above tuning p rocedure ,
set the MODE switch to USB or LSB as desired .
Set the VO X GAI N con trol to PTT and activate
the transmitter by pushing the microph one PTT
switch or the footswitch , if used. W hile speaking
in a n ormal voice into the microph on e , advanc e
the MIC GAIN c on trol until the meter kicks down
to the midscale of the green-c olored p ortion o f
the meter scale.
Note: When the METER switch is se t to IC ,
voice modulation p eaks wi ll indicate 1 5 0 -
200 mA. Actual peak current , h owever, is
approxi mately 2 times the in dicated valu e .
T o s e t t h e sensitivity o f the VOX system , begin
with the VO X GAIN control in the PTT position .
Advance the VO X GAIN and speak in a normal
voice . The VO X GAIN con trol should b e a dvanced
until the voice actuates the transmitter (do n o t
press t h e microphone PTT switch or foo tswitch , i f
used , during thi s adjustment).
Set the antitrip potentiometer under the top
cover to the minimum p oint which prevents the
speaker outpu t from tripping the VO X . D o no t
use more VO X GAIN nor anti trip than necessary .
Adjust the d elay poten tiometer under the top
cover for the desired release t im e .
I f desired, the AMGC circuit may be activated.
This circuit acts as a " microphone squelch;" that
is , it initiates a threshold for microphone inpu t
which mu st b e e x ceed ed before output from the
microphone amplifier will occu, r. T his feature
permits minor noises such as a TV in the operatio g
room to be p re sent without going out over the
air. Adjustment o f the AMGC d elay time is made
by a control under the top cover.
RF SPEECH P ROCESSOR ADJ U STMENT
(All models)
The FT-902D M speech p rocessor, when properl y
adjusted, is designed to improve the intelligibilit y
threshold at the receiving end by incre asing the
average SSB p ower outp u t . RF clipping is applied
to the IF signal , which is then filtered to remove
harmonics and out of band interm o dulation
products.
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