Yaesu FT-902DM Instruction Manual page 9

m inimum input level from the microphone t o
trigger t h e m icrophone am plifier. L ow-level back­
gr ound noi se w il l n o t activate the transmi tter
w i th the AM G C in operation . This circuit m a y be
c onsidered a "microphone squelch " s y stem . The
M
GAIN c on tro l functio n s n ormall y
AMGC s y stem in operation .
W hen the APF/MONI swi tch is in the AP F p osi­
tion , the audio peak
is activated . Th e exact frequency o f the audio
peak i s set by the APF F REQ knob . W hen this
swi tch is placed in the M ON I p osi tion , m onitor ­
ing of the m icrophone level m ay be accom plished
for o p erator convenience or tape recording b oth
QSO.
sid e s of a I n the CW mode, CW sid e t one
w ill b e heard regardless o f the posi tion o f the
APF/MONI sw i tch.
The A GC sw it ch con trols the length of the re­
c over y time f or the r e ceiver AGC circuitr y . Thi s
swi tch p rovides sl ow or fast recover y , and will
al so turn off the AGC i f desire d .
T h e PO/ IC/ A L C swi tch will h ereafter be re ferred
to as the METER sw rf ch . In the PO p o s i ti on,
relative tran smitter output power can b e observed .
In the IC p osi tion , transmitter final a m plifier 1
c athod e current m ay h e measure d . In the A LC
p osition, transm i t ter A LC volta g e m ay be read.
W hen the F T - 9 02DM is in the receive m od e , the
"S"
me ter f tt ncti ons as an
The NB/MARK swi tch provides for actu ation of
either the N oise Blanker (N B ) or cr y stal c alibrator
(MARK ) . The marker oscillator can produce cali­
brati on sign als a t intervals of either 25 kHz or
I
00 k H z by proper p osit i oning of a swi tch inside
the ca b in e t .
( 2 2) POWER
This is the m ain on/ o ff switch for the transceiver.
In the OFF p osition , the memor y circuits are
d i sa b le d , so that w h en the transceiver is turned to
O N again, the memor y circuits will have t o be
reset .
( 23) HEATER
W ith the H EATER swi tch in the down po sition ,
the transmi tter tube heaters are turned o ff . T his
reduces b atter y , d rain to
long peri o d s of liste ning with out excessive b a tter y
d rain. Pl acing this switch in the up position pro­
v ides suppl y voltage t o the tube heaters, and
a fter 3 0 se co p d s o f warm u p t he transm i t ter is
re ady for operation . This swi tch operates in both
the AC and DC m od e s .
w i th the
fil ter (AP F ) circuitry
m e ter.
I. I
amp and thus per m i t s
( 2 4 ) P HONES
This is a s tandard I /
m odatio n o f headphones . Th e in ternal sp eake r is
disabled when headphones are plugged into this
jack.
( 2 5 ) MIC
This fou r-cond u c tor
m icrophone plug for mi crophone in put a s well as
for PTT actuation .
MIC
TI
�
- 7 -
4"
for
phone j ack
j ack accom m oda tes
P TT swi tch
2 Ml( �/
3 PTT
4 N (
Mic plug
Headphone plug
accom­
the
lJ i
:
i