Yaesu FT-901DM Instruction Manual page 8

(8) PRES ELECT
This
control p retunes the signal circuits for b oth
trammit
and receive. The PRESELECT circui t
p rovides
continuous permeability tuning through­
out the frequency range of the transceiver.
BAND
(Q)
BAND
The swi tch provides sele ction of the b and
160
desi red, th rough
(re ceive only).
(10) RF GAIN/CLARIFIER
The RF
GAIN and C LARIFIER c on trols are
mounted on concen tric shafts. The RF GAIN
control p rovi d e s manual c ontrol o f the gain levels
RF
of the and IF amp lifiers on receive.
The
CLARI FIER con trol allows manual o ffset of
±2.5
of either the transmit or receive fre­
kHz
quency. Selection of transmi t or receive clarifier
made
is hy the two silver pushbu ttons t o the
of
left t e CLA RIFI ER c ontrol.
h
(11) ATT
(RF attenuator) button provid es in ser­
The ATT
tion 20 dB
of a a t tenuator in the incoming signal
minimize
p;:ith to receiver cross modulation caused
by extremely s trong local signals.
L/AF G AI
( 1 2 )
EVE
PROC L
The PROC
LEVEL an d AF GAIN con trols are
mounted
c oncen tric shafts. The PROC LEVEL
on
al lows manual con trol of the outpu t level
control
RF
of t h e speech processor. The p rocessor is
actu ated by p ressin g the silver pu shbu tton t o the
left of th e PROC LEVEL c ontrol .
The AF GAIN con trol adjusts the audio outpu t
at
level the spe aker and ph one j ack. Clockwise
rotation i n creases the audio ou tput.
( 1 3)TUNE
Th is pushbu tton, when depressed , places the trans­
mi t ter in the "tun e " c ondition for ten seconds
for tuning purpose s . After ten seconds, the trans­
ceiver is returned to the receive mode so as to
prevent d amage to the final amp lifier tubes cause d
by ex cessive "key down" time during tune-up .
(14) LOADING
This control tu nes the outpu t circuit of the pi net­
work to match the an ten na/fe edline impedance.
I
I 0 meters plus WWV JJY
N
( 1 5 ) PLATE
This con trol tun es the plate circuit o f the final
amplifier.
(16) CALIB
Whe n the M A RK swi tch is activated , the CALI B
knob provides manual con trol for z eroing the
calibration o f the digital display with the cali­
brator signal .
( 1 7 ) CARR/KEYER
The CARR and KEYER con trols are m ounte d
on concentric shafts. The CARR con trol varies
the amount o f carrier in the CW, AM , F S K , and
FM models o f operation.
The KEY E R control varies the speed of the
buil t-in Curtis 8043 IC electronic keyer.
( 1 8) VOX GAIN
This con trol selects MOX / PTT / VOX transmi t te r
relay con trol as we ll as adjusting t h e sensitivity o f
t h e VOX circuitry . The P T T position provide s
push-to-talk operation from a microphone PTT
switch or a footswitch. The MOX p osition provide s
manual transmit . I t must be re turned to the PTT
p osition for receiver recovery .
( 19) APF FREQ
This kn ob , when actuate d by turning on the APF
switch, provides manual con trol for peakin g the
au dio peak filter (APF) circuit on the d e sired
signal. This control will find its chie f use fulness
on CW, because its band wid th is much too n arrow
for n ormal S S B re cep tion.
(20) SQL/MIC GAIN
The SQL an d MIC GAIN con trols are m ounted on
concen tric shafts. The SQL control se ts the squelch
thre shold level for F M re ception.
The MIC GAIN con trol varie s the audio level from
the microphone amplifier stage . The control has
su fficient range to permit the use o f any low im­
pedance ( 5 00 - 6 00 Ohm) crystal o r dynamic
microphone . Clockwise rotation increases the leve l
of output from the microphone amplifier stage.
( 2 1 ) FUNCTION SWITCHES: AMGC, APF /MONI,
AGC, PO/IC/ALC,
The AMGC swi tch activates a microphone gain
threshold circuit
- 6 -
and
NB/MARK
which requires a particular