Yaesu FT-901DM User manual

INSTRUCTION
MANUAL
FT-901DM
YAESU MUSEN CO., LTD.

TABLE CONTENTS
GENERAL
SPECIFICATIONS
CONTROLS AND SWITCHES
REAR APRON CONNECTIONS. .
INSTALLATION
OPERATION
BLOCK DIAGRAM. es
CIRCUIT DESCRIPTION
MAINTENANCE AND ALIGNMENT.

ALL
MODE
HF
TRANSCEIVER
FT-901DM
GENERAL DESCRIPTION
The FT-901DM is a precision engineered, high-
performance HF transceiver of advanced design,
providing all band coverage (160 - 10 meters) on
all modes of operation: LSB, USB, CW, FSK, AM,
and FM. This transceiver operates at an input
power of 180 watts SSB/CW and 80 watts on AM,
FM, and FSK.
Advanced features include PLL (Phase Locked
Loop) frequency derivation, digital plus analog
frequency readout with large display LED digits,
a built-in Curtis 8043 IC electronic keyer, and
memory frequency control circuitry. State-of-the-
art receiver performance features include rejection
tuning,
dual-filter
variable
IF
bandwidth
tuning.
and,
for
CW.
an
audio
peak
filter
(APF)
for
un-
surpassed
rejection
of
unwanted
signals.
Other
built-in
features
include
VOX,
semi-break-in
CW
with
sidetone,
25
kHz
calibrator,
advanced
noise
blanker,
RF
speech
processor.
and
a
20
dB
RF
attenuator
for
protection
against
receiver
overload.
All
circuits,
except
the
transmitter
driver
and
final
amplifier
stages,
are
solid
state,
utilizing
modern
plug-in
printed
circuit
boards,
thus
per-
mitting
easy
maintenance.
The
FT-901DM
transceiver
is
entirely
self-con-
tained,
requiring
only an antenna
and power
source
for operation.
For base station
operation,
AC
power
voltages
of
100/110/117/200/220/234
VAC
may be chosen,
though
the unit normally
is sup-
plied with 117 volt capability.
A DC-DC
converter
unit provides
for mobile
or portable
operation.
Selection
of AC or DC power
source
is automati-
cally made when the proper
line cord is inserted.
For mobile operation a separate switch is provided
on
the
front
panel
to
turn
off
the
tube
heaters
while in the receive mode. With the heaters off,
current consumption is only 1.1 amp.
Among
the
available
options
on
economy
models
FT901D/SD/DE
are
the
memory
unit,
the
keyer
unit,
the
DC-DC
converter,
the
FM
unit,
and
the
cooling
fan.
Optional
equipment
on
all
models
are
the 600 Hz CW filter and the 6 kHz AM filter.
The entire FT-901DM transceiver weighs approxi-
mately
18
kg.,
and
is
342
mm
wide,
154
mm
high,
and
324
mm
deep.
A
diecast
front
panel
and
heavy-duty
case
provide
maximum
protection
against
damage
from
shock
and
vibration
during
travel use.

SPECIFICATIONS
GENERAL
Frequency
coverage:
160m 18-20 Mile
80m 35-40. MHz
410 70-75 MHz
20m 14.0-18,5 MHz
15m 21,0-21.5 Mz
Toma 28,0- 28.5 MHz
10m 28:5-29.0MHz
Vom 29,0- 29.5 MHz
1mb 29.5. 29.9 Mile
WWV/LIY 15.0-15.5 Milz, RX only
Power requirements:
‘AC 100/{10/117/200/220/234 W, $0}60 Ile
DC. 13.5 V, negative ground
(DC option FT-901D/SDIDF)
Power consumption:
(FT-901DM/D/DE
ACIITV: TOwatts receive
(45 watts HEATER OFF)
320 watts tansinit (max)
DE ILS Vs SA receive
(TA HEATER OFF)
2A transmit (max)
(FT9018)
AC IITV: 55 watts receive
(4S wats EATER OFF)
105 watts tansmmit (max)
DC IRS V: 3K A receive
(08 A HEATER OFF)
7.5.8 transmit (mux)
Size
342 (W) x 154 (HD) x 324 (0D) mm
Weight:
Ike
TRANSMITTER
Emission:
LSB, USB (AR). CW CAT), AM (ASD), FM.
(£3) (option FT-901SD/DE). FSK (1)
PA input power:
FT-901DM/D/DE
SSB/CW. 180 watts DC
AN/ESK/FM. 0 watts DC
F901sD
SSB/CW/FSK/FM: 20.watts DC
aN. S watts DC
Carrer suppression:
Better than 40 db
wanted sideband suppression:
Better than 40.48 1000 He
Spurious radiation:
etter than 40 UR below rated output
‘Transmitter frequency response
300-2700 He (~6 db)
‘Third order distortion produets:
Beiter than 31 dB below rated ourput
‘Transmitter frequency stability
tess thin 300 Hp after 10 exinute wasmup,
fess
than
100
1b
after
30
minute
wartnup,
Negative feedback:
dB at 14 MHZ
Modulation:
ABE: Balanced mods
ABI: Amplitude modulation of « low power
Pa: Variable-reacta
© frequeney. moguls
tion, mas. deviation #5 kH2 (F3 fea:
ture optional on FT-9O1SD/DE)
Antenna output impedance:
50-15 Ohms. unbalanced
Microphone input impedance:
500 - 600 Ohms

RECEIVER
Sensitivity
SSBICW/FSK
0.25
4V
for
SIN
10
dB
AM
TAY
for
SIN
1048
a
0.3
AV
for
20 48
gvieting
Image rejection:
18-21 Miz Better than 60.48
28 Mila -- Better than SOaD
IF rejection
‘etter than 70 dB
‘Selectivity, WIDTH control at “0
SSB: —60B/2.4kI2 60 dB/4.0 kHz
CW: 6 UB/O.6 KHz 60 0B/1.2 Hz
TAM: —6 dB/6.0kH2 60 dB/12.0kHr
AEM: 68/120 kHz -60.dB/24,0 kH2
AM and CW filters are optional all models
**EM UNIT optional on FT-901SD/DE.
Passband toning:
‘Continuous from 2.4 kHe. 10 300 He
Intermodulation
Better than 80 UB jmmunity at 20 kite offset
20.48 mpuis at 14 Mttz
Desensitization:
Better than 100 JB immunity at 20 kM? off
20 dD input at 14 MItz
APF response
Within 3 eB from 400 - 900 Hz
Audio outpur:
Better than 3 watts @ 10% THD
Audio output impedance:
4-16 0hms
FT-901D/SD/DE/OM MODEL DIFFERENCES
Buitein feature
X= Available option
i FEATURE [F801 | Frs0is0 | Frsoine | Freoion]
[Bano caYsTAt 160m [0 ° | o °
BAND CRYSTAL 80m ° ° 2 ©
BAND CRYSTAL 40m © 9 @ °
BAND CRYSTAL 16m 3 6 5 ©
BAND CRYSTAL 10mA -_: ° ° °
BAND CRYSTAL 108 ql 3 © ©
BAND CRYSTAL 10m © © 5 ©
[BAND cAYSTAL _—10n0 © ° © 5
BAND CRYSTAL WWV/UY RCV © om © oJ
VOXIWARKER UNIT ° ° e o |
[em unit ° x x 2
RF SPEEGH PROCESSOR oe 70 ° 6
[aM FILTER x x x 7]
OW FILTER x x x =
EYER UNIT x x 3 3
[MEMORY UNIT x x x o
COC CONVERTER x x x 3
COOLING FAN o x oO o
POWER OUTPUT Too w iow woow | T00w

“TUBE COMPLEMENT
12By7A 1
61468 2
SEMICONDUCTOR
COMPLEMENT
Germanium transistors:
T20A6 2
Silicon transistors
2SASGAA 2
28nei9 1
2sa733 4
DcsTY 3
2scs73, 10
28C535A
2SCTSSY 3
28C7850 5
28945 a
2sc1o00GR 5
28C1818GR 2
ascisisy 49
2Na827 1
MPSAI3 1
Ic
25KI9GR
2sKI9RL
2SK34E
38K40M
38K59Y
39KS9GR
110338
8083
PCTELOS
PCTSLOS
HPC14305
HPCI4308
wPciasi2
F4024cP
40192
LM308
MCI416P
MC3403P
Mcao4aP
(upc 1008)
MC 1401 1B
MC 140428
MMT4C90
MSLUSOY3
MSLOBOY4
MSMS61
MsMssor
MSM5562
MSM5364
SN754508
SN76S14N
SN74LSOON
SN74LO4N
SNT4LSOON
SNDALS]23N
SN7ILS192N
‘TATO60P
TATOGLAP
TA7063P
TA7059M
TA7205AP
TA7310P
‘Te5032P
1
1
1
1
1
a
1
Hl
5
'
1
1
1
'
Germanium diodes:
1N60
1S 188M
151007 (GB)
INTO)
Silicon diodes:
18158589
toot 7
top10 5
voos 2
Specifications subject to change without notice
Varactor diodes:
182209
182236 '
F C63 t
MVIog 10
Silicon vatistor diodes:
MVI3 t
Zener diodes:
wz0s0
Wz090
wzit0
Light-emitting diodes:
GD4-2038RD 11
Lightemitting display’
HPS082-7740 6

CONTROLS AND SWITCHES
This transceiver has been specifically designed for
ease of operation and versatility. The operator
may, however, be unfamiliar with the operation
of the controls, and improper adjustment thereof
may result in poor transceiver performance. Thus,
(1) MODE
The
MODE
switch
has
six
positions
for
selection
of
the
operating
mode
desired:
LSB,
USB,
CW,
FSK, AM, or FM.
(2)
The
REJECT-WIDTH
REJECT and WIDTH controls are mounted
on
concentric
shafts.
The
rejection
tuning
control
(REJECT),
when
activated
by
pressing
the
small
silver
pushbutton
left
the
REJECT
knob, provides a variable IF notch filter action
for
nulling
out
a
particular
interfering
signal
to the of
The WIDTH control varies the signal across the
passband
of
one
of
the
two
IF
8-pole
crystal
band-
pass filters used in this circuit, thus providing a
variable IF bandwidth for rejection of signals above
or below the desired signal.
(3) M
The M button is pressed to store a frequency in
the
memory
circuitry.
frequency
is
being read out on the digital display will be the
frequency stored when the M button is pushed.
Whatever
wy
7)
be certain that you understand the function of
every before operating the transceiver.
The various front panel controls and switches
are described in the following section.
control
®
(4) EXT
When pushed, the EXT button transfers frequency
control
from
the
FT-901DM
to
an
external
VFO,
such as the FV-901 fully synthesized scanning
VFO.
(5)
VFO
When the VFO button is pushed, frequency con-
trol is transfered from EXT or memory control to
the FT-901DM internal VFO.
(6) TX-MR-RX
Once a frequency has been stored by the memory
(M) button, that frequency may be recalled for
control of either the transmit or receive frequency
by pushing either the TX or RX MR button,
respectively.
(7)
MR
Once
a
frequency
has
been
stored
by
the
memory
(M)
button,
that
frequency
may
be
recalled
for
control
of
the
transceive
frequency
by
pushing
the MR button.

(8) PRESELECT
This control pretunes the signal cireuils for bath
transmit and receive. The PRESELECT circuit
Drowites continuous peemeability tuning through
‘ur the Frequency range of the bransecive
1) HAND,
Ihe BAND switch provides selection of the band
10 through 10 meters plus WWV/JIY
Arecrive nly
Uosire,
(10) RF GAIN/CLARIFIER
The RF GAIN und CLARIFIER controls are
hnowted on concentsic shafts, The RF GAIN
keonisol provides manual contro! of the gait eels
ff the RF and IF amplifies on receive,
‘The CLARIFIER control allows mana offset of
ELS Kllz of either the ttansmit oF receive tre
{queney. Selection of transmit oF reecive clarifier
ie hy the two silver pushbuttons to the
left of the CLARIFIER contol
an atr
The ATT (RF antequator) button provides inser
lion of 4 20 dB attenuator in the incoming signal
path fa minimize recviver cross modulation eaused
by extremely strong focal signa,
(12) PROC LEVELJAF GAIN
‘The PROC LEVEL and AF GAIN controls are
‘mounte on concentric shafts. The PROC LEVEL
contra! allows manual contro! of the outpat level
fof the RF speech processor. The processor is
actuated by pressing the silver pushbutton to the
left ofthe PROC LEVEL contrat
‘The AF GAIN control adjusis the audio output
level at the speaker and phone Jack. Clockwise
rotatinn increases the audio output
(13) TUNE
This pushbutton, when depressed, places the trans
milter inthe “Tune” condition for ten seconds
for tuning purposes. After ten seconds, the train
ceiver is returned to the receive mode so a to
al_ampitier mbes caused
‘ime
during
toneup.
prevent damage to the
by cxoessive “key down
(14) LOADING.
This control tunes the output eireuit of the ps net-
Work
to
match
the
antenna/feedtine
impedance.
(15) PLATE
This control tunes the plate circuit of the final
amplifier
(16) CALIB,
When the MARK switeh is activated, the CALIB
knob provides manual vontrol for zeroing the
calibration of the digital display with he eal
brator signal
(17) CARR/KEYER
The CARR and KEYER controls are mounted
fon concentric shafis. The CARR control varies
the amount of cartier in the CW, AM, FSK. and
FM models af operation
‘The KEVER contiol varies the speed of the
builtin Curtis 8043 IC electronic keyer,
(18) VOX GAIN
This control selects MOX/PTT/VOX transmitter
relay control as well as adjusting the sensitivity of
the
VOX
circuitry.
The
PIT
position
provides
pust-io-alk operation from 4 microphone PTT
switch oF a footswitch, The MOX position provides
‘manual transmit, It must be returned to the PTT
position
For
receiver
recovery
(19)
APF
FREQ.
‘This
knob,
when
actuated
by
cuming
on
the
APF
switch,
provides
manual
control
for
peaking
the
auitio
peak
filter
(APE)
citeuit
on
the
desited
signal.
This
control
witl
find
its
chief
wsefulness
‘on
CW.
because
is
bandwidth
is
much
tow
marrow
for
normal
SSB
reveption.
(20) SOLMIC GAIN
‘The SQL and MIC GAIN controls are mounted on
concentric shafts, The SOL control sets the squeleh
threshold level for FM reception,
‘The MIC GAIN control varies the audio lev! from
the microphone amplifier stage, The control has
sulficient range to permit the use of any low inv
edance (50 - 600 Ohm) erystal or dynamic
‘microphone.
Clockwise
rotation
increases
the
level
of
output
from
the
microphone
amplifier
stag,
(21) FUNCTION SWITCHES: AMGC, APF/MONI,
AGC, PO/IC/ALC, and NB/MARK
‘The
AMGC
switeh
activates
+
microphone
gain
threshold circuit which requires a particular

minimum input level from the microphone to
trigger
the
microphone
amplifier.
Low-level
back-
ground noise will not activate the transmitter
with
the
AMGC
in
operation.
This
circuit
may
be
considered
a
“microphone
squelch”
system.
The
M
GAIN
control
functions
normally
with
the
AMGC system in operation.
When
the
APF/MONI
switch
is
in
the
APF
posi-
tion,
the
audio
peak
filter
(APF)
circuitry
is
activated.
The
exact
frequency
of
the
audio
peak is set by the APF FREQ
knob.
When
this
switch
is
placed
in
the
MONI
position,
monitor-
ing
of
the
microphone
level
may
be
accomplished
for
operator
convenience
or
tape
recording
both
~
sides
of
a
QSO.
In
the
CW
mode,
CW
sidetone
will
be
heard
regardless
of
the
position
of
the
APEF/MONI
switch.
The
AGC
switch
controls
the
length
of
the
re-
covery
time
for
the
receiver
AGC
circuitry.
This
switch
provides
slow or fast recovery,
and will
also turn off the AGC if desired.
The PO/IC/ALC switch will hereafter be referred
to as the METER switch. In the PO position,
relative
transmitter
output
power
can
be
observed.
In the IC position, transmitter final amplifier
cathode current may be measured. In the ALC
position, transmitter ALC voltage may be read.
When the FT-901DM is in the receive mode, the
meter functions as an “S” meter.
The NB/MARK switch provides for actuation of
either the Noise Blanker (NB) or crystal calibrator
(MARK), The marker oscillator can produce cali-
bration signals at intervals of either 25 kHz or
100 kHz by proper positioning of a switch inside
the cabinet.
(22)
POWER
This is the main on/off switch for the transceiver.
In the OFF position, the memory circuits are
disabled, so that when the transceiver is turned to
ON again, the memory circuits will have to be
reset.
(23) HEATER
With the HEATER switch in the down position,
the transmitter tube heaters are turned off. This
reduces battery drain to 1.1 amp and thus permits
long periods of listening without excessive battery
drain. Placing this switch in the up position pro-
vides supply voltage to the tube heaters, and
after 30 seconds of warmup the transmitter is
ready\for operation. This switch operates in both
the AC and DC modes.
SS)
(24)
PHONES
This
is
a
standard
1/4”
phone
jack
for
accom-
modation
of
headphones.
The
internal
speaker
is
disabled
when
headphones
are
plugged
into
this
jack.
(25) MIC
This four-conductor jack
microphone
plug
for
microphone
input
as
well
as
for PTT actuation.
accommodates — the
Mic plug
Headphone plug

REAR
APRON
CONNECTIONS
O®
(1) GND
Threaded lug for ground connection. la
(2)
RF
OUT
Signal frequency output from the driver stage
may be obtained at this jack for use with optional
equipment, such as the FTV-901R VHF/UHF
transverter.
(3)
ANT
Coaxial connection for antenna.
(4)
POADJ
Sets PO meter sensitivity.
ond receiver receives its antenna connection
through thisjack.
ACC
Cessory socket. Provides access to transceiver
operating voltages and relay contacts.
—————
(7)
KEY
Three-conductor jack
paddle or external key.
for connection to keyer
(8) EXT VFO
Connections for external VFO.
OH/ODO®
w
7) \
5
———— a
“MU ( REC.)
(9)
FUSE
;
Fuse holder requires 5 amp fuse for 117 volt or
* 3 amp fuse for 220 volt operation. For 12 volt
DC operation, a 20 amp fuse
power
cable.
installed in the
When
replacing
fuses,
be
certain
to
install a fuse of the proper rating. The warranty
does not cover damage caused by improper fuse
replacement.
(10)
POWER
Power receptacle. Both AC and DC cables are
Std€tone output for second receiver (if used).
—
(12)
IF
OUT
2
Wide-bandwidth
8.9
MHz
IF
signal
for
connection
to a spectrum
analyzer,
ete.
(13) PATCH
Speech input terminal for phone patch connection,
Impedance is 500 ohms.
(14) A-PRIP
ntj-tfip
input
from
second
receiver
(if
used).
——
(15) SP
Audio
output
is
provided
at
this
jack
for
an
ex-
ternal speaker. Output impedance is 4 ohms, and

the internal speaker will be disabled when plug
is inserted.
(16) PTT
This jack may be used for external actuation of
the transmitter. As an example, a footswitch may
be connected to this jack to provide remote con-
trol
of
the
transmitter
relay,
leaving
the
operator’s
hands free for writing and tuning purposes.
(17) FSK
Input from the FSK terminal may be made
through
this
jack.
The
FT-901DM
is
set
up
for
170 Hz shift.
(18) IFOUT 1
Narrow
bandwidth
8.9
MHz
IF
output
is
avail-
able for use with an IF monitorscope,
etc.
(19) REMOTE
Provides switched 13.5 VDC for relay control
for external low-pass filter units, etc. As the band-
switch is rotated, 13.5 VDC will appear at various
pins on the REMOTE jack. Use a VOM to deter-
mine the proper pin for the band in use.
por —
oe nee 7
oc
ae
“Se
«
Van
External speaker
ACC plug
Pin plug
Cooling fan

INTERCONNECTIONS
430MHz ANTENNA
144MHz
ANTENNA
|
SOMHz ANTENNA
=F a |||]
—10=

INSTALLATION
This transceiver is designed to be a single-unit
station
for
fixed,
portable,
or
mobile
operation.
Consequently, power supply connections provid-
ing
for
operation
from
a
variety
of
source
voltages
are
available.
This
system
provides
the
flexiblity
required
for
changing
locations
or
quick
moves
from fixed to mobile operation.
BASE
STATION
INSTALLATION
The
FT-901DM
is
designed
for
use
in
many
areas
of
the
world
using
supply
voltages
that
may
differ
from
the
operator’s
local
supply
voltage.
For
this
reason,
be
sure
that
the
voltage
marked
on
the
rear
of
the
transceiver
agrees
with
the
local
AC
supply
voltage.
THIS
INSPECTION
MUST
BE
MADE
BEFORE
CONNECTING
THE
AC
POW-
ER CORD
TO THE POWER
OUTLET.
CAUTION
PERMANENT
DAMAGE
WILL
RESULT
IF
IM-
PROPER
AC
SUPPLY
VOLTAGE
IS
APPLIED
TO THE TRANSCEIVER.
The transceiver should be connected to a good
earth
ground,
The
ground
lead
should
be
made
with a heavy braid wire and should be connected
to
the
GND
terminal
on
the
rear
apron
of
the
transceiver.
We
do
not
recommend
the
use
of
power
con-
nectors
other
than
the
ones
supplied
by
Yaesu.
If
a
rig
brought
in
for
servicing
is
blowing
fuses
every
time
you
plug
it
in,
check
to
make
sure
that
no
“improvements”
have
been
made
to
the
power
cord
through
substitution
of
or
modification
to
the power
connector,
For
base
station
installation,
the
only
important
consideration
that
need
be
made
is
to
ensure
adequate
circulation
around
the
unit.
Do
not
place
books
or
papers
on
or
around
the
cabinet,
nor
should
the
unit
be
placed
on
top
of
another
heat-generating
device
such
as
a
linear
amplifier.
Avoid
heat
ducts
and
window
locations
which
are
exposed
to
the
hot
sun,
and
you
will
keep
your
transceiver
running
at
full
speed
for
a
long,
long
time.
Be
certain
to
ground
the
transceiver
through
a
heavy,
braided
cable
less
than
10
feet
long.
Cold
water
pipes
in
newer
houses
probably
are
unsatis-
factory
as
grounding
posts;
it is
much
better
practice to use a system of one or more ground
rods, with the ground line securely bonded to the
ground system.
MOBILE INSTALLATION
(Note:
The
DC-DC
converter
described
herein
is
built-in
on the FT-901DM,
and is an available
option
on the FT-901D/SD/DE
models)
The FT-901DM will operate satisfactorily from
any 13.5 Volt DC negative-ground battery source
by connecting the DC power cord to the rear
panel receptacle. For under-dash mounting, a
special mobile mounting bracket is available from
your dealer. In mobile installations the trans-
ceiver should be suited away from heater ducts.
No special precautions need be observed if ade-
quate ventilation spaces is available. A minimum
of
two
inches
of
air
space
above
the
cabinet
top
and
on
all
sides
is
recommended
to
allow
proper
air flow around the cabinet. Never stack other
units above or below the transceiver since the
accumulated heat from both units could cause
damage.
The
transceiver
requires
an
average
of
14
amps
on transmit,
with 20 amps
on voice peaks,
The
DC power
cable comes
equipped
with a 20 amp
fuse. When
making
connections
to the car battery,
be absolutely
certain
that the RED lead is con-
nected
to the positive
(+) terminal
and the BLACK
lead is connected
to the negative
(—) terminal.
Reversed
connections
could
permanently
damage
the transceiver.
ury]
lsocxe
r
ruse Fuse
mOLOER woLoeR

The
BLACK
lead
should,
preferably,
run
directly
to
the
negative
terminal
of
the
battery.
Using
the
car
frame
as
a
negative
connection
or
connecting
the
RED
lead
to
a
positive
point
such
as
the
ig-
nition
switch
places
the
transceiver
in
the
same
current
path
as
noise-creating
devices,
thus
failing
to
take
advantage
of
the
filtering
action
of
the
battery.
The
power
cable
should
be
kept
away
from
ignition
wires
and
should
be
as
short
as
possible
to
minimize
voltage
drop
and
to
provide
a
low
impedance
path
from
the
transceiver
to
the battery.
Before
connecting
the
power
cable
to
the
trans-
ceiver,
check
the
battery voltage
with
the
engine
running
(battery
charging).
If
the
voltage
exceeds
15
Volts
DC,
the
regulator
should
be
readjusted
so
that
the
highest
charging
rate
does
not
ex-
ceed
15
Volts.
The
transceiver
should
always
be
switched
OFF
while
the
car
engine
is
being
started
to
prevent
voltage
transients
from
damaging
power
supply
components.
Width
=
"1"
ANTENNA CONSIDERATIONS
The
FT-901
transceivers
are
designed
for
operation
using
an
antenna
system
presenting
a
50-75
ohm
resistive
load
at
the
antenna
jack.
Amateur
instal-
lations
seldom
meet
this
requirement
over
the
entire
spread
of
every
band,
but
the
final
amplifier
pi
network
is
sufficiently
forgiving
to
allow
for
minor
deviations
from
the
target
figure.
However,
significant
departures
from
the
50-75
ohm
range
will
result
in
seriously
degraded
transceiver
per-
formance.
If
an
open-wire
feedline
is
used,
or
if
the
input
impedance
of
the
antenna
system
presents
a very
high
or
very
low
impedance
at
the
coaxial
input,
some
sort
of
antenna
tuner
must
be
used
to
pro-
vide
a SO
- 75
Ohm
unbalanced
feedpoint
for
the
transceiver.
For
mobile
operation,
most
of
the
commercially-
available
antennas
on
the
market
will
provide
good
results
if
care
is
taken
to
tune
the
antenna
for
minimum
SWR.
The
outer
conductor
of
the
coaxial
cable
should
be
securely
grounded
to
the
automobile
chassis
at
the
antenna
mount.
Wssu cu
Rejection
Tuning
Action
SSB,
CW
SSB
Filters
Filter
10
7
|
‘
f
11h)
{|
to=400Hz
im
<2
to=600112
‘ompiorts
oe
1
_
APF
Action
—12—

OPERATION
“The tuning procedure for this transceiver is not
complicated. However, care should be exercised
when tuning so that peak performance of the
‘equipment is scoured. The following paragraphs
describe the procedure for receiver and transmitter
eration
INITIAL CHECK,
Before connecting the trunsceiver to 4 power
source, carefully examine the unit for any visible
damage, Check that all modules are firmly. in
place and that the conteels and switches are of-
erating
normally.
Make
sure
that
tke
voltage
spe-
cifcation marked on the rear panel matches your
supply voltage, and that the line fase oo the rear
Panel matches the supply voltage; for 117 VAC.
use
a
S
ump
fuse,
and
for
220
VAC
use
a
3
amp
fuse, For DC operation fuse holder is installed
in the DC cable, and a 20 amp fuse should be
installed here
FREQUENCY SELECTION
Frequency readout for the FT-201DM inciy
booth analog and digital readout, The analog reud-
‘out dial shows calibrations at the 100 kHz and
10 kHz points, and is marked, as well, ia 1 kEl2
increments for fine tuning. The digital readout
tisplays all digits of the operating frequency, with
resolution down to 100 Hz accuracy
RECEIVE OPERATION
(1) Preset the controls and switches as indicated
POWER... .OFF
HEATER... OFF
VFO Switch depresed
VOX GAIN, . PTT position
RF GAIN. Fully clockwise
Adjust subsequently for com
fortable level
Desiced band
Desired mode
BAND.
MODE
PRESELECT. .Desired band sexment
e
@)
a
o
oy
Turn the POWER switsh to ON. The meter
will Tight up snd the operating frequency
will be displayed on the dial window. Adjust
the AF GAIN control for 2 comfortable
listening level, and adiust the PRESELECT
control for maximum mesiver nose or signal
level. The PRESELECT control may require
repeaking as the main tuning dial Is tuned
e108 the band,
‘The RX CLARIFIER may be usilized if the
received signal is drifting, Pushing the RX
button and rotating dhe CLARIFIER control
will provide 4 means of offsetting the receiver
Frequency £2.5 kH2 without clanging the
transmitting frequency. “red LED indieator
will Light up when the CLARIFIER is in use
When pubetype noise is encountered, the
NB (Noise lanker) switch should be acti=
vated, providing fective suppression of
this type of nose
Rejection of adjacent-chanael interference
may be accomplished by several means. The
REJECT control may be utilized t0 place a
steep-skirt 30 dB noted attenuation on any
interfering signal within the IF pastband
‘The WIDTH control vavies the center fre-
queney of one of two IF filters (the other
is fixed and presents a boundary for narrow
ing the passband). Varying the WIDTH com
trol varias the IF selectivity from approxi:
rately 300 Hz to 2.4 kHz (at 2.4 KH the
WIDTH controt is at “O™ and the two filters
have the stme center frequency). Clockwise
rolalion from the center (°O") position
makes the passband narrow toward the high
frequency side, while counterclockwise ro
{ation narrows the passband on the low
Frequency sid.
For CW reception. the APF (Audio Peak
Filter) may be activated. This filter has
100 He peak bandwidih with very. steep
skirts so as to provide sinslesignal reception
for CW, with insertion loss of less than 1 dB
when the APF conttol is tuned exactly ta
the signal frequency. The APF FREQ control
varies the peak frequency from approximately
4400 Hz fo 900 Itz. The operator will observe
that the APE system provides a significant

improvement in signalto-noise ratio. The
selectivily of the APP circuit may be varied
hy adisting VRsy ule the top cover
(OY For extremely strong signals, the ATT (RE
attenuator) switch may be presied to activate
220 di attenuation of the incowning signal
This should prevent any chanee of overioat
Cf the receiver front end.
‘TRANSMITTER TUNE-UP.
‘The following tune-up procedure must be per-
formed prior ta commencing operation on the
desired mode: LSB, USB, CW, FSK, AM, ar FM.
See the: paragraphs relating (0 the specific mode
after basie transmitter tune-up 8 described.
Connect a dummy loud oF matched antenna to
the coaxial fitting on the rear apron. Preset the
‘eantrals.as Follows:
POWER OFF
HEATER OFF
CARK Fully counterclockwise position
MICGAIN. Folly counteeslockwie postion
ANG OFF
METER switch IC
SELECT VFO (Depressed)
BAND Desired band segment
USB or LSB
Desired band segment
Desired band segment
“To position show in table
PROC OFF (Not depressed
TUNE OF (Not depressed)
CLAR TX... .OFF (Not depressed)
VOX GAIN... PTT position
‘Turn the POWER and HEATER switches to ON,
From cof start. allow 60 seconds after the
HEATER switel ¢ turned on for warm-up of the
transmitter tubes. Bo certain that the accessory
plug is inserted in the accessory plug is inserted
Jn
the
accessory
sockel;
without
this
plug
being
so connected, there will he no power applied ta
the lube heaters, Heater voltage is supplied through
pins 1 and 2 of the accessory socket.
LOADING POSITIONS.
BAND
160
80
40
lon |
Note: LOADING postions are aominsl. Minor
variations from positions shown are 10
he expected
Set the VOX GAIN control to MOX, The meter
will now read final amplifier resting exthode
current, This should read .05 (50 mA) If itis
not, adjust the bias eosteol located ander the top
cover near the rear of the sot, Set the METER
switch to ALC and adjust the ALC control under
the top cover for full seae deflection of the meter.
Return the meter switeh to IC and the VOX GAIN,
conttal to PTT.
Not: On the PT-90ISD, resting exthode
‘current showld be 025 (25 mA).
PRE-TUNING
UMPORTANT NOTE: Subsequent transmitter
tuning utilizes the TUNE button instead of MOX
for actuating the transmitter, When presse, the
TUNE button causes the transmitter to be act
vated for ten seconds, after which time the FT-
901DM retums t0 the reecive condition, This is
2 protective feature that sould not be nullified
by use of the MOX eontrol.»
(1D) Adjust the PRESELECT control for maxi-
rum reveiver noise evel
2) Depress the TUNE button, Rotate the CARR
control until the meter reuding rises just
above the normal idling current of 0S (50
may,
B) Adjust the PRESELECT control for maxi-
‘urn meter indication,
Cavtion: if the meter reading exceeds 1 (100
mA) reduce the setting of the CARR, contrl.

(2) Rotate the PLATE control for a minimum
meter reading dip” in final amplifier
eallinde current)
(5) Push the TUNE button again to rote the
transceiver tothe receive condition,
FINAL TUNING
Final peak runing utlizes the relative power out
Dut position of the METER switch, At full cated
Power inte SO Ohm load, the meter will read
approximately 12 to. 2/3 ull scale. IF the PO
reading is too igh (olf scale) oF too low (1/4 seale
fr less} and the load impedance is very dlose 10
50 Ohms, the PO ADJ control on the rear apron
may be adjusted so as to provide 1/2 to 2/3 seale
election at Fill power, Once the PO meter is
calibrated, ofseale meter defections are the
result of reflected power dur (0 high SWR, and
corrective action may be required in the antenna
Final fransmitter peaking is deseribed below.
(1) See the METER switch to the PO position
and rotate the CARR control to the U1
o'clock position
Press the TUNF button and rotate the PRE:
SELECT control for a maximum meter reade
ing. Press the TUNE button agsin to return
to the revive condition,
(3) Peess the TUNE button and rotate the LOAD:
ING control for a maximum meter reading
Pres. the TUNE button agin to rerum 10,
the receive condition,
(4) Poss the TUNE button and rotate the PLATE
ontrol for s maximum meter reading. Press
the TUNE button again to return ¢© the re
ceive condition,
(3) Repeat steps 2 through 4, advaneing. the
CARR control approximately 2 units for
teach set of adjustments untit the CARR eon:
trot is fully clockwise. The transmitter is now
tuned for maximem power output
(6) Return the CARR control to the fully coun-
lerelockwise position, Reluen the METER
switch to IC
With Fomilisrity, some of steps 2 = 4 may be per
formed within one press of the TUNE button,
(aking advantage of the 1second timer. The
operator is discouraged. through. from excel
tthe TOsccond limitation imposed by the timer
Ghrough use of the MOX pesition oF the micro
phone PTT switch,
‘SSB OPERATION
After completion of the above tuning procedure
sel the MODE switch to USB or LSB as desired.
Set the VOX GAIN control to PT and activate
the inesmitter by pushing the microphone PTT
switch of the footswitch, if used. While speaking
in @ normal voioe into the niieroniione, sklvanes
the MIC GAIN control uatit the meter kicks down
{othe midscale of the greencolored portion of
the meter seale
Note: When the METER switch is set to 16,
Voice
modulation
peaks
will
indicate
150
>
200 ma. Actual peak evtrent. however. is
approximately 2 tines the indicated valve,
To set the sensitivity of the VOX system, bevin
the VOX GAIN control in the PTT position,
Advance the VOX GAIN and speak in a norma
voles. The VOX GAIN control should be advanced
luntil the voice aetuates the transmitter (do not
press the microphone PTT swite or footswitch. i
tus, during this adjustment
Set the antitip potentiometer under the top
over 10 the minimus point whieh prevents the
speaker outpul from tripping the VOX. Do not
lise more VOX GAIN nor antitrin than necessary
Agiust the delay potentiometer under the top
tote for the desired release time,
If desired, the AMGC circuit may be activated
“This circuit ete as a sierophone squtleh
is, it initiates 4 theeshotd for mierop!
whet
microphone amplifier will oceur. This feature
permits minor noises such as @ TV in the operating
oom to be present without going out over the
air, Adjustment of the AMGC delay time is made
by w control under the top cover.
RF SPEECH PROCESSOR ADJUSTMENT
{AIL models)
‘The FT-90IDM speech processor. when properly
adjusted, is designed (0 improve the intelligibility
threshold at the receiving em by increasing the
averoge SSB power oulput. RE clipping is applies
to the IP signal, which is then Billered to remove
harmonics and out of band. intermodulation
products

The
distortion
produced
by
RF
envelope
clipping
and
filtering
is
less
objectionable
than
that
caused
by an equivalent
amount
of audio
clipping.
RF
clipping
causes
no increase
in the peak power
output,
but it does clip the peaks
of the voice
waveform
so
as
to
increase
the
average
power
output.
With the processor switch (located immediately
to the left of the PROC LEVEL control) in the
OFF
position
(not
depressed),
set
the
METER
switch
to
the
ALC
position.
Speaking
at
a
normal
level,
set
the
MIC
GAIN
control
to
the
level
where
the
meter
indication
stays
in
the
green
portion
of
the meter scale. Press the processor switch and
adjust
the
PROC
LEVEL
control
to
the
position
where the ALC indication stays in the green por-
tion
of
the
meter
scale
while
speaking
in
a
normal
voice. Optimum setting of the MIC GAIN and
PROC
LEVEL
controls
may
require
observation
of the transmitted signal using an oscilloscope.
PROCESSOR ON
CW OPERATION
Note: The Curtis 8043 IC Keyer Unit is built-in
on the FT-901DM/DE, and is an available
option on the FT-901D/SD models.
For electronic keyer operation, insert a three con-
ductor
plug
attached
to
a
keyer
paddle
into
the
KEY jack on the rear apron. Keyer speed may
then be adjusted by varying the KEYER control
on the front panel.
—16—
For
straight
key,
bug,
or
external
electronic
keyer
use,
rotate
the
KEYER
control
fully
counter-
clockwise
into
the
click-stop.
The
desired
key
line
may
then
be
inserted
into
the
KEY
jack.
Refer
to
the
drawings
on
page
9
for
details
of
the
proper
key
line
plug
wiring.
The transmitter may be activated on CW by MOX,
PTT,
or
by
VOX
(semi-break-in)
as
desired.
The
key-up
voltage
across
the
key
terminals
is
7
volts,
while
the
key-down
current
is
1.5
mA,
so
most
external
electronic
keyers
may
be
used
with
the
FT-901DM without modification.
The
operator
may
select
any
power
output
desired
by advancing
the CARR
control
as desired.
NOTE:
Insertion
of
the
key
plug
automatically
disconnects
the
bias
supply
to
the
PA
tubes.
Therefore,
bias
current
will
not
be
indicated
when
the
METER
switch
is in the
IC
position.
AM OPERATION
AM operation of the transmitter is accomplished
by setting the MODE switch to the AM position
and inserting the proper amount of carrier with
the CARR control.
After
completing
basic
transmitter
tune-up,
place
the MODE
switch
in the AM position.
Activate
the transmitter,
and rotate
the CARR
control
until the meter
reads .10 (100 mA) in the IC po-
sition
of the METER
switch.
While
speaking
into
the microphone
in a normal
voice,
increase
the
MIC GAIN
control
until the meter
indicates
very
slight
movement
with voice peaks.
Care must be
exercised
that the CARR
control
is not advanced
too far. Do not exceed
.10 (100 mA) meter
indi-
cation
during
AM operation
or damage
to the
transmitter
final amplifier
tubes may result,
For AM reception, an AM filter is available as an
option.
FSK OPERATION
After
completing
basic
transmitter
tune-up,
place
the
MODE
switch
in
the
FSK
position.
The
FSK
terminal
input
may
be
connected
to
the
FSK
jack

on the rear panel. The FT-901DM is set up for
170 Hz shift, and the shift frequency may be ad-
justed somewhat by means of the trimmer capaci-
tors located under the top cover. The CARR con-
trol must be adjusted in the TUNE position for
not more than 100 mA. Excessive cathode current
may result in damage to the final amplifier tubes.
Audio output from the transceiver may be taken
from the SP jack in the rear apron.
FM OPERATION
Note:
The
FM
Unit
is
built-in
on
the
FT-901D/
DM, and is an available accessory on the
FT-901SD/DE models.
After completing the basic transmitter tune-up,
set the CARR control for 100 mA carrier level
in the FM mode. Speak into the microphone in
a normal voice. The MIC GAIN and PROC LEVEL
controls have no effect in the FM mode.
For FM reception, the SQL control on the front
panel should be advanced only as far as required
to silence background noise. When adjusted just
past the silencing threshold, the squelch circuitry
will provide noise-free reception with maximum
sensitivity to weak FM signals.
DIAL CALIBRATION
The frequency readout of the FT-901DM is de-
signed to indicate the carrier frequency. Con-
sequently, there will be a 3 kHz difference be-
tween USB and LSB. When calibrating the dial
and digital display, the CLARIFIER switch should
always be OFF.
(1) For SSB calibration, place the NB/MARK
switch in the MARK position to activate the
internal marker signal generator. The choice
of 25 kHz or 100 kHz marker intervals may
be made by changing the position of switch
S601, Which is located on the VOX unit.
As the main tuning knob is turned, a beat
note will be heard every 25 kHz or 100 kHz,
depending on the position of S¢o, -
dial and secure a zero beat (lowest pitch ‘fre-
quency) with the marker signal nearest the
desired operating frequency.
Q)
Tune the
(3) Turn the ribbed calibration ring on the main
tuning knob shaft to calibrate the analog
scale precisely to the zero or 25 kHz point.
Adjust the CALIB control for a precisely
correct reading in the digital window (for
example, 14.225.0).
For CW calibration, secure a zero beat as
above, then adjust the CALIB control until
the digital display frequency indication is
705 Hz higher than the zero beat (for example,
14.000.7). Then rotate the main tuning dial
to secure the zero or 25 kHz reading on the
al display (14.000.0); rotate the ribbed
calibration ring on the main tuning knob
shaft to align the analog dial precisely with
the calibration mark and the digital display.
In the CW mode, to repeat, the transmitter
(4)
(5)
carrier frequency is the frequency being
displayed.
(6)
In
the
AM
and
FM
modes,
the
zero
beat
signal is not available, Place the WIDTH con-
and tune the dial
indication
the
trol in the “O” position,
for maximum S-meter
marker signal to establish
point.
the
- calibration
on
ny Point
-2-3kHz (AM.N)
5
6kHz
(AM.W)
10--12kHz
(FM)
meter Deflection
Frequency
SELECT SWITCHES/MEMORY SYSTEM
OPERATION
(Note: The memory unit is built-in on the DM
model, optional on the D/SD/DE models)
Frequency control of the FT-901DM is by means
of the internal VFO, the memory unit, an ex-
ternal VFO, or various combinations of the three.

Split.
memory system or the FV-901 synthesized ses
hing VFO. The switches
queney control may be obtained with th
wolved
in
frequency
‘control are a follows
MR
RX MR
vFo
EXT
Note:
‘This button recalls the memorized fre-
queney for control of the transceive
frequency.
‘This button recalls the memorized fre
quency for control of the transmit fre
quency,
‘This button recall the memorized fre
{quency for control of the receive fhe
quency,
Frequency control is by means of the
internal VFO as controlled by the main
tuaing knob,
‘This switch selects the PV-901 synthe
sized scanning VEO for frequeney or
‘tol a8 follows: with the EXT and MR.
hnuttons
pushed,
transceive
frequency.
control is by mieans of the external VFO.
With the EXT and TX MR_ buttons
pushed, the extemal VEO. controls
the trinsmil frequency while the internal
VEO
controls
the
receive
frequency.
With the EXT and RX MR buttons
Pushed, the extemal VEO controls the
receive frequeney while the internal
VFO controls the transmit frequency
‘This button is used to store a frequency
in-memory. THE FREQUENCY DIS-
PLAYED ON THE DIGITAL READ-
OUT WILL BE THE FREQUENCY
STORED WHEN THE M BUTTON
IS PRESSED, When the M button is
pressed, the frequency previously stored
in memory will be destroyed. When the
power is turned off, the frequency is
Tost from memory.
Because of “round-olf error” the disital
Aisplay and -memory system may exhibit
2 100 He difference between the VEO
condition and the memory recall condi:
tion,
Operation of the memory system & perhaps best
\eseribed by the use of some examples
o
a
8
Note
You are operating on a net on 3970 klz and
must QSY down 10 kllz to handle a piece of
traffic. With the VFO button depressed and
the main dist on 3970 kHz, press M; 3970 Is
how memorized, Move the main dial dows
to 3960 kHz to handle the message. When
finished, press MR for instant return to 3970
KHz, The main dial may be left at 3960 kHz
if further QSY to that trequency is antici-
pated. To retum to 3960 KH, simply press
VFO,
You ate operating split frequency on 40
meter phone, and you hear DXtDX on 7030
kHz, listening for calls on 7205 kll2. With
the VFO button depressed and the main
dial on 7090 KFIz, press M to store 7090 kFle
in memory, and press RX MR 0 lock the
receiver on 7090 kHz. Turn the main tuaing
dial to 7205 kHz; you will now be tansmit-
{ing on 7205 kflz and listening on 7090 bli
To listen 10 the pileap on 7208 kHz of
stations calling DXIDX, push VFO: you wi
now be listening and transmitting on 7208
kflz, and another press of RX MR will retry
you to 7090 kHz for receive, If DXIDX
‘oul! begin to duift slightly in frequency,
push TX MR and M to store 7205 klle in
memory and tock the transmitiee on that
frequency. Place the main dial on 7080 KH
for precise tracking of the unstable DXIDX
signal
You find DXIDX on 21270 kH2, working,
stations by onder of call area, By pressing the
M bution, 21270 kHz may be stored in
‘memory and the operator may periodically
check to se if his call urea is being acknow:
edged by pressine MR or RX MR,
After the M- bution is pushed, the ¥CO
requires 10 seconds to stabilize on the
memorized frequency. If one of the MR
buttons is pushed during this 10second
period, some “drifting” of the memorized
frequency may he observed.