Yaesu FT-902DM User manual

INSTRUCTION
MANUAL
FT-902DM
YAESU MUSEN CO., LTD.
TOKYO JAPAN

ALL MODE HF TRANSCEIVER
FT-902DM
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GENERAL DESCRIPTION
The FY-902DM is a precision engineered, high per-
formance HF transceiver of advanced design, pro-
viding all band coverage (160, 80.40, 30. 20, 17,
15, |2,and |]Ometers) on all modes of operation:
LSB, USB, CW, FSK, AM, and FM. This trans-
ceiver operates alan input power of 180 watts
on 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 displuy LED digits,
a built-in Curtis 8044 IC electronic keyer, and
memory frequency control circuilry. Staite-of-the-
art receiver performance features Include rejection
tuning,
dualfilter
variable
IF
bandwidth
tuning,
and,
for
CW,
audio
peak
frequency
(APF)
tuning
for
unsurpassed
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
RE
attenuator
for
protection
against
receiver
overload,
All
circuits,
except
the
transmilter
driver
and
final
amplifier
stages,
are
solid
state,
utilizing
modern
plug-in
printed
circuit
boards,
thus
per-
mitting
easy
maintenance.
The FT-902DM transceiver is entirely self-con-
lained, requiring only an antenna and power source
for operation. For base station operation, AC
power voltages of LOO/110/117/200/220/234 VAC
may be chosen, though the unit normally is sup-
plied with 117 volt capability. A DC-DC converter
unil provides fer 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 olf 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
FT-902D/SD/DE are the memory unit, the keyer
unit, the DC-DC converter, the FM unil, and the
cooling fan. Optional equipment on all modets are
the 600 [lz CW filter and the 6 KHz AM filter.
The entire PT-902DM 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 1.8 - 2.0 MHz
80m 3.5 - 4.0 MHz
40m 7.0- 7.5 MHz
30m 10.0 - 10.5 MHz
20m 14.0 - 14.5 MHz
17m 18.0 - 18.5 MHz
15m 21.0 - 21.5 MHz
12m 24.5 - 25.0 MHz
10mA 28.5 - 28.5 MHz
10mB 28.5 - 29.0 MHz
10mC 29.0 - 29.5 MHz
10mD 29.5 - 29.9 MHz
Power requirements:
AC 100/110/117/200/220/234 V, 50/60 Hz
DC 13.5 V, negative ground
(DC option FT-902D/SD/DE)
Power consumption:
(FT-902DM/D/DE)
AC 117 V: 70 watts receive
(45 watts HEATER OFF)
320 watts transmit (max)
DC 13.5 V: 5A receive
(1.1 A HEATER OFF)
21 A transmit (max)
(FT-902SD)
AC 117V: 55 watts-receive
(45 watts HEATER OFF)
105 watts transmit (max)
DC 13.5 V: 3.8 A receive
(0.8 A HEATER OFF)
7.5 A transmit (max)
Size:
342 (W) x 154 (H) x 324 (D) mm
Weight:
I8kg
TRANSMITTER
Emission:
LSB, USB (A3j), CW (Al), AM (A3h), FM
(F3) (option FT-902SD/DE), FSK (F1)
PA input power:
FT-902DM/D/DE
SSB/CW: 180 watts DC
AM/FSK/FM: 80 watts DC
FT-902SD
SSB/CW/FSK/FM: 20 watts DC
AM: 5 watts DC :
Carrier suppression:
Better than 40 dB
Unwanted sideband suppression:
Better than 40 dB @ 1000 Hz
Spurious radiation:
Better than 40 dB below rated output
Transmitter frequency response:
300 - 2700 Hz (6 dB)
Third order distortion products:
Better than 31 dB below rated output
Transmitter frequency stability:
Less
than
300
Hz
after
10
minute
warmup:
less than 100 Hz after 30 minute warmup.
Negative feedback:
6 dB at 14 MHz
Modulation:
A3J: Balanced modulator
A3h: Amplitude modulation of a low power
stage
F3: Variable-reactance frequency modula-
tion, max. deviation +5 kHz (F3 fea-
ture optional on FT-902SD/DE)
Antenna output impedance:
50-75 Ohms, unbalanced
Microphone input impedance:
500 - 600 Ohms

RECEIVER Passband tuning:
Continuous from 2.4 kHz to 300 Hz
Sensitivity:
SSB/CW/FSK 0.25 pV for S/N 10 dB Intermodulation:
AM 1 uv for S/N 10 dB Better than 80 dB immunity at 20 kHz offset
FM 0.3 uV for 20 dB quieting 20 dB inputs at 14 MHz
Image rejection: Desensitization:
1.8- 25 MHz - - Better than 60 dB Better than 100 dB immunity at 20 kHz off
28 MHz - - Better than 50 dB 20 dB input at 14 MHz
IF
rejection:
APF
response:
Better than 70 dB Within 3 dB from 400 - 900 Hz
Selectivity, WIDTH control at “0” Audio output:
SSB: -6 dB/2.4kHz —60 dB/4.0 kHz Better than 3 watts @ 10% THD
*CW: -—6dB/0.6kHz —60dB/1.2 kHz
*AM: —6dB/6.0kHz -—60 dB/12.0 kHz Audio output impedance:
**FM: —6 dB/12.0 kHz —60 dB/24.0 kHz ALAS Ohms
*AM and CW filters are optional, all models
**FM UNIT optional on FT-902SD/DE
FT-902D/SD/DE/DM MODEL DIFFERENCES
O = Built-in feature X = Available option
FEATURE " FT-9020 | FT-902SD | FT-902DE ' FT-902DM —
BANDCRYSTAL 160m OO O See ae Oe.
BAND CRYSTAL 80m ss O om cm oO
| BAND CRYSTAL 40m | fe) O eo if oO
BAND CRYSTAL 30m | eee OT ee 2
“BAND CRYSTAL 20m G2. oO | O Oo.
BAND CRYSTAL 17m Oo | om 30 ic)
-BANDCRYSTAL 15m =| O..— O Ge. | Onc!
BAND CRYSTAL 12m | Or. fon it ee Oo.
| BAND CRYSTAL —-10mA__ O O oO oan
BAND CRYSTAL 10mB leg Orch — JO o. -|. =-6
_BAND CRYSTAL __10mC “Or, = lit OL I Or). - Oe
BAND CRYSTAL —_10mD io “© O 0
-VOX/MARKER UNIT 0 O on O-
FM UNIT as em al oa a ae % O. |
_RF SPEECH PROCESSOR _ oO O sue), i Os
AM FILTER 7 x x x XP
CW FILTER | —, x Ne x 4
FM FILTER = x . a a x
_KEYER UNIT ; | x -. or eas)
MEMORY UNIT ; | x x = oe ee Cs
_DC-DC CONVERTER - | x x x O
COOLING FAN o |... & ec or |i
_POWER OUTPUT = = =—S |s~Ss«100 W 10W- 100 W 100 W

TUBE COMPLEMENT
12BY7A 1
6146B 2
SEMICONDUCTOR
COMPLEMENT
Germanium Transistor:
T20A6 2
Silicon Transistor :
2SA496Y 2
2SA564A-R 2
2SA639 1
28A733 3
2SA952L 13
28C372Y 4
2SC380TM-Y 15
2SC535A 1
2SC732TM 5
2SC735Y 3
2SC785-O 3
2SC1674L 1
2SC1815Y 29
2SC1815GR 11
2S8C2407 2
MPSA13 1
FET:
2SK19GR 11
2SK19TM-BL 10
2SK34E 1
3SK40M 3
3SK51-03 9
3SK59Y 1
3SK59GR 1
3SK73 1
JF1033B 4
J310 1
Ic:
MC3403P
MC14011BCP
MC14042BCP
MC4044P
(uPC1008C)
TA7205AP 1
TA7063P 2
TA7061AP 2
TA7310P |
TA7089M 1
TA7060P 1
I
2
3
1
1
]
NON
TC503 2P
uPC14305
uPC14308
uPC14312
uPAS4H
SN75450B
Specifications subject to change without notice.
SN74LS192N
SN74LSO0ON
SN74LS04N
SN74LS123N
MSM5562
MSM9520RS
MM74C90N
NJM78LOS5A
NJM78L08
LM308
8044
34024PCQM
Germanium Diode:
1N60
1S188FM
181007
Silicon Diode:
181555
1SS53
10D1
10D10
VO6B
SM1-12
— i OND Ss RE OND SO
12
6
30
101
ee WN wo ON
Varactor Diode:
182209 2
182236 ]
FC63 ]
MV104 12
Zener Diode:
WZ050 2
WZ060 1
WZ090 5
WZ110 2
Schottky Barrier Diode:
ND487C2 1
LED:
GD4-203SRD 12
LED Display:
HP5082-7623 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,
be certain that you understand the function of
every control before operating the transceiver,
The various front panel controls and switches
are described in the following section,
/
(1) MODE
The MODE switch has six positions for selection
of the operating mode desired! LSB, USB, CW.
FSK, AM, or FM.
(2) REJECT-WIDTH
The REJECT und WIDTH controls are mounted
on concentric shafts: The rejection tuning control
(REJECT). when activated by pressing the small
the left of the REJECT
knob, provides u variable IF notch filter action
for nulling Oul a particular interfering signal,
silver pushbutton. to
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. Whatever lrequency is
being read out on the digital display will be the
lrequency stored when the M button is pushed.
mA
* Tololeloioroy
mes AH) SEES FOG
(4) EXT
When pushed, the EXT button transfers frequency
control from the FT-902DM to an external VFO,
such as the FV-901DM fully synthesized scanning
VFO.
(5) VEO
When the VFO button is pushed, frequeney con-
trol is transfered from EXT or memory control to
the FT-902DM 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 reeeive 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 circuits for both
transmit and receive. The PRESELECT circuit
provides continuous permeability tuning through-
out the frequency range of the transceiver.
(9) BAND
The BAND switch provides selection of the band
desired, 160 through 10 meters.
(10) RF GAIN/CLARIFIER
The RE GAIN and CLARIFIER controls are
mounted on concentric shafts. The RF GAIN
control provides manual control of the gain levels
of the RF and IF amplifiers on receive.
The CLARIFIER control allows manual offset of
42.5 kHz of either the transmit or receive fre-
quency. Selection of transmit or receive clarifier
is made hy the two silver pushbuttons to the
left of the CLARIFIER control.
(11) ATT
The ATT (RF attenuator) button provides inser-
tion of a 20 dB attenuator in the incoming signal
path to minimize receiver cross modulation caused
by extremely strong local signals.
(12) PROC LEVEL/AF GAIN
The PROC LEVEL and AF GAIN controls are
mounted on concentric shafts. The PROC LEVEL
control allows manual control of the output level
of the RF speech processor. The processor is
actuated by pressing the silver pushbutton to the
left of the PROC LEVEL control.
The AF GAIN control adjusts the audio output
level at the speaker and phone jack. Clockwise
rotation increases the audio output.
(13) TUNE
This pushbutton, when depressed, places the trans-
mitter in the “tune” condition for ten seconds
for tuning purposes. After ten seconds, the trans-
ceiver is returned to the receive mode so as to
prevent damage to the final amplifier tubes caused
by excessive “key down” time during tune-up.
(14) LOADING
This control tunes the output circuit of the pi net-
work to match the antenna/feedline impedance.
(15) PLATE
This control tunes the plate circuit of the final
amplifier.
(16) DIM
This control allows dimming of the meter and dial
lamps.
(17) CARR/KEYER
The CARR and KEYER controls are mounted
on concentric shafts. The CARR control varies
the amount of carrier in the CW, AM, FSK, and
FM models of operation.
The KEYER control varies the speed of the
built-in Curtis 8044 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 PTT position provides
push-to-talk operation from a microphone PTT
switch or 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 turning on the APF
switch, provides manual control for peaking the
audio peak filter (APF) circuit on the desired
signal. This control will find its chief usefulness
on CW, because its bandwidth is much too narrow
for normal SSB reception.
(20) SQL/MIC GAIN
The SQL and MIC GAIN controls are mounted on
concentric shafts. The SQL control sets the squelch
threshold level for FM reception.
The MIC GAIN control varies the audio level from
the microphone amplifier stage. The control has
sufficient range to permit the use of any low im-
pedance (500 - 600 Ohm) crystal or dynamic
microphone. Clockwise rotation increases the level
of output from the microphone amplifier stage.
(21) FUNCTION SWITCHES: AMGC, APF/MONI,
AGC, PO/IC/ALC, and NB/MARK
The AMGC switch activates a 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
APF/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-902DM 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.
(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 accommodates the
microphone plug for microphone input as well as
for PTT actuation.
MIC
Mic plug
Headphone plug

REAR
APRON
CONNECTIONS
(1) GND
Threaded lug for ground connection.
(2) RF OUT
Signal frequency output from the driver stage
may be obtained at this jack for use with optional
equipment, such as the FTY-90O1R transverter.
(3) ANT
Coaxial conneclion for antenna.
(4) PO ADJ
Sets PO meter sensitivity.
(S) RCV ANT
A second receiver receives its antenna connection
through this jack,
(6) ACC
Accessory socket. Provides access to transceiver
operating voltages and relay contacts.
(7) KEY
Three-conductor jack for connection to keyer
paddle or external key,
(8) EXT VFO
Connections for external VFO.
ral
(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 ts installed in the
power cable, When replacing fuses, be certain to
install a fuse of the proper rating. The
caused by improper fuse
warranty
does not cover damage
replacement.
(10) POWER
Power receptacie. Both AC and DC cables are
supplied.
(11) TONE
Sidetone output for second receiver (if used).
(12) IF OUT 2
Wide-bandwidth 8.9 MHz IP signal for connection
to a spectrum analyzer, ete,
(13) PATCH
Speech input terminal for phone patch connection.
Impedance is 500 ohms,
(14) A-TRIP
Anti-trip input from second receiver (if used).
(15) SP
Audio output is provided at this jack for an ex-
ternal speaker. Outpul impedance ts 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- PIN No.
; ; 1 HEATER
trol of the transmitter relay, leaving the operator’s 2 HEATER
hands free for writing and tuning purposes. 4 +300V
5 +800V
6 —100V
7 ALC
(17)
FSK
9
TX
GND
.
10
RX
GND
Input from the FSK terminal may be made WNC
through this jack. The FT-902DM is set up for
1
170 Hz shift. eens
(18) IF OUT 1
Narrow bandwidth 8.9 MHz IF output is avail- KN
able for use with an IF monitorscope, etc. PExTIN
3 EXT OV
(19) REMOTE 4 AGC OUT
5 TX12V
6 GND
Provides switched 13.5 VDC for relay control
for external low-pass filter units, etc. As the band- EXT VFO PLUG
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. — i
HU et
S>
oot neeney
MMON © q
AO he Ss ‘3 i+
Se )
Ma
ML
Pin plug
Cooling fan |
External
speaker
,
\

INTERCONNECTIONS
TELEPHONE LINE
FL-2100Z FT-902DM LINE SP-901P
REOUT RE IN” GNO ~ ALG RY - ?
! @ 1) Pp
wT
|
Bag
.
ak
oa
titowzw
OU
;
-
PIN
je)
| FV-101Z/ FV-901DM
PIN 1
PING - GND
ACC PIN 9 (INNER CONOUCTOR)
* PIN 8 (OUTER CONDUCTOR)
ace PIN 7 (INNER CONDUCTOR)
exe) “PIN 8 (OUTER CONDUCTOR)
O
Gp ¢
: ~
aed
@)
U
EXTERNAL RECEIVER
HF ANTENNA OPOOO
MUTE PLUG
FTV- Sono EXT ;) FT-9020M
430MHz ANTENNA 5
wenwrewns (Coll WM: fe) OUTPUT
144MHz ANTENNA | r . ll
ag 0
50MHz ANTENNA |
-_ i=}
CABLE C
CABLE A

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-902DM 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-902DM, and is an available
option on the FT-902D/SD/DE models)
The FT-902DM 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.
FUSE
HOLDER
FUSE
HOLOER
FUSE
HOLOER
—-]]--

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.
J]
Width ="
Width = '"'-1"'
Width Control Action
Rejection
Tuning
Action
ANTENNA CONSIDERATIONS
The FT-902 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 50 - 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.
(LSB Carrier}|
10.76 MHz
x
z
°
o
o
o
Cf tol
(ssB) (cw)
SSB, CW SSB
Filters Filter
a
3
— | 4
g 10)-—o =a |
2 ++ | Lt
=- ++
70 ‘o=eoons ||
ml
Ss Ji J
oF
10°
10
Frequency(Hz)}
APF Action

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 secured. The following paragraphs
describe the procedure for receiver and transmitter
operation.
INITIAL CHECK
Before connecting the transceiver to a power
source, carefully examine the unit for any visible
damage. Check that all modules are firmly in
place and that the controls and switches are op-
erating normally. Make sure that the voltage spe-
cification marked on the rear panel matches your
supply voltage, and that the line fuse on the rear
panel matches the supply voltage; for 117 VAC,
use a 5 amp fuse, and for 220 VAC use a 3 amp
fuse. For DC operation a fuse holder is installed
in the DC cable, and a 20 amp fuse should be
installed here.
FREQUENCY SELECTION
Frequency readout for the FT-902DM includes
both analog and digital readout. The analog read-
out dial shows calibrations at the 100 kHz and
10 kHz points, and is marked, as well, in 1 kHz
increments for fine tuning. The digital readout
displays 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
V FON ceo. Switch depressed
VOX GAIN... .PTT position
RF GAIN ... .Fully clockwise
AF GAIN ....Adjust subsequently for com-
fortable level
BAND....... Desired band
MODE....... Desired mode
PRESELECT. .Desired band segment
(2)
Turn
the
POWER
switch
to
ON.
The
meter
will
light
up
and
the
operating
frequency
will
be
displayed
on
the
dial
window.
Adjust
the
AF
GAIN
control
for
a
comfortable
listening
level,
and
adjust
the
PRESELECT
control
for
maximum
receiver
noise
or
signal
level.
The
PRESELECT
control
may
require
repeaking
as
the
main
tuning
dial
is
tuned
across
the
band.
(3)
The
RX
CLARIFIER
may
be
utilized
if
the
received
signal
is
drifting.
Pushing
the
RX
button
and
rotating
the
CLARIFIER
control
will
provide
a
means
of
offsetting
the
receiver
frequency
+2.5
kHz
without
changing
the
transmitting
frequency.
A
red
LED
indicator
will
light
up
when
the
CLARIFIER
is
in
use.
(4) When pulse-type noise is encountered, the
NB (Noise Blanker) switch should be acti-
vated, providing effective suppression of
this type of noise.
(5) Rejection of adjacent-channel interference
may be accomplished by several means. The
REJECT control may be utilized to place a
steep-skirt 30 dB notch attenuation on any
interfering signal within the IF passband.
The WIDTH control varies the center fre-
quency of one of two IF filters (the other
is fixed and presents a boundary for narrow-
ing the passband). Varying the WIDTH con-
trol varies the IF selectivity from approxi-
mately 300 Hz to 2.4 kHz (at 2.4 kHz the
WIDTH control is at “0” and the two filters
have the same center frequency). Clockwise
rotation from the center (‘0’) position
makes the passband narrow toward the high
frequency side, while counter-clockwise ro-
tation narrows the passband on’ the low-
frequency side.
(6) For CW reception, the APF (Audio Peak
Filter) may be activated. This filter has a
100 Hz peak bandwidth with very steep
skirts so as to provide single-signal reception
for CW, with insertion loss of less than ] dB
when the APF control is tuned exactly to
the signal frequency. The APF FREQ control
varies the peak frequency from approximately
400 Hz to 900 Hz. The operator will observe
that the APF system provides a significant

improvement in signal-to-noise ratio. The
selectivity of the APF circuit may be varied
by adjusting VR<o, under the top cover.
(7) For extremely 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.
TRANSMITTER TUNE-UP
The following tune-up procedure must be per-
formed prior to commencing operation on the
desired mode: LSB, USB, CW, FSK, AM, or FM.
See the. paragraphs relating to the specific mode
after basic transmitter tune-up is described.
Connect a dummy load or matched antenna to
the coaxial fitting on the rear apron. Preset the
controls as follows:
POWER........ OFF
HEATER....... OFF
CARR......... Fully counter-clockwise position
MIC GAIN...... Fully counter-clockwise position
AMGC......... OFF
METER switch . .IC
SELEGT™ 4 5 -2ueces VFO (Depressed)
BAND......... Desired band segment
MODE......... USB or LSB
PLATE ........ Desired band segment
PRESELECT... .Desired band segment
LOADING...... To position shown in table
PROC ......... OFF (Not depressed)
LUNE es oe o ue OFF (Not depressed)
CLAR TX...... OFF (Not depressed)
VOX GAIN..... PTT position
Turn the POWER and HEATER switches to ON.
From a cold start, allow 60 seconds after the
HEATER switch is turned on for warm-up of the
transmitter tubes. Be certain that the accessory
plug is inserted in the accessory plug is inserted
in the accessory socket; without this plug being
so connected, there will be no power applied to
the tube heaters. Heater voltage is supplied through
pins | and 2 of the accessory socket.
LOADING POSITIONS
BAND POSITION
ws
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Note: LOADING positions are nominal. Minor
variations from positions shown are to
be expected.
Set the VOX GAIN control to MOX. The meter
will now read final amplifier resting cathode
current. This should read .05 (50 mA).* If it is
not, adjust the bias control located under the top
cover near the rear of the set. Set the METER
switch to ALC and adjust the ALC control under
the top cover for full scale deflection of the meter.
Return the meter switch to IC and the VOX GAIN
control to PTT.
*Note: On the FT-902SD, resting cathode
current should be .025 (25 mA).
PRE-TUNING
(IMPORTANT NOTE: Subsequent transmitter
tuning utilizes the TUNE button instead of MOX
for actuating the transmitter. When pressed, the
TUNE button causes the transmitter to be acti-
vated for ten seconds, after which time the FT-
902DM returns to the receive condition. This is
a protective feature that should not be nullified
by use of the MOX control.)
(1) Adjust the PRESELECT control for maxi-
mum receiver noise level.
(2) Depress the TUNE button. Rotate the CARR
control until the meter reading rises just
above the normal idling current of .05 (50
mA).
(3) Adjust the PRESELECT control for a maxi-
mum meter indication.
Caution: if the meter reading exceeds .1 (100
mA) reduce the setting of the CARR control.
= 14-—

(4) Rotate the PLATE control for a minimum
meter reading (‘“dip” in final amplifier
cathode current).
(5) Push the TUNE button again to return the
transceiver to the receive condition.
FINAL TUNING
Final peak tuning utilizes the relative power out-
put position of the METER switch. At full rated
power into a 50 Ohm 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 impedance is very close to
50 Ohms, the PO ADJ control on the rear apron
may be adjusted so as to provide 1/2 to 2/3 scale
deflection at full power. Once the PO meter is
calibrated, off-scale meter deflections are the
result of reflected power due to high SWR, and
corrective action may be required in the antenna
system.
Final transmitter peaking is described below:
(1) Set the METER switch to the PO position
and rotate the CARR control to the 11
o’clock position.
(2) Press the TUNE button and rotate the PRE-
SELECT control for a maximum meter read-
ing. Press the TUNE button again to return
to the receive condition.
(3) Press the TUNE button and rotate the LOAD-
ING control for a maximum meter reading.
Press the TUNE button again to return to
the receive condition.
(4) Press the TUNE button and rotate the PLATE
control for a maximum meter reading. Press
the TUNE button again to return to the re-
ceive condition.
(5) Repeat steps 2 through 4, advancing the
CARR control approximately 2 units for
each set of adjustments until the CARR con-
trol is fully clockwise. The transmitter is now
tuned for maximum power output.
(6) Return the CARR control to the fully coun-
ter-clockwise position. Return the METER
switch to IC.
With familiarity, some of steps 2 - 4 may be per-
formed within one press of the TUNE button,
taking advantage of the 10-second timer. The
operator is discouraged, through, from exceeding
the 10-second limitation imposed by the timer
through use of the MOX position or the micro-
phone PTT switch.
SSB OPERATION
After completion of the above tuning procedure,
set the MODE switch to USB or LSB as desired.
Set the VOX GAIN control to PTT and activate
the transmitter by pushing the microphone PTT
switch or the footswitch, if used. While speaking
in a normal voice into the microphone, advance
the MIC GAIN control until the meter kicks down
to the midscale of the green-colored portion of
the meter scale.
Note: When the METER switch is set to IC,
voice modulation peaks will indicate 150 -
200 mA. Actual peak current, however, is
approximately 2 times the indicated value.
To set the sensitivity of the VOX system, begin
with the VOX GAIN control in the PTT position.
Advance the VOX GAIN and speak in a normal
voice. The VOX GAIN control should be advanced
until the voice actuates the transmitter (do not
press the microphone PTT switch or footswitch, if
used, during this adjustment).
Set the antitrip potentiometer under the top
cover to the minimum point which prevents the
speaker output from tripping the VOX. Do not
use more VOX GAIN nor antitrip than necessary.
Adjust the delay potentiometer under the top
cover for the desired release time.
If desired, the AMGC circuit may be activated.
This circuit acts as a “microphone squelch;” that
is, it initiates a threshold for microphone input
which must be exceeded before output from the
microphone amplifier will occur. This feature
permits minor noises such as a TV in the operating
room to be present without going out over the
air. Adjustment of the AMGC delay time is made
by a control under the top cover.
RF SPEECH PROCESSOR ADJUSTMENT
(All models)
The FT-902DM speech processor, when properly
adjusted, is designed to improve the intelligibility
threshold at the receiving end by increasing the
average SSB power output. RF clipping is applied
to the IF signal, which is then filtered to remove
harmonics and out of band intermodulation
products.

Che distortion produced by RF envelope clipping
and filtering is less objectionable than that caused
by an equivalent amount of audio clipping. RI
clipping causes no increase in the peak power
output, but it do&és clip the peaks of the voice
waveform so as to increase the average powe!
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 partion of
the meter scale. Press the processor switch and
idjust 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 OFF
CW OPERATION
Note
The
Curtis
8044
IC
Keyer
Unit
is
built-in
on
the
FT-902DM/DE,
and
is
an
available
option
on
the
FT-902D/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.
For
straight
key.
bug.
or
external
electron
kevel
KEYER
control
fully
counter
clockwise
into
the
click-stop:
The
desired
key
line
use rotate the
may
then
be
inserted
into
the
KEY
jack.
Refer
to
the
drawings
on
page
9
for
détails
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
ts
7
volts
while
the
key-down
current
is
1.5
mA,
so
most
the
external
electroni¢
kevers
may
be
used
with
FT-902DM
without
modification
The
operator
may
select
any
power
OUTPUT
desires
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
sill
nol
he
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 pasition
and inserting the proper amount of carrier with
the CARR control
After completing basic transmitter tune-up, plac
the MODE switch in the AM position, Activate
the transmitter, and rotate the CARR control
until the meter reads .10. (100 mA) in the LC 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 advaneed
too far. Do not exceed .10 (100 mA) meter indi-
caution during AM operation or damage to the
transmitter final amplifier tubes may result.
For AM reception, an AM filter is available as an
Option,
PSK OPERATION
After completing basic transmitter tune-up, place
the MODE switch in the FSK position. The PSK
terminal inpul may be connected to the FSK jack

on the rear panel. The FT-902DM 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
The FM Unit is built-in on the FT-902D/
DM, and is an available accessory on the
FT-902D/DE models.
Note:
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.
In areas of very high occupancy, where channels
are crowded, an additional FM crystal filter is an
available option.
DIAL CALIBRATION AND FREQUENCY
DETERMINATION
The FT-902DM mixing scheme accounts for the
difference in carrier frequencies between USB and
LSB. For this reason, no recalibration is required.
Once the calibration is properly aligned (at the
factory, or in shop), no further adjustment is
required for accurate frequency derivation. The
25 kHz or 100 kHz calibrator is included largely
for alignment purposes, as it provides a useful
reference signal for signal peaking, etc.
Frequency readout on the FT-902DM digital
display is straightforward. The full operating
frequency is displayed, with resolution to 100 Hz.
The analog display on the transceivers provides
easy determination of the operating frequency.
The frequency displayed on the analog sub dial
is
added
to
the
lower
band
edge
frequency.
For example, if the analog dial indicates 074, as
shown in the example, and the BAND switch is on
40 meters (lower band edge: 700C kHz), the
operating frequency will be 7074 kHz. By rotating
the BAND switch, this position of the analog
display will produce 14074 kHz for 20 meters,
21074 for 15 meters, etc. For 80 and !2meters,the
lower band edges are 3500 kHz and 24500 kHz,
while for 160 meters the band edge is 1.5 MHz.
Therefore, the dial should read 074 to produce
3574 kHz, but 374 for 1874kHz. Be careful so as
not
to
operate
outside
the
amateur
bands.
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-902DM is by means
of the internal VFO, the memory unit, an ex-
ternal VFO, or various combinations of the three.
_ 17 oe

Split-frequency control may be obtained with the
memory system or the FV-901DM synthesized scan-
ning VFO. The switches involved in frequency
control are as follows:
MR
TX MR
RX MR
VFO
EXT
Note:
This button recalls the memorized fre-
quency for control of the transceive
frequency.
This button recalls the memorized fre-
quency for control of the transmit fre-
quency.
This button recalls the memorized fre-
quency
for
control
of
the
receive
fre-
quency.
Frequency control is by means of the
internal VFO as controlled by the main
tuning knob.
This switch selects the FV-901DM synthe-
sized
scanning
VFO
for
frequency
con-
trol as follows: with the EXT and MR
buttons
pushed,
transceive
frequency
control
is
by
means
of
the
external
VFO.
With the EXT and TX MR _ buttons
pushed,
the
external
VFO
controls
the transmit trequency while the internal
VFO
controls
the
receive
frequency.
With the EXT and RX MR buttons
pushed, the external VFO controls the
internal
receive frequency while the
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
lost from memory.
Because of “round-off error” the digital
display and memory system may exhibit
a
100 Hz difference between the VFO
condition and the memory recall condi-
tion.
Operation of the memory system is perhaps best
described by the use of some examples:
(1)
(3)
Note:
You are operating on a net on 3970 kHz and
must QSY down 10 kHz to handle a piece of
traffic. With the VFO button depressed and
the
main
dial
on
3970
kHz,
press
M;
3970
is
now memorized. Move the main dial down
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 frequency is antici-
pated. To return to 3960 kHz, simply press
VFO.
You are operating split frequency on 40
meter phone, and you hear DXIDX on 7090
kHz, listening for calls on 7205 kHz. With
the VFO button depressed and the main
dial on 7090 kHz, press M to store 7090 kHz
in memory, and press RX MR to lock the
receiver on 7090 kHz. Turn the main tuning
dial to 7205 kHz; you will now be transmit-
ting on 7205 kHz and listening on 7090 kHz.
To listen to the pileup on 7205 kHz of
stations calling DX1DX, push VFO; you will
now be listening and transmitting on 7205
kHz, and another press of RX MR will return
you to 7090 kHz for receive. If DXIDX
should begin to drift slightly in frequency,
push TX MR and M tto store 7205 kHz in
memory and lock the transmitter on that
frequency. Place the main dial on 7090 kHz
for precise tracking of the unstable DX1DX
signal.
You find DXIDX on 21270 kHz, working
stations by order of call area. By pressing the
M button, 21270 kHz may be stored in
memory and the operator may periodically
check to see if his call area is being acknowl-
edged by pressing MR or RX MR.
After the M button is pushed, the VCO
10 seconds to stabilize on the
memorized frequency. If one of the MR
buttons is pushed during this 10-second
period, some ‘“‘drifting” of the memorized
frequency may be observed.
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